The Royal Botanic Garden Edinburgh has a history of research into the genus Rhododendron stretching back over 100 years. The legacy of this work is a herbarium that contains many type specimens, an amazing living collection and many publications covering the whole genus. A large amount of the written work on Rhododendron was created just before the digital age and so is only available on paper and spread across many separate publications. An example of this is what could be called "The Edinburgh Rhododendron Monograph". It covers almost a thousand species and was published over 26 years in seven separate publications across two journals and a book. It is not available or indexed in a single form anywhere.
In 2011 I was awarded a Encyclopedia of Life Rubenstein Fellowship to extract the species descriptions from these publications and make them available within EOL. On completion of this work I had a database filled with information about rhododendrons and decided to make it available in an electronic form. This publication is the result of exporting the data from the database.
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What is presented here does not contain the full texts from the source publications and is not meant as a replacement for them. All keys are omitted. All subgeneric, section, subsection, group and series descriptions and comments are omitted. All notes on cultivation and horticultural value have been omitted. There are no images (maps, diagrams graphs). What remains are the species, subspecies and variety descriptions along with notes on distribution, habitat and nomenclature.
The reader is referred to the source publications for the full text on anything not contained here. Each species description is accompanied by a full citation to the appropriate source publication.
This is not a 'proper' publication in that it has not been edited or proof read. The text is of varying quality and contains errors. The reader should be aware of this and is expected to interpret the text on this understanding.
A major source of errors is the quality of the Optical Character Recognition (OCR) of the text scanned in the originals. The two source publications from the "Notes from the Royal Botanic Garden Edinburgh" have been scanned at high quality and should have fewer errors than the publications from "Edinburgh Journal of Botany" that were scanned manually. The most recent publication, George Argent's book on vireyas, was kindly made available in electronic form and so has not been through the OCR process.
A second source of errors is the tagging of the original text into a set of uniform fields for all species. This was done partially automatically and partially by hand with the possibility of errors being introduced at both stages. Sometimes the format of the original treatment does not fit a standard pattern and has had to be adapted.
A third class of error is systemic. This publication is a flat list of species descriptions extracted from a hierarchical set of taxon descriptions with no attempt to reconcile the fact that some of the characteristics of the species may only have been mentioned in higher level taxa in the source publication.
A final major source of errors could be termed the "Rumsfeld Errors" - the unknown unknowns. There may be sources of error that are unknown at this time.
In summary: This data is published on the understanding it would be more useful if it were available with errors than not available at all.
This publication is a snap shot taken at the end of a project. There are currently no resources available for further development of this particular work although curation and research on Rhododendron at the Royal Botanic Garden Edinburgh continues.
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Shrub, 1.5-2.5m. Leaves elliptic, thick and coriaceous, 3-6 x 1.1-2.2cm, c.3 x as long as broad, apex acute, base cuneate, margin strongly recurved, not undulate, glabrous when mature, with red punctate hair bases overlying the veins beneath; petioles 0.5-lcm, papillate. Inflorescence 6—12-flowered, dense; rhachis c.5mm; pedicels 20—30mm, sparsely hairy and stipitate-glandular. Calyx c.lmm, sparsely hairy, glandular-ciliate. Corolla open-campanulate, lacking nectar pouches, glabrous within, white to pale rose, with purple flecks, 28-35mm. Ovary and style glandular throughout. Capsule 18-20 x c.8mm.
Habitat: Mountain summits
Distribution: China (NE Yunnan)
Material seen in Kunming from NE Yunnan differs from the type in having rufous-tomentose perulae but is otherwise a good match. Lo Shiueh of McLaren is assumed to be Luoxue in NE Yunnan though this is not certain.
A distinctive species, probably allied to R. annae and R. araiophyllum.
Type: China, Yunnan, Lo Shiueh Mt, vi 1937, McLaren 'LP 33 (holo. E; iso. BM).
Occurs in Countries: CN Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: purple, rose, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):293
Shrub or small tree to 3m. Twigs rounded, green, finely covered in small brown scales, quickly glabrescent; internodes 1–4cm. Leaves in loose pseudowhorls 10–20 together. Blade 18–32 x 4–6mm, narrowly elliptic to linear, often slightly broader in the distal ½; apex broadly pointed; margin entire, strongly recurved, often completely rolled when dry; base tapering; sparsely scaly and quickly glabrescent above, sparsely but more persistently scaly below. Scales sub-circular or shallowly lobed, often with large centres. Mid-vein deeply impressed above, thickly prominent between the revolute parts of the lamina beneath; lateral veins obscure. Petiole 3–8 x 1–1.5mm, grooved above, laxly scaly. Flower buds to 10 x 7mm, ovoid-conical, with the erect subulate points of the bracts standing out, dark-red. Outer bracts keeled, apiculate, inner ones ovate with subulate acumen, the margins densely scaly, minutely hairy or glabrous outside. Bracteoles c.10 x 0.5mm, linear, glabrous, irregularly incised distally. Inflorescence of 2–4-flowered open umbels. Flowers half-hanging to hanging, pink with a violet tinge, without scent. Pedicels 16–20 x c.1mm, densely patently long-hairy, laxly scaly with fragile scales. Calyx c.3mm in diameter, disc-like, weakly angled, sometimes becoming reflexed, patently hairy outside and with a few scales. Corolla 20–25 x 30–34mm, broadly tubular below, sub-campanulate, dilated towards the mouth; tube 18–20 x 6–8 x 9–10mm, sub-densely covered with soft, white, patent hairs and almost without scales, although often with small clusters of scales at the lobe junctions; lobes 13–15 x 8–10mm, broadly obovate-spathulate, hairy outside, glabrous inside, not, or overlapping to c.½. Stamens at first clustered on the lower side of the mouth, becoming irregularly spreading, exserted to c.7mm; filaments linear, patently hairy for the lower ¼–1⁄3, glabrous distally; anthers 2–2.5 x c.1mm, broadly oblong, each cell with a small basal apiculus. Disc prominent, glabrous or with hairs on the upper margin. Ovary c.5 x 3mm, ovoid, densely patently white-hairy, and with scattered brown scales, abruptly contracted distally; style with a few hairs at the base otherwise glabrous, c.12mm, expanding to c.20mm, lying on the lower side of the tube; stigma rounded, bright red, becoming exserted to c.8mm. Fruit 12 x 6mm, obovoid-cylindric, dark purple, densely short-hairy and laxly scaly. Seeds 1.8mm, without tails 0.8mm, the longest tail 0.6mm.
Habitat: Terrestrial in summit shrubberies. Locally common.
Distribution: Malaysia (Borneo), Sabah, Mt Kinabalu, E ridge above the Mesilau R.
Altitude: 3160-3650m
Latin – Abies – genus of coniferous trees; folium – leaf. The distinctive narrow leaves superficially looking like those of an Abies.
This species has an extraordinarily restricted distribution, having been found only in the vicinity of the type locality.
Type: Collenette 602, 12 Dec. 1960. North Borneo, Mt Kinabalu, new route (E ridge), c.3200m (L, K).
Occurs in Countries: MY Altitude Ranges: 3,000 - 4,000m Subgenus: Vireya Habit: Tree Fl. Colour: white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:199
Shrub to 1m. Twigs 1–2mm in diameter, rounded, at first covered with flat stellate scales, quickly glabrescent; internodes 1.5–4cm. Leaves 4–6 in tight to somewhat loose pseudowhorls. Blade 25–50 x 10–20mm, elliptic or slightly obovate; apex broadly acute, obtuse to rounded; margin entire, flat, narrowly cartilaginous, often red; base broadly tapering; sub-densely scaly on both sides, glabrescent and shiny above, more persistently scaly below. Scales irregularly stellately lobed with a broad marginal flange and small slightly darker brown centre, not or only slightly impressed. Mid-vein slightly impressed into a narrow groove above, broad and slightly raised for the proximal 6–8mm beneath, otherwise smooth; lateral veins 6–8 per side curving upwards at c.45°, very slightly raised above, smooth or obscure beneath. Petiole 3–4 x 1.5–2mm, not or only weakly grooved above, flattened, scaly, and often minutely hairy. Flower buds to 27 x 12mm, ellipsoid or narrowly ovoid, acutely pointed, the tips of the bracts slightly spreading, white with conspicuous waxy deposits. Bracts to 15 x 8mm, ovate, apiculate, translucent, often flecked with brown, almost totally glabrous but with a few scales near the midline, lacking marginal scales. Inflorescence of 3–5 flowers in an open umbel, mostly horizontal but sometimes semi-erect to half-hanging, usually bicoloured with a yellow tube and orange lobes, sometimes pure yellow and occasionally almost completely orange. Pedicels 13–18 x c.1.5mm, red, sub-densely scaly, without hairs. Calyx obliquely thickened, disc-shaped, obscurely lobed, c.3mm in diameter. Corolla 15–30 x 40–55mm, shortly tubular-funnel-shaped; tube 10–15 x 6–7 x 12–17mm, sparsely stellately scaly outside, densely white-hairy inside; lobes 15–27 x 15–24mm, obovate, spreading horizontally or a little reflexed, overlapping to c.½ on upper side of the flower, not overlapping or only to 1⁄3 on the lower side. Stamens unequal, irregularly spreading, mostly on the lower side of the mouth, sometimes in two groups on each side, exserted to c.6mm but reflexing back against the corolla with age; filaments linear, white, densely white-hairy in the proximal 5–6mm, glabrous and filiform distally; anthers 2.7–3 x 1.25mm, narrowly oblong, shortly apiculate basally. Disc deeply lobed, minutely hairy on the upper side, otherwise glabrous. Ovary 5–6.5 x 2–3mm, cylindrical, abruptly contracted distally, densely stellate-scaly, without hairs; style 10–14mm, at first depressed to the lower side of the mouth, later becoming central in position, completely glabrous or with some scales at the base; stigma c.3mm in diameter, circular, yellow. Fruit 26–35 x 5–6mm, spindle-shaped, with pronounced longitudinal grooves, scaly.
Habitat: An epiphyte in dense montane rain forest.
Distribution: Philippines, Palawan, Mt Mantalinajan, Brooke’s Point.
Altitude: Around 1725m
Greek – acro – summit; philus – loving. A summit-loving plant but not apt – see below.
Known only from this single location.
Type: Edaño PNH 34, 13 May 1947. Philippines, Palawan, Mt Mantalingahan, Brooke’s Point, at c.1725m (A, BM, K, L, PNH).
Occurs in Countries: PH Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:206
Small shrub or shrub to 6m. Twigs short, spreading, rounded to obtusely angular especially towards the end of each internode; upper internodes 3–7cm, densely dark-scaly at the ends, silvery on older parts. Leaves 3–6 close together at the upper nodes or condensed in pseudowhorls. Blade 60–120 x 25–60mm, ovate or elliptic-ovate; apex shortly-acuminate, obtuse; margin flat or slightly revolute; base mostly rounded, sometimes very broadly tapering, densely scaly on both sides initially, glabrescent above, pits where the scales were attached remaining visible; beneath permanently covered. Scales overlapping with broad central cushions and wide irregularly lobed margins, the largest dark-brown, almost black, the smaller paler brown. Mid-vein strongly impressed above, thick and rigid beneath, continuing the petiole and gradually narrowing distally; lateral veins 6–8 per side, wide-spreading, from right angles to 45°, straight or slightly curved to the margin, distinctly anastomosing, deeply depressed above, strongly prominent beneath, veins laxly reticulate and distinctly impressed above, not or only slightly raised beneath, the whole surface deeply rugose; dark green and glossy above, brown beneath. Petiole 12–28 x 2–4mm, almost rounded in section, grooved above, densely scaly. Flower buds to 20 x 12mm, broadly ovoid, smooth. Bracts to 20 x 13mm, ovate, truncate at the base, obtuse at the apex, greenish but covered all over with minute, fine, brownish or greyish hairs and scaly outside along the median line and towards the apex outside, but glabrous towards the thin margin, the margin itself fringed with white hairs and occasional scales. Bracteoles to 15mm, linear to filiform, sub-spathulate-dilated at the top, patently hairy. Flowers 6–15 in an open umbel, hanging or half-hanging. Pedicels 8–12mm, thick, densely scaly and also finely hairy between the scales. Calyx c.2.5mm in diameter, a low scaly ring, or shallowly 5-lobed, densely scaly. Corolla 34 x 22mm, tubular or narrowly funnel-shaped, orange or red; tube 20 x 5–6 x 6–7mm, sub-densely to sparsely or occasionally glabrous outside, shortly sub-densely hairy in the lower ½ inside, straight, cylindrical, the base slightly 5-pouched; lobes 12 x 7–9mm, half-spreading, not overlapping, with a few well-spaced scales outside. Stamens arranged irregularly all round the flower, exserted to c.10mm, very slightly dimorphic; filaments linear, flattened nearly to the top, densely white-patent-hairy in the proximal 1⁄3; anthers 2.5–2.8 x 1mm, pale brown, without basal appendages. Disc glabrous. Ovary c.6 x 2mm, cylindrical, densely brown-scaly, gradually tapering to the thick style, which is scaly in its proximal ½ and lies on the lower side of the tube; stigma c.1.5mm in diameter, rounded, sometimes distinctly lobed. Fruit 25–34 x 4–5mm, cylindrical, longitudinally grooved, shortly tapering at both ends, densely scaly, splitting to the base, with the valves strongly curving back. Seeds 5–6mm, without tails 1mm, the longest tail 2.8mm.
Habitat: Terrestrial in mossy forest and open shrubberies, especially on ridges, occasionally as an epiphyte but always in well-illuminated situations. Occurring from 1830 to 3350m, common on Mt Kinabalu but subject to fluctuations in the size of the populations as it is a species which appears to be very adversely affected by droughts in El Niño years.
Distribution: Malaysia (Borneo), Sabah, Mt Kinabalu and one record from Mt Alab in the Crocker Range.
Altitude: 1830-3350m
Latin – acuminatus – tapering from inwardly curved sides to a narrow point, referring to the acuminate leaves.
The only natural hybrid recorded is with R. fallacinum, a solitary intermediate plant without flowers growing within the zone of overlap between these two species on Mt Kinabalu. It would be surprising if hybrids with R. lamrialianum did not also occur but these may be difficult to recognise without flowers. In cultivation this species appears difficult – most records of it growing successfully when checked have proved to be R. rugosum which although with superficially similar leaves has quite different dendroid scales. Of the many introductions to the Royal Botanic Garden Edinburgh just one has grown successfully, although very slowly. It flowered for the first time in 1997. Rhododendron acuminatum is quite distinct amongst section Malayovireya species. The orange to red, more or less hanging flowers are produced in a moderate-sized umbel, the leaves are long-petiolate and strongly rugose, the veins deeply impressed on the upper leaf surface and strongly protruding beneath. These vegetative characters are sufficient to separate this species from R. fallacinum which grows together with R. acuminatum in part of its range on Mt Kinabalu. The flowers of R. acuminatum are very sparsely covered (if not glabrous) with much smaller scales than R. fallacinum and the limp, slightly hanging disposition of the flowers in R. acuminatum is quite different. The flower buds are unusual in this section in often having occasional scales on the margins amongst the simple hairs. The variation in this character needs further observation.
Type: Low s.n. Malaysia (Borneo), Sabah, Mt Kinabalu (K, CGE).
Occurs in Countries: MY Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: orange, red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:111
Shrub or small tree, (0.5-)1.3-4m. Leaves narrowly elliptic to elliptic, 6-11 x 2-4cm, 2-2.5 x as long as broad, apex acute, base usually rounded, lower surface usually with a dense (rarely sparse) unistrate finely ramiform, spongy to matted tomentum, yellowish at first, maturing to a rich olive-brown, intermixed with at least some glands; petioles l-2cm, glabrescent or with a persistent tomentum and some stipitate glands. Inflorescence 4-12-flowered; rhachis up to 10mm; pedicels 20-30mm, densely tomentose and glandular. Calyx (4-)8-15mm, glandular, lobes oblong, unequal. Corolla campanulate, white flushed pink or pale pink, sometimes with purple flecks, 30-45mm. Ovary densely stipitate-glandular; style usually glandular in the lower third. Capsule 10-18 x 6-8mm.
Habitat: Thickets, open pastures, cliffs
Distribution: China (SE Xizang, W Yunnan, SW Sichuan)
Altitude: 3000-4250m
Illustrations:
The density of the glands on the leaves and petioles varies considerably; the most glandular forms have a leaf indumentum that has a matted appearance. There is however no justification for maintaining the essentially glandular R. adenophorum as distinct from the eglandular R. adenogynum as there is no clear dividing line between them.
8*. R. X detonsum Balfour f. & Forrest, Notes R.B.G. Edinb. 11: 48 (1919) - R. adenogynum x ? Type: China, Yunnan, Sungkwei divide, eastern flank, 10-11000ft, 26°12'N, v 1917, Forrest 13789 (holo. E; iso. K). Ic.: Bot. Mag. 157: t. 9359 (1934). Shrub, 1-3.5m. Leaves obovate to broadly elliptic, 6-10 x 3-4cm, 2.3-2.8 x as long as broad, apex acuminate, base rounded, lower surface with a sparse unistrate brown evanescent ramiform tomentum ; petioles 1.5-2cm, glabrescent. Inflorescence 6-10-flowered; pedicels 20-25mm, sparsely glandular. Calyx 3-5(-6)mm, glandular. Corolla campanulate, pink, with purple flecks, 40-50mm. Ovary glandular, also with a few hairs; style glandular for three-quarters of its length. Capsule unknown. china (W Yunnan). Rocky slopes, thickets, etc., 3050-3950m. There is every reason to believe that R. x detonsum is a natural hybrid of R. adenogynum, especially since a plant raised from seed of typical R. adenogynum (as Forrest 5868) is a good match with the type of R. x detonsum.
Type: China, Yunnan, eastern flank of the Lichiang Range, 27°12'N, 11-12000ft, vi 1906, Forrest 2395 (holo. E; iso. K)
Synonymy: R. adenophorum Balfour f. & W. W. Smith, Notes R.B.G. Edinb. 9: 211 (1916). Type: China, Yunnan, mountains in the NE of the Yangtze Bend, 27°45'N, 12000ft, vii 1913, Forrest 10429 (holo. E; iso. A, K).
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: pink, purple, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):340
Shrub, up to 3m; young shoots densely tomentose, with a few stalked glands. Leaves coriaceous, obianceolate, 9-16 x 2.5-4cm, 2.6-4.5 x as long as broad, apex acuminate to shortly cuspidate, glabrous above when mature, with a dense, felted, grey to fawn indumentum beneath; petioles c.3cm, tomentose. Inflorescence lax, 6-8-flowered; rhachis 10-15mm; pedicels 30-40mm, long-stipitate-glandular. Calyx 3-6(-15)mm, lobes ligulate, membranous, gland-ular-ciliate. Corolla funnel-campanulate, pale rose, 42-50mm. Ovary densely fulvous long-stipitate-glandular; style glabrous. Capsule c.15 x 7mm, cylindrical.
Habitat: Thin woods
Distribution: China (E Sichuan, Hubei)
Altitude: 1500-2200m
Illustrations:
R. adenopodum has been traditionally included in subsection Pontica but differs from the remaining species in its stipitate-glandular ovaries and in its shallowly lobed corolla. Furthermore, its distribution is more in line with the other species in subsection Argyrophylla than it is with those of subsection Pontica.
Type: E Sichuan, environs de Tchen-keou-tin, Farges (iso. E)
Synonymy: R. youngae Fang, Contr. biol. Lab. Sci. Soc. China, Bot. ser. 12: 24 (1939). Type: China, Sichuan, Nan-Chuan-hsien, Kin shan, 2000m, 13 iv 1930, Chang 59 (holo. SZ; iso. E, Hb. Inst. Bot. Guangzhou). R. simiarum Hance subsp. youngae (Fang) Chamberlain, Notes R.B.G. Edinb. 37:329(1979)
Occurs in Countries: CN Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: rose
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):318
Shrub; young shoots densely setose-glandular. Leaves ovate to lanceolate or elliptic, coriaceous, 7-10.5 x 2.4-3.4cm, c.3 x as long as broad, apex acute to acuminate, base rounded, margin cartilaginous, papillate, upper surface glabrous when mature, with a few setae overlying the midrib, lower surface setose and sparsely tomentose, tomentum evanescent, at least towards apex, or ± persistent; petioles, like midribs, densely glandular-setose. Inflorescence lax, 6—8-flowered; rhachis c.5mm; pedicels 15-25mm, densely glandular-setose. Calyx c.7mm, densely glandular-setose. Corolla (in cultivation) funnel-campanulate, pale pink with purple flecks, 35-50mm. Ovary densely glandular setose; style glabrous. Capsule c.20 x 4mm, curved. china (SW Sichuan-Muli). Spruce forests,
Altitude: 3350-3550m
Allied to R. glischrum and its immediate allies, but clearly differentiated by its leaf shape, texture and size. R. adenosum occurs in an area to the east of the range of R. glischrum. The wild-collected material lacks flowers; the details of the corolla have therefore been taken from cultivated specimens.
Synonymy: R. glischrum var. adenosum Cowan & Davidian, Notes R.B.G. Edinb. 21: 147 (1953). Type: China, SW Sichuan, mountains of Kulu, 3540m, ix 1929, Rock 18228 (= Rock seed no. 3837, cult. E) (holo. E). R. kuluense Chamberlain, Notes R.B.G. Edinb. 36: 116 (1978)
Altitude Ranges: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: pink, purple
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):284
Shrub to 1m. Twigs erect, rounded, 2–3mm in diameter, densely covered with low sub-circular scales, and sparsely very shortly hairy. Stems with prominent leaf scars and low rounded axillary protrusions. Leaves densely, spirally arranged. Blade 7–12 x 2–5mm, elliptic to narrowly elliptic, gradually acuminate; apex acute to obtuse; margin flat or slightly recurved sometimes slightly crenulate; base tapering, shiny dark green above, and gradually glabrescent, paler and sub-densely scaly beneath. Scales sessile, impressed, rounded, with the margin narrow, entire to undulate; centre large and dark brown. Mid-vein impressed above and obtusely raised beneath especially in the proximal ½, lateral veins obscure. Petiole 1–2.5 x c.1mm, grooved, laxly scaly and hairy above, densely scaly below, curved to a right angle with the blade. Flower buds 10–12 x 7–10mm, ovate, smooth with the bracts fully appressed, brown near the base and the tips of the bracts, otherwise green. Bracts to 7 x 4mm, gradual changing from the upper foliage leaves, ovate to obovate, apiculate, scaly in the distal ½ and with short appressed hairs outside throughout; fringed with long white hairs at the margins. Bracteoles to 6mm, filiform, hairy. Inflorescence 6–12-flowered, the flowers half-hanging to hanging. Pedicels 10–14 x c.1mm, pink, densely covered with patent hairs of various lengths and sparsely scaly. Calyx oblique, small, undulate, with white hairs and scales outside and at the margin, glabrous inside. Corolla 18–21 x 8–9mm, tubular, bright orange-red, without scent; tube 13–15 x 5–6 x 7–8mm, with long white patent hairs and small laxly spaced scales outside, glabrous inside; lobes 3–5 x c.4mm, straight not reflexed, overlapping up to c.¾, obovate, apex rounded, hairy and scaly along the midline to the apex. Stamens exserted to c.2mm, loosely clustered on the lower side of the mouth, unequal; filaments linear, glabrous; anthers oblong-ellipsoid, c.1.5mm. Disc glabrous. Ovary c.3 x 2mm, ovoid-conical, densely covered with overlapping scales, without hairs; style glabrous, green; stigma elongate-obconical. Fruit c.11 x 4–6mm, elongate-ovoid, densely scaly, 5-ribbed, with a c.10mm persistent style; valves half-spreading, slightly curved, not twisted, the placentae remaining firmly attached to the central column. Seeds 1.3–1.8mm, without tails c.1mm, the longest tail to 0.5mm. The very short tails are often highly branched.
Distribution: Indonesia, N Sumatra, Atjeh, Gajolands: Mt Losir, Mt Lembuh, Mt Putjuk Angasan and Mt Kemiri. In open summit heathland
Altitude: 2600-3460m
Greek – adinos – close; phullon – leaf. Alluding to the densely leafy stems.
A wild hybrid of this species with R. sumatranum was collected by David Binney on Mt Kemiri, Sumatra (19982482) in 1998.
Type: Ripley & Ulmer 58. Indonesia, Sumatra, Atjeh, Mt Losir (PH, A).
Occurs in Countries: ID Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: orange, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:42
Large shrub or tree to 4m. Twigs thick, rounded, densely dark-brown scaly; internodes 3.5–16cm. Leaves 6–9 together in tight pseudowhorls at the upper 2 or 3 nodes. Blade 40–90 x 20–40mm, elliptic; apex shortly acuminate or apiculate, sub-acute to obtuse; margin broadly revolute (the leaves somewhat convex); base tapering, glabrescent at maturity above, or with a few small silvery scales remaining, very densely dark-brown persistently scaly beneath. Scales entire, with a broad marginal flange and moderately large, dark centre, dense with many touching or slightly overlapping. Mid-vein impressed over its entire length above, strongly prominent beneath; lateral veins 5–10 per side, spreading, straight below, anastomosing towards the edge, slightly but distinctly depressed above, weakly raised beneath or indistinct. Petiole 18–22 x 2–3mm, distinctly grooved above in the distal ½, densely brown-scaly. Flower buds spherical, brown, but with long, wide-spreading, protruding, broadly subulate bract apices, and a long acute point. Bracts broadly ovate, long acuminate, densely brown-scaly in the upper ½ outside, green near the base, inside brown-scaly for a broad band near the margins and densely scaly on the acumen. Bracteoles to 10mm, filiform, with just a few scales. Inflorescence of 5–10 flowers held horizontally in a compact, open umbel. Flowers 15–18 x 34–40mm, orange, without scent. Pedicels 10–14 x 2–3mm, orange, thickened distally, often curved, densely scaly with some long stalked scales but without hairs. Calyx 3–4mm in diameter, small, oblique, disc-shaped, angular, densely scaly outside. Corolla campanulate; tube 11–15 x 7–10 x 16–20mm, laxly to sub-densely inconspicuously scaly outside, glabrous inside; lobes 12–15 x 17–21mm, obovate-circular, rounded, slightly retuse, or sometimes subdivided into miniature lobe-like structures, spreading horizontally or reflexed back, with some scales outside near the base, overlapping to c.halfway. Stamens regularly arranged all round the mouth of the flower, very slightly dimorphic; filaments 10–13mm, pink, linear, glabrous; anthers c.2 x 1mm, oblong, dark brown, exserted to c.2mm. Disc glabrous. Ovary c.4 x 3.5mm, conical-ovoid, densely scaly, without hairs, abruptly contracted distally; style 8–10mm, glabrous; stigma 2–3mm in diameter, centrally placed in the mouth, rounded to weakly 5-lobed. Fruit ellipsoidal, 14–17 x 6–7mm, smooth, densely brown-scaly. Seeds 4mm including the tails.
Habitat: In dense sub-alpine forest
Distribution: Indonesia, Sumatra, West Coast to Benkulen: Mt Singgalang, Mt Kerintji, W side of Barisan Range and Mt Pesagi.
Altitude: 2300-2870m
Latin – aequabilis – uniform or consistent; a rather obscure reference.
First introduced into cultivation by Dr Willem Meijer who collected seed from the type locality which was distributed by the Rijksherbarium in 1957 and grown successfully at Kew, where it was figured in Curtis’s Botanical Magazine (Hunt 1974). It was also collected by Peter Valder in 1975 (see History chapter); progeny from his plants are now widely cultivated. This species is one of the easiest of the albovireyas and has most attractive deep bronze new foliage. The bright orange flowers can be disappointing when the plants are young, often being overtopped by new foliage, but as the plant matures the flowers become more prominent and often give a wonderful display of colour. Flowering appears to be irregular in cultivation, often with two good flowerings a year and sometimes the occasional odd branch flowering out of synchrony with the rest of the plant.
Type: Docters van Leeuwen 3985, 29 Jan. 1920. Sumatra, Mt Singgalang (BO, A, L, SING).
Synonymy: R. album (non Blume) Ridl., J. Fed. Mal. St. Mus. 1917. 8: 58.
Occurs in Countries: ID Altitude Ranges: 2,000 - 3,000m Subgenus: Vireya Habit: Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:129
Low shrub to 0.5 m. Young growth lepidote and sometimes puberulent. Leaves narrowly elliptic to elliptic, 47-80 x 13-25 mm, thick, apex ± obtuse, base rounded-cuneate, lower surface pale green, scales 1-2 x their own diameter apart, upper surface dark green, elepidote, puberulent along the main vein at the base (and along the petiole). Inflorescence rachis 20-50 mm, flowers 12-16, pedicels densely lepidote. Calyx lobes variable in shape, from narrowly triangular to oblong, apex acute or rounded, 4-6 mm, lepidote, often margined with scales. Corolla white or greenish white, with tubular base and rotate limb, tube 6-8 mm, lobes c. 5 mm, elepidote and glabrous outside, sparsely pilose within the tube. Stamens 10, exserted, filaments pilose towards the base. Capsule lepidote, ± cylindric, c. 7 mm
Habitat: Cliffs and forests
Distribution: Afghanistan, Pakistan
Altitude: 2000-3000m
Illustrations:
Known from several collections from the Kurrum valley, which crosses the border between Afghanistan and Pakistan
Type: Afghanistan, Kurrum valley, abundant from 7-8000 ft, at Shendtoi Kaiwas, Aitchison (holo. K)
Occurs in Countries: AF, PK Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: green, white
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):156
Shrub, 0.3-3m. Leaves elliptic to broadly ovate-lanceolate, 4-12 x 2-5cm, 1.7-2.5(-2.8) x as long as broad, apex ± acute, base cuneate to rounded-cordate, lower surface covered with a dense unistrate compacted to spongy ramiform tomentum, whitish or yellowish at first, sometimes turning deep reddish-brown, continuous, or splitting and becoming patchy; petioles l-2cm, tomentose at first, later glabrescent. Inflorescence 10-20-flowered; rhachis less than 5mm; pedicels 10-30mm, sparsely tomentose to glabrescent. Calyx 0.5-lmm, glabrous Or with a few scattered glands, lobes rounded. Corolla campanulate, white, often flushed with pink, with purple flecks, 30-35mm. Ovary and style glabrous. Capsule 10-20 x 4-6mm.
Habitat: Open forests, among rocks
Distribution: China (SE Xizang, NW Yunnan, SW Sichuan)
Altitude: 3350-4550m
R. aganniphum was originally distinguished from R. glaucopeplum by its supposedly eglandular leaf indumentum. The type of the former does however have a few glands; R. glaucopeplum is therefore reduced to synonymy.
Five specimens from S Xizang, an area to the W of the main range of the species, are atypical in their stiff broad leaves (resembling R. clementinae) but the corollas are 5-lobed. The status of these plants-Ludlow, Sherriff & Elliot 12002; Ludlow & Sherriff 811, 1568, 1760; and Kingdon-Ward 11613-s uncertain.
R. aganniphum apparently intergrades with R. phaeochrysum, at least locally (q.v.).
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: pink, purple, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):354
Indumentum remaining pale and intact at maturity
Type: China, Yunnan/Xizang Border, Dokar La, 14-15000ft, Kingdon-Ward'768 (iso. E).
Synonymy: R. schizopeplum Balfour f.& Forrest, Notes R.B.G. Edinb. 11:13(1919). Type: China, NE Yunnan, mountains NW of Atuntze, 28°35'N, 14000ft, vi 1917, Forrest 14094 (holo. E). R.fissotectum Balfour f. & Forrest, ibid. 13:44 (1920). Type: China, NW Yunnan, W of Atuntzi, vi 1917, Forrest 14049 (holo. E; iso. K). R. glaucopeplum Balfour f. & Forrest, ibid. 13: 46 (1920). Type: China, NW Yunnan, Mekong/Yangtze divide, vii 1917, Forrest 14133 (holo. E; iso. K). R. doshongenseTagg, Notes R.B.G. Edinb. 15: 310 (1928). Type: China, Xizang, Doshong-La, 12-13000ft, 26 vi 1924, Kingdon-Ward 5863 (holo. E; iso. K).
Indumentum turning deep red-brown and becoming patchy
Var. flavorufum intergrades with var. aganniphum and there are a number of intermediates that could be referred to either variety. Extreme forms are however clearly distinct.
Synonymy: R. flavorufum Balfour f. &Forrest, Notes R.B.G. Edinb. 11: 65 (1919). Type: China, SE Xizang, Tsarong, on Ka-gwr-pw, Mekong/Yangtze divide, 28°10'N, 14000ft, vii 1917, Forrest 14345 (holo. E; iso. K).
Shrub, 1.5—3m. Leaves coriaceous, obovate to elliptic, 6-11 x 2.5-5cm, 2.2-2.5 x as long as broad, apex rounded, acuminate, base rounded, margin not undulate, upper surface glabrous, lower surface with a thin veil of dendroid hairs embedded in a surface film, with numerous red punctate hair-bases overlying the veins; petioles 1.5—2cm, glabrous. Inflorescence 10-15-flowered; rhachis at most 5mm; pedicels 15—20mm, stipitate-glandular. Calyx 2—3mm, lobes rounded, glandular. Corolla campanulate to tubular-campanulate, with nectar pouches, glabrous within, rose-pink, usually with darker margins and at least a few crimson flecks, 40—50mm. Ovary stipitate-glandular, with a few rufous dendroid hairs; style glandular, usually almost to tip. Capsule up to c.30 X 9mm, curved.
Habitat: Rhododendron thickets, open pine forests, stony slopes
Distribution: China(W Yunnan)
Altitude: 2200-3350m
Closely allied to R. leptopeplum and R. tanastylum but distinguished from both by the glandular style and the leaf shape. Two gatherings, McLaren L 49 & L 60, may be hybrids of this species. The leaf indumentum suggests R. agastum but the more acute leaves and almost glabrous styles do not.
Type: China, W Yunnan, head of the Taping-pu Valley, 7000-8000ft, v 1913, Forrest 9920 (nolo. E).
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: crimson, rose
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):301
Shrub or small compact tree to 6m. Twigs rounded, tips laxly to densely reddish-brown, scaly. Leaves 4–5 together in pseudowhorls, spaced 7–20cm apart. Blade 40–75 x 25–48mm, elliptic to obovate-elliptic; apex broadly acuminate to obtuse, sometimes apiculate by a small gland or a little retuse; margin entire, somewhat revolute proximally; base broadly tapering to the petiole or rounded-obtuse, sparsely to sub-densely minutely scaly on both sides especially beneath. Scales circular, entire or shallowly undulate at the marginal zone; centre large, impressed. Mid-vein slightly impressed above, distinctly raised though somewhat flattened beneath; lateral veins 6–10 per side, straight, anastomosing with each other and the primary veins near the edge, very slightly impressed above, a little raised or inconspicuous beneath, reticulation obscure, rarely distinct. Petiole 9–22 x 1.5–2mm, grooved above, somewhat flattened and sparsely scaly. Bracts c.15 x 10mm, ovate to obovate, scaly outside. Bracteoles c.12 x 1mm, filiform below, linear-spathulate distally, sparsely scaly. Inflorescence an open umbel of 6–12 flowers. Pedicels 6–18mm, thick, densely scaly. Calyx very small, circular, irregularly denticulate. Flowers trumpet-shaped but broadest just above the middle, white or with the tube tinged with pink, with the scent of carnations. Corolla 80–100 x 15–20mm; tube 70–85 x 3 x 4–6.5mm, cylindrical at least below, curved, sparsely to sub-densely scaly outside, laxly hairy and often sparingly scaly, in the lower ½ inside; lobes 10–15 x 8–12mm, rounded to obovate, spreading at a right angle, sparsely scaly or mostly glabrous outside, glabrous inside. Stamens slightly or not exserted from the throat; filaments very slender, sub-densely to sparsely covered with spreading hairs in the lower ½, glabrous above; anthers 3–4 x 0.8mm, orange, oblong, the cells apiculate at the base. Disc glabrous. Ovary 7–10 x c.2mm, elongate-conical, densely scaly; style slender, slightly exserted, densely to laxly scaly almost to the top, without hairs; stigma shortly conical, crenulate. Fruit c.100 x 5–6mm, red-brown, cylindrical, tapering at both ends, obtusely 5-angled.
Habitat: Moss forest, in damp ground or swampy open places
Distribution: Indonesia, New Guinea (W), Mt Agathodaemontop in Hellwig Mts; Mts Hubrecht and Wichmann on the southern and near Lake Habbema on the northern side of the Orange Mts; Mt Amdutakin in the Hindenberg Range. Papua New Guinea, Telefomin, West Sepik District and W of Oksapmin.
Altitude: 2500-3450m
Named after the mountain from which it was first collected which in turn was named after the Greek god Agathodaimon, the good genius, to whom a cup of pure wine was drunk at the end of dinner.
An odd form was collected by Katik & Taho (NGF 37952) from Tukwabit village, Lae, Morobe District. This is much further east than all the other collections and from considerably lower altitude (1800m). It had remarkably short broad flowers c.60mm long and with a broad tube up to 10mm wide. The bracts were shortly hairy outside and this specimen would appear to be intermediate between this species and R. herzogii or possibly a hybrid. The differences between R. agathodaemonis and R. herzogii are not clearly established. Sleumer (1973) modified his view of the difference from his (1966) Flora Malesiana account in the light of observations on flower length made by Peter Stevens and then made the chief difference fruit size. On the basis of limited herbarium specimens especially of R. agathodaemonis there does seem to be a difference in the corolla tube shape which is used in this account, and bract shape may produce further good morphological differences. Further observations are needed to clarify the situation.
Type: von Römer 1245. Mt Agathodaemontop, Hellwig Mts, Papua New Guinea, 2577m (BO).
Occurs in Countries: ID, PG Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:63
Shrub or small tree to 3(-5)m tall, usually non-rhlzomatous; young twigs red- or yellow-brown, sparsely to densely covered with unicellular and multicellular eglandular hairs, occasionally only multicellular eglandular hairs present, rarely with both unicellular and multicellular gland-tipped hairs. Vegetative bud scales glabrous to sparsely unicellular pubescent abaxially; margin unicel-lular-ciliate, rarely ciliate and glandular. Leaf blade membranaceous, ovate or obovate to elliptic, 6.1-7.7(-9.4) x 1.9-2.3(-2.4)cm; base acute to oblique; apex acute to obtuse, often mucronate; adaxial surface sparsely to densely covered with unicellular and multicellular eglandular hairs, the young unfolding leaves rarely with multicellular gland-tipped hairs, occasionally glabrous to sparsely covered with only unicellular hairs, rarely only with scattered multicellular eglandular hairs, the midvein sparsely to densely covered with unicellular hairs; abaxial surface sparsely to densely covered with unicellular hairs, rarely glabrous, the midvein and secondary veins densely covered with unicellular and multicellular eglandular hairs, rarely with multicellular gland-tipped hairs; margin entire, ciliate with multicellular eglandular hairs; petiole 0.2-0.5(-0.8)cm long. Flower bud scales chestnut brown; abaxial surface glabrous to very sparsely covered with unicellular hairs; margin unicellular ciliate. Flowers appearing before or as the leaves expand; inflorescence a shortened raceme of 6 to 12 flowers. Pedicels (0.4-)0.6-0.9(-l ,2)cm long; usually sparsely to densely covered with unicellular, multicellular eglandular and gland-tipped hairs, but occasionally lacking unicellular or multicellular gland-tipped hairs. Sepals less than 0.1-0.2 (-l.O)mm long, often varying in length on the same flower; margins setose with multicellular eglandular hairs, rarely glandular-fimbriate; abaxial surface sparsely to densely covered with unicellular and multicellular eglandular hairs, occasionally only with unicellular hairs, or with unicellular and multicellular gland-tipped hairs, or with unicellular, multicellular eglandular and gland-tipped hairs. Corolla white with a yellow blotch on the upper corolla lobe, fragrance sweet and delicate, the tube longer than the limb and gradually expanding into it; upper corolla lobe 0.9-1.4(-1.5)x(0.7-)0.8-1.2(-1.3)cm;laterallobes(1.0-)l.l-1.7(-1.9)x(0.5-)0.6-1.0(-1.2)cm corolla tube (1.6-)1.7-2.4(-2.8) x 0.1-0.3(-0.4)cm wide at base; outer surface of corolla sparsely to densely covered with unicellular and multicellular gland-tipped hairs, the gland-tipped hairs often continuing In tines up the corolla lobes; Inner surface of corolla densely covered with unicellular hairs. Stamens (3.7-)4.5-6.1(-6.6)cm long, with dense terete or flattened unicellular hairs on proximal 2.3-3,4(-3.8)cm of filament, exserted (1.7-)2.5-3.9(-4.5)cm beyond throat of corolla. Style (3.5-)4.4-6.4(-7.4)cm long, with dense unicelluar hairs on proximal (0.0-)0.4-1.3(-1.7)cm, exserted (1.7-)2.7-4.3(-5.2)cm beyond throat of corolla, stigma (0.15-)0.12-0.2 (-0.3)cm wide. Ovary 0.2-0.4cm long, 0.1-0.2cm wide at the base, densely covered with multicellular eglandular hairs over unicellular hairs, rarely with multicellular gland-tipped hairs or with both eglandular and gland-tipped hairs. Capsules (1.4-)1.5-2.1(-2.2) x 0.3-0.4cm, narrowly ovate to cylindiic, moderately to densely covered with unicellular hairs and sparsely to moderately covered with multicellular eglandular hairs. Seeds pale to dark chestnut brown, ovate or elliptic to fusiform, (1.8-)2.1-3.2(-3.8) x 0.4-0.8(-1.0)mm, body (0.9-)l.l-1.8(-1.9) x 0.2-0.5mm; testa expanded and dorsiventrally flattened surrounding the body, the cells elongate, with tapering end-walls
Habitat: Upland woods, bluffs and hillsides along water-courses, stream bottoms
Distribution: USA: Alabama and adjacent Tennessee, Georgia and Florida.
Altitude: 0-500m
Illustrations:
Hybrids between R. alabamense and R. canescens are known to occur in Harris Co., Early Co. and Clarke Co., Georgia; Tishomingo Co., Mississippi; and Leon Co., Florida. These plants generally possess glabrous bud scales, and pink corollas with a yellow blotch on the upper corolla lobe. See Appendix for citation of representative specimens of these hybrids.
The variation in flower colour from all white to tinged with pink has been suggested to be a result of hybridization and subsequent introgression with R. canescens (Skinner, 1955,1961). In addition, the slightly pubescent bud scales of some individuals have also been considered as evidence of widespread hybridization (Skinner, 1961). While hybrids between R. alabamense mdR. canescens do occur (see below), pink-tinged corollas also occur in otherwise all white populations of R. viscosum, R. atlanticum and R. arboresc ens. Therefore the pink blush on an otherwise white corolla does not necessarily imply the historical occurrence of hybridization with a pink-flowered species. Likewise, the variation in pubescence on the floral bud scales does not always require the occurrence of hybridization with R. canescens. Pubescent bud scales are found scattered throughout the range ofR. alabamense and do not seem to be more common in the southern part of this species'range as suggested by Skinner (1961).
This species is more common in north-central Alabama, especially in Winston, Cullman and Tuscaloosa counties, than in other parts of its range where it has arather discontinuous distribution. The yellow blotch on the upper corolla lobe distinguishes R. alabamense from the other white-flowered species in eastern North America. It is isolated from the sympatric R. viscosum and R. arbor esc ens by flowering time. Without flower colour R. alabamense is often difficult to distinguish from R. canescens. In general R. alabamense has much less unicellular pubescent corollas and the floral bud scales are glabrous or only slightly unicellular pubescent. In addition, these two species are often ecologically isolated as R. alabamense occurs in dry woods and R. canescens usually occurs in bottom-lands and along stream banks.
Chromosome number: 2n = 26 (Janaki-Ammal et al., 1950; Li, 1957)
Flowering primarily in April and May, but occasionally as early as March or as late as June.
Synonymy: Azalea alabamense (Rehder) Small, Man. S.E. US Fl. 996 (1933). Type: Alabama, Cullman Co.: without definite locality, T. G. Harbison 6292 (holo. US).
Occurs in Countries: US Altitude Ranges: 0 - 1,000m Subgenus: Pentanthera Habit: Tree Fl. Colour: yellow
Kron, K.A. (1993) A Revision of Rhododendron Section Pentanthera. Edinburgh Journal of Botany 50(3):284
Shrub, l-2m; young shoots floccose-tomentose, eglandular. Leaves elliptic, 8.5-9.5 X c.2.2cm, c.4 x as long as broad, apex rounded, apiculate, base rounded, upper surface glabrous, lower surface with a continuous bistrate indumentum, the upper layer light brown and ramiform-tomentose, the lower layer felted and ± compacted; petioles 0.5-lcm, sparsely floccose-tomentose. Inflorescence 5-6-flowered; rhachis 2-3mm; pedicels c.lOmm, sparsely tomentose. Calyx cupular, 3-4mm, lobes fleshy, sparsely tomentose, rounded. Corolla tubular-campanulate, bright crimson-rose, c.30mm. Ovary densely tomentose, tapering into the style. Capsule not known.
Habitat: Open forests
Distribution: China (NW Yunnan)
Altitude: Around 3000m
Only known from the type specimen which is apparently part of a mixed gathering which includes elements that have affinities with R. sperabile. R. albertsenianum and the next species, R. euchroum, share a bistrate indumentum, a rare feature in subsection Neriiflora.
Type: China, W NW Yunnan, Mekong/Salween divide, 27°40'N, 10000ft, vii 1917, Forrest 14195 (holo. E)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: crimson
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):413
Deciduous shrub to c.2 m high, young branches with brown strigose hairs. Leaves scattered along the shoots or clustered at their ends; blade membranous, narrowly elliptic or lanceolate to oblanceolate, to c.80 x 24 mm, base narrowly cuneate, apex acute, margin minutely serrate, when young ciliate on the mid-rib and margin, becoming more or less glabrous; petiole c.4 mm long, with strigose hairs. Inflorescence buds lateral, spaced along the shoots of the previous year, above leaf scars, 1-2-flowcred, flowers pendulous, borne below the expanded leaves; bud scales mostly fallen at anthesis; pedicels up to c. 10 mm long, with a minute glandular indumentum, and strigose hairs around the base. Calyx lobes oblong-ligulate, deeply divided, c.8 x 3-4 mm, with glandular hairs on the margin and strigose and glandular hairs on the outer surface. Corolla bowl-shaped, almost actino-morphic, c.20 mm across, with a short tube and spreading lobes, white (rarely marked with yellow), usually minutely puberulous on the inner and outer surfaces. Stamens 10(12 in rare6-merous flowers) equal, filaments c.lOmm long, pilose below. Ovary globose, 2 mm long, setose and glandular; style straight, impressed, pilose below. Capsule globose, enclosed in the persistent calyx, c.8 mm long, glandular and with strigose hairs. Seed with ligulate appendages at each end.
Habitat: Undershrub in upper montane forest and forming thickets in open places at and above the tree line and along stream banks
Altitude: 1200-2300m
An erect growing shrub often with trailing branches from the base of the plant. The white nodding cup-shaped flowers scattered along the leafy branches are distinctive, and resemble a prunus rather than a rhododendron. The flowers are borne on short lateral leafy branches along the main stems and also below the terminal cluster of leaves.
Type: USA, Rocky Mts, Drummond s.n. (holo. K).
Synonymy: Cladothamnus campanulatusGreene,Erythraea3:65(1895). Described from Canada (British Columbia) and the USA (Washington State). Azaleastrum albiflorum (Hooker) Rydberg, Mem. New York Bot. Gard. 1:297 (1900). A. warreniiA. Nelson, Bot. Gaz. 56:67 (1913). Type: USA, Colorado, Jackson Co., Mt Zarkel, 14 vii 1911, Warren. R. warrenii(A. Nelson) Macbridc, Contr. Gray Herb n.s. 56:55(1918). Ic: Bot. Mag. 65, t 3670(1839).
Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Candidastrum Habit: Non-Tree
Philipson, W.R. & Philipson, M.N. (1986) A Revision of Rhododendron III. Subgenera Azaleastrum, Mumeazalea, Candidastrum and Therorhodion. Notes from the Royal Botanic Garden Edinburgh 44(1):17
Shrub to 3m. Twigs smooth, finely longitudinally striated when dry and with scattered dark-brown scales; internodes 5–12cm. Leaves 3–5 together in tight pseudowhorls. Blade 40–80 x 23–37mm, elliptic, narrowly ovate or obovate; apex broadly acute, obtuse or rounded; margin entire, slightly revolute; base broadly tapering to rounded; laxly silvery scaly but quickly glabrescent and dark green above, persistently laxly scaly and paler below. Scales rounded, variable in size, with a broad marginal flange and small centre. Mid-vein distinct, above broad at the base and longitudinally grooved but quickly tapering to a narrow, impressed channel, green; broad and strongly raised throughout its length below, deep reddish-purple; lateral veins 7–9 per side, issuing at an angle of 45–90°, strongly impressed above, almost to the leaf edge, giving a rugose surface, very prominent and red in colour below. Petiole 8–12 x 3–4mm, red, weakly grooved above, scaly. Flower buds to c.20 x 10mm, glossy dark purplish-red, elliptic. Bracts ovate, often with a dark purple median line, the tips of the bracts broadly pointed and reflexed to c.4mm, these tips scaly both inside and out. Inflorescence a 6–10-flowered open or one-sided umbel, the flowers semi-erect to horizontal, white, or pale pink, fragrant. Pedicels red, 12–26 x c.2mm, minutely rough with scales and short simple hairs. Calyx a low lobed scaly and hairy ring, 1–1.5mm high. Corolla 40–46 x 35–45mm; tube 35–40 x 9 x 5mm, straight, covered in scales outside, densely short-hairy inside near the base; lobes 18 x 14–18mm, slightly forward pointing or spreading to the perpendicular, overlapping to c.halfway, slightly scaly outside. Stamens irregular in length, included c.2mm below the mouth; filaments white or pale pink, tapering slightly distally, hairy throughout their length; anthers c.2.8 x 1.25mm, brown with a finely granular surface and oblique pores. Disc lobed, with short erect hairs. Ovary 5.5 x 3.5mm, ovoid to almost conical, tapering slightly towards both base and apex, densely scaly and covered in short forwardly directed hairs; style 37 x c.1mm, sparsely scaly in the lower 1⁄3 and with forwardly directed, semi-patent hairs to within 3–4mm of the stigma; stigma irregularly lobed, c.1mm, cream, eventually protruding to 6mm from the mouth of the flower. Fruit 17–25 x 4–7mm, narrowly ellipsoid, strongly longitudinally grooved. Seeds 4–4.5mm, without tails c.1.1mm, the longest tail to 1.9mm.
Habitat: It grows in upper montane, mossy forest dominated by Phyllocladus, Drimys and Vaccinium and is common in open islands of scrub amongst bryophytes and lichens on the summit sandstone ridge.
Distribution: Indonesia, S Kalimantan (Borneo), Pergunungan, Meratus, Mt Halauhalau (G. Besar).
Altitude: 1400-1800m
Latin – albo – white; rugosum – the name of another superficially similar Bornean Rhododendron species but differing in the white (or very pale) flower colour.
It is known only from the mountain on which it was originally collected.
Rhododendron alborugosum is a very distinct species. It was originally confused with R. rugosum no doubt because of a superficial resemblance in the rugose leaves, but that species has dendroid scales, and pendent, much darker pink flowers. It has also been determined in the past as R. suaveolens Sleumer, which has superficially similar flowers, but that species has smooth, much larger leaves, a corolla which is glabrous outside and a much larger umbel of 14–20 flowers.
Type: Dransfield 2910, 24 Oct. 1972. Indonesia (Borneo), South Kalimantan, Mt Halauhalau (G. Besar), Pergunungan, Meratus, Barabai (BO, L).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:162
Shrub to 2.5m tall; bark thin with shallow vertical furrows; young twigs pale to reddish brown, sparsely to moderately covered with multicellular gland-headed hairs, becoming glabrous with age; new foliage shoots arising from axillary buds associated with foliage leaves of the previous year's shoot (i.e. below terminal bud), and some terminal buds. Vegetative bud scales glabrous to moderately unicellular-pubescent abaxially, sometimes with a few multicellular gland-headed hairs near apex, sparsely to moderately unicellular-pubescent adaxially, especially near apex, and sometimes with a few multicellular gland-headed hairs near apex; margin fringed with unicellular hairs or with mixed unicellular and gland-headed hairs; lowermost scales with long aristate apices or rudimentary blades. Leaves deciduous, dark green adaxially, pale green or occasionally glaucous abaxially, turning yellow to red in autumn, alternate (with internodes becoming more closely spaced towards tip of shoot), thus leaves sometimes appearing pseudowhorled at shoot apices. Blade membranaceous, obovate to occasionally elliptic, 2.1-13.5 x0.9-6.3cm; base attenuate with blade decurrent along petiole; apex shortly acuminate, acute to obtuse, with a short mucro; midvein strongly raised and prominent abaxially, the secondary veins slightly raised abaxially; adaxial surface, including midvein, moderately covered with multicellular gland-headed and eglandular hairs, the midvein unicellular-pubescent; abaxial surface glabrous to moderately covered with unicellular hairs, especially near base, and usually with a few multicellular gland-headed hairs, the lateral (and sometimes all) surfaces of midvein very sparsely to densely covered with straight to crisped, unicellular hairs, especially towards base, and with multicellular gland-headed hairs and usually also + flattened glandular to eglandular hairs, the secondary and tertiary veins similar but less frequently unicellular-pubescent and usually lacking!flattened glandular hairs; margin serrulate and often with conspicuous irregular undulations, with a fringe of multicellular gland-headed and eglandular hairs; petiole ± lacking to 6mm long, sparsely unicellular-pubescent, especially adaxially, and with scattered multicellular gland-headed hairs, the base of petiole abruptly expanded into a very broadened point of attachment, forming a ± triangular'slight protuberance below terete portion. Flower buds larger than, but otherwise similar to, vegetative buds. Flowers appearing before or with the leaves; inflorescence an umbellate raceme of 2 to 5 flowers. Pedicels 5-27mm long, moderately to densely covered with multicellular gland-headed hairs, sometimes also sparsely unicellular-pubescent. Calyx lobes broadly Ungulate to ovate-triangular, 1-3.5 x 1.5-2mm; apex rounded; margin fringed with multicellular gland-headed and sometimes also eglandular hairs; adaxial surface glabrous; abaxial surface sparsely to densely covered with multicellular gland-headed hairs, sometimes also very sparsely unicellular-pubescent. Corolla pink to red-purple, with greenish spots on the upper 3 lobes, fragrant, zygomorphic, broadly rotate to funnelform, the tube much shorter than the limb and gradually expanding into it; upper corolla lobe 1-1.7 x 1-1.6cm; laterallobes 1.2-2.2x0.7-1.7cm; corolla tube 0.4-lcm long; outer surface of corolla glabrous; inner surface of corolla sparsely unicellular-pubescent towards base. Stamens 10, declinate, dimorphic, the upper 5, 0.8-1.7cm long, the lower 5, 2.2-3.3cm long, included to equalling corolla; filaments glabrous distally, becoming densely covered with flattened unicellular hairs proxi-mally, the shorter filaments more pubescent than the longer ones. Ovary 3-4mm long, moderately to densely covered with multicellular gland-headed hairs, sometimes with a few unicellular hairs at apex; style declinate, 2.4-3.4cm long, glabrous to unicellular-pubescent near base. Capsules ovoid, 0.8-1.3 x 0.5-0.7cm, moderately covered with multicellular gland-headed hairs, sometimes with a few unicellular hairs at apex. Seeds shiny and light brown, ellipsoid, 0.7-1.6x0.3-0.5mm; testa tightly appressed to body, with cells at each end elongated and fused to form ± stellate-globular tails 0.1-0.3mm long, the cells covering body elongate. Cotyledons lacking multicellular hairs or very occasionally with a few gland-headed hairs and with venation represented by midvein and a small number of poorly developed secondary veins.
Habitat: In coniferous or deciduous forests and thickets
Distribution: Japan (Hokkaido, Honshu)
Altitude: 800-2300m
Illustrations:
Rhododendron albrechtii is a phylogenetically isolated species of equivocal relationship. It is possibly most closely related to R. schlippenbachii, R. quinquefolium and R. pentaphyllum, being weakly linked with these species in at least some cladograms on the basis of its dimorphic stamens (present in R. schlippenbachii and slightly developed in R. pentaphyllum) and possibly also the loss of fringed seeds (see Cladistic Analysis). The species is here considered tentatively to be an isolated (and possibly cladistically basal) member of sect. Sciadorhodion. This placement agrees with that arrived at by M. Philipson (1980) on the basis of cotyledon characters. It is noteworthy that occasional multicellular gland-headed hairs similar to those of R. pentaphyllum, R. quinquefolium and R. schlippenbachii occur on R. albrechtii cotyledons in a varying but small proportion of different seedling populations (M. Philipson, 1970, 1980). The presence of such hairs may be an additional synapo-morphy linking this species with sect. Sciadorhodion. However, a cladistic relationship to R. vaseyi (of sect. Rhodora) can be hypothesized due to the presence of acuminate leaf apices in both species. The seeds of R. albrechtii have a small appendage (or tail) at each end, as do those of both R. vaseyi and R. canadense (a probable symplesiomorphy) and, like these species, the vegetative shoots (bearing alternate and not obviously 5-whorled leaves) develop from axillary buds associated with foliage leaves of the previous season (other likely symplesiomorphies). The phenetic closeness of R. albrechtii and R. vaseyi has been noted by Sargent (1888), Gray (1879), Rehder (1921a), and Wood (1961). It is likely that R. albrechtii diverged early in the evolutionary history of Rhododendron subgen. Pentanthera, and since nearly all features of this species are plesiomorphic, determining the species'cladistic relationships are difficult.
Synonymy: Azalea albrechtii (Maxim.) Kuntze, Revis. Gen. PI. 2: 387 (1892). Type: Japan, Hakodate, in subalpine valley near Nodafu, 1861, C. Maximowicz (lecto. LE, n.v.).
Occurs in Countries: JP Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Pentanthera Habit: Non-Tree Fl. Colour: green, red
Judd, W.S. & Kron, K.A. (1995) A Revision of Rhododendron VI. Subgenus Pentanthera (Sections Sciadorhodion, Rhodora and Viscidula). Edinburgh Journal of Botany 52(1):22
Shrub to 1m. Twigs 3–4mm in diameter, rounded, densely covered with brown scales; internodes 1.5–8cm. Leaves 4–5 together in dense pseudowhorls. Blade 40–100 x 12–30mm, narrowly elliptic, acuminate; apex acute; margin entire, flat or slightly revolute, markedly so in dry specimens; base acutely tapering; moderately silvery scaly above initially, becoming glabrescent in the mature state; dull with dense, golden-brown scales beneath. Scales flat, with many touching or slightly overlapping each other, forming a continuous layer, the marginal zone wide in relation to the small darker centre, deeply and irregularly crenate to moderately lobed, disappearing in old leaves leaving depressed scale centres or small pits. Mid-vein distinctly impressed for the entire length above, and grooved near the base, strong and prominently raised beneath for almost the entire length; lateral veins 6–10 per side, irregular, spreading, straight below, anastomosing towards the margin, slightly raised above when dry, obscure beneath. Petiole 10–25 x 2–2.5mm, grooved above, very densely brown-scaly. Flower buds 10–13 x 5–7mm, green, with dense brown scales, sub-spherical but with a distinct c.3mm apiculus, the bracts all appressed but sometimes with a few basal, linear ones, spreading, but inwardly curling and with cataphylls around the base; basal bracts triangular, very densely brown-scaly outside and with dense scales inside at the apex, other bracts ovate, densely brown-scaly outside and with a fringe of scales along the margins, glabrous inside. Bracteoles to 10mm, linear, scaly. Inflorescence 8–13-flowered in an open umbel, the flowers semi-erect to half-hanging. Pedicels 15–20 x c.1.25mm, slender, pink, densely scaly, the scales on short stalks and minutely, patently hairy. Calyx disc-shaped or triangularly lobed, the lobes 1–2mm, covered with, and fringed with, scales. Corolla 13–18 x 18–27mm, campanulate, cream or very pale yellow, without scent; tube 8–11 x 4–6 x 11–15mm, brown-scaly outside, glabrous inside except for a few long hairs near the base; lobes 8–10 x 9–13mm, sub-circular, erect or semi-erect and half overlapping, scaly outside except near the margins. Stamens exserted to c.4mm, at first, with the anthers curved inwards towards the centre of the flower, later regularly wide-spreading around the mouth, c.11mm; filaments linear, patently hairy in the basal 1⁄3, glabrous above; anthers c.1.8mm, broadly oblong. Disc hairy or glabrous. Ovary c.3 x 1.5mm, conical, densely scaly, with a mixture of purple-coloured and brown scales but without simple hairs, tapering distally; style 6–7mm, thick, mostly deflected to the lower side of the flower, curving towards the centre as the flower ages, scaly in the proximal ½ with both purple and brown scales, glabrous distally; stigma thick, deeply 5-lobed. Fruit 15–20 x 4–5mm, densely scaly, the valves curling back, the placentae weakly spreading and breaking away from the base. Seeds 5–6mm, without tails c.1mm, the longest tail 2.5mm.
Habitat: Epiphytic in montane forest. Locally common.
Distribution: Indonesia, W Java, Mts Salak, Gedeh, Telaga above Puntjak and Telaga Warna and vicinity, reported from C Java (Kedu: Dieng, coll. Junghuhn), but not recollected there recently.
Altitude: 1200-1700m
Latin – albus – white, alluding to the flower colour but not apt.
Type: Zippelius s.n. Indonesia, Java, Mt Salak, Megame(n)dong (A, L).
Synonymy: Vireya alba (Blume) Blume, Bijdr. Fl. Ned. Ind. 1826. 855.
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: brown, cream, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:130
Shrub to 3m. Twigs 2–3mm in diameter, rounded, laxly stellate-scaly, early glabrescent and smooth; internodes 4–8cm. Leaves in loose pseudowhorls in the upper ½ of the internodes. Blade 25–40 x 12–20mm, elliptic or ovate-elliptic, more rarely sub-obovate; apex shortly and broadly sub-acuminate, or almost rounded, with a faint apical gland; margin pale, cartilaginous, entire or weakly crenulate with impressed scales; base broadly tapering or rounded, sometimes sub-truncate or sub-cordate, sub-densely scaly above but quickly glabrescent, sub-densely and persistently scaly below. Scales sub-stellate or obtusely lobed, marginal zone wide; centre minute, slightly impressed. Mid-vein broad proximally, impressed above, prominent in the lower ½ beneath, becoming hardly visible towards the apex of the blade; lateral veins c.5 per side, spreading, slightly conspicuous above only. Petiole 1.5–3 x 1–1.5mm. Outer bracts to 18 x 7mm, ovate, sub-acuminate or obtuse, inner ones ovate-oblong to sub-spathulate, all hairy outside and fringed with scales. Bracteoles to 15mm, linear, laxly hairy. Inflorescence a 3–4-flowered open umbel. Flowers hanging. Pedicels 15–20 x 1mm, slender, densely covered with reddish-brown sub-stellate scales and very short white hairs. Calyx c.2.5mm in diameter, oblique, disc-shaped, margin obscurely lobed, scaly and very shortly hairy. Corolla 25–32 x 15–20mm, tubular, red, glabrous outside and in; tube 20–25 x c.4 x 6–7mm, cylindrical, straight, the base 5-pouched; lobes 7–9 x 7–9mm, spreading, obovate-spathulate or nearly circular. Stamens unequal, the longest nearly as long as the corolla; filaments linear, glabrous; anthers 2.7 x 1mm, oblongoid; bases sometimes shortly appendaged. Disc prominent, glabrous. Ovary c.4 x 2.5mm, thick, sub-ovoid to conical, densely covered with short, sub-patent white hairs and with scales between the hairs, abruptly contracted distally; style slender, glabrous, as long as the stamens; stigma sub-globose. Fruit 20–28 x c.5mm, sub-cylindrical, tapering at both ends, sub-densely hairy and laxly scaly.
Habitat: Terrestrial in shrubbery, or epiphytic in low forest. Common.
Distribution: Indonesia, C Sulawesi, summit of Mt Kambuno
Altitude: Around 3000m
Latin – alternans – alternating, presumably referring to the leaves which were originally described as partly opposite.
Not recollected and never cultivated.
Type: Eyma 1363, 28 July 1937. Celebes (C), Masamba, top of Mt Kambuno, 2860m (L, A, BO, K).
Occurs in Countries: ID Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:212
Shrub or small tree to 3m. Twigs 2–4mm in diameter, appressed scaly at first, quickly glabrescent and smooth; internodes 1.5–2.5cm. Leaves 3–6 together in tight pseudowhorls. Blade 30–90 x 12–25mm, obovate or elliptic; apex broadly tapering, obtuse to rounded, sometimes apiculate with a terminal gland; margin narrowly cartilaginous, slightly revolute; base broadly tapering, rarely rounded; densely scaly at first on both sides, glabrescent above, laxly persistently scaly beneath. Scales small, marginal zone very thin, quickly disappearing, lobed; centre minute, dark and impressed. Mid-vein deeply impressed above, prominently raised below, often becoming broader near the base; lateral veins 6–8 per side, irregularly curved-upwards, anastomosing, faintly impressed in old leaves above, a little prominent beneath, reticulation lax, visible beneath only. Petiole 5–9 x 1–1.5mm, grooved above, flat, laxly scaly. Bracts to 12 x 5mm, ovate-acuminate, laxly scaly outside or glabrous. Bracteoles c.10mm, filiform below, slightly dilated distally. Inflorescence 3–6-flowered open umbels, the flowers hanging. Pedicels 8–20mm, slender, laxly to sub-densely scaly. Calyx c.4mm in diameter, disc-shaped, irregularly and shortly 5-lobed, glabrous. Corolla 20–60mm, tubular-funnel-shaped, bright red; tube 18–50 x c.4 x 7–12mm, laxly scaly outside, glabrous inside or laxly hairy, tube slightly to distinctly curved; lobes 12–15 x 10–13mm, spreading, broadly obovate-spathulate, sometimes with a few scales outside. Stamens clustered on the upper side of the flower, at the mouth or exserted to 6mm; filaments linear and laxly papillose-hairy proximally for c.2⁄3, glabrous and filiform distally; anthers c.2.5 x 1mm, oblong. Disc very prominent, glabrous. Ovary c.7 x 2mm, obovoid-cylindrical, densely scaly, but without hairs, gradually tapering distally; style slender, scaly at the base, glabrous distally, becoming slightly exserted; stigma thick, rounded. Fruit 40–50 x 5–7mm, sub-cylindrical, slightly curved, sub-densely scaly. Seeds 3mm, without tails c.0.8mm, the longest tail 1.3mm.
Distribution: Papua New Guinea, Fatima River, Spreader Divide, Bulldog Road, Mt Kaindi, Mt Missim, Mt Albert Edward, Mt Victoria, Mt Yule
Altitude: 2600-3600m
Latin – alte – high up; cola – dweller. Alluding to the high altitude at which it was found.
Van Royen & Kores (1982) regarded R. alticola as a widespread and polymorphic species, transferring it to series Javanica (of Sleumer 1966) as the leaves of many collections exceed 40mm in length. It is certainly very similar to R. culminicola and differs from that variable species in that the ovary is said always to be without hairs. Material in Edinburgh has been cultivated under this name since 1967; this was collected by Michael Black (no. 81) from the Fatima River area and agrees with the informal description in van Royen & Kores (1982) of the form from that area, except that it has hairs on the inside of the corolla tube. Hairs inside the corolla have also been found on specimens from Mt Yule and the Bulldog Road – these may represent a different taxon. A Woods specimen (3064A) from the Mt Albert Edward area has sparse hairs on the ovary also and may represent a hybrid. The hybrid R. alticola x R. spondylophyllum was collected by Paul Kores from Mt Victoria and it would be surprising if hybrids with R. culminicola did not occur. High altitude species tend to be the most difficult to cultivate. The ‘Black’ collection grows well, with beautiful deep red flowers which are for some time held semi-erect due to the persistence of the bracts at the base in a collarette.
Type: Brass 4332, May–July 1933. New Guinea (SE), Mt Albert Edward, Central District, c.3600m (L, BO).
Occurs in Countries: PG Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Tree Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:298
Shrub, 0.6-4.5m. Leaves oblong to oblanceolate, 5-17 x 2-4cm, 2-6.2 x as long as broad, apex apiculate, base rounded to cuneate, lower surface with a bistrate indumentum, the upper layer ramiform-tomentose, ± continuous, pale brown and lanate or more felted and mid- to reddish-brown, or partially detersile and usually rufous, lower layer whitish and compacted; petioles 0.8—2cm, usually persistently brown-tomentose. Inflorescence 10-20-flowered; rhachis 10-18mm; pedicels 10-20mm, tomentose. Calyx 0.5-lmm, tomentose, lobes rounded. Corolla campanulate to funnel-campanulate, white to pink, with crimson flecks, sometimes with a purple basal blotch, 30—40mm. Ovary sparsely glandular and tomentose to almost glabrous, though with a few simple papillate hairs; style glabrous. Capsule 12-20 x c.5mm.
Habitat: Pine forests, cane brakes, open stony places
Distribution: China (SE Xizang, NW Yunnan, SW & C Sichuan)
Altitude: 3050-4250m
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: crimson, pink, purple, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):348
Leaf indumentum usually pale ochraceous brown, lanate with long fine ramiform hairs, continuous; ovary with a few papillae, otherwise ± glabrous
Closely resembling R. taliense but with at least a few papillae or ramiform hairs on the ovary. The type specimen is apparently a mixed gathering; part is referable to var. alutaceum and part to var. russotinctum.
Type: China, NW Yunnan, Kari Pass, Yangtze/Mekong divide, 27°40'N, viii 1917, Forrest 13098 (holo. E; iso. K)
Synonymy: R. globigerum Balfour f. & Forrest, Notes R.B.G. Edinb. 13: 259 (1922). Type: China, SW Sichuan, Muli Mts, 28°12'N, 11-12000ft, vi 1918, Forrest 16376 (holo. E; iso. K). R. roxieanum Forrest var. globigerum (Balfour f. & Forrest) Chamberlain, Notes R.B.G. Edinb. 36: 119 (1978)
Leaf indumentum mid- to rufous-brown, not lanate, sometimes with upper layer discontinuous; ovary with a sparse indumentum of rufous ramiform hairs and glands. Leaf indumentum with a continuous felted upper layer composed of short fine usually mid-brown ramiform hairs.
Var. iodes closely resembles R. phaeochrysum var. levistratum but differs in the usually narrower leaves and the sparsely tomentose and/or glandular ovary.
Synonymy: R. iodes Balfour f. & Forrest, Notes R.B.G. Edinb. 13: 49 (1920). Type: China, SE Xizang, Tsarong, on the Dokar La, Mekong/Salween divide, 12000ft, vi-vii 1918, Forrest 16745 (holo. E; iso. K)
Leaf indumentum mid- to rufous-brown, not lanate, sometimes with upper layer discontinuous; ovary with a sparse indumentum of rufous ramiform hairs and glands. Leaf indumentum with upper layer discontinuous, composed of ramiform rufous hairs.
Illustrations:
Var. russotinctum intergrades with both var. alutaceum and var. iodes
Synonymy: R. russotinctum Balfour f. & Forrest in Notes R.B.G. Edinb. 11: 129 (1919). Type: China, W NW Yunnan, mountains N of Atuntzu, 28°25'N, 13000ft, vi 91, Forrest 13971a (holo. E). R. triplonaevium Balfour f. & Forrest, ibid. 13: 62 (1920). Type: China, NW Yunnan, Tseku, Soulie 1029 (iso. BM, E, K). R. tritifolium Balfour f. & Forrest, ibid. 13: 63 (1920). Type: W NW Yunnan, Mekong/Salween divide, 28°12'N, vii 1917, Forrest 14140 (holo. E; iso. K).
Shrub. Twigs rounded and densely scaly becoming glabrescent; internodes 2.5–9cm. Leaves 4 together in pseudowhorls, sub-sessile. Blade 25–60 x 12–28mm, broadly elliptic to elliptic; apex broadly tapering, sub-obtuse; margin slightly revolute; base sub-truncate, rounded to sub-cordate; at first scaly becoming glabrescent above, persistently and laxly scaly beneath. Scales irregularly dentate at margin, flat, each on top of a minute epidermal tubercle. Mid-vein flat or weakly impressed above, thick and very prominent beneath in the proximal 2/3, less so distally; lateral veins 7–8 per side, straight below, curved-anastomosing near the margin, hardly visible above, somewhat raised beneath, reticulation inconspicuous. Petiole 2–3 x c.1.5mm, scaly. Bracts to 14 x 9mm, ovate-acuminate, acute, outer ones scaly and sub-densely covered with hairs outside, inner ones hairy only. Bracteoles to 10 x 1mm, linear to sub-spathulate-linear, laxly hairy. Inflorescence 7–9-flowered. Pedicels 7–12 x c.0.5mm, densely scaly and shortly sub-patently greyish hairy. Calyx c.2.5mm in diameter, minute, membranous, wavy, irregularly fringed. Corolla trumpet-shaped, proximally white, pink-coloured distally; tube 30–33 x 2.5 x 3.5mm, cylindrical, straight, distinctly pouched at the base, laxly short-hairy and scaly outside, the scales completely disappearing by maturity, shortly hairy in the proximal ½ inside, glabrous distally; lobes 10–12 x 7–8mm, slightly spreading, obovate-spathulate, hairy outside at the base, otherwise glabrous, though distinctly ciliate. Stamens slightly exserted; filaments linear, hairy in the proximal 1⁄3, glabrous distally; anthers 1.8–2 x 0.7mm, oblong, base obtuse. Disc prominently 10-lobed, glabrous. Ovary 6–7 x 1.6mm, sub-cylindrical, densely hairy and scaly, abruptly narrowed distally; style hairy and scaly to nearly the top; stigma thick, conical-globose, just below the mouth.
Habitat: Said to be common in secondary forest on stony and peaty soil.
Distribution: Indonesia, Sulawesi (C), Masamba District near Limbung
Altitude: Around 1700m
Latin – amans – loving; a lovable rhododendron.
Known only from the type collection. Not cultivated.
Type: Steup 206, 19 Aug. 1937. Celebes, Central, Masamba, Limbung-Porio, 1700m (L, BO).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: pink, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:169
Tree, to 5m; young shoots densely covered with white soft hairs, later glabrescent. Leaves broadly ovate-rhombic, 4-9 x 3-9cm, apex acuminate, upper surface with long scattered brown hairs, lower surface with adpressed brown pubescent hairs, especially on midrib; petioles 5-10mm, densely adpressed-brown-pubescent. Inflorescence 1-3-flowered; pedicels 6-13mm, densely pubescent. Corolla open-campanu-late, 25-40mm, reddish-orange, upper lobe with darker flecks, lobes 25mm, oblong. Stamens 10, glabrous. Ovary densely brown-pubescent; style with white pubescent hairs at base. Capsule ovoid, 15-20mm, densely pubescent.
Distribution: Japan (Hondo, Idzu Peninsula)
Altitude: Around lOOm
Illustrations:
Closely allied to R. sanctum and possibly conspecific; differing in its often longer pedicels and in its red flowers. R. amagianum apparently flowers in mid July, about one month later than R. sanctum, and has an extremely restricted range.
Synonymy: R. weyrichii Maxim, var. amagianum (Makino) Hatusima, Sci. Rep. Yokosuka City Mus. 15: 23 (1969)
Occurs in Countries: JP Altitude Ranges: 0 - 1,000m Subgenus: Tsutsusi Habit: Tree Fl. Colour: red
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):152
Shrub, 1 -3-1 -6 m. Young growth loriform-setose. Leaves elliptic, broadly acute at the apex, 70 x 33 mm, upper surface dark green or brownish, somewhat rugose, elepidote except near the base, the base of the midrib loriform-setose, margins entire, sparsely loriform-setose, lower surface brownish with rather dense scales which are contiguous or up to their own diameter apart; petioles sparsely loriform-setose. Inflorescence 2-3-flowered, pedicels densely lepidote. Calyx conspicuous, deeply 5-lobed, the lobes ovate-oblong, c. 9 mm, lepidote on the outer surface, loriform-ciliate on the margins. Corolla funnel-campanulate, pale yellow, 38 mm, tube 20 mm, glabrous and very sparsely lepidote outside, sparsely pubescent inside. Stamens 10, filaments rather sparsely pubescent towards the base. Ovary densely lepidote, style impressed, very sparsely lepidote at the extreme base. Capsule unknown.
Distribution: China (SE Xizang)
Known only from the type collection.
Type: S Tibet, ChayulChu, Natrampa, 11500 ft, 27 iv 1936, Ludlow & Sherriff1365 (holo. BM, iso. E)
Occurs in Countries: CN Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):42
Shrub, 1-5-5 m. Leaves narrowly ovate or obovate or narrowly elliptic, ± acute at the apex, cuneate-rounded at the base, 30-60(-80) x 15-32 mm, dark green and persistently lepidote above, densely lepidote beneath with contiguous or overlapping, dark brown, somewhat unequal, large, broadly rimmed scales; petiole, and midrib for a short distance from the base, pubescent. Inflorescences 3(-5)-flowered, pedicels lepidote and sometimes puberulent near the base, 10-15 mm. Calyx undulate or very weakly lobed, iepidote, sometimes filiform-acicular-ciliate. Corolla yellow, often with greenish or darker yellow spots on the upper lobes, 20-26 mm, tube 8-11 mm, variably lepidote outside, rarely elepidote. Stamens 10, filaments pubescent towards the base. Ovary lepidote, style usually glabrous, rarely puberulent at the base. Capsule lepidote, cylindric, (9~)11-13 mm.
Habitat: Thickets on hillsides
Distribution: China (C Sichuan)
Altitude: 2600-4500m
Illustrations:
Superficially similar to R. triflorum but distinguished by its greyish brown, shredding bark, large, denser leaf scales and the lack of indumentum on the corolla.
Type: none cited, typifiable from the illustration which is based on material cultivated from seed collected by Wilson
Synonymy: R. chiengshienianum Fang, Ic. PL Omeiensium 1:1, t. 36 (1942). Type: China, Szechuan, Omei hsien, Mt Omei, 3000 m, 27 v 1940, Sun 2229 (iso. E)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: green, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):78
Very similar to R. concinnum, differing as follows: petioles with a dense indumentum of loriform hairs, young growth loriform setose; corolla c. 34 mm, tube c. 18 mm.
Habitat: Thickets
Distribution: China (NW Sichuan)
Altitude: 2300-3000m
Illustrations:
Known only from the type collection and material in cultivation
Type: China, Szechuan, Mupin, 2300-3000 m, vi 1908, Wilson 3444 (iso. E)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Rhododendron Habit: Non-Tree
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):76
Shrub to 50 cm. Leaves 9-18 x 5-9 mm, broadly elliptic or rotund, apex rounded with a short reflexed mucro, base truncate or broadly cuneate, undersurface a uniform rusty brown, the scales irregularly contiguous. Inflorescence c. 3-flowered, pedicels densely lepidote, 2-3 mm. Calyx 4-5 mm, lobes ovate with a central band of scales, margins densely ciliate. Corolla and stamens unknown. Style up to 15 mm, pubescent towards the base. Capsule lepidote, 5 mm.
Distribution: China (SW Sichuan)
Known only from very limited material (2 collections) and in need of further study when more material is available.
Type: China, Szechuan, m. Lose-schan, nr. Ningvuen, c. 3900-4250 m, 16 iv 1914, Handel-Mazzetti 1414 (holo. W, iso. A)
Occurs in Countries: CN Subgenus: Rhododendron Habit: Non-Tree
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):100
Dwarf prostrate or creeping shrub to 15cm. Twigs very slender, 0.5–0.7mm in diameter, densely covered with shortly stalked dendroid or sub-sessile stellate scales at first, warty in the older glabrescent parts; internodes 0.5–2.5cm. Leaves 3–5 together in tight pseudowhorls at the upper 3–4 nodes. Blade 3–7 x 1–2.5mm, elliptic or sub-obovate; apex sub-acute or obtuse; margin entire, flat; base broadly tapering, initially scaly on both sides, glabrous above at maturity, laxly and more persistently scaly beneath. Scales brown, flat or slightly concave; marginal zone rounded or obtusely lobed; centre small, slightly impressed. Mid-vein visible only near the base above and slightly impressed there, slightly raised and visible for a greater length beneath; lateral veins obscure. Petiole 0.5–1 x 0.3mm, not grooved, brown-scaly. Flower buds to 6 x 3mm, narrowly ovoid with an acute apex, pale brown or pink, laxly scaly outside, the bract tips slightly spreading. Bracts narrowly ovate-acuminate, laxly scaly outside and along the margins. Bracteoles 4–5mm, linear. Pedicels 6–7 x 0.75mm, very slender, densely covered with dendroid stellate scales and sparse white hairs. Flowers solitary. Calyx c.2mm in diameter, obliquely cup-shaped, shortly obtusely 5-lobed. Corolla 10–18 x 7–18mm, funnel-shaped, white flushed with reddish purple near the base; tube 5–7 x 3–5 x 5–7mm, laxly scaly outside, glabrous inside; lobes 5–8 x 4–5mm, elliptic, semi-erect or half-spreading, not overlapping when fully open. Stamens distinctly dimorphic, regularly arranged all round the mouth, the longest exserted to 1.5mm; filaments 8 and 6.5mm, pink, linear, glabrous; anthers c.0.7 x 0.4mm, oblong. Disc densely hairy along the upper margin. Ovary c.1.8 x 1mm, broadly sub-ovoid-cylindrical, densely covered with short, spreading hairs, less densely scaly between the hairs; style c.1.5 x 0.2mm, sparsely hairy at the base or to halfway; stigma green, thick-globose. Fruit 10–15 x c.2mm, fusiform, pink, shortly hairy and scaly. Seeds 3–4mm including the tails.
Habitat: In montane forest, open grassland or alpine shrubberies, epiphytic on moss on trees, or trailing over fallen logs
Distribution: Indonesia, New Guinea (W), Mt Carstensz. Papua New Guinea, Bismarck Mts and Wahgi–Jimmy Divide. New Britain: Mt Lululua, in the Pomio subdistrict.
Altitude: 1190-3500m
Latin – Anagallis (Primulaceae); florum – flower. With flowers like an Anagallis (pimpernel).
This species was for some time confused with R. rubineiflorum (for differences see under that species).
Type: Kloss s.n. New Guinea (W), Ascent to Mt Carstensz Camp VIb (BM).
Synonymy: R. linnaeoides Schltr., Bot. Jahr. 1917. 55: 144, f.2.
Occurs in Countries: ID, PG Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: purple, red, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:147
Shrub to c.75cm. Twigs robust, rounded, laxly scaly. Leaves c.5 in pseudowhorls. Blade 110–180 x 35–58mm, ovate-elliptic; apex gradually long-acuminate, acute; margin flat or weakly recurved; base obtuse, rounded or slightly cordate; glabrescent above with age, sub-densely scaly beneath. Scales stellately lobed in the marginal zone; centre impressed, leaving minute pits when scales are gone. Mid-vein narrowly grooved above, thick and obtusely prominent beneath in the proximal part; lateral veins 12–15 per side, ascending, anastomosing, very slightly raised or impressed above, obscure beneath; reticulation obscure. Petiole 10–12 x 3mm, strong, grooved above, flattened, transversely rugulose, minutely scaly. Inflorescence of c.6 flowers. Pedicels 40–50 x c.2.5mm in diameter, laxly minutely scaly, more densely so below the calyx, without hairs. Calyx c.4.5mm in diameter, oblique, obtusely and inconspicuously 5-angular, ciliate. Corolla 55–66mm, funnel-shaped, lobed in the upper 2⁄3, red, fleshy; tube c.20 x 8 x 9mm, sparsely minutely scaly outside, laxly hairy inside, distinctly 5-angular or pouched at the base outside, deeply 5-grooved lengthwise in the proximal part inside, the ribs extending upwards to the middle of the corolla lobes; lobes 35–40 x c.20mm, sub-ovate-elliptic, obtuse, spreading. Stamens nearly as long as the corolla; filaments linear and shortly patently hairy below, narrower and glabrous distally; anthers 5.5–6 x c.1mm, linear-oblong, obtuse at the base. Disc prominent, practically glabrous. Ovary c.10 x 3mm, conical-cylindrical, densely covered with thick, nearly round, scales, no hairs, tapering distally; style c.48mm, scaly and sparsely minutely hairy, or nearly papillose, at the base, glabrous distally; stigma thick-rounded.
Habitat: Common terrestrial in shady peat swamps
Distribution: Indonesia, New Guinea (W), Oranje Mts, Mt Goliath.
Altitude: Around 1500m
Latin – angulatus – angled, alluding to the distinctly angled corolla.
Known only from the type collection
Type: De Kock 177. New Guinea (SW), Mt Goliath, Juliana Range, 1500m (BO).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:296
Shrub, 0.5-6m. Leaves coriaceous, elliptic to oblanceolate, 6.5-15 x 2-3.5cm, 3.5-4.5 x as long as broad, apex acuminate, base cuneate to rounded, margin usually slightly undulate, both surfaces glabrous though with red punctate hair bases overlying the veins beneath; petioles l-3cm, glabrous. Inflorescence 7-12(-17)-flowered; rhachis 5-35mm; pedicels 15-30mm, densely stipitate-glandular. Calyx l-2mm, lobes rounded, gland-fringed. Corolla open-campanulate, lacking nectar pouches, white with a rose flush, with or without purple flecks, 25—40mm. Ovary densely glandular; style glandular to tip. Capsule 13-25 X 6-8mm.
Distribution: China (W Yunnan, ?Guizhou), NE Upper Burma
The type of R. annae does have smaller flowers than is usual for the species and this has been used as the main diagnostic feature to separate R. annae from R. laxiflorum. The holotype of R. hardingii has equally small flowers however, while the isotype material has larger flowers and matches the type of R. laxiflorum.
Bodinier's type of R. annae is supposed to have been collected in Guizhou near Guiyang. If this is confirmed, then this species has a surprisingly disjunct distribution; all the remaining material comes from Mid-West Yunnan.
Type: China, ?Guizhou, Montagne de Lou Tsang Kuan, 1500m, 7 v 1897, Bodinier 1588 (holo. E; iso. K).
Synonymy: R. laxiflorum Balfour f. & Forrest, Notes R.B.G. Edinb. 13: 50 (1920). Type: China, W Yunnan, Shweli/Salween divide, 8000ft, v 1919, Forrest 17953 (holo. E; iso. K). R. hardingii Tagg, Notes R.B.G. Edinb. 16: 196 (1931). Type: China, W Yunnan, 3 days march S of Tengyueh, 24°20'N, 98°33'E, 6000ft, Harding (Forrest) 26313 (holo. E).
Occurs in Countries: CN, MM Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: purple, rose, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):293
Small shrub to 1 m, often closely and intricately branched. Leaf-bud scales persistent or not. Leaves ovate or elliptic, rarely almost orbicular, (10-)14-35 x 8-16 mm, rounded to the base and to the subacute'mucronate or rarely slightly emarginate apex, above dark green, lepidote or elepidote, beneath dark brown (rarely rather pale) with dense, overlapping scales in 2-3 tiers, those of the lowest tier as dark as, or darker than the rest. Inflorescence dense, many-flowered, pedicels short, lepidote, puberulent or entirely glabrous. Calyx lobes oblong, 3-5-4-5 mm, usually somewhat lepidote outside, margin loriform-ciliate, inner surface variably pubescent. Corolla usually white or pink, rarely cream or yellowish, tube 6-12 mm, lobes 4-7-5 mm, glabrous and elepidote outside, densely pilose within the tube. Stamens (5-)6-8(-10). Ovary lepidote. Capsule 4-5 mm, lepidote, scarcely exceeding the calyx.
Two subspecies may be recognised. Though they differ essentially in only one character, they do show geographical replacement
Occurs in Countries: BT, CN, IN, NP Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: cream, pink, white, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):158
Habitat: Open slopes and hillsides
Distribution: Nepal, India (Uttar Pradesh, W Bengal, Sikkim, Arunachal Pradesh), Bhutan, China (S Xizang)
Altitude: 3350-4900m
Illustrations:
Type: Nepal, in Alpe immensa nivosa, Gossain Than Nepalensium dicta, Wallich (holo. K)
Synonymy: R. haemonium Balfour f. & Cooper, Notes R.B.G. Edinb. 9:283 (1916). Type: Bhutan, Pumo La, Timpu, 13000 ft, 15 v 1915, Cooper 3903 (holo. E). R. anthopogon var. haemonium (Balfour f. & Cooper) Cowan & Davidian, Rhodo. Yearbook 2:68 (1947)
Habitat: Open slopes and ledges, rarely in sparse forest
Distribution: India (Kashmir, Himachal & Uttar Pradesh), Nepal, Bhutan
Altitude: 3350-4500m
Illustrations:
Essentially a western vicariant of subsp. anthopogon, but with a distinct outlier in Bhutan
Synonymy: R. hypenanthum Balfour f., Notes R.B.G. Edinb. 9:291 (1916) Type: described on the basis of a number of syntypes from the W Himalaya (all at E)
Shrub to 1-6 m. Leaf-bud scales deciduous. Leaves ovate-elliptic, (20-)25-40 X (10—) 11 —21 mm, rounded at the base, rounded to somewhat tapered to the mucronate apex, sparsely lepidote or elepidote above, beneath pale brown with scales which are all borne ± at one level, overlapping, plastered to the surface, all with well developed domed centres and narrow, scarcely lacerate rims. Inflorescence dense, many-flowered. Pedicels pubescent, elepidote. Calyx lobes 3-4-5 mm, oblong-obovate, glabrous and elepidote outside, margin erose and with a few scales, glabrous within. Corolla white or greenish white, rarely flushed pink, tube 5-10 mm, lobes relatively small, 1-5-3 mm, scarcely overlapping, densely pilose at the throat and inside the tube. Stamens 5. Ovary lepidote, sometimes pubescent. Capsule lepidote, 4-4-5 mm
Habitat: Scrub and forest margins
Distribution: China (Quinghai, Gansu)
Altitude: 3050-3350m
Illustrations:
Very distinct in its scale type and its very dense inflorescences of flowers with curiously solid-looking corollas with short lobes, and characteristic calyces.
Type: China occidentalis, Terra Tangutica (prov. Kansu), 1872, Przewalski (iso. E)
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: green, pink, white
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):163
Shrub or small tree, 3-12m. Leaves elliptic-obovate to oblong, 6-16 x 2-4.5cm, (2.5-)3-4 x as long as broad, apex acuminate to acute, base ± cuneate, margin not undulate, upper surface glabrous when mature, lower surface ± glabrous, with a few red punctate hair-bases overlying the veins;petioles l-2cm, glabrescent. Inflorescence dense, 10-15-flowered; rhachis 5-10mm; pedicels 10-15mm, sparsely rufous-tomentose. Calyx l-2mm, glabrous to stipitate-glandular. Corolla 6-7-lobed, tubular-campanulate, with nectar pouches, glabrous within, rose-magenta to crimson, occasionally magenta-blue or pale peach, with a variable amount of crimson flecks, with or without a basal blotch, 30-45mm. Ovary usually glabrous, occasionally with a few rufous hairs; style glabrous. Capsule 20-25 x c.5mm.
Habitat: Open rocky slopes, deciduous woodland, etc.
Distribution: China (Yunnan, SE Xizang), NE Upper Burma
Altitude: 2700-4000m
Illustrations:
R. anthosphaerum is a variable species, both in leaf shape, and in corolla size and colour. Several entities may be recognised within the species but complete intergradation apparently occurs. The names used below are given only as a guide without implying any format taxonomic status. 1. Leaves elliptic, apex ± acute..................R. anthosphaerum sensu stricto 4- Leaves oblong to obovate, apex rounded and apicuiate....................-... .2 2. Leaves up to 8cm long............................................R. gymnogynum + Leaves 8-16cm long.................................................................3 3. Corollac.30mm, blue-magenta...................................R. chawchiense + Corolla 35 -45mm, crimson to rose-magenta .,....................R. eritimum I am uncertain as to how far the four entities are differentiated geographically, a problem that can only be resolved by detailed population sampling. It is clear however that plants matching the types of both R. eritimum and R. anthosphaerum occur together on the Sungkwei Pass and in the Lichiang Snow Range. However, plants matching the type of R. eritimum appear to be more frequent in the northern part of the species'range.
Type: China, Yunnan, ascent to the Sungkwei Pass, 11000-12000ft, iv 1906, Forrest 2042 (holo. E;iso. K).
Synonymy: R. eritimum Balfour f. & W. W. Smith, Trans. Bot. Soc. Edinb. 27: 190 (1917). Type: China, E NW Yunnan, mountains of the Chungtien Plateau, 9000ft, iii 1914, Forrest 12416 (holo. E; iso. BM). R. hylothreptum Balfour f. & W. W. Smith, ibid. 27: 195 (1917). Type: China, E NW Yunnan, summit of the Sungkwei Pass, 11000- 12000ft, v 1910, Forrest 5848 (holo. E; iso. K). R. gymnogynum Balfour f. & Forrest, Notes R.B.G. Edinb. 13: 47 (1920). Type: China, W Yunnan, Shweli/Salween divide, 11000ft, v 1918, Forrest 17495 (holo. E; iso. K). R. heptamerum Balfour f. in Notes R.B.G. Edinb. 13: 48 (1920). Type: NE Upper Burma, above Hpimaw, 8500-9000ft, iv 1919, Forrest 17827 (holo. E; iso. K). R. chawchiense Balfour f. & Farrer, Notes R.B.G. Edinb. 13:247 (1922). Type: NE Upper Burma, Chawchi Pass, 10500ft, 15 v 1920, Farrer 1552a (holo. E; iso. K). R. persicinum Handel-Mazzetti, Akad. Wiss. Wien Math.-Naturwiss. KL, Anz. 60: 97 (1924). Type: China, NW Yunnan, in montium inter Dali et Hodjing, silvis temperatis jugi Dsuningkou, 3050-3350m, 27 v 1915, Handel-Mazzetti 6549 (iso. A, E).
Occurs in Countries: CN, MM Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: crimson, magenta, peach, rose
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):303
Dwarf matted shrub, 0.3-0.6(-1.5)m; young shoots with a floccose tomentum; perulae persistent. Leaves obovate to oblanceolate, 3-6.5 x 1.4-2.4cm, 1.7-2.6 x as long as broad, apex rounded, apiculate, base ± cuneate, upper surface glabrous, lower surface papillate, glaucous, usually glabrous at maturity though sometimes with vestiges of reddish-brown or whitish indumentum persisting on the main veins and midrib; petioles broad, 0.3-0.6cm, usually with a floccose indumentum when young. Inflorescence 4-6-flowered; rhachis c.2mm; pedicels 15-30mm, floccose-tomentose, also with long dendroid hairs. Calyx 3-6mm, cupular, lobes glandular-ciliate, otherwise glabrous. Corolla thin, tubular-campanulate, white or yellow flushed pink to orange or rose, (30-)35—45mm. Ovary coarsely rufous-tomentose with a few glandular setae. Capsule 8-15 x c.6mm.
Habitat: Cliffs, meadows
Distribution: NE Upper Burma & adjacent China (NW Yunnan)
Altitude: 3600-4500m
Plants with a more persistent though patchy indumentum, probably hybrids of R. aperantum, have been referred to R. aperantum var. subpilosum Cowan (Notes R.B.G. Edinb. 20: 84, 1940). They are as follows: Forrest 25596 (type-holo. E), 25563, 25757, 25878.
Type: NE Upper Burma, Chawchi Pass, 12000ft, vii 1921, Farrer 1671 (holo. E; iso. K).
Occurs in Countries: CN, MM Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: orange, pink, rose, white, yellow
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):400
Shrub to 1m. Twigs c.4mm in diameter, green, rounded, laxly to sub-densely, pale-brown scaly and minutely, sparsely shortly patently hairy; internodes 2–12cm. Leaves loosely spirally arranged along the stem. Blade 50–100 x 43–60mm, broadly ovate or ovate-elliptic, occasionally broadly elliptic; apex obtuse, rarely rounded and mucronate but without an obvious apical gland; margin entire, flat, with a thin (c.0.5mm), reddish-purple edge; base distinctly cordate, occasionally broadly tapering and then with translucent auricles at the base of the lamina; glabrescent above, laxly and more persistently scaly beneath. Scales stellate, pale-brown, marginal zone appressed to the leaf surface; centres small and impressed. Mid-vein strongly raised above for about ¾ of the length of the leaf, slightly raised beneath or shallowly impressed in the proximal ½; lateral veins 7–10 per side, spreading almost perpendicularly, strongly raised above, the leaf surface deeply sulcate between the veins, disappearing before the margin, reticulation weak or obscure. Petiole 10–23 x 4–5mm, reddish-purple, rounded above, without a groove, sparsely to sub-densely scaly. Flower buds ovoid, 20–35 x 15–22mm, bracts firmly appressed except for a very short point. Outer bracts translucent, truncate to emarginate, almost glabrous, with just a few small scales outside but without any on the margins. Inflorescence a 5–8-flowered open umbel, the flowers held horizontally. Pedicels 34–38 x c.3mm, shortly, white, patent-hairy and with a few papillae towards the distal end but without scales. Calyx green, glabrous or with a few low, irregular papillae. Corolla 55–65 x 50–60mm, bright golden yellow, often flushed with orange on the tube and around the edges of the lobes, without scent; tube c.30 x 12 x 22mm, funnel-shaped, glabrous outside but densely shortly white, patent-hairy in the proximal ½ inside, conspicuously 5-lobed at the base; lobes 35 x 27mm, spreading almost at a right angle and overlapping to over halfway, glabrous. Stamens irregularly spreading around the mouth of the flower, occasionally in two groups, slightly dimorphic; filaments white, densely white hairy proximally, the hairs thinning distally and becoming glabrous for the uppermost 2⁄3; anthers c.4 x 1mm, arching inwards, tapering towards the base which is distinctly apiculate. Disc purplish-brown, lobed, shortly white hairy on the upper side. Ovary 10 x 5mm, green, sparsely patently white hairy and with a few rounded silvery scales, abruptly tapering distally; style 20 x 1.5mm, glabrous, green, slightly broadened to the pink, circular but 5-lobed stigma. Fruit 20–30 x 8–10mm, green or flushed red, often flecked with white, fusiform. Seeds c.3mm, without tails 0.8mm, the longest tail 1.5mm.
Habitat: Common in the sub-alpine shrubbery of the summit ridge, growing on deep peat which overlies limestone.
Distribution: Malaysia (Borneo), Sarawak, 4th Division, Mulu National Park, Mt Api.
Altitude: Around 1600m
Named after Mt Api, the mountain where it was found, which in the Malaysian language means ‘mountain of fire’. This is the only known locality of this species, which in addition has fiery-coloured flowers.
Rhododendron apiense is a peculiar species somewhat reminiscent of R. intranervatum Sleumer (from southern Sarawak) in having broad, sulcate leaves but it has sub-densely scaly (and minutely hairy), not laxly scaly young twigs, the ovary is only sparsely patently hairy, compared with the densely appressed hairy ovary of R. intranervatum, and it is much less sulcate. The mid-vein is only slightly raised beneath in this species, being level with the surface from about the midpoint of the leaf, often from the base, whereas in R. intranervatum it is strongly raised underneath to the apex. It differs from R. javanicum ssp. brookeanum, to which it is probably most closely related, in that the leaves are less than twice as long as wide with most leaves having a cordate base. It has distinctly basally apiculate anthers and a broader ovary with a shorter broader fruit. Apart from the distinctive leaf shape, the flowers differ from R. javanicum ssp. brookeanum in having larger, much more overlapping lobes and it grows at higher altitude than most forms of this species. Introduced into cultivation in Edinburgh in 1978, it is a lanky shrub which did not flower well until it was quite large and even then it has not produced the truly magnificent flowers which it did in the wild. It is still an attractive species and it is possible that it may perform better in climates with stronger light.
Type: Argent RBGE 19781745, 22 May 2001. Sarawak, 4th Division, G. Api (SAR, E).
Occurs in Countries: MY Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: orange, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:261
Erect shrub to c.1m, commonly branching from the base and branching profusely above as well. Twigs rounded, densely covered with dark-brown scales but these becoming paler and giving the stems a grey appearance with age. Leaves 3–6 together in loose pseudowhorls, 2–7cm apart. Blade 30–110 x 10–40mm, elliptic to obovate-elliptic, variable in shape and size; apex shortly acuminate, sub-acute or obtuse; margin flat or slightly revolute, often irregularly somewhat crenate or dentate in the distal part; base broadly to narrowly tapering, dull silvery-green above often with a somewhat bluish tinge from a distance, initially densely scaly on both sides, those above predominantly silvery but with visible brown centres to the largest scales, glabrescent with age; below, densely and persistently brown-scaly, but often with narrow areas of the leaf surface visible between the scales. Scales with broad striate flanges and large swollen centres, the largest scales well spaced, with large dark centres. Mid-vein slightly impressed above, very prominent beneath in the lower part of the lamina; lateral veins 6–7 per side, irregularly spreading, the upper ones straight, all anastomosing, very slightly depressed above in fully mature leaves, somewhat raised or only faintly visible beneath, reticulation hardly visible. Petiole 9–15 x 2–3mm, weakly grooved distally, densely brown-scaly. Flower buds to 17 x 12mm, ovate, broadly pointed, with all bracts firmly appressed, purple or green. Bracts ovate to sub-circular, glabrous except for the fringe of simple white hairs and a patch of overlapping brown scales on the outside near the apex, which often extend down the middle line. Flowers 6–15 in an open umbel. Bracteoles filiform, shortly patently hairy and with a few scales especially towards the apex. Pedicels 7–11 x c.1mm, densely scaly. Calyx c.2mm in diameter, disc-shaped, covered in brown scales. Corolla 16–20 x 16–20mm, pinkish-orange; tube 13–18 x 4–7 x 5–9mm, straight, often somewhat 5-angled, glabrous or very laxly scaly outside, at least at the sinuses of the lobes; lobes 4–7 x 5–11mm, spreading horizontally or sometimes a little reflexed, broadly rounded or emarginate. Stamens at first clustered in the centre of the flower later spreading irregularly round and reaching or slightly exceeding the mouth of the tube; filaments linear, flat, glabrous; anthers broadly oblong, c.1.7mm. Disc green, glabrous or with a few scales on the upper side. Ovary 4–5 x c.2mm, sub-ovoid-conical, densely scaly; style as long as or shorter than the ovary, thick, scaly at the base, glabrous in the upper ½; stigma thick, rounded. Fruit 20–25 x 3–4mm, spindle-shaped. Seeds 5–6mm, without tails 0.8–0.9mm, the longest tail 3mm.
Habitat: Mostly epiphytic in moss forest on peaks and ridges
Distribution: Philippines, Mindanao, Davao Province, Mt Apo, Mt McKinley. Bukidnon Province, Mt Lipa, Katanglad Mts. Agusan Province, Mt Urdaneta. Common on Mt Apo
Altitude: 1380-2930m
Named after Mt Apo where it was first collected, the highest mountain in the Philippines.
Copeland (1929) discusses the existence of two forms which had been suggested by Elmer (1911), one having slightly larger, entire, spreading leaves, the other with smaller leaves, ‘feebly dentate towards the apex, and tend[ing] to ascend strictly’. He concludes ‘that not even a varietal distinction can be made’ as the flowers are identical. In cultivation in Edinburgh there are two forms with differently coloured flower buds – purple and green – but with no other visible difference. This species might be regarded as an extreme variant of the R. malayanum complex but it is distinct in the smaller flowers which have a regular, circular or slightly 5-sided tube, not the laterally compressed tube characteristic of R. malayanum, as well as a shorter style. It is distinct from the only other Malayovireya so far known from the Philippines – R. nortoniae – by the much shorter flowers which are only ½ as long as in that species. Rhododendron apoanum was described and figured in the Gartenflora (Stein 1885) but the colour plate would appear to have been painted from a herbarium collection with directions from the collector as to the colours; there is no indication that it was cultivated. It took over 100 years to realise the horticultural promise of this species when it was finally introduced to cultivation via Edinburgh in 1993 from material collected on Mt Apo. It is one of the easiest species of this section to grow and flowers freely several times a year, the small size of the flowers being made up for by the freedom with which they are produced and the very attractive bluish-green aspect of the foliage.
Type: Schadenberg, Feb. 1882. Philippines, Mindanao, Mt Apo (B†, neotype Elmer 11386 the same locality L, A, BM, E, K, NY).
Occurs in Countries: PH Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: pink
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:112
Shrub; young shoots densely spreading-glandular-pubescent and setulose. Leaves dimorphic, coriaceous; spring leaves elliptic-oblong, 3.5-3.8 x 1.5cm, c.2 x as long as broad, apex shortly acuminate, margins entire; upper surface with lamina soon glabrescent, lower surface with a yellowish brown pubescence and a few short strigose hairs; summer leaves elliptic-oblong to linear, 15-18 x c.7mm, otherwise as for spring leaves; petioles 2-2.5mm, densely spreading-setulose and glandular pubescent. Inflorescence c.I4-flowered, pedicels 5-7mm, densely strigose. Calyx strigose, lobes small, triangular. Corolla narrowly funnel-shaped, rose-red, c.l8mm; tube 10mm, 2.5mm at base, 4mm broad below lobes. Stamens 5, filaments glabrous. Ovary setose; style glabrous. Fruit not known.
Distribution: China (Fujian)
Illustrations:
Allied by the author to R, falcinellum, a species treated by us as a synonym of R. rufulum, but differing from the latter in the yellowish brown leaf indumentum, etc.
Type: China, Fujian, Shanghang Xian, Wong-Yong, 400-500m, 13 v 1974, L.G. Li (L.K. Lee) 740740 (holo. Inst. Mat. Med. Fujian)
Occurs in Countries: CN Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: rose
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):102
Shrub or small tree, 1.5—6.5m. Leaves sub-coriaceous, elliptic to oblanceolate, 5.5-13 x 1.8-3.2cm, 3-5 x as long as broad, apex acute to cuspidate, base cuneate, margin plane to slightly undulate, upper and lower surfaces glabrous when mature, punctate hair-bases apparently lacking; petioles 0.7-1.5cm, fioccose-tomentose. Inflorescence lax, 5—10-flowered; rhachis c.5mm; pedicels 15-20mm, slender, smooth to minutely hairy. Calyx l-2mm, lobes rounded, glabrous to sparsely ciliate. Corolla open-campanulate, nectar pouches lacking, glabrous within, white flushed rose, with a basal blotch, sometimes also with purple flecks, 28-35mm. Ovary with a sparse covering of short white simple hairs; style glabrous. Capsule 10—16 x 3—4mm.
Habitat: Mixed forests
Distribution: China (Mid W Yunnan), ne Upper Burma
Altitude: 2300-3350m
Distinguished from R. annae by its glabrous style and the lack of punctate hair-bases.
Type: China, W Yunnan, Shweli/Salween divide, 9000-lOOOOft, vi 1913, Forrest 11918 (holo. E; iso. BM, K).
Occurs in Countries: CN, MM Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: purple, rose, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):294
Shrub or small tree to 6m tall, usually non-rhizomatous; young twigs yellow-brown or rarely red-brown, glabrous or rarely very sparsely covered with unicellular hairs. Vegetative bud scales glabrous abaxially; margin unicellular-ciliate. Leaf blade membranaceous, ovate or obovate to elliptic, (4.5-)4.8-7.8(-10.5) x (1.6-) 1.9-2.6(-3.0)cm; base acute to oblique; apex acute to obtuse, often mucronate; adaxial surface glabrous, the midvein sparsely to densely covered with unicellular hairs; abaxial surface glabrous, sometimes also glaucous, the midvein sparsely covered with multicellular eglandular hairs, occasionally glabrous; margin entire, ciliate with multicellular eglandular hairs; petiole (0.2-)0.4-0.9(-1.6)cm long; glabrous or sparsely covered with multicellular eglandular hairs. Flower bud scales chestnut brown; abaxial surface glabrous or rarely with very sparse unicellular hairs; margin unicellular ciliate. Flowers appearing with the leaves or after they have expanded; Inflorescence a shortened raceme of 3 to 7 flowers. Pedicels (0.6-)1.0-1.6 (-2.1)cm long, sparsely to densely covered with unicellular and multicellular gland-tipped hairs, occasionally only with multicellular eglandular or gland-tipped hairs, rarely glabrous. Sepals less than 0.1-0.5(-0.8)cm long, often varying in length on the same flower; margins glandular-fim-briate and setose or only glandular-fimbriate, rarely only setose; abaxial surface glabrous to sparsely covered with multicellular gland-tipped hairs, eglandular hairs or with both, rarely additionally covered with unicellular hairs. Corolla white, fragrance sweet, with a cinnamon quality, the tube longer than the limb and gradually expanding into it; upper corolla lobe (1.0-)1.3-1.9(-2.1) x (0.7-)0.9-1.4(-1.8)cm; lateral lobes (1.2-) 1.4-2.0(-2.4) x (0.5-)0.6-0.9 (-1.2)cm; corolla tube (2.0-)2.3-2.9(-3.3)cm long, 0.2-0.5(-0.6)cm wide at base; outer surface of corolla sparsely covered with unicellular hairs and multicellular gland-tipped hairs that continue in lines up the corolla lobes; inner surface of corolla sparsely to densely covered with unicellular hairs. Stamens (4.4-)5.3-6.9(-8.2)cm long, with dense terete or flattened unicellular hairs on proximal (2.7-)3.0-3.8(-4.5)cm of filament, exserted (2.3-)2.9-4.3(-5.0)cm beyond throat of corolla. Style (5.3-)5.6-6.9(-7.5)cm long, exserted (3.2-)3.6-4J(-5.4)cm beyond throat of corolla, with dense unicellular hairs on proximal (0.0-)0.2-1.4(-2.6)cm; stigma 0.1-0.3cm wide. Ovary (0.2-)03-0.4cm long, 0.1-0.3cm wide at the base, densely covered with multicellular glaAd-tipped hairs and unicellular hairs. Capsules (1.1ó)1.2ó1.7 x 0.5-0.8cm, ovate, sparsely covered with unicellular hairs and moderately covered with multicellular gland-tipped hairs. S eeds pale to dark chestnut brown, ovate or elHptic to fusiform, (0.8-)l.l-1.6(-2.0) x (0.4-)0.6-1.0 (-l.l)mm,tody(0.7-)0.8-1.8 of the seed, the cells short with transverse end-walls orisodlametric.
Habitat: Along mountain streams, shrub balds and moist woods.
Distribution: USA: West Virginia to Tennessee, North Carolina, Georgia and adjacent Alabama.
Altitude: 300-1500m
Illustrations:
Rhododendron arborescens also hybridizes with R. cumberlandense and hybrids have been collected especially on Gregory Bald, Blount Co., Tennessee and in Jackson Co., Alabama. These hybrids vary considerably in morphology, from glabrous, white-flowered plants with unicellular-clliate bud-scale margins to pubescent, pink or reddish-flowered plants with glandular bud-scale margins. Putative hybrids also occur between R. arborescens and R. cumberlandense In Morgan County, Tennessee and in Union and Walker Counties, Georgia. Possible hybrids between R. arborescens, R. viscosum and J?, cumberlandense occur on Gregory Bald, Blount Co., Tennessee.
Rhododendron arborescens is most closely related to R. viscosum, and can be distinguished from It by the glabrous, yellow-brown branchlets, the red style and filaments which contrast with the white corolla and the distinctive seeds that lack a loose, expanded testa. Rhododendron arborescens is sympatric with R. viscosum and blooms during the same time of year. Both species are often found growing In close proximity to each other and hybridize occasionally, although these hybrids are sometimes difficult to detect. Reproductive Isolation may be related to pollinators as the fragrance of the two species is quite different and the flowers of R. viscosum have concolorous styles and filaments.
Chromosome number: 2n = 26 (JanaM-Ammal et al., 1950; Li, 1957)
Flowering from May to August, occasionally as early as April or as late as September.
Rhododendron arborescens is quite uniform morphologically throughout its range. The most noticeable variation occurs In leaf size and glaucousness which appear to be a function of habitat. Rehder (1921) described one form as a variety (R. arborescens var. richardsonii) which Is a smaU-leaved, compact form found In exposed situations on the tops of balds or mountains In the Appalachians.
Synonymy: Azalea viscosa Marshall, Arbust. Amer. 15 (1785) non L. Type: n.v. Azalea arborescens Pursh, Fl. Am. Septentr. 152 (1814). Type: n.v. Azalea fragrans Raf., Ann. Nat. 12 (1820). Type: n.v. Rhododendron arborescens (Pursh) Torr. var. richardsonii Rehder, Monogr. Azaleas 168ó 169 (1921). Azalea arborescens Pursh var. richardsonii (Rehder) Ashe, J. Elisha Mitchell Sci. Soc. 38: 91 (1922). Type: North Carolina, Macon Co.: on Wayoh [sic] Bald, alt. 5200 ft, T G. Harbison 170 (holo. A).
Occurs in Countries: US Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Pentanthera Habit: Tree
Kron, K.A. (1993) A Revision of Rhododendron Section Pentanthera. Edinburgh Journal of Botany 50(3):287
Usually a tree (l-)5-50m, with a well-defined trunk. Leaves narrowly to broadly elliptic or ovate, 6.5 — 19 x 1.8—5cm, 2.2-6.5 x as long as broad, upper surface reticulate to bullate, glabrous, lower surface with a dense compacted to spongy, white to fawn dendroid tomentum, occasionally also with a floccose rufous upper layer; petioles l-2cm, with a loose indumentum intermixed with glands, sometimes glabrescent at maturity. Inflorescence 10-20-flowered, dense; rhachis 15-20mm; pedicels 5-10mm, pilose and glandular. Calyx l-2mm, lobes rounded, sparsely glandular to ± glabrous. Corolla fleshy, ± tubular-campanulate, pink to deep crimson, rarely pure white, with dark flecks and nectar pouches, 30-50mm. Ovary white-tomentose, sometimes also glandular. Capsule 15-30 x c.6mm.
R. arboreum is an extremely variable species, especially with respect to leaf shape and leaf indumentum, with a wide geographical range and clear-cut geographical differentiation. This species reaches its greatest complexity in NE India and adjacent E Nepal and Bhutan where there is intergradation between subsp. arboreum and subsp. cinnamomeum, though the former predominates below 2500m and the latter above 2900m. Subsp. delavayi apparently intergrades with subsp. arboreum in NW Burma where a range of intermediates occurs. It is also sometimes difficult to distinguish some forms of subsp. delavayi from subsp. cinnamomeum, especially where the ranges of the two approach one another, as in SE Bhutan. The two isolated subspecies, subsp. zeylanicum and subsp. nilagiricum, are closer to one another than they are to subsp. delavayi, from which they are clearly divided.
Natural hybrids occur between var. roseum and three other species: R. barbatum, R. campanulatum and R. wallichii.
Occurs in Countries: BT, CN, IN, LK, MM, NP, TH Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: carmine, crimson, pink, red, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):328
Leaves (8—)10—19 x (2.4-)3-5cm, 3-4(-5) x as long as broad, apex acute, upper surface reticulate, lower surface with a compacted, usually white to silvery indumentum. Corolla bright red to carmine, rarely pink or white.
Habitat: Usually in open or mixed forests
Distribution: N India(from Kashmir to Sikkim), Nepal, Bhutan
Altitude: 1850-3200m
Subsp. arboreum apparently merges with both subsp. cinnamomeum var. roseum and subsp. delavayi.
Type: a plate accompanying the type description, drawn from plants seen near Srinagar (Kashmir) by Capt. Hardwicke in 1796.
Synonymy: R. puniceum Roxburgh, Fl. British India 2: 409 (1832). Type: N India, mountains N of Nohilkhund, Hardwicke, n.v. R. windsorii Nuttall, Hooker's J. Bot. Kew Gard. Misc. 5: 357 (1853). Type: Nepal, on the ridges and slopes of Ropprye, 7-9000ft, Nuttall (holo. K)
Leaves 6.5-11 x 2.5-6cm, 2.5-3.7 x as long as broad, apex acute, upper surface reticulate, lower surface with a bistrate indumentum, the upper layer loose and floccose, rufous, the lower whitish to fawn and compacted. Corolla pink to carmine, occasionally white.
Habitat: Open forests and rocky slopes
Distribution: E Nepal, NE India (Bengal & Sikkim)
Altitude: 2750-3650m
Type: Nepal, 1821, Wallich 760, n.v.
Synonymy: R. cinnamomeum [Wallich ex] G. Don, Gen. Syst. 3: 844 (1834). Type: as above. R. campbelliae Hooker f., Rhododendrons Sikkim Himalaya t.6 (1849). Type: N India, Sikkim, 9-10000ft, Hooker, n.v. R. arboreum Smith subsp. campbelliae (Hooker f.) Tagg in Stevenson (ed.), The Species of Rhododendron 15 (1930).
Leaves 6.5-ll x 2.2-4.5cm, 2.7-3.5 x as long as broad, apex acute, upper surface reticulate, lower surface with a unistrate compacted, usually fawn or whitish indumentum. Corolla pink to carmine, rarely white.
Habitat: Open forests, rocky slopes
Distribution: E Nepal, NE India (Bengal, Sikkim, Arunachal Pradesh), Bhutan, China (CXizang)
Altitude: 2750-3650m
Var. roseum intergrades with both subsp. arboreum and subsp. delavayi.
Type: the above plate drawn from a plant in 1828, cultivated by Mr Knight from seed sent from Nepal by Jenkinson.
Synonymy: R. arboreum Smith var. album Wallich, PL Asiat. Rar. 2:23, t.123 (1830). Type: Nepal, in monte Sheopore, 10000ft, Wallich, n.v, R. album Buchanan-Hamilton in Sweet, British Fl. Gard. ser. 2,2: t.148 (1832). Type: Nepal, Narainhatty, iii 1803, Buchanan-Hamilton, n.v.
Leaves 7—13.5(—15.5) x 2-2.4cm, 2.8-4.4 x as long as broad, apex acute, upper surface reticulate, lower surface with a unistrate spongy, whitish to fawn indumentum. Corolla usually deep crimson to carmine.
Habitat: Open forests, etc.
Distribution: NE India (Meghalaya, Manipur, Assam, Arunachal Pradesh), Burma, Thailand, China (Yunnan, Guizhou)
Altitude: 1500-3000m
Synonymy: R. delavayi, Bull. Soc. Bot. France 33: 231 (1886). Type: China, Yunnan, in monte calcareo Houangli-pin, 2500m, Delavay 242 (iso. E, K). R. pilovittatum Balfour f. & W. W. Smith, Notes R.B.G. Edinb. 10: 134 (1917). Type: China, W Yunnan, on the Yung-peh Mountains, 9000ft, vi 1914, Forrest 12745 (holo. E; iso. K). Ic: Bot. Mag. 133: t.8137 (1907)
Leaves (7.5-)9-15(-18) x 1.8-3(-4.2)cm, 4.5-6.5 X as long as broad apex acute to shortly cuspidate, with a loose spongy, fawn indumentum below. Corolla usually crimson to carmine.
Distribution: NE India (Arunachal Pradesh), China (W Yunnan).
A specimen from C Xizang (Kingdon-Ward 19245), with narrow leaves but a compacted leaf indumentum, is probably referable to this variety.
Synonymy: R. peramoenum Balfour f. & Forrest, Notes R.B.G. Edinb. 13: 56 (1920). Type: China, W Yunnan, Shweli/Salween divide, vi 1918, Forrest 17708 (holo. E; iso. K).
Leaves 8.5-12 x 3.8-6cm, 1.8-2.4 x as long as broad, apex ± rounded, apiculate, upper surface rugose, lower surface with a spongy yellowish-brown indumentum. Corolla carmine.
Habitat: Upland forests
Distribution: S India (Tamil Nadu)
Altitude: Around 2250m
Illustrations:
Synonymy: R. nilagiricum Zenker, Amer. Sci. Nat. ser. 2, 6: 150 (1836). Type: S India, Saladia, Nilgiri Hills, Utacamund, Schmidt (iso. E).
Leaves 8-11 x 3.5-4.5cm, 2.2-2.8 X as long as broad, apex blunt to acute, upper surface with strongly impressed veins, bullate, margin strongly recurved, lower surface with a spongy brownish indumentum. Corolla carmine.
Habitat: Upland regions
Distribution: SRI lanka
Altitude: Around 2300m
Illustrations:
Synonymy: R. zeylanicum Booth, Gard. Chron. 150 (1850). Described from a plant cultivated in Sir Charles Lemon's garden in Cornwall
Tall shrub. Twigs rounded, thick, at first sub-densely scaly, later glabrescent; internodes 6–16cm. Leaves 5–7 together in pseudowhorls, in which 3–4 leaves are normal, the rest much smaller. Blade 40–110 x 20–60mm, ovate to elliptic-ovate, often asymmetrical; apex shortly acuminate, sub-acute; margin entire, sub-revolute proximally; base sub-truncate-rounded or broadly tapering, sometimes sub-cordate, sub-densely scaly on both sides, the scales slowly disappearing above, persistent for a long time beneath. Scales flat, small, the margin irregularly deeply dentate; centre not impressed. Mid-vein slightly depressed above, thickly prominent beneath proximally, less so distally; lateral veins 8–11 per side, slightly curved, irregular, anastomosing with each other before the margin, faintly impressed or raised above, raised beneath, reticulation dense, more visible beneath only. Petiole 4–12 x 1.5–2mm, grooved above, sub-densely scaly. Bracts to 10 x 7mm, ovate to broadly obovate, laxly scaly and with hairs outside. Bracteoles to 15mm, narrowly linear, glabrous or laxly scaly. Inflorescence an 8–15-flowered open umbel. Pedicels 8–11mm, densely scaly, obliquely thickened below the calyx. Calyx small, rim-like, wavy, indistinctly 5-lobed. Corolla trumpet-shaped, pink; tube 45–50 x c.2.5 x 3.5–4.5mm, cylindrical, slightly curved, gradually expanding from the base but then a little constricted below the mouth, laxly to sub-densely scaly outside, densely hairy inside almost to the mouth; lobes 10–12 x 8–12mm, broadly spathulate to nearly circular, laxly scaly outside at the base and in the middle, glabrous inside. Stamens exserted; filaments linear below, filiform above, shortly hairy nearly to the top; anthers 3.5–4 x 1mm, oblong, base obtuse. Disc glabrous below, densely hairy on the upper margin. Ovary 7–8 x c.2mm, cylindrical, gradually tapering distally, densely appressed-hairy and obscurely scaly; style as long as the corolla tube, covered with sub-patent hairs and scales nearly to the top; stigma thick, shortly obconical.
Habitat: Usually epiphytic in ridge forests, occasionally terrestrial in clearings
Distribution: Papua New Guinea, Mts Tafa and Suckling.
Altitude: Around 2400m
Named after Richard Archbold and his daughter Anne, American philanthropists and explorers who financed the expedition on which this plant was collected.
Type: Brass 4855, May–Sept. 1933. New Guinea (E), Central District, Mt Tafa (L, A, BO, NY).
Occurs in Countries: PG Altitude Ranges: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: pink
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:177
Erect shrub to 2m. Twigs rounded, densely pale-brown-scaly; internodes 3–8cm. Leaves scattered in the upper ½ of the upper 1–2 internodes. Blade 20–40 x 15–26mm, elliptic, broadly elliptic or rarely sub-ovate-elliptic; apex obtuse to very shortly acuminate or apiculate, with a blunt terminal gland; margin minutely crenulate, not or only very slightly revolute; base sub-truncate to rounded; very densely reddish brown-scaly beneath at least initially the scales forming a continuous layer. Scales lobed or rounded with a broad marginal flange, centres variable, slightly impressed, becoming glabrescent and then densely pitted. Mid-vein flat above, slightly prominent beneath; lateral veins 5–7 per side, the lower 2–3 from, or from slightly above, the base, the remainder straight at first, curving distally and obscurely anastomosing, faintly impressed above, slightly raised beneath, somewhat rugose above when mature. Petiole 3–4 x 2–3mm, not grooved above, flattened, scaly. Flower buds broadly ovoid, c.15 x 10mm. Bracts to 15 x 10mm; outer bracts ovate, inner ones sub-spathulate, blunt, with white silky hairs and also scaly along the midline outside. Bracteoles to 3mm, slender. Inflorescence 7–13-flowered, in an open umbel, hanging, without scent. Pedicels 15–25 x c.1mm, densely brown-scaly but without hairs. Calyx disc-shaped, c.3.5mm in diameter, densely scaly outside, the margin wavy and spreading, indistinctly, bluntly 5-lobed. Corolla 23–27 x 20–27mm, tubular- campanulate, pink; tube 12–18 x 6–7 x 9–11mm, a little pouched at the base, laxly to sub-densely scaly outside and with a few simple hairs outside at the base and a few inside near the base only; lobes 12 x 11mm, broadly obovate to nearly rounded, retuse or irregularly crenulate, spreading almost to the perpendicular, overlapping to c.halfway. Stamens regularly arranged in a circle, just included or slightly exceeding the corolla tube in length, weakly dimorphic; filaments 1–3mm, white, filiform, glabrous or with some sparse hairs near the base; anthers 18 x 1.2mm, brown, oblong. Disc glabrous or with dense long hairs on the upper side. Ovary 4–5 x 3–4mm, green, thick, conical, abruptly contracted to the style, covered with patent or somewhat distally pointed white hairs which obscure dense silvery scales; style 4–6mm, thick, glabrous; stigma large, sub- conical, distinctly 5-lobed, centrally placed.
Habitat: On open sandy ridges
Distribution: Indonesia, SW Central Sulawesi, Latimodjong Range.
Altitude: 2600-3000m
Latin – arenicola – sand dwelling, alluding to the fact that it was first collected on a dry sandy ridge.
Introduced into cultivation by Galloway and Smith from Mt Rantemario where it was common at 2700m. It flowered for the first time in cultivation in Edinburgh in December 2003 with most attractive pale pink flowers. Plants in cultivation tend to be less scaly than those from the wild, with dense but not overlapping scales on the undersides of the leaves.
Type: Eyma 955, 24 June 1937. Indonesia, Sulawesi, Enrekang, Batubóllong-Madjadja, NNW of Madjadja, 2900m (BO, L).
Occurs in Countries: ID Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: pink, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:132
Shrub to 2.5m. Twigs 2–3mm in diameter, sparsely scaly and papillose-hairy in the youngest parts, becoming glabrescent; internodes 2–10cm. Leaves 3–5 together in tight pseudowhorls. Blade 40–100 x 15–45mm, obovate-elliptic; apex obtusely tapering or nearly rounded; margin entire, slightly revolute in dry specimens; base tapering or broadly tapering, glabrescent above when mature, sub-persistently and sub-densely to laxly scaly beneath. Scales small, with the marginal zone irregularly lobed and a minute dark centre, slightly impressed, each scale surrounded by a dark halo, also very finely punctate by minute emergences of the epidermis beneath. Mid-vein slightly depressed and with minute, papillose, spreading hairs above, as wide as the petiole and obtusely prominent in the lower part beneath; lateral veins 6–10 per side, spreading, obscurely inarched at the margin, slightly prominent on both sides, reticulation inconspicuous. Petiole 6–12 x 1–1.5mm, with minute, papillose, spreading hairs above. Outer bracts to 15 x 8mm, ovate, obtuse, inner ones oblong-obovate, laxly scaly and minutely hairy outside, becoming glabrescent, fringed with scales. Bracteoles to 23 x 0.5–4mm, filiform below, spathulate distally, papillose. Inflorescence a 4–10-flowered umbel. Pedicels 8–12mm, slender, laxly to sub-densely scaly and finely patently hairy. Calyx c.3mm in diameter, disc-shaped, membranous, sub-obtusely and very shortly unequally lobed, wavy, spreading to reflexed, glabrous outside, distinctly ciliate. Corolla 25–35mm, tubular below, expanded upwards, oblique, deep pink; tube 15–20 x 3–4 x c.5mm, sub-cylindrical, straight or slightly curved, glabrous outside, laxly hairy inside; lobes 7–10 x 5–8mm, sub-erect, or somewhat spreading, obovate-spathulate. Stamens spreading all round the mouth, unequal, the longest as long as the corolla; filaments linear and laxly hairy below, filiform and glabrous distally; anthers 2mm, obovate. Disc shortly hairy. Ovary c.4 x 2mm, sub-cylindrical, densely short-hairy and minutely scaly (the scales covered by hairs), abruptly contracted distally; style slender, sometimes with some hairs at the very base, equalling the stamens in length; stigma club-shaped, obconical, oblique. Fruit (sub-mature) 20 x 4mm, fusiform, densely hairy, surmounted by the glabrous, 20mm style.
Habitat: At the edge of forest,locally common, epiphytic or more rarely terrestrial.
Distribution: Indonesia, New Guinea (W), Arfak and Nettoti Mts.
Altitude: 1200-2135m
Named after the mountains from where this species was described.
Said to be close to R. angiense J.J.Sm. but differing in the shortly hairy pedicels and non-scaly corolla. Introduced into cultivation from seed sent by Professor Sleumer to the Australian Rhododendron Society in 1962. Doubtfully still in cultivation.
Type: Beccari 5792. New Guinea, W Arfak Mts, Hatam (FI).
Synonymy: R. undulaticalyx J.J.Sm. in Gibbs, Phyto. Fl. Arfak Mts. 1917. 168.
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: pink
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:309
Shrub or small tree, 2-12m. Leaves elliptic to oblanceolate, 6-16 x 1.8-6cm, 2.7—3.6 x as long as broad, apex acute to acuminate, upper surface glabrous, lower surface with a thing silvery to fawn compacted indumentum embedded in a surface film; petioles 1 -2cm, floccose at first, soon glabrescent. Inflorescence lax, 4-10-flowered; rhachis 10-15mm; pedicels 20-25mm, floccose, sometimes also glandular. Calyx c.2mm, floccose, lobes broadly triangular, sometimes glandular-ciliate. Corolla funnel-campanulate to open-campanulate, white to pale pink, with purple flecks, 30-55mm. Ovary with a thin white floccose to rufous-glandular indumentum; style glabrous. Capsule 10-25 x 3-4mm, narrowly cylindrical, curved.
Habitat: Bamboo thickets, forests, open slopes
Altitude: 1600-3650m
A very variable species with some geographical variation. Closely allied to R. pingianum (q.v.).
Occurs in Countries: CN Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: pink, purple, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):325
Leaves 6-9(-1 l)cm; corolla 30-35mm. Leaf indumentum white to silvery; ovary eglandular or glandular. Ovary and pedicels eglandular.
Distribution: China (Yunnan, Sichuan, Shaanxi)
Illustrations:
The corolla varies from open-campanulate (var. cupulare) to funnel-campanulate (R. argyrophyllum sensu stricto). This character, however, is lost in the herbarium and there is in any case considerable overlap.
Type: China, W Sichuan, circa Moupine, 3000m, Abbe David (iso. E).
Synonymy: R. chionophyllum Diels, Bot. Jahrb. 29: 512 (1900). Syntypes: China, Sichuan, Nan chuan, Bock von Rosthorn 2157, 2161, n.v. R. argyrophyllum Franchet var. cupulare Rehder & Wilson in Sargent, (ed.), PL Wilsonianae 1: 526 (1913). Type: China, W Sichuan, Mupin, 2000-3000m, vi 1905, Wilson 3442 (iso. E,K).
Leaves 6-9(-1 l)cm; corolla 30-35mm. Leaf indumentum white to silvery; ovary eglandular or glandular. Ovary and pedicels glandular.
Distribution: China (E Sichuan, W Hubei)
Illustrations:
Synonymy: R. hypoglaucum Hemsley, J. Linn. Soc. Bot. 26: 25 (1889). Type: China, Hubei, Patung district, Henry 723 (holo. K). R. gracilipes Franchet, J. Bot. (Morot) 9: 391 (1895). Type: China, E Sichuan, environs de Tchen-keou-tin, Farges 52 (iso. E, K).
Synonymy: R. argyrophyllum Franchet var. nankingense Cowan, Notes R.B.G. Edinb. 21: 148 (1953). Type: China, Guizhou, Lao Shan, 1250m, i 1931, Steward et al. 499 (holo. E); also in cultivation at Edinburgh as 'F46 flowered 7 v 1946(E). R. argyrophyllum Franchet var. leiandrum Hutchinson, Bot. Mag. 144: t.8767 (1918). Type: a plant cultivated at Kew from seed collected in 1908 in W Sichuan as Wilson 1353, n.v.
Leaves 6-9(-1 l)cm; corolla 30-35mm. Leaf indumentum fawn; ovary eglandular.
Distribution: China (W Sichuan, Mt Omei)
Close to subsp. argyrophyllum and possibly only a local variant.
Synonymy: R. argyrophyllum Franchet var. omeiense Rehder & Wilson in Sargent (ed.), PI. Wilsonianae 1: 527 (1913). Type: China, W Sichuan, v 1904, Wilson 3962 (holo. A; iso. K).
Shrub to 2.5m. Twigs rounded, tips sparsely to sub-densely stellately scaly; internodes 2–12cm. Leaves 4–5 in well-marked pseudowhorls. Blade 70–100 x 30–60mm, elliptic, broadly elliptic, to sub-obovate-elliptic; apex very shortly obtuse; margin entire, flat or slightly revolute; base rounded or broadly tapering, the extreme base sometimes truncate to slightly sub-cordate; sub-densely scaly on both sides initially, early glabrescent above, more persistently scaly beneath. Scales thin, flat, brown, often on minute low epidermal elevations which are still visible as pale spots when the scales have gone, marginal zone thin, irregularly deeply incised; centre very small. Mid-vein impressed above, very prominent beneath especially proximally; lateral veins 8–10 per side, straight basally, sometimes forking, obscurely curved-anastomosing before the margin, smooth above when fresh, (raised when dry), prominent beneath, laxly reticulate, more visible beneath, veinlets obscure. Petiole 8–15 x 2.5mm, grooved above, semi-rounded, brown-scaly. Flower buds to 30 x 12mm, narrowly ovate, acutely pointed, green, the bract tips spreading and recurving, densely hairy and with a few scales outside and fringing the bract margins. Bracts ovate to obovate-spathulate. Bracteoles c.20 x 2.5mm, linear-spathulate, laxly hairy. Inflorescence an open one-sided umbel of 5–7 flowers, held horizontally or half-hanging. Pedicels 15–25 x c.2mm, sub-densely scaly, sometimes with a few hairs below the calyx, red. Calyx distinct, scaly and laxly hairy outside, glabrous inside, irregularly, deeply 5-lobed, lobes triangular, c.3 x 2mm, occasionally subulate up to 7mm, red, fringed often becoming reflexed. Corolla 55–60 x 35–40mm, trumpet-shaped, white or pink with white lobes; tube 45–60 x 5–6 x 10–12mm, straight or slightly curved, angled in section and grooved proximally, very laxly scaly or practically glabrous outside, densely long-hairy inside in the proximal 1⁄3, becoming less densely so and glabrous in the distal 1⁄3; lobes c.15–20 x 14–18mm, broadly obovate to nearly circular, spreading, overlapping to c.halfway, glabrous. Stamens loosely clustered on the lower side of the mouth, exserted to c.6mm, hanging down on the lower side in older flowers; filaments slender, white, densely hairy at the base, becoming less so, and completely glabrous in the distal 1⁄3; anthers 3–4 x c.1mm, oblong, base obtuse. Disc glabrous or hairy. Ovary 10–12 x 2.5–3mm, elongate-conical, 5-ribbed, densely covered with appressed white hairs, which cover some scales, gradually tapering distally; style densely hairy and very laxly scaly in the proximal ½, glabrous and more slender distally; stigma broadly obconical, distinctly 5-lobed, becoming exserted to 12mm.
Distribution: Papua New Guinea, Mt Dayman, summit; Central/Northern District, Mt Suckling; Milne Bay District, Mt Vineuo, Goodenough Is.
Altitude: 2250-2710m
Named after the collector William Edington de Margrat Armit, Belgian officer of the Queensland mounted police, who led the Argus expedition to Papua on which this species was collected.
Type: Armit, 1894. New Guinea, Milne Bay District, Mt Dayman, 2710m (BRI, MEL).
Occurs in Countries: PG Altitude Ranges: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: pink, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:178
Shrub, 4.5m; young shoots adpressed-brown-strigose. Leaves probably dimorphic, chartaceous; spring leaves elliptic-ovate lanceolate, 3.5-6.5 x 1.6-2.8cm, c.2.3 x as long as broad, apex acuminate, base cuneate, margin with stiff incurved hairs, ± entire, upper surface sparsely adpressed-strigose, lower surface adpressed rufous-strigose, densely so on midrib and lateral veins; petioles 6-12mm, densely adpressed strigose. Inflorescence 3-flowered; pedicels 5-7mm, densely brown-strigose with large stiff and thinner crisped hairs. Calyx ± obsolete, strigose. Corolla open funnel-shaped, light pink, darker inside, 23-27mm; tube 6-7mm, glabrous, 3mm broad at base, 6mm broad above. Stamens 5, 30mm long, scabrid at base. Ovary densely strigose; style glabrous 35mm. Capsule unknown.
Habitat: River beds
Distribution: N E India (Arunachal Pradesh)
Altitude: Around 1500m
This new species is geographically isolated, and is the most westerly of the subgenus.
Probably allied to R. saxicolum but with a more acute leaf, corolla darker, tube glabrous within.
Type: N E India, Arunachal Pradesh, Subansiri district, Yachuli, 1500m, 28 iv 1977, H.B. Naithani Ser.II:894 (holo. E, iso. DD)
Occurs in Countries: IN Altitude Ranges: 1,000 - 2,000m Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: pink
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):131
Epiphytic, spreading shrub. Twigs c.2mm in diameter, slender, initially covered with reddish, dendroid scales; internodes 3–7cm. Leaves 3–4 together in pseudowhorls at the upper 2–3 nodes, sub-sessile. Blade 25–45 x 15–30mm, ovate; apex very broadly tapering to rounded; margin revolute distally; base a little cordate; sub-densely scaly above, quickly glabrescent but rough with the persistent epidermal scale bases, densely scaly and more persistently scaly beneath, eventually glabrescent here also but remaining rough with epidermal tubercles. Scales reddish-brown, stellate-dendroid, the tubercles often very pale in colour after the scales have fallen. Mid-vein impressed above, prominent beneath; lateral veins inconspicuous on both sides, without reticulation. Petiole 2 x 1.5mm, scaly. Bracts to 15 x 7mm, thin, ovate to spathulate, sparsely scaly at first becoming glabrous. Bracteoles c.10mm, linear to filiform, glabrous. Inflorescence 3–6-flowered. Pedicels 11–15mm, slender, very densely stellate-scaly, not hairy. Calyx 2–3mm in diameter, obliquely rimmed, shortly or hardly 5-lobed, densely scaly outside. Corolla 26–30mm, tubular, zygomorphic, pink to purplish; tube c.20 x 4–5 x 6–7mm, curved, initially, densely, later more sparsely scaly, often finally glabrescent outside, laxly papillose-hairy inside; lobes c.10 x 6mm, unequal, spreading, obovate-spathulate. Stamens almost equalling the corolla in length; filaments linear, laxly papillose-hairy in the proximal ½, glabrous distally; anthers 2 x 1.3mm, obovate-elliptic, the base obtuse. Disc glabrous below, hairy on the upper margin. Ovary c.4 x 1.5mm, sub-cylindrical, densely covered with reddish-brown, stellate scales and more sparsely with paler hairs, abruptly contracted distally; style scaly at the base, and sometimes sparsely patently hairy in the proximal ¼, otherwise glabrous; stigma sub-globose.
Habitat: Primary forest
Distribution: Indonesia, New Guinea (W), Wandamen Peninsula, Wondiwoi Mts.
Altitude: 800-1800m
Latin – asper – rough or uneven; erimum – the superlative ending, very rough. Alluding to the large persistent epidermal tubercles on the leaves.
Type: Koster 13744, March 1962. New Guinea, Wandamen Peninsula, Wondiwoi Mts, 1800m (A, CANB, K, L).
Occurs in Countries: ID Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: pink
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:74
Small shrub. Twigs reddish, densely covered with rounded scales on stalks later rough with the persistent scale stalks and when dry, the surface minutely rugose. Leaves in loose to moderately compact pseudowhorls of 4–8 together. Blade 16–22 x 7–10mm, broadly spathulate to elliptic; apex rounded to slightly emarginate with a shortly protruding, mucronate gland; margin recurved especially proximally; base tapering or narrowly tapering, somewhat decurrent; upper surface sparsely scaly, the scales not impressed and the surface becoming glabrescent; below moderately to sparsely and persistently scaly. Scales round and impressed with broad swollen centres and narrow flanges. Mid-vein impressed above and raised below throughout its length; lateral veins 1–2 per side, narrowly impressed above, and weakly raised below, in smaller leaves totally obscure. Petiole 1.5–2 x c.1mm, scaly. Outer bracts subulate, scaly outside, fringed with hairs and with a few hairs inside near the apex, inner bracts ovate scaly outside, fringed with short hairs, glabrous inside. Bracteoles sub-linear, becoming broader distally, fringed with hairs, the truncate apices especially fringed with long white hairs. Inflorescence 3-flowered. Pedicels 10–20 x c.1mm, densely to sparsely scaly. Calyx 2.5–3 x 1.5–2mm, lobes broadly elliptic, scaly outside and with scales on the margin whose stalks give the lobes an irregular edge. Corolla c.7 x 5mm, pale pink; tube c.5 x 4 x 5mm, densely scaly outside, glabrous inside; lobes c.3 x 2.5mm, with a few scales outside in the basal ½. Stamens exserted, with long hairs in the middle part of the filaments; anthers 1.5mm, orange in colour. Ovary c.3 x 1.75mm, densely scaly but without simple hairs; style c.3mm, glabrous. Fruit c.25mm. Seeds small with tails.
Habitat: Epiphytic on alders and other trees in open pastures. On boulders in the valley of the Di Chu (Kingdon-Ward 7163).
Distribution: Myanmar, (Upper), Base Camp, Seinghku Wang, 28°5'N 97°30'E.
Altitude: 1900-2100m
Latin – asper – rough – the diminutive form – slightly or minutely rough, referring to the stems.
A very imperfectly known species very similar to R. vaccinioides, differing chiefly in the pseudowhorled arrangement of the leaves. The isotype in Edinburgh is mixed with R. insculptum, and the paratype 7163 (also in Edinburgh) shows some variation in that it has faint pinnate venation which is not evident in the type, but this specimen is without flowers. This species apparently grows with R. insculptum but besides having differently coloured flowers is said to flower about one month later. It also differs in the smaller leaves without the very distinct lateral veins of R. insculptum and lacks simple hairs on the ovary.
Type: Ward 6801, 30 May 1926. Upper Burma, Seinghku Wang (K, E).
Occurs in Countries: MM Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:30
Shrub to 2m. Twigs 2–4mm in diameter, thick, densely stellate-scaly, rounded, densely warty and rough to the touch; internodes 3–10cm. Leaves 5–10 together in pseudowhorls. Blade 25–60 x 15–50mm, ovate, elliptic or sub-circular, sometimes obovate-elliptic, sub-sessile; apex obtuse to rounded; margin distinctly recurved in dry specimens; base broadly rounded or mostly shortly cordate; densely stellate-scaly on both sides at first, quickly glabrescent above, the scales more persistent beneath, rough with the numerous minute tubercles on both sides especially beneath. Scales small, deeply divided, sub-sessile each on top of a small persistent elevated pale tubercle. Mid-vein a little impressed above, strongly obtusely prominent in its basal ½ beneath, gradually less so distally; lateral veins 5–9 per side, inconspicuous, spreading irregularly, faintly anastomosing before the margin, very slightly impressed in fully mature leaves above, somewhat prominent beneath, rigid, greyish green to dark green above, brown below. Petioles 1–2.5 x 1–2mm, somewhat flattened. Bracts to 20 x 10mm, membranous, outer ones smaller, ovate to sub-circular, shortly subulate-acuminate, scaly and shortly hairy outside at the apex; inner ones larger, obovate to spathulate, glabrous. Bracteoles to 20 x 1mm, linear, laxly hairy or nearly glabrous. Inflorescence a 5–9-flowered umbel. Pedicels 15–30 x c.1mm, red, densely stellate-scaly. Calyx c.4mm in diameter, oblique, in the form of a shallow cup, densely scaly outside, very shortly and obtusely 5-lobed. Corolla 35–45 x 35–45mm, regular, white or to deep pink, sometimes with the tube of a more intense colour than the lobes, scented; tube 20–28 x 4 x 10mm, funnel-shaped, laxly scaly outside and sparsely hairy inside; lobes 15–19 x 15–19mm, spreading perpendicularly, sub-circular with some scales at the base outside, glabrous otherwise. Stamens somewhat exserted from the throat; filaments linear, sparsely hairy in the proximal ½–2⁄3, glabrous distally; anthers 3–4 x 1mm, oblong. Disc low, hairy at the upper margin only. Ovary conical-cylindrical, densely covered with white spreading hairs and stellate scales which are often hidden between and below the hairs, gradually tapering distally; style 20–23mm, slender and covered with spreading hairs and some scales in the lower ½–2⁄3, glabrous distally; stigma globose. Fruit 15–18 x 6–8mm, sub-cylindrical, densely brown-stellate-scaly and hairy.
Habitat: Terrestrial in heath-forest on ridges at the edge of degraded Nothofagus forest, or on the burnt open summit areas, on poor clayey soil, granite and quartzite
Distribution: Indonesia, New Guinea (W), Arfak Mts.
Altitude: 2150-2750m
Latin – asper – rough, alluding to the leaves which are rough due to the persistent epidermal tubercles.
Sleumer (1966) described wild hybrids of this species with R. laetum. These hybrids were characterised by glossy, shortly acuminate leaves, less distinct epidermal tubercles, the bracts densely hairy outside and c.2.5cm long. The pedicels were also scaly and hairy, the anthers c.4mm long, the ovary densely hairy and the corolla varying from pale greenish-yellow to pink and then often with yellow or greenish colour in the lower part of the tube.
Type: Gjellerup 1203, 30 April 1912. New Guinea, Arfak Mts, Angi Lakes (lectotype, BO, L).
Occurs in Countries: ID Altitude Ranges: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: pink, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:74
Small tree. Leaves oblanceolate, 18-20 x 5-6 cm, c.3.5 x as long as broad, apex rounded, base cuneate, lower surface with a sparse discontinuous whitish stellate indumentum; petioles 1.5-2.5 cm, floccose. Inflorescence 15-20-flowered; rhachis 20-25 mm; pedicels 35-50 mm, glabrous or with a few hairs. Calyx c. 2 mm. Corolla 5-lobed, funnel-campanulate, white tinged with rose, apparently with a basal blotch, c. 45 mm. Stamens c. 20, puberulent at base. Ovary and style glabrous; stigma discoid.
Distribution: China (C Sichuan)
Most probably allied to R. calophytum with which it shares the discoid stigma and large number of stamens but from which it differs in its stellate leaf indumentum, a unique feature in subsection Fortunea.
Type: China, Sichuan, Wen tchuan hsien, in valle Scha pa, 3500-4000 m, 27 iv 1914, Limpricht (iso. K)
Occurs in Countries: CN Subgenus: Hymenanthes Habit: Tree Fl. Colour: rose, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):229
Shrub or small tree usually less than l(-3)m tall, very strongly rhizomatous; young twigs red-brown, rarely yellow-brown, sparsely to densely covered with multicellular eglandular hairs or with multicellular gland-tipped hairs, occasionally also with unicellular hairs, rarely with unicellular and multicellular eglandular and gland-tipped hairs. Vegetative bud scales sparsely to densely covered with unicellular hairs or glabrous abaxially; margin unicellular-ciliate, occasionally ciliate and glandular, rarely completely glandular. Leaf blade membranaceous, ovate or obovate to elliptic, (3.2-)3.4-4.7(-5.2) x (0.8-) 1.1-1.9(-2.0)cm; base acute to oblique; apex acute to obtuse, often mucronate; adaxial surface glabrous, occasionally sparsely covered with unicellular and multicellular gland-tipped hairs, or with only multicellular gland-tipped hairs, rarely densely covered with only unicellular hairs, the midvein densely covered with unicellular hairs; abaxial surface glabrous, often paler than the adaxial surface, rarely also glaucous, occasionally with scattered multicellular gland-tipped hairs, rarely with scattered multicellular gland-tipped hairs and unicellular hairs or scattered multicellular eglandular hairs, or densely covered with unicellular hairs, the midvein with multicellular eglandular or gland-tipped hairs, occasionally also with unicellular hairs, rarely with multicellular eglandular and gland-tipped hairs; margin entire, ciliate with multicellular eglandular hairs; petiole 0. l-0.4(-0.5)cm long, sparsely to densely covered with unicellular hairs and multicellular eglandular hairs, or with unicellular hairs and multicellular gland-tipped hairs, or with only multicellular eglandular and gland-tipped hairs, rarely with all three types of hairs. Flower bud scales chestnut brown; abaxial surface sparsely to densely covered with unicellular hairs, frequently glabrous; margin unicellular-ciliate, rarely unicellular above and glandular below. Flowers appearing before or with the leaves; inflorescence a shortened raceme of 4 to 13 flowers. Pedicels (0.4-)0.7-1.4(-2.0)cm long, sparsely to densely covered with unicellular hairs and multicellular gland-tipped hairs, or only with multicellular gland-tipped hairs, rarely with multicellular eglandular and gland-tipped hairs or with unicellular and multicellular eglandular hairs. Sepals less than 0.1-0.3(-1.0)cm long, often varying in length on die same flower; margins glandular-fimbriate, occasionally setose or with both gland-tipped and eglandular multicellular hairs; abaxial surface sparsely to densely covered with unicellular and multicellular gland-tipped hairs or with only multicellular gland-tipped hairs, occasionally with unicellular and multicellular eglandular hairs, rarely with all three types of hairs or glabrous. Corolla white, or white and tinged with pink or lilac, occasionally yellowish, fragrance sweet, musky and heavy, the tube longer than the limb and gradually expanding into It; upper corolla lobe (0.8-)1.0-L8(-2.2) x (0.6-)0.7-1.2(-1.6)cm; lateral lobes (L0-)1.2-2.0(-2.4) x (0.4-)0.5-0.9(-1.3)cm; corolla tube (1.6-)1.9-2.6(-3.1)cm long, (0.1-)0.2-0.4(-0.5)cm wide at base; outer surface of corolla densely covered with unicellular and multicellular gland-tipped hairs, the gland-tipped hairs continuing in distinct Enes up the corolla lobes, occasionally lacking unicellular hairs; inner surface of corolla sparsely to densely covered with unicellular hairs or glabrous. Stamens (3.2-)4.1-5.4(-6.3)cm long, with dense terete or flattened unicellular hairs on proximal (1.8-)2.4-3.3(-3.8)cm of filament, exserted (3.0-)4.2-5.1(-6.3)cm long, exserted (1.7-)2.4-3.8(-4.3)cm beyond throat of corolla, with dense unicellular hairs on proximal (0.3-)0.6-1.7(-2.6)cm; stigma 0.1-0.2(-0.3)cm wide. Ovary 0.2-0.4(-0.6)cm long, 0. l-0.2(-0.3)cm wide at the base, sparsely to densely covered with multicellular gland-tipped hairs and unicellular hairs, occasionally with multicellular eglandular hairs and unicellular hairs, or eglandular, gland-tipped hairs, unicellular hairs, rarely with only multicellular gland-tipped hairs. Capsules (1.0-)1.2-1.8(-2.4) x 0.4-0.6(-0.8)cm, ovate to narrowly ovate, sparsely covered with unicellular hairs and moderately to densely covered with multicellular gland-tipped hairs, often glaucous. Seeds pale to dark chestnut brown, ovate or elliptic to fusiform, (L2-)1.9-3.4(-3.5)x(0.6-1.0) expanded and dorsiventrally flattened surrounding the body, the cells elongate over the body of the seed, becoming shorter in the expanded portion of the testa, with transverse end-walls (Fig. 9).
Habitat: Sandy pinelands, swamps, shrub bogs, or along streams. Femald (1942) cites this species as 'thoroughly distinctive'of the Coastal Plain.
Distribution: Delaware to south-eastern Georgia along the Atlantic Coastal Plain
Altitude: 0-150m
Illustrations:
Chromosome number: 2n = 26 (Janakl-Ammal et al., 1950; Li, 1957)
Flowering primarily in April and May; however, this species may flower as early as March and Intermittently flower as late as November In the southern part of its range.
The relationship of Rhododendron atlanticum to the other white-flowered unblotched species, R. viscosum and R. arborescens, is not resolvable at present (see Phylogenetic Analysis). It Is distinct from both of these species by its flowering before or as the leaves expand. While!?, atlanticum Is isolated geographically from R. arborescens, it Is entirely sympatric with R. viscosum and is very similar to it morphologically. Rhododendron atlanticum Is quite variable In pubescence, flower colour and leaf size. Generally, however, It is more glabrous than R. viscosum, and has smaller leaves, which usually differ In length-to-width ratio from those of R. viscosum. In Virginia the leaves of R. atlanticum tend to be larger than the leaves of individuals throughout the rest of the species9 geographic range. Flower colour in R. atlanticum varies from white to pink (Weatherby & Griscom, 1934; personal observation) to white with a yellowish tinge (Femald, 1941). These forms have been formally recognized by Femald (1941) and by Ashe (1921) and Coker (1920), but in this treatment are not recognized because variation in corolla colour shows no correlation with other morphological characters or geographical distribution. Usually R. atlanticum is a low-growing, strongly rhizomatous species that has less well-developed branching than R. viscosum (which often can also be rhizomatous). However, sterile specimens of rhizomatous R. atlanticum and of glabrous, rhizomatous forms of R. viscosum can be nearly indistinguishable because of the natural variation within populations of R. atlanticum and R. viscosum.
Synonymy: Azalea atlantica Ashe, Bull.Charles.Mus.l3:26(1917).TyPe:SouthCaroUna, Georgetown Co ï moist pine woods, Kinlock, 1 v 1916, W. W. Ashe s.n. (lecto., designated here, GH). Azalea atlantica Ashe var. luteo-alba Coker, J. Elisha Mitchell Sci. Soc. 36: 98, pi. 1 (1920). Rhododendron atlanticum (Ashe) Rehder var. luteo-album (Coker) Rehder, Monogr. Azaleas 150 (1921). R. atlanticum (Ashe) Rehder f. luteo-album (Coker) Fern. Rhodora 43: 622. (1941).Type: South Carolina, Darlington Co.: flatwoods, Hartsville, 4 iv 1918, /. L. Coker, Jr s.n. (lecto., designated here, NCU). Azalea neglecta Ashe, Bull. Torrey Bot. Club 47: 581 (1920). Rhododendron neglectum (Ashe) Ashe, Rhodora 23: 179 (1921). R. atlanticum (Ashe) Rehder f. neglectum (Ashe) Rehder, Monogr. Azaleas, 149-150 (1921). Type: South Carolina, Darlington Co.: moist pine woods, Kinlock, Georgetown, 1 v 1916, W. W. Ashe s.n. (holo. GH). Rhododendron atlanticum (Ashe) Rehder f. confusumVzm., Rhodora43: 622 (1941). Type: Virginia, Princess Anne Co.: dry oak thicket, Virginia Beach, 4 v 1935, Fernald & Griscom 4479 (holo. GH). Rhododendron atlanticum (Ashe) Rehder f. tom6>/o&wmFern.,Rhodora43:622 (1941). Type: Virginia, Nansemond Co.: a considerable colony, 6-9dm high, in dry white sand of pineland, south west of Marsh Hill School, south of South Quay, 10 v 1940, Fernald & Long 11881 (holo. GH; iso. GH, NY, PH).
Altitude Ranges: 0 - 1,000m Subgenus: Pentanthera Habit: Tree Fl. Colour: lilac, pink, white, yellow
Kron, K.A. (1993) A Revision of Rhododendron Section Pentanthera. Edinburgh Journal of Botany 50(3):290
Erect shrub to 3m. Twigs c.2.4mm in diameter, densely covered with sub-stellate, shortly stalked brownish scales and very short papillose hairs at the upper internodes, older parts glabrescent and minutely warty; internodes 3.5–9cm often with prominent sub-spherical lateral buds in the upper leaf axils. Leaves spirally arranged in the upper 2⁄3 of the internodes. Blade 17–38 x 12–25mm, broadly elliptic or ovate-elliptic, sometimes sub-obovate-elliptic; apex broadly tapering, sub-acuminate or obtuse to rounded, the thick apical gland prominent; margin indistinctly cartilaginous and distinctly crenulate, flat; base rounded or slightly cordate, fully mature leaves with the remains of the scales persisting, a little rough, finally glabrescent above, sub-densely scaly beneath. Scales small, membranous, marginal zone irregularly crenate or denticulate, quickly disappearing to leave persistent large, blackish-red, impressed, circular centres. Mid-vein reddish-brown and more densely and persistently scaly than the rest of the upper surface, slightly impressed above, robust and obtusely prominent beneath; lateral veins 3–5 per side, spreading, faintly impressed above, slightly raised beneath, often inconspicuous above or rarely so on both sides. Petiole 4–5 x 1–1.5mm, flattened, densely scaly. Bracts 10–15 x 8–12mm, outer bracts ovate, bluntly pointed, the inner ones obovate, glabrous, but scaly on the margins. Inflorescence an open umbel of 2–3 flowers, half-hanging to hanging. Pedicels 10–15 x c.1mm, densely covered with dark, reddish, stellate, shortly stalked scales, but without hairs. Calyx 3–4mm in diameter, a low disc, shortly obtusely 5-lobed, densely scaly outside. Corolla 35–45 x 25–30mm, bright red when fresh, becoming dark purple in the drying process, without scent; tube 25–35 x 6–8 x 10–15mm, straight or distinctly curved, with 5 small pouches at the base, densely covered with thick sub-stellate scales outside, glabrous inside; lobes 10–15 x 10–13mm, spreading, broadly obovate or sub-circular, slightly retuse, scaly outside except towards the margins. Stamens exserted to 10–15mm, clustered on the upper side of the flower; filaments linear, 1.5mm wide at the base, glabrous; anthers 3.5–4 x c.1.5mm, broadly ellipsoid, each cell bearing a short basal apiculus. Disc prominent, glabrous. Ovary 5–6 x c.3mm, ovoid-conical, gradually tapering distally, densely sub-stellately scaly but without simple hairs; style nearly equalling the stamens in length, sub-densely to sparsely scaly in the proximal 1⁄3, glabrous distally; stigma rounded. Fruit 20–25 x 6mm, fusiform-cylindrical, shortly tapering at the base, more gradually so towards the apex, a little oblique, remaining densely scaly. Seeds 20–25mm, without tails c.10mm, the longest tail to 8mm, often with a broad tail at one end and a much more slender finely pointed one at the other.
Habitat: Common on the edge of sub-alpine forest or alpine shrubbery
Distribution: Papua New Guinea, Eastern Highlands, Mt Wilhelm; Western Highlands, Mt Kinkain.
Altitude: 3590-3840m
Latin – atro – blackish or very dark; purpureus – purple. The plant with dark blackish-purple flowers, but not apt (see below).
A hybrid with R. commonae has been recorded from Mt Wilhelm and hybrids with R. womersleyi are also found, having smaller leaves and hairs at the base of the style.
Type: Womersley NGF 8870, 1 Aug. 1956. Papua New Guinea, Mt Wilhelm, Lake Piunde vicinity, 3620m (L, BM, BRI, CANB, K, LAE, SING).
Occurs in Countries: PG Altitude Ranges: 3,000 - 4,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: purple, red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:227
Large shrub or small tree; young shoots covered with adpressed flattened brown hairs. Leaves monomorphic, persistent, elliptic, 2-8 x l-3cm, 2-2.7 x as long as broad, apex acuminate, margin entire, base broadly cuneate to + rounded; both surfaces covered with adpressed shining brown hairs, glabrescent above except on midrib, lower surface paler, persistently adpressed brown-hairy, densely so on midrib and veins; petioles 5-8mm, strigose. Inflorescence 2-4-flowered; pedicels 6mm, densely covered with adpressed flattened shining brown hairs. Calyx 2~4mm, indumentum as for pedicels, lobes short, deltoid. Corolla funnel-campanulate, glabrous, red with darker flecks at base of upper lobes, 15-30mm; tube 7-10mm, glabrous, 4mm wide at base. Stamens 10, unequal, to c.30mm, shortly pilose below middle. Ovary densely covered with adpressed flattened shining brown hairs; style glabrous. Fruit not known.
Habitat: Thickets
Distribution: China (S Sichuan, NE Yunnan)
Altitude: 750-1800m
Type: China, Yunnan, prope Tchen-fong-chan, haud procul a Takouan, Delavay (iso. E, K?)
Occurs in Countries: CN Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Tsutsusi Habit: Tree Fl. Colour: red
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):128
Shrub up to 10 m, though often less. Young growth pilose or more rarely glabrous. Leaves narrowly elliptic to elliptic, more rarely very narrowly elliptic, acute to acuminate at the apex, cuneate at the base, usually evergreen, more rarely subdeciduous to deciduous, (4G-)50-100(~110) x 18~30(-40) mm, upper surface ± elepidote, glabrous or with fine filiform-acicular hairs along the midrib and/or the main veins, lower surface lepidote with distant golden or brown scales, the midrib with an indumentum of long, ± straight hairs, at least towards the base, this indumentum extending on to the petiole or not, petiole sometimes just puberulent. Inflorescences (2-)3(-5)-flowered, pedicels 8-22 mm, sparsely lepidote, sometimes puberulent. Calyx disc-like or obscurely lobed with lobes up to 3 mm, lepidote, often puberulent and variably ciliate. Corolla openly funnel-shaped, 28-40 mm, tube 11-16 mm, purple, lavender or almost blue, rarely white, with greenish or brownish spots inside, tube lepidote or sparsely pilose outside, pubescent within. Stamens 10, filaments pubescent towards the base. Ovary lepidote, variably pilose towards the apex.
A complex species, widely distributed and divisible into four subspecies
Occurs in Countries: CN Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: blue, brown, green, lavender, purple, white
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):72
Leaves ± evergreen; corolla blue to purple with greenish or brownish spots. Petiole with filiform-acicular hairs only, or glabrous; corolla blue to lavender. Indumentum of leaf midrib beneath extending along the underside of the petiole; leaf upper surface with filiform-acicular hairs along most of the veins; corolla tube lepidote
Habitat: Rocky exposed sites and forest margins
Distribution: China (E Sichuan, Hubei, scattered)
Altitude: 1300-3000m
Illustrations:
A distinct subspecies which vicariates with the more westerly subsp. chasmanthum; intermediates between the two occur in central and western Sichuan. R. vilmorinianum, on the basis of the type specimens, is clearly synonymous with subsp. augustinii; the description of vilmorinianum given by Balfour, and material identified as such by him and subsequent authors (Hutchinson, Davidian) is, however, a different plant which is known only in cultivation and is almost certainly a garden hybrid between R. augustinii and R. yunnanense. It has petioles and leaves fringed with loriform setae, the upper surface pubescent along the main veins and midrib, and a lepidote corolla tube; the leaf scales are like augustinii, but the characteristic patch of hairs on the midrib is lacking and the corolla is white or pink.
Type: Hupeh, Patung distr., Henry 1420-1, 3736 (holo. K)
Synonymy: R. vilmorinianum Balfour f., Notes R.B.G. Edinb. 12:181 (1920) quoad typ. non descr. vel spec. cult. Type: material raised by Vilmorin, possibly from seed collected in E Szechuan by Farges (holo. E). R. augustinii var._yw/Fang, Contr. Biol. Lab. Sci. Soc. China 12:78 (1939). Type: China, Szechuan, Pao hsung hsien (Mupin), 2300- 2500 m, Yu 1976 (n.v.)
Leaves ± evergreen; corolla blue to purple with greenish or brownish spots. Petiole with filiform-acicular hairs only, or glabrous; corolla blue to lavender. Indumentum only on leaf midrib beneath, not or scarcely extending on to petiole; leaf upper surface glabrous or with filiform-acicular hairs along the midrib only; corolla tube elepidote, usually pilose outside.
Habitat: Forests, forest margins and scrub
Distribution: China (N & NW Yunnan, SW & NW Sichuan, SE Xizang)
Altitude: 2200-3650m
Illustrations:
As mentioned above, subsp. chasmanthum vicariates with subsp. augustinii. The type of R. hirsuticostatum is somewhat intermediate between the two, but closer to subsp. chasmanthum than to subsp. augustinii
Synonymy: R. chasmanthum Diels, Notes R.B.G. Edinb. 5:212 (1912). Type: China, Yunnan, Mekong/Salween Divide, NW of Tseku, 10-12000 ft, x 1904, Forrest 513 (holo. E). R. augustinii var. chasmanthum (Diels) Davidian, R.H.S. Rhodo. Yearbook 17:164 (1963). R. augustinii forma grandifolia Franchet, Journ. de Bot. 12:261 (1898). Type: China, Setchuen occidental (i.e. Yunnan), Tehrana pres de Tsekou, Soulie 1012 (holo. P—n.v., iso. E). R. augustinii forma subglabra Franchet, loc. cit. Type: China, Setchuen occidental (i.e. Yunnan), Tehrana pres de Tsekou, Soulie 1009, 1010 (iso. E). R. hirsuticostatum Handel-Mazzetti, Wien Akad. Anzeig. 27:27 (1920). Type: China, Szechuan, Schao-shan ad austro-or. urbis Ningyuen, 2200-2500 m, 15 iv 1914, Handel-Mazzetti 1353 (holo. WU—n.v., iso. E). R. chasmanthoides Balfour f. & Forrest, Notes R.B.G. Edinb. 13: 246 (1922). Type: China, Yunnan, Tseku, Soulie 1012 (holo. E)
Leaves ± deciduous; corolla white with brownish spots
Habitat: Thickets and forests
Distribution: China (NW Yunnan)
Altitude: 3350-3650m
A very handsome shrub, separated from subsp. chasmanthum by characters that are not entirely clear cut (deciduousness of leaves, corolla colour)
Synonymy: R. hardyi Davidian, Rhododendrons with Magnolias and Camellias 1974:47. Type: China, Yunnan/SE Tibet border, western range of Mekong on Kaakerpo, Doker la and Tsarung, 11500 ft, v-vi 1932, Rock 23010 (holo. E)
Leaves ± evergreen; corolla blue to purple with greenish or brownish spots. Petiole with loriform as well as filiform-acicular hairs; corolla purple.
Habitat: Scrub and thickets,
Distribution: China (NW Yunnan)
Altitude: Around 4000m
A curious plant, known only from two gatherings and material in cultivation, in some respects (presence of loriform hairs, purple corolla) similar to R. trichanthum (p. 74). It is perhaps a naturally occurring hybrid, but field observations on this point are necessary.
Synonymy: R. augustinii var. rubrum Davidian, R.H.S. Rhodo. Yearbook 17: 165 (1963). Type: China, Yunnan, Shiu-lu shan, 13000 ft, Forrest 25914 (holo. E). R. bergii Davidian, Quart. Journ. Amer. Rhodo. Soc. 30:210 (1976). Type: as for var. rubrum
Dwarf shrub, 0.2- lm; young shoots ± glabrous; perulae persistent for up to four years. Leaves ovate to broadly elliptic, 2.5-15.5 X 1.2-7cm, 2-2.5 x as long as broad, apex rounded, base cuneate to rounded, upper and lower surfaces glabrous when mature; petioles 0.5-lcm, velutinous-tomentose. Inflorescence lax. 5-8-flowered; rhachis c.lOmm; pedicels 25-35mm, sparsely dendroid-pilose. Calyx 2-3mm, lobes rounded-triangular, pilose. Corolla widely campanulate, yellow, usually with at least a few flecks, 25-30mm. Ovary rufous-tomentose; style glabrous. Capsule c. 10 x 4mm.
Habitat: Alpine slopes
Distribution: USSR (C & E Siberia, Kamchatka, Sakhalin, Kuriles), Korea, Japan (Hokkaido, Honshu), N China (Jilin)
Altitude: 1500-2700m
See also Busch, Fl. Siber. Orient. Extremi (Ericaceae), 18 (1915)
8*. R x nikomontanum (Komatsu) Nakai, Bot. Mag. (Tokyo) 31: 242 (1917)- R. aureum x R. brachycarpum. Syn: R. chrysanthum Pallas var. nikomontanum Komatsu in Matsumura, Ic. Fl. Koisikav. 3:1.195 (1917). Described from Nikko in Japan. R. brachycarpum G. Don var. lutescens Koidzumi, Bot. Mag. (Tokyo) 30: 17 (1916). Type: Japan, Mt Ontakisan. Intermediate between the two parents, with the more robust habit and leaf shape of R. brachycarpum and the yellowish flowers of R. aureum. This taxon was first recognised as a hybrid by Ohwi (Fl. Japan (English version) 698, 1965).
Occurs in Countries: CN, JP, RU Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: yellow
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):313
Leaves 2.5-6.5(—8)cm long; perulae persistent
Illustrations:
Type: USSR, ad Lacum Baical, Georgi (LE, n.v.)
Synonymy: R. chrysanthum Pallas, Reise 3: 729 (1776). Type: USSR, Montes Sajanensium ut et Dauriae, totiusque Siberiae orientalibus. R. officinale Salisbury, Parad. Lond. t.80 (1807), superfluous name under R. aureum.
Leaves 9- 15.5cm long; perulae usually deciduous
Var. hypopitys may be no more than a shade form of var. aureum but superficially the two taxa are sufficiently distinct to merit varietal rank.
Synonymy: R. hypopitys Pojarkova in Fl. URSS 18: 721, t.l, f.l (1952). Type: USSR, in parte septentrionali jugi Schote-Alinj, 1934, Soczava (LE, n.v.)
Shrub or small tree, 2-6m; young shoots setulose-glandular. Leaves oblong to oblong-oblanceolate, 15-20(-30) x 4.5-8(-10)cm, 2.5-3(-3.5) x as long as broad, apex rounded, apiculate, base auriculate, margin fringed with small glands, lower surface with scattered villous hairs, especially on the midrib and main veins, also glandular, sometimes ± glabrous at maturity; petioles densely setulose-glandular, l-3cm. Inflorescence 6-15-flowered; rhachis 20-40mm; pedicels 20-25mm, stout, stipitate-glandular. Calyx c. 2mm, sparsely stipitate-glandular, lobes minute. Flowers fragrant. Corolla 7-lobed, funnel-shaped, white or cream to rosy pink, with greenish colouring inside at base, 80- 110mm. Stamens 14. Ovary densely stipitate-glandular; style glandular to tip. Capsule 20-35 x 8-10mm, cylindrical
Distribution: China (E Sichuan, W Hubei, E Guizhou)
Illustrations:
Type: China, Hubei, Patung district, 1885, Henry 513 (holo. K)
Occurs in Countries: CN Subgenus: Hymenanthes Habit: Tree Fl. Colour: cream, green, pink, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):241
Latin – aurum – gold, alluding to the gold-mining area in which it was found to be abundant.
Type: Lam 7753, 4 Oct. 1954. Papua New Guinea, Morobe District, Lae–Bulolo road above Patop Creek (L, CANB, SING).
Occurs in Countries: PG Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Vireya Habit: Tree Fl. Colour: orange, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:299
Shrub or tree to 4m. Twigs 2–4mm in diameter, green, a little flattened and densely brown scaly; internodes 5–15cm. Leaves 4–7 in dense pseudowhorls at the upper 1–2 nodes and with 2–4 much smaller leaves associated. Blade 70–140 x 30–60mm, elliptic or broadly elliptic; apex acute, sub-acute or shortly acuminate; margin entire, slightly revolute; base tapering into the petiole, glabrescent above when mature, densely scaly beneath when young, less so in mature leaves. Scales small, brown, fragile, sessile or very shortly stalked, marginal zone irregularly and deeply stellate-incised; centre often extended into a short stalk, not or hardly impressed. Mid-vein broad at the base, narrowed and slightly impressed above, thick and prominent beneath; lateral veins 6–8 per side, rather straight below, curved and obscurely anastomosing before the edge, nearly smooth above, slightly raised beneath, reticulation inconspicuous on both sides. Petiole 7–12 x 3–5mm, grooved above, scaly. Flower buds to 34 x 6mm, broadly ovate, with the outermost bracts narrowly triangular, spreading and reflexing, as a collarette inside the foliage leaves, tips of the main bracts shortly triangular, spreading and reflexing, green, scaly. Bracts 15–20 x 4–10mm, ovate-acuminate, apex blunt or very shortly contracted into a sharp point, densely scaly on both sides at the apex, glabrous elsewhere, inner bracts obovate-elliptic to sub-spathulate, glabrous outside, all initially with scales along the margins. Bracteoles 10–15 x 1–2mm, linear-sub-spathulate. Inflorescence an 8–14-flowered complete umbel. Pedicels thick, 20–50 x 1–1.5mm, sub-densely stellately scaly, very laxly though distinctly shortly hairy. Calyx disc-shaped, wavy, c.3mm in diameter. Corolla funnel-shaped, orange or orange-yellow initially, fading to yellow, 60–80mm, laxly stellately scaly outside, laxly hairy in the lower ½ of the tube inside; tube 30–40 x 4–5 x 10–15mm, straight, markedly 5-angled; lobes 20–30 x 18–25mm, obovate, spreading. Stamens sub-equal, exserted to 15mm; filaments linear, sub-densely hairy in the proximal 1⁄3, glabrous distally; anthers 3.5–4 x c.1.3mm, broadly oblong, base obtuse. Disc very prominent, white-hairy at the upper margin. Ovary c.10 x 2.5mm, sub-conical-cylindrical, densely and shortly hairy and scaly, tapering distally; style densely hairy and scaly for the proximal ¾, densely and exclusively scaly for the subsequent c.2mm, glabrous for the upper c.10mm; stigma thick-globose and deeply 5-lobed. Fruit elongate-cylindrical, shortly tapering at the base, more gradually so at the apex, hairy and scaly, often curved, 60–100 x 5–6mm, the valves becoming twisted. Seeds 7–12mm including the tails.
Habitat: Occasionally in floating immature peat swamps in forest clearings, generally in dry grassy or shrubby hillsides together with Grevillea papuana Diels. or on schistes or steep rock. Locally common.
Distribution: Papua New Guinea, Morobe District, Mt Misim, Wagau, Mapos and in the Wau–Bulolo area.
Altitude: 915-1740m
The flower buds are very distinctive in this species, with short reflexed tips which are scaly both inside and out.
Differing from the type subspecies by having both white hairs and scales on the outside of the corolla tube.
Habitat: It was growing at c.1520m in grassland above lower montane forest and appears to be well established as two collections were made 12 years apart from similar localities.
Altitude: Around 1520m
Latin – hirsutus – covered with long stiff hairs, alluding to the hairs on the outside of the corolla.
The flowers are described as yellow in one collection but with a yellow tube and salmon pink lobes in the other. Remaining colour in one of the herbarium sheets clearly indicates a yellow tube and pink or orange lobes.
Type: Woods & Black 1121, 12 May 1968. Papua New Guinea, Morobe District, above Garaina, Saureli Bubu to Arabuka (E, A, L, LAE, SYD).
Very similar to R. xanthostephanum, differing as follows: often taller, bark not as conspicuous, leaves narrowly elliptic to elliptic, undersurface brown with unequal, ± contiguous or overlapping scales, the smaller sunk in pits but reaching the leaf surface; calyx lobes reflexed; corolla pale yellow or cream, sometimes with a faint pink flush.
Habitat: Sheltered cliffs
Distribution: China (SE Xizang—Tsangpo gorge)
Altitude: 2150-2600m
Very similar to R. xanthostephanum but consistently distinguishable by the reflexed calyx lobes and the less deeply sunk scales.
Type: China, S Tibet, Tsangpo gorge near Pemakochung, 8000 ft, 18 vi 1924, Kingdon Ward 6278 (holo. E)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: cream, pink, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):128
Shrub or small tree to 5m tall, usually non-rhizomatous; young twigs red-brown, densely covered with unicellular hairs and multicellular gland-tipped hairs. Vegetative bud scales densely covered with unicellular hairs abaxially; margin glandular. Leaf blade membranaceous, ovate or obovate to elliptic, (4.7-)5.4-8.8(-10.0) x (2.1-)2.2-3.2(-3.9)cm; base acute to oblique; apex acute to obtuse, often mucronate; adaxial surface densely covered with unicellular hairs, or widi unicellular hairs and multicellular gland-tipped hairs, the midvein densely covered with unicellular hairs; abaxial surface densely covered with unicellular hairs, the midvein densely covered with unicellular hairs and multicellular gland-tipped hairs; margin entire, ciliate with multicellular eglandular and gland-tipped hairs; petiole 0.2-0.5cm long, densely covered with unicellular hairs and multicellular gland-tipped hairs. Flower bud scales chestnut brown; abaxial surface densely covered with unicellular hairs; margin glandular. Flowers appearing before or with the leaves; inflorescence a shortened raceme of 10 to 24 flowers. Pedicels (0.5-)0.6-l.l(-1.7)cm long, densely covered with unicellular hairs and multicellular gland-tipped hairs. Sepals less than 0.1-0.2cm long, often varying in length on the same flower; margins glandular-fimbriate; abaxial surface densely covered with unicellular hairs and multicellular gland-tipped hairs. Corolla yellow, apricot or orange to red-orange, fragrance musky-sweet, the tube longer than the limb and gradually expanding into it; upper corolla lobe 0.9-1.4(-l.8) x 0.6-1.2(-1.4)cm; lateral lobes (l.l-)1.2-1.7(-2.0)x0.5-0.9(-l.l)cm; corolla tube 1.8-2.3(-2.4)cm long, 0.2-0.4(-0.5)cm wide at base; outer surface of corolla sparsely to densely covered with unicellular hairs and multicellular gland-tipped hairs; inner surface of corolla sparsely to densely covered with unicellular hairs. Stamens (5.2-)5.4-6.8(-7.7)cm long, with dense terete or flattened unicellular hairs on proximal (2.5-)2.8-3.6(-3.7)cm of filament, exserted (3.3-)3.5-4.8(-5.7)cm beyond throat of corolla. Style (5.4-)5.5-6.8(-7.5)cm long, exserted (3.2-)3.6-4.9(-5.5)cm beyond throat of corolla, with dense unicellular hairs on proximal (0.3-)0.5-1.7(-2.2)cm; stigma 0.1-0.2(-0.3)cm wide. Ovary 0.3-0.5(-0.6)cm long, 0.1-0.2cm wide at the base, densely covered with multicellular gland-tipped hairs and unicellular hairs, or also with multicellular eglandular hairs. Capsules (1.4-) 1.6-2.3 (-2.5) x (0.3-)0.4-0.5cm, narrowly ovate, moderately to densely covered with unicellular hairs and sparsely to moderately densely covered with multicellular gland-tipped hairs. Seeds pale to dark chestnut brown, ovate or elliptic to fusiform, (l.l-)1.7-2.8(-2.9) x 0.7-0.9(-1.0)mm, body 1.0ó1.5(ó1.7) x (0.2-)0.3-0.5(-0.6)mm; testa expanded and dorsiventrally flattened, surrounding the body, the cells short throughout, with transverse end-walls
Habitat: Upland mixed mesic hardwoods, bluffs of rivers or stream banks, river bottoms, swamps
Distribution: USA: Florida pan-handle and adjacent Georgia, Alabama and Mississippi
Altitude: 0-100m
Illustrations:
Rehder (1947) described a new form of R. roseum (= R. prinophyllum) from Stewartstown, Pennsylvania, but the type specimen is indistinguishable from R. austrinum. Rehder states that the plant grew in the woods near Gable's home in Stewartstown, although it is most likely an escape from cultivation.
Rhododendron austrinum is most closely related to R. luteum and R. occidentale. It is quite variable in flower colour, ranging from yellow to orange with a dark pink to red tube. Morphologically, it resembles R. canescens but can be distinguished from it by the consistently glandular nature of the bud-scale margins, pedicels, petioles and leaf margins. It is interesting to note that while the bud-scale margins of R. canescens can be mixed glandular and unicellular-ciliate in some populations, this character state is restricted to populations in central Georgia where R. austrinum does not occur. In areas where R. canescens is sympatric with R. austrinum the bud-scale margins of the former are consistently eglandular, as are the pedicels, petioles and leaf margins. These two species are usually isolated ecologically: R. canescens usually occurs in stream bottoms or low areas, and R. austrinum in upland woods. Hybrids do occur, however, and these usually appear intermediate in flower colour, but retain the eglandular nature of R. canescens. Specimens from Jackson Co., Mississippi are apparently R. austrinum, but those from neighbouring George Co. are entirely like R. canescens except for the orange-red flower colour noted on the label. Whether these specimens represent natural hybrids or whether they are cultivated hybrids is not possible to determine without further information.
Flowering from March to April; occasionally as late as May.
Chromosome number: 2n = 26 (Janaki-Ammal et al., 1950; Li, 1957)
Synonymy: Azalea austrina Small, FL S.E. US ed. 2. 1356, 1375 (1913). Type: Wooded hillsides, Chattahoochee, Florida, iv and x, Curtiss 1718* (holo. NY). Rhododendron roseum (Loisel.) Rehder f. lutescens Rehder, Contr. Gray Herb. 165:9 (1947). Type: Pennsylvania: J. P. Gable, Stewartstown, Rehder s.n. (holo. A).
Occurs in Countries: US Altitude Ranges: 0 - 1,000m Subgenus: Pentanthera Habit: Tree Fl. Colour: apricot, orange, red
Kron, K.A. (1993) A Revision of Rhododendron Section Pentanthera. Edinburgh Journal of Botany 50(3):293
Shrub or tree to 9m. Twigs smooth, green, sparsely scaly when young. Leaves 4–6 in tight pseudowhorls between which are scattered scale leaves that soon fall off. Blade 35–80 x 15–35mm, elliptic to broadly elliptic; apex rounded or retuse; margin entire, strongly recurved even in the fresh state in fully mature leaves; base rounded or broadly tapering; sparsely scaly, quickly becoming glabrescent above and often beneath as well, smooth. Scales variable in size, slightly impressed, sub-circular to lobed, mostly with small centres and relatively broad flanges. Mid-vein impressed above and strongly raised below throughout its length; lateral veins 4–6 per side, widely spreading, very slightly raised beneath, almost smooth and fairly obscure above. Petiole 1–2 x 2.5–3mm, sparsely scaly, weakly grooved above. Flower buds to 20 x 13mm, pale green, ovoid, the scales thick and fleshy, the broadly tapering points reflexed well away from the surface of the bud. Outer bracts fringed with minute brown scales along their edges and evenly covered with very fine, minute, patent white hairs on the outer side and also on the inner, near the apex. Bracteoles 11–14 x c.1mm, linear, hairy outside. Inflorescence 3–6-flowered, (8 in cultivation), the flowers displayed horizontally to half-hanging in an open umbel. Pedicels 23–32 x c.2mm, densely hairy and with a few scales. Calyx 3mm in diameter, a low hairy ring or with broad, well-marked lobes. Corolla 30–35 x 33–40mm, pink, not scented; tube 17–22 x 8–10 x 12–15mm, scaly outside, hairy near the base inside; lobes c.18 x 16–20mm, slightly emarginate, spreading almost to right angles, overlapping to c.2⁄3, finely scaly outside. Stamens arranged regularly all round the flower, distinctly dimorphic to about ½ the length of the anthers; filaments 15mm, pink, with spreading hairs in the proximal 1⁄3; anthers 3mm, pale brown. Ovary 3.5 x 2.5mm, densely hairy with spreading hairs and a sparse covering of silvery scales; style 6–13mm, hairy in the proximal 1⁄3; stigma 2mm in diameter, glossy red, central in position. Fruit to 14 x 7mm, softly hairy. Seeds 2.4mm, without tails 1.2mm, the longest tail 0.8mm.
Habitat: Low ridge forest or more open shrub-covered ridges.
Distribution: Malaysia (Borneo), Sabah, Mt Tambuyukon endemic
Altitude: 2000-2500m
Named in honour of Andrew Bacon, a keen Sabah naturalist, who participated in the ascent of Mt Tambuyukon on which the first flowering material of this species was collected.
Type: Argent & Walpole 1459, 12 March 1980. Malaysia, Sabah, Kinabalu N.P., G. Tambuyukon (E, SAN).
Occurs in Countries: MY Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Tree Fl. Colour: pink
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:267
Shrub to 2m. Twigs 3–6mm in diameter, rounded, densely sub-stellately scaly at first, becoming glabrescent; internodes 3–10cm. Leaves 5–10 in tight pseudowhorls, sub-sessile or shortly petioled. Blade 120–250 x 30–85mm, elliptic to ovate-elliptic; apex sub-caudate-acuminate or acute; margin flat; base obtusely or broadly acutely tapering, rarely rounded, often unequal, glabrescent above at maturity; laxly scaly beneath. Scales small, flat, marginal zone irregularly lobed; centre small, weakly or not impressed, finally glabrescent beneath and then with dark spots. Mid-vein narrow and impressed above, broader and bluntly prominent beneath; lateral veins 8–12 per side, ascending, curved-anastomosing before the margin, the major veins distinctly grooved above, prominent beneath, reticulation finely raised on both sides. Petiole 3–4 x 2–3mm, semi-rounded, grooved above, scaly. Bracts to 25 x 10mm; outer bracts ovate to obovate, cuspidate or shortly acutely acuminate, laxly scaly outside and on the margins, shortly appressed hairy in the middle or towards the apex; inner bracts sub-spathulate, acuminate, laxly scaly outside, but not hairy. Bracteoles to 20mm, filiform to linear-sub-spathulate, sub-glabrous. Inflorescence 4–15-flowered, in a complete umbel. Pedicels 25–55 x c.1.5mm, laxly scaly especially at base and apex, without hairs. Calyx c.4mm in diameter, sub-oblique, rim-like. Corolla 75–100mm, funnel-shaped, yellow with orange or pink lobes; tube 50–60 x 6–8 x 20–25mm, pouched at the base, laxly scaly outside, shortly hairy inside; lobes 30–40 x 25–30mm, spreading, broadly obovate to sub-circular. Stamens sub-equal, exserted to c.15mm; filaments linear, shortly patently hairy in the proximal ½, glabrous distally; anthers c.4 x 1.2mm, oblong. Disc hairy on the upper margin, glabrous below. Ovary 10–12 x 2–2.5mm, sub-cylindrical, shortly and densely covered with distally pointing hairs and with scales, tapering gradually distally; style equalling the stamens when receptive, densely covered with sub-patent hairs and with scales to near the top; stigma thick, 5-lobed. Fruit 150–200 x 4–5mm, elongate-fusiform, often curved, laxly hairy and scaly.
Habitat: Terrestrial along rivulets or in rocky places
Distribution: Papua New Guinea, East Sepik Province, Torricelli Mts; Maboro Range; West Sepik Province, Telefomin; Waria R. region; Bundi to Simbu road; Mendi S District, Kawkawsaw Humu; Southern Highlands Province, Kagua District, Lamame, Vulkara Range; Milne Bay District, Mt Suckling.
Altitude: 215-1600m
Named after Carl G. Baenitz, German botanist and teacher.
Reported as being visited by a large butterfly by Tom Reeve in 1978. There is a letter in the Sydney Herbarium from T.L. Fenner, of the Department of Primary Industry, with the specimen, confirming the butterfly as Papilio euchenor.
Type: Schlechter 14357, April 1892. New Guinea (E), Torricelli Mts (B†, BO, BRSL, K).
Occurs in Countries: PG Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: orange, pink, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:320
Shrub to 1m. Twigs 1–1.5mm, slender, rounded, tips laxly scaly and sometimes shortly patently hairy; internodes 1–5cm. Leaves 6–15 together in loose pseudowhorls. Blade 15–27 x 5–12mm, spathulate-elliptic to obovate; apex broadly acute to obtuse or broadly acute; margin flat or slightly revolute when dry, minutely crenulate; base long-tapering; glabrous and shiny above; laxly to sub-densely and persistently scaly beneath. Scales with the marginal zone irregularly lobed; centre small, impressed. Mid-vein narrowly impressed above, flat or slightly raised in the proximal ½ beneath; lateral veins obscure. Petiole 0.5–2.5 x 1mm, weakly to distinctly grooved above, laxly scaly. Flower buds to 16 x 6mm, ovoid with an acute, subulate point, glossy green flushed with red. Bracts to 14 x 3mm, narrowly ovate-acuminate or elliptic, shortly subulate, membranous, glabrous. Bracteoles c.5mm, linear-spathulate. Flowers solitary, occasionally paired, stiffly held, horizontal to half-hanging. Pedicels 4–6 x c.2mm, densely, shortly, patently hairy and scaly. Calyx c.2.5mm in diameter, disc-shaped, obscurely obtusely 5-lobed, sparsely scaly and hairy. Corolla 12–16 x 8–9mm, tubular, red or orange; tube 7–15 x 4–6 x 4–5mm, straight, laxly scaly outside, laxly hairy in the proximal ½ inside; lobes 3–4 x 3–4mm, sub-erect, ovate to sub-circular. Stamens slightly dimorphic, as long as the corolla tube, arranged regularly in the mouth of the corolla; filaments flat, linear, laxly patently hairy in the proximal ½; anthers 1mm, obovoid. Disc low, glabrous. Ovary 4–5 x c.2.5mm, sub-ovoid-cylindrical, densely hairy and scaly (the scales covered by the hairs), abruptly contracted distally; style c.4mm, columnar, glabrous, central or lying on the lower side of the mouth. Fruit 20–25 x 3.5–4.5mm, fusiform, with a short sub-persistent style, laxly hairy and scaly. Seeds narrow-fusiform, c.3mm including the long tails.
Habitat: Mostly epiphytic in primary montane forest on mountain ridges, also in heath-forest, and colonising roadsides and landslips, locally common.
Distribution: Philippines, Mindanao, Mt Apo, Camiguin Is., Mt Hibok-hibok; Palawan, Mt Mantalingajan. Malaysia (Borneo), Sarawak, Mt Penrissen, Mt Mulu, Kelabit Highlands (4th Div.), Baru Laga Plateau (7th Div.). Sabah, Mt Kinabalu, Mt Alab, Mt Lotung. Indonesia, Sulawesi, Mt Sojol; Maluku, Mt Binaia.
Altitude: 900-2135m
Named after the ‘Bagobones’ – an ethnic group in the southern Philippines.
Type: Clemens s.n. Philippines, Mindanao, Davao, Mt Apo (UC).
Synonymy: R. cuneifolium Stapf var. subspathulatum Ridl., J. Str. Br. R. As. Soc. 1900. 33: 23. R. galioides J.J.Sm., Bull. Jard. Bot. Buit. III, 1935. 13: 445.
Occurs in Countries: ID, MY, PH Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: orange, red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:213
Shrub, 0-5-2 m. Leaves very narrowly elliptic to elliptic, rarely obovate or ovate, obtuse to rounded at the apex, cuneate to rounded at the base, (21-)30-50 X (10-)14-19(-26) mm, upper surface densely lepidote when young, the scales quickly deciduous, lower surface usually dark brown with dense, overlapping scales. Inflorescence (4-)5-8-flowered, rachis elongate, pubescent, pedicels 12-22 mm, lepidote. Calyx 5-lobed, the lobes ± deltoid, (1 ■ 5-)2-4 mm, lepidote, often fringed with loriform setae. Corolla magenta to purple, often with darker spots, 12-14.5 mm, tube 5-7(-9) mm, usually densely lepidote outside, especially on the tube. Capsule lepidote, 5-7.5 mm
Habitat: Forests, hillsides, screes or rocks
Distribution: India (Sikkim), Bhutan, China (S Xizang)
Altitude: 3050-4250m
Illustrations:
A uniform and easily recognised species. One specimen, Ludlow, Sherriff & Hicks 20659, has remarkable dendroid hairs fringing the calyx
Type: a cultivated plant supposedly derived from Bailey 5, seed collected in S Tibet (holo. E)
Synonymy: R. thyodocum Balfour f. & Cooper, Notes R.B.G. Edinb. 11:148 (1919). Type: Bhutan, Champa Pumthang, 14000 ft, 23 ix 1914, Cooper 2224 (holo. E)
Occurs in Countries: BT, CN, IN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: purple
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):151
Shrub, 0.6—2m; young shoots covered in glandular setae. Leaves obovate to elliptic, 8-12 x (2.5-)3-4cm, 2.3-3.2 x as long as broad, apex rounded, acuminate, base rounded to cordate, upper surface glabrous, lower surface with a continuous felted dark brown indumentum intermixed with glands which are prominent on midrib towards base; petioles 1—2cm, covered with stipitate glands. Inflorescence lax, 4-8-flowered; rhachis c.3mm; pedicels 20-25mm, stipitate-glandular. Calyx 3-6mm, stipitate-glandular, lobes rounded, unequal. Corolla campanulate, white to creamy yellow, usually flushed with pink, with a broad blotch and purple flecks, 30-35mm. Ovary densely stipitate-glandular; style usually glandular at base. Capsule 15-20 x 4-5mm.
Habitat: Scrub, conifer forests, etc.
Distribution: China(SE Xizang, NW Yunnan), NE Upper Burma
Altitude: 3350-4000m
Closely allied to R. selense and probably hybridising with it.
Type: China, SE Xizang, Tsarong, Salween/Kiu-chiang divide, E of Chamatong, vi 1922, Forrest 21761 (holo. E).
Occurs in Countries: CN, MM Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: cream, pink, purple, white, yellow
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):277
Shrub, l-4.5m. Leaves ovate-lanceolate to elliptic, 4.5-12 x 2-4cm, 2-2.3 x as long as broad, apex acute to acuminate, base rounded, lower surface with a dense compacted to spongy unistrate lanate ramiform tomentum, silvery white when young, sometimes turning pale pinkish-cinnamon at maturity, usually shining and with a thin surface film; petioles 1 -2cm, glabrescent. Inflorescence 6-12-flowered; rhachis less than 5mm; pedicels 10-20mm, sparsely hairy and glandular. Calyx 6-10mm, glandular, lobes elliptic, rounded, glandular-ciliate. Corolla campanulate, pale to deep pink, with purple flecks, 35-40mm. Ovary glandular; style glandular in the lower third. Capsule 10-20 x c.7mm.
Habitat: Rocky slopes, Rhododendron thickets
Distribution: China (W Yunnan, SW Sichuan)
Altitude: 3350-4550m
Illustrations:
There is no clear dividing line between var. balfourianum, with a compacted leaf indumentum, and var. aganniphoides, with a thick spongy indumentum; the two taxa are therefore not maintained as distinct. R. balfourianum resembles R. aganniphum in its foliage but the latter may be distinguished by its short calyx and glabrous ovary. The silvery leaf indumentum, sometimes turning pinkish, distinguishes the present species from the allied R. adenogynum.
Type: China, W Yunnan, eastern flank of the Tali Range, 25°40'N, 11 — 12000ft, vii 1906, Forrest 4166 (holo. E; iso. A, K)
Synonymy: R. balfourianum Diels var. aganniphoides Tagg & Forrest, Notes R.B.G. Edinb. 15: 306 (1927). Type: China, SW Sichuan, mountains around Muli, 28°12'N, 100°50'E, 12000ft, vi 1921, Forrest 20456 (holo. E)
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: pink, purple
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):341
Shrub to 1.2m, slenderly branched. Twigs c.2mm in diameter, rounded, laxly scaly; internodes 2–5cm. Leaves 5–7 together in tight pseudowhorls. Blade 20–35 x 5–10mm, narrowly obovate; apex rounded, shortly retuse; margin slightly revolute, entire or sub-crenulate; base tapering, decurrent; initially sub-densely scaly on both sides, glabrescent above, persistently scaly beneath. Scales small, marginal zone irregularly stellately divided, quickly disintegrating; centre small, red brown, impressed. Mid-vein impressed above, obtusely prominent in the proximal ½ beneath, becoming flat distally; lateral veins and reticulation obscure. Petiole 1–2 x c.1mm, flattened. Bracts to 6 x 4mm, ovate-sub-acuminate, glabrous and shining outside. Bracteoles c.8mm, filiform below, sub-spathulate distally, glabrous. Inflorescence 2–3-flowered, sometimes reduced to a solitary flower. Pedicels 12–15mm, slender, densely stellate-scaly, without hairs. Calyx c.3mm in diameter, shortly cup-shaped, mostly very oblique, densely scaly, with obtuse lobes to c.1mm. Corolla c.20mm, open campanulate, membranous, red, lobed to halfway; tube c.10 x 3–4 x c.10mm, laxly scaly outside, glabrous inside; lobes c.10 x 6–7mm, obovate-sub-spathulate. Stamens c.12mm, exserted to c.6mm, slightly unequal; filaments linear, sub-densely patently hairy proximally; anthers c.2 x 1.2mm, broadly oblong. Disc glabrous. Ovary c.4 x 2mm, ovoid-conical, abruptly contracted distally, densely scaly; style 6–8mm, slender, glabrous; stigma rounded.
Distribution: Indonesia, N Sumatra, Gajo Lands, Redelong Volcano.
Altitude: Around 1830m
Named after the collector, W.N. Bangham, an American who collected in Sumatra with his wife for the Arnold Arboretum.
Previously known only from the type collection, it was recently re-found and introduced into cultivation by Paul Smith from Mt Banda Hara in 2001. It is superficially similar to R. pubigermen but has much longer, more slender leaves as well as lacking hairs on the ovary. It has not been cultivated for long enough to know how it will perform as it only flowered for the first time in Edinburgh in 2005.
Type: Bangham 917, Dec. 1931–Feb. 1932. Sumatra, Atjeh, Redelong Volcano, c.1830m (A, K, SING).
Synonymy: R. pubigermen J.J.Sm. var. banghamiorum J.J.Sm. in Merr., Contr. Arn. Arb. 1934. 8: 123.
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:195
Large shrub or small tree, 1.5-6m; young shoots with long stiff bristles (rarely glabrous). Leaves elliptic to obovate, (9-)l 1-19 x 3.5-6.5cm,c.3 x as long as broad, apex acute to acuminate, base rounded to cuneate, upper surface ± glabrous, lower surface with scattered dendroid hairs and stipitate glands, with or without bristles on the midrib; petioles l-2cm, glabrous or with a dense covering of glandular bristles. Inflorescence dense, 10-20-flowered; rhachis c.5mm; pedicels 5-10mm, glabrous. Calyx cupular, 10-15mm, often with reddish tints, glabrous or with a few hairs at base, lobes well-developed, rounded, erose. Corolla fleshy, tubular-campanulate, crimson to blood-red, with darker nectar pouches, rarely pure white, 30-35mm. Ovary densely stipitate-glandular, also with some dendroid hairs; style glabrous. Capsule 15-20 x c.5mm, curved.
Habitat: Open slopes, amongst scrub, Abies forest, etc.
Distribution: N India (Uttar Pradesh, Sikkim, Bengal, W Arunachal Pradesh), China (S Xizang), Nepal, Bhutan.
Altitude: 2700-3700m
Illustrations:
Closely allied to R. smithii. Natural hybrids between R. barbatum and R. arboreum are recorded.
Type: Nepal, Gopain Than, Wallich 757 (holo. K)
Synonymy: R. nobile Wallich, pro parte, nomen nudum. R. lancifolium Hooker f., Rhododendrons Sikkim Himalaya t.4 (1849). Type: Sikkim, Hooker (holo. K).
Occurs in Countries: BT, CN, IN, NP Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: crimson, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):380
Shrub, 4.5m. Leaves ovate, 5.5-7 x 4-4.7 cm, 1.4-1.9 x as long as broad, apex apiculate, base cordate, lower surface covered with a thin brown velutinous tomentum composed of radiate hairs; petioles c.lcm, finely tomentose. Inflorescence c.7-flowered; rhachis c.l2mm; pedicels 7-10mm, with a thin discontinuous tomentum. Calyx c. 1mm, ± glabrous, lobes rounded. Corolla open-campanulate?, c.35mm, pale yellow with purple flecks. Ovary and style glabrous. Capsule not known.
Distribution: China (N Sichuan)
Altitude: Around 3800m
Allied to R. lacteum with which it shares yellow flowers and a radiate leaf indumentum, but with smaller leaves with cordate bases and smaller flowers with glabrous ovaries.
Type: China, N Sichuan, Barkam Xian (Ma-erh-Kang), Gong Zhang Mts, 3800m, 20 vi 1957, Li, X. 71626 (holo. PE)
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Non-Tree
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):363
Shrub or small tree, 3-10m. Leaves obovate to oblanceolate, 17-25 x 8.5-13cm, 1.8-2.4 x as long as broad, apex ± rounded, base cuneate, upper surface giabrescent, with deeply impressed veins, lower surface with a bistrate indumentum, the lower layer compacted, the upper thick, greyish at first, usually soon becoming rufous, composed of only slightly fimbriate, broadly cup-shaped hairs; petioles 2—3cm, strongly flattened and winged, giabrescent. Inflorescence 15-25-flowered; rhachis 30-60mm; pedicels 30-40mm, sparsely grey- to rufous-tomentose, eglandular. Calyx c.2mm, tomentose, lobes rounded. Corolla fleshy, 8-lobed, obliquely campanulate, pale yellow with a crimson blotch, 35-50mm. Stamens 16. Ovary densely rufous-tomentose. Capsule 20-30 X 7-10mm, straight or curved.
Habitat: Abies forests, Rhododendron thickets, open slopes
Distribution: NE Burma, China(W Yunnan)
Altitude: 3000-3700m
Closely allied to R. semnoides (q.v.). The following specimens are intermediate between R. basilicum and R. rex subsp. arizelum and are probably hybrids: Forrest 8990, 17691, 18116, 18375, 18860, 23284. These may be distinguished from R. basilicum by their only slightly flattened, scarcely winged petioles and by the strongly fimbriate cup-shaped hairs on the leaves.
Type: China, Yunnan, Shweli/Salween divide, vi 1913, Forrest 12078 (holo. E; iso. A, K)
Synonymy: R. megaphyllum Balfour f. & Forrest, Notes R.B.G. Edinb. 12: 138 (1920). Type: China, W Yunnan, Shweli/Salween divide, 11000ft, vi 1918, Forrest 17650 (holo. E). R. regale Balfour f. & Kingdon-Ward, Notes R.B.G. Edinb. 12: 156 (1920). Type: NE Upper Burma, Htawjaw, valley Naumchaung, 12000ft, 19 v 1914, Kingdon-Ward 1565 (holo. E). R. gratum T. L. Ming, Acta Bot. Yunnanica 3: 118 (1981). Type: China, W Yunnan, Yunlong Xiang, Chaojian, Zibeng Shan, 3200m, 21 iv 1980, C. H. Yang 80-0008 (holo. Herb. Inst. Bot. Kunming; iso. E).
Occurs in Countries: CN, MM Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: crimson, yellow
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):253
Dwarf shrub, 0.6-1.5m. Leaves elliptic to oblong, 4-7 x 1.5-2cm, 2.7-3.5 x as long as broad, apex ± cucullate, base rounded, lower surface with a dense bistrate indumentum, the upper layer dark rufous-brown, loosely and finely ramiform-tomentose, the lower layer compacted; petioles 0.5 -1.5cm, densely brown-tomentose. Inflorescence 10-15-flowered; rhachis c.5mm; pedicels 10-15mm, glabrescent. Calyx c.0.5mm, glabrous. Corolla campanulate, white flushed rose, with crimson flecks, 30-35mm. Ovary densely rufous-tomentose; style glabrous. Capsule c. 10 x 5mm.
Habitat: Bouldery slopes, thickets, margins of pine forests, etc.
Distribution: China (SE Xizang, NW Yunnan)
Altitude: 3350-4250m
R. bathyphyllum has close affinities with R. roxieanum var. cucullatum and R. alutaceum var. russotinctum but differs from both in its densely tomentose, eglandular ovary, etc.
Type: China, SE Xizang, on Ka-gwr-pw, Mekong/Salween divide, 28°30'N, 13000ft, viii 1917, Forrest 14718 (holo. E)
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: crimson, rose, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):348
Straggling shrub, up to 3m; young shoots stellate-setose and stipitate-glandular. Leaves obovate to elliptic, 6-9 x 3.2-4.4cm, 2-2.4 x as long as broad, apex rounded, apiculate, base + rounded, upper surface rugulose, glabrous, lower surface with a dense unistrate fulvous dendroid-tomentose indumentum; petioles 1.5-2cm, setulose to tomentose. Inflorescence 6—10-flowered; rhachis c.5mm; pedicels 10- 15mm, setulose-tomentose. Calyx c.5mm, cupular, sparsely tomentose. Corolla fleshy, tubular-campanulate, carmine to blood-red, c.35mm. Ovary stellate-tomentose. Capsule at least 12 X 6mm, persistently tomentose.
Habitat: Bamboo forests, rocky gullies
Distribution: NE Upper Burma, ne India (Arunachal Pradesh)
Altitude: 3000-3350m
Illustrations:
Closely allied to R. piercei (q.v.)
Type: China, Xizang, Seingku Wang, 10000ft, 1 vi 1926, Kingdon-Ward6805 (holo. BM; iso. K)
Occurs in Countries: IN, MM Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: carmine
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):386
Apparently small shrub. Twigs 4–8mm in diameter, rounded, with lax sub-stellate, appressed scales when young, becoming glabrescent, smooth, and pale; internodes 5–17cm. Leaves 5–8 together in pseudowhorls, sub-sessile. Blade 100–160 x 40–60mm, elliptic to ovate-elliptic, apex gradually long-acuminate (2–3cm), acute, or nearly so; margin slightly revolute; base broadly tapering, extreme base sub-truncate, glabrescent at maturity, but remaining blackish punctate above; laxly and more persistently scaly beneath but eventually glabrescent and punctate beneath too. Scales small, marginal zone irregularly sub-stellately lobed; centre minutely impressed. Mid-vein 2–4mm wide, obtusely prominent on both sides proximally; lateral veins 10–12 per side, obliquely ascending, faintly interarching before the margin, little raised on both sides, sometimes hardly visible, reticulation obscure. Petiole 0–2 x 2–4mm, flattened. Flower buds 30–35 x 10–15mm, ovoid-acuminate. Bracts to 30 x 10mm; outer bracts ovate, acuminate, inner ones oblong-ovate, all sub-acute, glabrous outside, margin initially scaly. Bracteoles to 25 x 0.5mm, filiform, glabrous. Inflorescence 4–6-flowered. Pedicels 20–30mm, laxly scaly. Calyx c.4mm in diameter, oblique, disc-shaped, obscurely lobed, sub-glabrous. Corolla 50–65mm, funnel-shaped, red or orange; tube 30–35 x 5–6 x 15–20mm, lobed at the base, sub-cylindrical near the base, gradually widened distally, glabrous outside, densely shortly white-hairy in the proximal ½ inside; lobes 20–30 x 15–20mm, obovate spathulate. Stamens unequal, the longest nearly as long as the corolla; filaments linear and densely sub-patently white-hairy proximally, filiform and glabrous distally; anthers c.4 x 1mm, oblong, base obtuse. Disc prominent, glabrous. Ovary c.10 x 2.5mm, sub-cylindrical, glabrous or very laxly scaly, tapering distally; style nearly as long as the corolla tube, glabrous; stigma rounded. Fruit 40–60 x 6–7mm, sub-fusiform, red, slightly curved, glabrous.
Distribution: Indonesia, Sumatra, West Coast: Mt Singgalang, Mt Sago. Epiphytic in montane mossy forests.
Altitude: 1400-2450m
Named after the famous Italian collector and early explorer Odoardo Beccari.
Apparently rare, not recently recollected and never cultivated. The status of this species is still very uncertain. The differences between this species and R. sessilifolium remain matters of degree. The orange or red flower colour suggests that this might be a hybrid between R. sessilifolium and perhaps R. rarilepidotum.
Type: Beccari P.S. 218, Giugno-Luglio 1878. Sumatra, West Coast, Mt Singalang, c.1700m (FI, BM, K, L, MEL).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: orange, red, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:253
Shrub or tree, 1.8—9m. Leaves oblanceolate to elliptic, 9-19 x 2.6-8.2cm, 3—5.3 x as long as broad, apex apicuiate, base attenuate to rounded, lower surface with a thin unistrate compacted fawn to brown indumentum composed of radiate hairs; petioles 1.5-2cm, sometimes winged, glabrous or floccose. Inflorescence 10-25-flowered; rhachis c.25mm; pedicels 15-25mm, sparsely hairy. Calyx 0.5- 1mm, glabrous, lobes rounded. Corolla broadly campanulate, white flushed rose to pink, with or without purple flecks and a basal blotch, 35-45(-55)mm. Ovary densely white- to brown-tomentose; style glabrous. Capsule 20-45 x 6-9mm, curved.
Distribution: China (SE Xizang, NW Yunnan, SW Sichuan), NE Upper Burma.
Illustrations:
In general form R. beesianum resembles R. uvarifolium (subsection Fulva) but its leaf indumentum suggests a closer affinity with R. nakotiltum and R. dignabile.
Type: China, Yunnan, E Flank of the Lichiang Range, 11 —12000ft, v 1906, Forrest 2323 (holo. E; iso. K)
Synonymy: R. colletum Balfour f. & Forrest, Notes R.B.G. Edinb. 11: 39 (1919). Type: China, W NW Yunnan, Mekong/Salween divide, 11000ft, vii 1917, Forrest 14450 (holo. E; iso. K). R. emaculatum Balfour f. & Forrest, ibid. 13: 42 (1920). Type: China, SE Xizang, Tsarong, Dokar-la, Mekong/Salween divide, vii 1917, Forrest 14352 (holo. E; iso. K).
Occurs in Countries: CN, MM Subgenus: Hymenanthes Habit: Tree Fl. Colour: pink, purple, rose, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):365
Slender, loosely branched, erect shrub or small tree to 5m. Twigs 1.5–4mm in diameter, thick to slender, densely to very densely covered with deep brown stellate scales which easily fall off and are absent from the older parts which are brown and rough with the numerous fine persistent tubercles; internodes 1.5–10cm. Leaves 3–7 together in pseudowhorls, often variable in shape and size in the same whorl. Blade 30–60 x 10–35mm, narrowly ovate, to broadly elliptic, obovate or sub-circular; apex obtuse, broadly acute, sometimes apiculate; margin strongly revolute to almost flat and more densely and often more persistently scaly than the rest of the leaf beneath; base broadly tapering or rounded; very densely reddish-brown scaly on both sides at first, quickly glabrescent especially above where it can become shiny but rough, more persistently scaly below. Scales irregularly stellately divided to the centre, dendroid, very fragile, each from the top of a minute, persistent, epidermal tubercle. Mid-vein slightly impressed above, strong and prominent beneath; lateral veins 4–7 per side, straight below, curved and anastomosing before the margin, very slightly impressed above and raised beneath, often inconspicuous or completely covered by the scales beneath, reticulation dense, visibly prominent on both sides in fully mature leaves, occasionally slightly impressed above. Petiole 4–15 x c.2mm, weakly grooved in the distal ½, or the groove inconspicuous, densely covered with brown stellate scales. Flower buds c.12 x 8mm, densely brown scaly with erect to slightly spreading bract points. Bracts to 10 x 7mm; the outer ones ovate subulate, densely scaly outside and fringed with marginal scales; the inner ones ovate acuminate and apiculate. Bracteoles to 10mm, linear and glabrous or scaly at first proximally, sub-spathulate and laxly hairy distally. Inflorescence a 1–5-flowered open umbel. Flowers horizontal to half-hanging. Pedicels 10–15 x 7–10mm, densely brown-stellate scaly, becoming glabrescent. Calyx 3–4mm in diameter, disc-shaped or cup-shaped, densely stellate scaly or shallowly and obtusely 5-lobed. Corolla 20–45 x 10–18mm, most commonly dark red, at least at higher altitudes, sometimes pink or cream, rarely greenish or white; tube 15–25 x 4–7 x 6–10mm, curved or straight, at first densely covered with golden-brown stellate scales outside, completely glabrous inside; lobes 7–12 x 6–11mm, spreading perpendicularly, sub-circular, overlapping ½–2⁄3, scaly on the proximal part outside. Stamens unequal, clustered on the upper side of the mouth, slightly exserted to c.5mm; filaments linear, red, glabrous or rarely with a few hairs; anthers 2–2.5 x c.1.2mm, obovate-oblong, brown to dark red. Disc low, without simple hairs but sometimes with a few scales. Ovary 6–8 x 2.5–3mm, elongate-conical or sub-ovoid, densely stellate-scaly, usually abruptly tapering distally; style thick, as long as the stamens and exclusively stellate-scaly to the top at flowering, but becoming glabrescent distally as the fruit develops; stigma broadly obconical, slightly 5-lobed. Fruit 20–40 x 5–6mm, thick-fusiform, often a little wider in the distal ½, longitudinally grooved, densely brown scaly, usually with the persistent remains of the style. Seeds 2–4mm, without tails to 1.2mm, the longest tail c.1.5mm.
Habitat: Predominantly terrestrial but also epiphytic in mossy forest and on tree-ferns in grassland.
Distribution: Indonesia, New Guinea (W), along the Main Range from the Wissel Lakes. Papua New Guinea, main range east to Mt Victoria and Mt Dayman; also on Mt Saruwaged and Bismarck Mts.
Altitude: 1400-4000m
Named after M.W. Beyerinck, 1851–1931, a Dutch microbiologist.
A widely distributed species, both altitudinally and geographically. Sleumer (1966) conceived this species in a broad sense and acknowledged that it might ultimately be united with R. phaeochitum. For differences between this species and R. phaeochitum see under that species. Van Royen & Kores (1982) reported that it had been found on all major mountain ranges from the Nassau Mts to Mt Dayman and that ‘it is an extremely polymorphic species. Plants from different geographic locations vary considerably in stature, flower color, leaf size, leaf shape and texture. In addition the species also appears to vary throughout its altitudinal range’. Specimens of Rhododendron beyerinckianum obtained from lower altitudes tend to be larger, more robust than high altitude collections, their leaves are larger, less leathery and the indumentum is poorly to moderately well developed. Material from higher altitude tends to be more compacted than low altitude material, the leaves are smaller, more leathery, frequently somewhat revolute and the indumentum is generally very well developed’.
Type: von Römer 1199, Aug. 1876. W New Guinea, Hellwig Mts, Mt Agathodaemon (BO, L).
Synonymy: R. schultzei Schltr., Bot. Jahr. 1918. 55: 154. R. dasylepis Schltr., Bot. Jahr. 1918. 55: 153, f.4. R. saavedranum Diels, Bot. Jahr. 1929. 62: 486. R. beyerinckianum var. longipetiolatum J.J.Sm., Nova Guinea 1936. 18: 94. R. chrysopeplon Sleumer, Bot. Jahr. 1949. 74: 540.
Occurs in Countries: ID, PG Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Vireya Habit: Epiphyte, Tree Fl. Colour: cream, green, pink, red, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:75
Shrub aim, young shoots densely covered with reddish-brown strigose hairs. Leaves dimorphic, coriaceous; spring leaves obovate to obovate-elliptic 3.5-5 x 1.5cm, 2.2-2.6(-3.3) x as long as broad, apex shortly acuminate, margin revolute, base cuneate, upper surface sparsely strigose at first, becoming glabrescent, lower surface pale, adpressed reddish-brown-strigose, especially on midrib; summer leaves spathulate-ovate, 15-20 x 7-9mm, otherwise as for spring leaves; petioles short. Inflorescence 2-4-ftowered; pedicels c.5mm, densely reddish-brown-strigose. Calyx strigose, minute. Corolla funnel-campanulate, reddish purple, 18mm; tube c.5mm. Stamens 5, pubescent below, anthers with apical projections. Ovary strigose; style glabrous. Fruit cylindrical, strigose, 12-13 x 3-4mm.
Habitat: By streams
Distribution: China (Guangdong)
Close to R. naamkwanense but differing in its larger leaves, 4-flowered inflorescence, and in the form of the anthers.
Type: China, Guangdong, Conghua Xian, Rhu-Tin, in rivulo, prope vallem, 16 iii 1973, S.Q. Chen (S.H.Chun) 18489 (holo. IBSC)
Occurs in Countries: CN Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: purple, red
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):133
Shrub to 3m. Twigs 3–4mm in diameter, rounded, sub-densely scaly, longitudinally striate when dry; internodes 5–13cm. Leaves in tight pseudowhorls of 3–4, but inserted over 1–2cm. Blade 40–75 x 30–65mm, ovate to circular, rarely obovate; apex obtuse to rounded; margin cartilaginous, entire, narrowly revolute; base auriculate, the sides broadly turned down; laxly silvery scaly above, quickly becoming glabrescent; below laxly to sub-densely and more persistently scaly. Scales sub-circular to broadly sub-stellately lobed; the marginal flange broad, thin and transparent, the centres moderately small and impressed. Mid-vein raised above in the proximal 1⁄3–½, then impressed, grooved where it is raised; below raised throughout its length but decreasing distally; lateral veins 5–7 per side, wide-spreading, above slightly raised and minutely grooved, beneath very slightly raised; straight but branching and anastomosing before the margin. Petiole 2–4 x 2–4mm, sometimes grooved above distally, scaly. Bracts to 18 x 12mm, the outermost scaly outside, inner ones with scales on the margins, shortly hairy outside and minutely hairy inside. Inflorescence of 5–9 flowers in an open umbel. Flowers 60–65 x 35–40mm. Pedicels 30–35 x c.1mm, densely scaly. Calyx c.4mm in diameter, disc-shaped, densely scaly and fringed on the margin with scales. Corolla red; tube 40–62 x 5–6 x 12–27mm, sub-densely scaly outside, densely hairy with irregular or somewhat retrorse hairs inside; lobes 15–23 x 12–21mm, reflexed, overlapping to c.halfway, scaly outside except near the margins. Stamens exserted to c.12mm, clustered on the upper side of the mouth; filaments hairy in the proximal ½–2⁄3, glabrous distally; anthers c.3mm, curved. Disc densely hairy on the upper side, otherwise glabrous. Ovary c.8 x 3mm, elongate-conical, densely hairy and scaly, tapering gradually distally; style c.45 x 1mm, densely hairy and scaly for the proximal 3–5mm, then glabrous distally, purplish-red; stigma c.4mm in diameter, rounded, yellow. Fruit 28–38 x 6–7mm, fusiform, longitudinally grooved, pale brown.
Habitat: Epiphytic in mixed montane forest, secondary forest with climbing bamboo, or terrestrial at forest margins and in fire-induced grassland with Gleichenia.
Distribution: Papua New Guinea, Western Highlands between Laiagam and Kandep, c.4 miles W of Wabag; Southern Highlands, Mt Ambua, Mt Hagen, Mt Kerewa, Mt Giluwe, Ibiwara (Tari Gap).
Altitude: 2500-3300m
Named after Michael Black, an English medical doctor who collected in New Guinea and grew vireya rhododendrons at his home in Grasmere.
Type: Vink 17280, 28 July 1966. New Guinea (E), Southern Highlands District, Tari subdistrict, Mt Ambua, 3390m (LAE, L, K).
Synonymy: R. sleumeri A.Gilli, Ann. Naturh. Mus. Wien 1980. 83: 435.
Occurs in Countries: PG Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:310
Tree to c.3m. Twigs 4–9mm in diameter, sub-angular, sparsely appressed-scaly when young, becoming glabrescent and often whitish; internodes 5–20cm. Leaves 2–3 together in loose pseudowhorls with additional leaves on the internode. Blade 90–190 x 30–48mm, broadly elliptic; apex shortly and abruptly acuminate, sub-acute; margin narrowly revolute when dry; base broadly tapering, often unequal; sparsely scaly to glabrescent above, sub-persistently laxly to sub-densely scaly beneath. Scales minute, flat, the broad marginal zone irregularly sub- stellately lobed and breaking up early; centre small, hardly impressed. Mid-vein as wide as the petiole proximally, flat or shallowly impressed above, thick and obtusely prominent beneath; lateral veins 9–12 per side, high- ascending, at an acute angle, curved and anastomosing before the margin, with several intermediate smaller veins, all parallel, faintly impressed or raised above, distinctly prominent beneath, reticulation slightly raised beneath only. Petiole 10–20 x c.3mm, flattened, scaly, striate lengthwise. Bracts to 60 x 25mm, outer bracts 15–20 x 10mm, ovate, obtuse, initially hairy outside especially at the base, later glabrescent, distinctly rough to the touch, inner bracts elliptic to spathulate, very densely hairy outside. Bracteoles c.20 x 1–1.5mm, linear to sub-spathulate, densely hairy. Inflorescence c.10-flowered in a complete umbel. Pedicels 12–17 x 1.5mm, sub-densely sub-stellate-scaly. Calyx c.3mm in diameter, disc-like, short. Corolla 65–75mm, tubular below, expanded distally, white, scented; tube 45–50 x 5–6 x 6–7mm, cylindrical, straight, the base lobed, glabrous outside, densely shortly hairy inside; lobes 20–25 x 15–20mm, broadly obovate-spathulate or sub- circular. Stamens exserted to c.10mm; filaments linear and densely patently hairy in the proximal 2⁄3, glabrous and filiform distally; anthers 6–7 x 1.5mm, oblong, each cell contracted into a short basal apiculus. Disc prominent, glabrous. Ovary 9–10 x 3–4mm, sub-cylindrical, yellowish hairy (scales not visible), tapering distally; style thick, slightly exceeding the stamens, densely hairy proximally, sub-densely or laxly so and minutely scaly distally, glabrous for the terminal 6–8mm; stigma c.3mm in diameter, thick-knob-like. Fruit 35–40 x 7–8mm, thickly fusiform-cylindric, laxly shortly hairy, somewhat rugose, slightly curved.
Habitat: Summit vegetation
Distribution: Indonesia, Sulawesi, Ngilalaki, E of Lake Lindu; Latimodjong Mts.
Altitude: 2200-2335m
Named after the collector, Siebe Bloembergen, a Dutch botanist who worked in Indonesia.
Type: Bloembergen 3972, 9 July 1939. Indonesia, Celebes, Central, E of Lake Lindu, towards the top of G. Ngilalaki, 2335m (BO, A, L).
Occurs in Countries: ID Altitude Ranges: 2,000 - 3,000m Subgenus: Vireya Habit: Tree Fl. Colour: white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:288
Much-branched shrub, to 2m; young shoots covered with adpressed rufous hairs. Leaves persistent, monomorphic, oblong-lanceolate, 2-5 x l-2cm, apex subacute, mucronuiate, base cuneate, upper surface sparsely covered with adpressed straight rufous hairs, lower surface with impressed veins and densely covered with adpressed straight rufous hairs; petioles 5~-10mm, channelled above, indumentum as for leaves. Inflorescence 4-6~flowered; pedicels 4-6mm, covered with adpressed rufous hairs and subtended by the sub-persistent bud-scales. Calyx with 5 minute acute or rounded teeth covered with adpressed rufous hairs. Corolla funnel-campanulate, white, 40-50mm long and as wide. Stamens 10, papillose below middle. Ovary densely covered with adpressed strigose hairs; style pilose below middle. Capsule 10~20mm, oblong-ovoid, covered with grey-brown hairs.
Habitat: Cliffs
Distribution: Japan (Bonin Islands)
Illustrations:
This is the only Rhododendron found in the Bonin Islands. It grows on the cliffy summit of Tsutsyiyama. The foliage resembles that of R. simsii and the flowers those of R. mucronatum.
Type: Japan, Bonin Islands, T. Nakai & H. Toyoshima, n.v.
Occurs in Countries: JP Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: white
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):118
Shrub; young shoots glabrous. Leaves elliptic, 4-5 x c. 1.5cm, 2.6-3.5 x as long as broad, apex acute, base rounded, upper surface glabrous, lower surface glabrous, mammillate, eglandular, veins not raised; petioles c.0.5cm, densely and shortly stipitate-glandular. Calyx c.4mm, densely glandular, lobes rounded, irregular. Corolla probably open-campanulate and pale pink, 22-25mm. Ovary glandular; style glandular to tip. Capsule not known.
Distribution: China (C Sichuan)
Only known from the poor isotype cited above. The leaves and glandular style suggest an affinity with R. cerasinum. There is also a (less likely) possibility that R. bonvalotii is a hybrid of R. souliei (subsection Campylocarpa); further material is required before a firm decision can be made.
Type: China, Sichuan, autour de Tatsien lou, Bonvalot (iso. E).
Occurs in Countries: CN Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: pink
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):418
Usually an epiphytic shrub, rarely on rocks, up to 2 m. Young growth with a dense indumentum of twisted and matted loriform setae. Leaves narrowly ovate to ovate-oblong, acuminate at the apex, rounded at the base, very hard and leathery, 78-112 x 38-52 mm, upper surface with dense, matted loriform setae on the midrib (and rarely secondary veins), margin loriform-ciliate, lower surface with dark brown, close, ± equal scales. Inflorescence (3-)4-6(-10)-flowered, pedicels stout, up to 15 mm, covered with matted loriform setae. Calyx lobes green, ovate to oblong, (7-) 10-15 mm, lepidote and loriform-ciliate. Corolla campanulate, dull to bright yellow, sometimes spotted, 25-27 mm, tube 15-16 mm, lepidote on the lobes and tube outside, pilose within the tube. Ovary lepidote. Capsule ± ovoid, up to 15 mm
Habitat: Forests and scrub
Distribution: India (Arunachal Pradesh), China (S Xizang)
Altitude: 1800-2450m
Illustrations:
I have seen no material with more than six flowers in the inflorescence, though the illustration in the Botanical Magazine, t. 7149, shows such a plant
Type: Bhutan'(i.e. India, Arunachal Pradesh, cf. Ludlow, Trans. Bot. Soc. Edinb. 41:359, 1972), Gescherong Hills, Booth (holo. K)
Synonymy: R. mishmiense Hutchinson & Kingdon Ward, Notes R.B.G. Edinb. 16:173 (1931). Type: Assam, Mishmi hills, Delei valley, 7-8000 ft, Kingdon Ward 8046 (holo. E)
Occurs in Countries: CN, IN Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):134
Latin – borneense – from Borneo, indicating the island of origin.
Type: Endert 4256, 17 Oct. 1925. Borneo, Central East, W Kutei, Mt Kemul (BO, A, L).
Synonymy: R. quadrasianum S.Vidal var. borneense J.J.Sm., Bull. Jard. Bot. Buit. III, 1935. 13: 444.
Occurs in Countries: ID, MY Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Fl. Colour: red, white, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:44
Shrub to 2m. Twigs shortly hairy. Leaves spiral. Blade c.10 x 1–1.5mm, narrowly obovate to almost linear, densely spirally arranged especially towards the tips of the young shoots. Pedicels slender, c.5mm, hairy. Calyx both hairy and ciliate on the margins, lobes very short. Corolla c.10 x 3–4mm, tubular, slightly dilated distally, red, densely covered with round scales and sparse long white hairs. Stamens exserted; anthers 0.5mm. Ovary hairy.
Habitat: Epiphytic in sub-montane forest, or terrestrial in open peaty locations, locally abundant.
Distribution: Malaysia (Borneo), Sarawak, Mt Mulu.
Altitude: Around 1300m
Latin – angusti – narrow; issimum – the superlative. The most narrow leaved.
Flowers June
This is an extreme form of R. borneense which approaches R. ericoides in the size of its leaves.
Type: Anderson 4215, 28 June 1961. Borneo, Sarawak, Mt Mulu, path from Melinau Paku (SAR, K, L, fragment).
Shrub to 2m. Twigs rounded, shortly hairy and scaly, quickly glabrescent, older stems rough with raised leaf scars. Leaves arranged spirally but mostly only persisting at the very ends of the twigs. Blade 14–18 x 5–8mm, obovate or spathulate; apex rounded or slightly retuse; margin entire, slightly revolute; base tapering, sparsely scaly and quickly glabrescent above, sparsely but persistently scaly below and sometimes with a few short hairs near the base. Scales round, slightly impressed. Mid-vein slightly impressed above and raised below, the lateral veins weak, up to 3 per side, not raised or impressed, sometimes not visible. Petiole 2–3 x c.1mm, weakly grooved above, scaly and often shortly hairy. Flower buds to 6 x 2mm, slender, ellipsoid, with scattered scales outside and a distinct fringe of hairs around the bract margins. Bracts ovate to spathulate. Bracteoles 3.5 x c.0.5mm, narrowly spathulate, with a few hairs near the apex. Inflorescence of mostly solitary flowers, occasionally 2 or 3 together, horizontal to half-hanging. Pedicels 6–8 x c.1mm, hairy and scaly, pink. Calyx a low hairy and scaly disc. Corolla 20 x 10mm, red or yellow, without scent; tube 15 x 6 x 8mm, straight, lobed near the base, densely scaly and with white erect hairs at least in the proximal ½ outside, glabrous inside; lobes 4 x 5mm, erect, or slightly spreading, overlapping for about ½ their length, scaly outside, rarely with a few simple hairs. Stamens loosely arranged on the lower side of the mouth, exserted to c.4mm; filaments c.18mm, glabrous; anthers 7mm, brown. Ovary c.2 x 1mm, densely sub- patently hairy and with a few scales; style 13–16mm, entirely glabrous or hairy in the proximal ½, slightly swollen distally, lying on the lower side of the tube; stigma exserted to c.5mm, club-shaped, purple, 0.75mm in diameter. Fruit c.8 x 3mm. Seeds 1.6mm, without tails 0.7mm, the longest tail 0.6mm.
Habitat: Mostly epiphytic in montane forest.
Distribution: Indonesia, Kalimantan. Malaysia (Borneo), Sarawak and Sabah. Brunei. Widespread on the mountains of Borneo, said to be common on Mt Kemul, but only recorded in Sabah from Mt Lotung in the south.
Shrub to 3m. Leaves 8–13 x 2–4mm, narrowly obovate. Corolla hairy (sometimes only sparsely so), and scaly, red or yellow, c.15mm. Pedicels scaly and hairy. Ovary scaly and densely white-hairy.
Habitat: Mostly epiphytic in sub-montane mossy forest, low shrubby kerangas and amongst bare sandstone rocks
Distribution: Malaysia (Borneo), Sabah, northern in distribution, from Mt Kinabalu, along the Crocker Range, to Mt Lotung. Sarawak, Mt Murud, Mt Dulit and Mt Tanggoi. Brunei, Mt Pagon.
Altitude: 1200-1900m
Latin – villosum – with long soft hairs, presumably alluding to the hairs on the twigs, pedicels and flowers.
Flowers Jan.–Dec
Leaves consistently smaller than in ssp. borneense but larger than in ssp. angustissimum.
Type: Hallier 575, 1893–94. Borneo (W), Mt Damus, Upper Sambas River (BO, CAL, K, L, P, U).
Synonymy: R. quadrasianum S.Vidal var. villosum J.J.Sm., Bull. Jard. Bot. Buit. III, 1935. 13: 444.
Shrub to 2 m. Leaves narrowly elliptic to narrowly obovate, acute to rounded at the apex, cuneate at the base, 35-55 X 12-20(-23) mm, upper surface dark green, lower surface with scales more than 2 x their own diameter apart, the smaller scales clear or milky. Inflorescence 3-7(-10)-flowered, pedicels lepidote, 12-25(-30) mm, rachis distinct, more than 4 mm, lepidote or very rarely minutely puberulent. Calyx lobes rounded at the apex, slightly glaucous, lepidote at the base and sometimes around the margin. Corolla campanulate, pale or greenish yellow, 10-20 mm, tube 6-11 mm, elepidote or sparsely lepidote outside. Capsule ± globose or ovoid-globose, c. 8 mm.
The species varies in the density of scales on the lower leaf surface; two subspecies are distinguishable
Occurs in Countries: CN, MM Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: green, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):144
Habitat: Scrub and thickets
Distribution: China (C Yunnan)
Altitude: 3050-3350m
Illustrations:
Subsp. brachyanthum is entirely restricted to the area around Tali, and is separated from the much more widespread subsp. hypolepidotum by about 160 km.
Type: China, Yunnan, in monte Tsang chan pro-pe Tali, Delavay 159 (holo. P—n.v., iso. E)
Habitat: Dry, open situations in forest and scrub, rarely epiphytic
Distribution: NE Burma, China (NW Yunnan, SE Xizang)
Altitude: 3050-4000m
Illustrations:
Subsp. hypolepidotum is much more widespread than subsp. brachyanthum and much more variable, particularly in the density of the scales on the lower leaf surface. Some specimens have very abundant darker scales, whereas others have these very distant, though the yellow scales may be fairly close. In general, the closer the yellow scales, the more likely they are to have the milky appearance characteristic of those of R. pruniflorum.
Synonymy: R. brachyanthum var. hypolepidotum Franchet, Journ. de Bot. 12:262 (1898). Type: China, Yunnan, Tsekou, Se la, Soulie 1027 (holo. P—n.v., iso. E). R. hypolepidotum (Franchet) Balfour f. & Forrest, Notes R.B.G. Edinb. 13:266(1922). R. charitostreptum Balfour f. & Kingdon Ward, Notes R.B.G. Edinb. 13:244 (1922). Type: NE Upper Burma, Imaw Bum, 11-12000 ft, 2 vii 1919, Kingdon Ward 3302 (holo. E)
Shrub, 2-3m; young shoots tomentose, soon glabrescent. Leaves oblong to obovate,7-ll x 3-4.5cm, 2.3-2.5 (-3) x as long as broad, apex ± rounded, apiculate, base rounded, upper surface glabrous, lower surface glabrous or with a compacted greyish to fawn indumentum; petioles l-2cm, glabrous, with lamina slightly decurrent. Inflorescence lax, 10-20-flowered; rhachis 20-40mm; pedicels c.30mm, sparsely tomentose. Calyx c.2mm, tomentose, lobes glabrous. Corolla broadly funnel-campanulate, white to pale rose-pink, with greenish flecks, c.25mm. Ovary densely tomentose; style c.l5mm, glabrous. Capsule 20-30mm long.
Subsp. tigerstedii, from mainland Korea and the offshore Dagelet Island, is described as differing from subsp. brachycarpum in its larger leaves, 15-25cm long, and in its large white flowers (c. 70mm in diam.), etc. I have not seen sufficient wild-collected material of subsp. tigerstedtii to confirm the constancy of these differences, but from the description, the distinctions made appear to be relatively trivial.
Occurs in Countries: JP Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: green, rose, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):307
Leaves with a compacted grey to fawn indumentum beneath, even when mature
Distribution: Japan, E Korea
Described from Japan
See also Doleshy (1968)—ref. p. 305
Synonymy: R. brachycarpum G. Don var. roseum Koidzumi, Bot. Mag. (Tokyo) 30: 77 (1916). Type: Japan, in alpis Yeso, n.v. R. faurieiFranchet var. rufescensNakai, Trees Shrubs Japan, ed. 2,1: 56 (1927). Type: uncertain. 1R. brachycarpum G. Don subsp. tigerstedtii Nitzelius, Deutsche Baum- schule no. 7: 207 (1970). Type: a specimen from a cultivated plant grown in Mustila, Finland, originating from Kongo San in E C Korea (nolo. GB, n.v.)
Leaves ± glabrous beneath when mature
Distribution: Japan, Korea
Illustrations:
Ohwi (Fl. Japan, English Version, 698,1965) implies that R. brachycarpum of G. Don has entirely glabrous leaves and that R. fauriei is synonymous with it. However, Don clearly states that the leaves of R. brachycarpum have an indumentum on the lower surface. The synonymy cited here follows from the correction of this error. Nakai (loc. cit.) implies that all the material from Korea has glabrous leaves which is not entirely true. However, most of the Korean material seen is referable to subsp. fauriei which does appear to have a wider range than does the type subspecies. R. hidaense Makino (in Hara, Enum. PL Japon. 1: 33 (1948)-Type: Japan, Prov. Hida, in silva Aoya, vii 1939, Makino, n.v.) is probably a hybrid between this and the next species (see Hara, loc. cit.).
Synonymy: R. fauriei Franchet, Bull. Soc. Philom. Paris ser. 7, 10:145 (1886). Type: Nippon septentrionalis, in monte Schichinake, prope Aomori, 21 vi 1886, Faurie 758 (iso. E, K). R. brachycarpum G. Don var. roseiflorum Miyoshi, J. Coll. Sci. Imp. Univ. Tokyo 27: 8 (1910), no type designated.
Shrub to 1m. Twigs red-brown. Leaves either in pseudowhorls at the end of the branchlets or scattered and spiral. Blade c.100 x 45mm, elliptic; apex shortly acuminate; base obtuse, decurrent into the petiole, shining and minutely blackish pitted above, sparsely covered with pale scales beneath. Petiole 15mm. Inflorescence 5-flowered. Pedicels c.20mm, strong, hairy. Corolla 40mm, narrowly obconical, yellow; lobes c.15mm, rounded. Stamens c.30mm; filaments minutely hairy in the proximal part; anthers c.3mm, oblong, base minutely appendaged. Disc hairy, at the upper margin. Ovary c.8 x 3mm, sub-cylindrical, densely hairy, abruptly contracted distally; style c.9mm, glabrous; stigma 2mm in diameter, rounded.
Distribution: Philippines, Cebu
Greek – brachus – short; gynum – ovary. Alluding to the very short pistil.
Once found.
This species is based on a single specimen that has since been destroyed; Sleumer saw no material. The description here is modified from Sleumer’s translation of the original Latin. Copeland in discussing this species (1929) regarded it as related to R. teysmannii (R. javanicum ssp. teysmannii) and R. kochii. It would appear to belong to the R. javanicum complex but it is clearly distinct from R. kochii in both flower colour and leaf shape. Copeland also states: ‘On the other hand this species represents a transition from the ones just mentioned to R. leytense and R. loheri, which share the yellow flowers and appendaged anthers, but have somewhat smaller leaves, not at all acuminate, and drying to a dark brown colour. All the species here mentioned are alike in the hairiness of the ovary and filaments. Rhododendron brachygynum differs from all the others in the fact that the pistil is only about half as long as the stamens’.
The status of this species will not be satisfactorily evaluated without further collections from the type locality. It probably will turn out to be a minor variant of R. leytense (itself very similar to the R. javanicum complex). The very short pistil, the character to which Copeland appears to give most significance, may well be the result of examining very young flowers. The style elongates substantially in many species as flowers age and pass from the early unreceptive stigma phase to the later receptive one.
Type: Sudlon, Cenabre & De la Cruz F.B. 28346. Philippines, Cebu (PNH†).
Occurs in Countries: PH Subgenus: Vireya Habit: Non-Tree Fl. Colour: yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:282
Shrub to 3m. Twigs 2–3mm in diameter, densely scaly, greyish often whitish when dry; internodes 2–10cm. Leaves reflexed, 4–5 together in tight pseudowhorls. Blade 40–80 x 20–40mm, elliptic, obovate-elliptic to obovate; apex broadly tapering, obtuse or rounded; margin entire, wavy, flat or only slightly and narrowly revolute; base more broadly to narrowly tapering; sub-densely scaly on both sides initially, early glabrescent above, more slowly so beneath. Scales flat, marginal zone angular or dentate; centre small, slightly impressed. Mid-vein thick, grooved and strongly raised in the proximal ¼–1⁄3, then smooth or impressed above, beneath, strongly raised and gradually tapering throughout its length; lateral veins 7–10 per side, issuing at c.45°, almost smooth often obscure, reticulation obscure. Petiole 6–12 x 1.5–2mm, weakly grooved above, densely scaly initially. Bracts to 20 x 13mm, green when fresh, outer ones ovate, firm, scaly at apex and margin, fringed with scales, inner ones thinner, broadly spathulate, very laxly hairy in the proximal part on both sides, otherwise glabrous. Bracteoles to 18mm, filiform, laxly hairy. Inflorescence an 8–14-flowered open umbel. Pedicels 4–8 x 0.5mm, densely scaly. Calyx c.2mm in diameter, oblique, rim-like, obscurely lobed, scaly outside. Corolla narrowly trumpet-shaped, pure white, scented, 40–50mm; tube 23–40 x 2–2.5 x 2.5–3mm, straight or curved, densely stellately scaly outside, shortly hairy inside; lobes 10 x 4–5mm, spreading becoming strongly reflexed, obovate, not or hardly overlapping. Stamens irregularly centrally grouped, exserted to c.10mm; filaments narrowly linear and densely hairy in the proximal ¾, slender and glabrous distally; anthers 3–4mm, narrowly oblong, base obtuse. Disc slightly prominent, laxly short-hairy. Ovary c.8 x 1.3mm, narrowly cylindrical, dense white or yellowish hairs covering scales, tapering distally; style exserted from the mouth for c.5mm, densely hairy at the base, then more laxly hairy and densely scaly, exclusively scaly for the distal 1⁄3; stigma obconical, green.
Habitat: Epiphytic or terrestrial in Castanopsis and Nothofagus forests, also on mossy ridges and valley forest.
Distribution: Indonesia, New Guinea (W), Vogelkop Peninsula, Tamrau, Tohkiri and Nettoti Range.
Altitude: 1200-2000m
Greek – brachypodus – short stalked, alluding to the short-stalked flowers.
A distinctive species with extremely narrow flowers (amongst the New Guinea species of this group) reminiscent of R. jasminiflorum. The flowers were recorded in the field as becoming fragrant towards the evening.
Type: van Royen & Sleumer 7065, 26 Oct. 1961. New Guinea (NW), Tohkiri Mts, East crest 1400m, on path Surerem–Chaquai (L, A, BO, CANB, G, K, LAE, UC).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:171
Shrub to 2 m with thin lepidote branches. Young shoots purplish, puberulous. Leaves ovate to elliptic, up to 35 x 15 mm, ± acute at the apex, rounded to subcuneate at the base, ± glabrous and elepidote above, sparsely lepidote with large, golden scales beneath. Bud scales of the leaf buds persistent. Inflorescence 4-6-flowered, pedicels sparsely lepidote, puberulous at the base. Calyx weakly 5-lobed, the lobes 1-2 mm, sparsely lepidote, the margins filiform-acicular-ciliate. Corolla openly funnel-shaped, 15-25 mm, white with many reddish spots, sparsely lepidote and puberulent towards the sinuses outside, puberulent inside the tube. Stamens 10, filaments pubescent towards the base. Ovary lepidote and sparsely puberulent towards the apex. Style shorter than the longest stamens at anthesis, glabrous or sparsely pilose at the base. Capsule lepidote, 10-15 mm.
Habitat: In woodland and on cliffs,
Distribution: China (C Sichuan)
Altitude: Around 3300m
Illustrations:
Type: China, W Szechuan, near Wen chuan hsien, 3300 m, vii 1908, Wilson 3421 (iso. K)
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: red, white
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):88
Erect shrub to 2.5m. Twigs rounded, reddish and often whitish, when dry, smooth, tips laxly to densely covered with small, flat, sub-stellate scales; internodes 5–16cm, often with conspicuous broad hemispherical to rounded buds in the leaf axils. Leaves spiral, equally spaced along the branches. Blade 30–50 x 15–25mm, elliptic, broadly elliptic or sub-obovate; apex broadly obtuse or rounded, apiculate with a thick prominent gland; margin flat or weakly revolute, entire or minutely irregular to denticulate-crenulate and narrowly cartilaginous; base broadly tapering and somewhat decurrent, more rarely almost rounded, laxly scaly above but quickly glabrescent, the scales leaving minute pits, more persistently brown-scaly beneath. Scales small, sub-circular, variously sub-stellately lobed; centre small, slightly impressed. Mid-vein impressed above especially at the base and obtusely prominent beneath; lateral veins 6–8 per side, ascending at an angle of c.45°, slightly impressed above, raised or inconspicuous beneath, reticulation visible only beneath. Petiole 3–6 x 1.5–2mm, grooved above, flattened, scaly. Flower buds to 30 x 14mm, ovoid, smooth with the bracts fully appressed, green or flushed with purplish red. Bracts 20–30 x c.15mm, membranous, glabrous except for the fringe of scales on the margins, outer, ovate, obtuse or emarginate. Bracteoles c.20 x 1–1.5mm, linear, glabrous. Inflorescence 3–6-flowered, in an open or one-sided umbel, the flowers hanging vertically or sometimes half-hanging. Pedicels 20–25 x c.1.5mm, laxly sub-stellately scaly below, more densely so distally, without hairs. Calyx 4–5mm in diameter, very obliquely disc-shaped, shortly, obtusely, 5-lobed, scaly outside. Corolla 45–50 x 25–30mm, dull yellow or greenish-yellow with a strong red flush on the proximal ½ of the tube, without scent, narrowly funnel-shaped, fleshy, glabrous both in and outside; tube 30–38 x 6–7 x 10–15mm, almost straight; lobes 12–15 x 14–18mm, broadly rounded to ovate, spreading horizontally, overlapping to c.halfway. Stamens very unequal, loosely clustered on the lower side of the mouth, exserted to c.10mm; filaments linear, glabrous, pale yellow; anthers 2.5–3 x 1.3–1.5mm; cells obovoid and basally apiculate. Disc green, prominent, glabrous. Ovary c.5 x 2.5mm, sub-ovoid-cylindrical, very densely covered with silvery sub-circular or angled, flat scales, gradually tapering distally; style slender, laxly scaly proximally for up to 10mm, glabrous distally, exserted up to 15mm from the corolla; stigma thick-capitate, green. Fruit 15 x 6mm, obliquely fusiform-cylindrical.
Habitat: Shrubby forest, or grassy margins of Podocarpus forest, or open shrubberies on ridges, locally plentiful
Distribution: Indonesia, New Guinea (W), near Lake Habbema and the Wamena R. on N slope of Mt Wilhelmina (Trichora).
Altitude: 3200-3225m
Named in honour of Leonard Brass, famous for his botanical collecting expeditions in New Guinea.
Sleumer (1973) notes under R. ultimum that it may not be specifically different from that species. In fact, in the field, the differences are very obvious: R. brassii grows at a lower altitude and is a tall, erect shrub with green or silvery-green leaves, whereas R. ultimum is at higher altitude and is a low, spreading shrub with purplish leaves. Both have been grown side by side in cultivation and retain their distinctive habits. A hybrid with R. versteegii (R. x nebulicola) has been described from the wild by Danet (2005).
Type: Brass 9139, Aug. 1938. New Guinea (W), Lake Habbema, 3225m camp (A, BO, L).
Occurs in Countries: ID Altitude Ranges: 3,000 - 4,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: green, red, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:223
Small tree, 4-7m; young shoots glandular-setose. Leaves elliptic, 8.5—12 x 2.5-4cm, 2.4—4.3 x as long as broad, apex bluntly acuminate, base cuneate, lower surface glabrous though with numerous red sessile punctate glands; petioles l-3cm, glabrous at maturity. Inflorescence 2-3-flowered; rhachis c.3mm; pedicels 10-25mm, densely stipitate- to setose-glandular. Calyx 2-3.5mm, lobes rounded, stipitate-glandular, especially on margins. Corolla campanulate, purple, 35-40mm. Ovary densely long-stipitate-glandular; style glandular in lower half. Capsule 12-20 x 6-8mm.
Habitat: Forests
Distribution: China (Guizhou, Guangxi, Guangdong)
Altitude: 500-2000m
Closely allied to R. mengtszense, with which it shares a setose-glandular indumentum.
Type: China, Guangxi, Lungsheng Hsien, Pingshui Hsiang, Taosan Chun, 6 ix 1955, Kwangfu Exped. 8, n.v.
Occurs in Countries: CN Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: purple
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):292
Much-branched shrub; young shoots slender, covered with adpressed flattened shining brown hairs. Leaves persistent, chartaceous, ovate-elliptic, 1-3 x 0.6-1.7cm, 1.8-2.5 x as long as broad, apex obtuse and mucronate, margin entire, base broad, cuneate-rounded, both surfaces with scattered adpressed pilose shining brown hairs that turn grey, upper surface with impressed midrib, lower surface reticulate; petiole 2-5mm. Inflorescence 2-several-flowered; pedicels 3-5mm, covered with shiny flattened white hairs. Calyx 2-4mm, indumentum as for pedicels, 5-lobed. Corolla funnel-campanu-late, rose-pink with crimson spotting on upper lobes, 25mm. Stamens 5(-6), filaments pilose below middle, anthers apiculate at base. Ovary conic, densely pilose; style pilose at base, dilated at apex. Capsule not known.
Distribution: China (Taiwan)
Illustrations:
The plant in cultivation in Edinburgh has a low, spreading habit. In this it apparently matches the type specimen.
Type: Taiwan, Nanto, Mt Pusasai, iv 1909, Mori, n.v. (nolo. TI)
Occurs in Countries: CN, TW Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: crimson, rose
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):124
Shrub to 3m. Twigs 3–4mm in diameter, rounded or somewhat angled, at first sub-densely covered with flat, sub-stellate scales, later glabrescent; internodes 7–10cm. Leaves c.5 together in pseudowhorls at the upper 1–2 nodes, sub-sessile. Blade c.150 x 50–70mm, broadly elliptic to elliptic; apex shortly acuminate, sub-acute; margin flat; base broadly tapering, the extreme base sub-truncate-obtuse; upper surface glabrescent but densely, minutely, pitted; undersurface sub-densely scaly. Scales flat, thin, reddish-brown, the marginal area variously lobed; centre small, flat. Mid-vein as wide as the petiole at the base, narrowed upwards and slightly impressed above, prominent beneath; lateral veins 8–10 per side, with additional, less distinct ones between them; straight at the base, curved distally, indistinctly anastomosing along the margin, flat or faintly raised above, more distinct and raised beneath, reticulation visible above, almost obscure beneath. Petiole 1–2 x 3–4mm. Outer bracts to 20 x 10mm, ovate-acuminate, with a distinct, sharp point (3–4mm), very laxly scaly along the outer middle line or glabrous outside, densely scaly at the apex inside; inner bracts elliptic-sub-spathulate, glabrous, except scaly along the margins. Bracteoles c.20 x 1mm, filiform, sub-glabrous. Inflorescence a 6–7-flowered umbel. Pedicels 40–60 x c.1.5mm, dilated at the apex, laxly scaly, not hairy. Calyx to 3mm in diameter, oblique, a wavy rim. Corolla 75–80mm, funnel-shaped, tube yellow, lobes orange; tube 40 x 4–5 x 15mm, laxly to very laxly sub-stellately scaly outside, shortly hairy in the lower ¾ inside, straight; lobes c.40 x 25mm, obovate, spreading. Stamens unequal, the longest exserted to c.20mm; filaments linear and sub-densely hairy in the proximal ½, filiform and glabrous in the distal ½; anthers c.4 x 1.2mm, oblong, the base obtuse. Disc very prominent, white-hairy at the upper margin, glabrous below. Ovary 10–12 x 2–2.5mm, cylindrical, tapering distally, very densely scaly and laxly shortly white-hairy; style c.55mm, densely scaly and shortly hairy in the lower 2⁄3, more laxly scaly and without hairs to the apex; stigma thick, rounded, with 5 distinct, almost club-shaped lobes. Fruit cylindrical, scaly and hairy, c.80 x 3–4mm.
Distribution: Papua New Guinea, Western Highlands, Jimmy Valley, Karap village.
Altitude: Around 1725m
Latin – brevis – short; pes – foot. Alluding to the very short petioles.
One collection only.
A poorly known species very reminiscent of R. aurigeranum in that the tips of the bracts are scaly on both sides but this species has much shorter petioles.
Type: Womersley & Millar NGF 7605. Papua New Guinea, Western Highlands, Jimmy Valley, near Karap (LAE).
Occurs in Countries: PG Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: orange, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:318
Shrub to 2m. Twigs 1–2mm in diameter, slender, rounded, laxly leaved, the tips brown, at first densely covered with stellate scales, older parts glabrescent and rough with scale bases; internodes 2–8cm. Leaves 3–5 together in tight pseudowhorls. Blade 40–55 x 10–22mm, narrowly elliptic, widest in the middle; apex acute to obtuse; margin slightly revolute; base broadly tapering or sub-truncate-rounded, sub-densely scaly on both sides initially. Scales minute, deeply stellately divided and sub-dendroid, falling early, and becoming glabrescent, each on top of a persistent epidermal tubercle, which gives a rough texture. Mid-vein scaly for a long time, very slightly impressed above, prominent beneath; lateral veins 4–6 per side, curved and anastomosing, faintly visible on both sides. Petiole 2–3 x c.1mm, scaly, flattened. Bracts to 8 x 6mm, ovate to obovate-spathulate, apiculate or obtuse, membranous, glabrous, minutely fringed with scales. Bracteoles to 10mm, filiform, sub-glabrous. Inflorescence a c.3-flowered open umbel. Pedicels 10–12 x 0.4mm, very slender, densely minutely stellate-scaly, without hairs. Calyx c.2mm in diameter, sub-oblique, small, obscurely 5-lobed, stellately scaly outside. Corolla 30–40mm, tubular, distinctly zygomorphic, pale pink, thin; tube 20–28 x 4–5 x 7–10mm, cylindrical, curved, glabrous outside, laxly hairy inside; lobes 10–12 x c.7mm, elliptic to spathulate, spreading and somewhat reflexed, not or only very slightly overlapping. Stamens exserted, 6–7mm, clustered on the upper side of the flower; filaments narrowly linear, glabrous at the base, then laxly hairy, but again glabrous distally; anthers 1.8–2 x 1mm, oblong. Disc very shortly hairy at the upper margin, glabrous elsewhere. Ovary c.4 x 1.5mm, elongate-ovoid, densely and exclusively stellate-scaly, gradually tapering distally; style c.18mm, relatively thick, laxly covered with short, sub-patent hairs almost to the top; stigma shortly club-shaped.
Habitat: Epiphytic in tall forest
Distribution: Indonesia, New Guinea (W), Cycloop Mts.
Altitude: 1065-1830m
Greek – bryo – relating to moss; philos – loving. Alluding to the mossy branches on which this species was originally found growing.
Type: Cheesman 51, March 1936. New Guinea (NW), Mt Cyclops (BM).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: pink
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:77
Erect, few-stemmed shrub or small tree to 6m, the trunk 2–3m to 5cm in diameter. Twigs 3–10mm in diameter, rounded, covered with a persistent though fragile covering of reddish-brown stellate scales; internodes 6–25cm. Leaves 4–6 together in tight pseudowhorls. Blade 8–20 x 4.5–13cm, elliptic or ovate-elliptic, rarely broadly elliptic or ovate, slightly unequal sided; apex very shortly sub-acuminate, obtuse or rounded; margin flat; base rounded; young leaves thickly covered with stellate reddish-brown scales, mature ones glabrescent above, more persistently scaly beneath especially along the main veins. Scales dendroid, with the marginal zone deeply divided and the small centre deepened or prolonged downwards into a kind of foot. Mid-vein as wide as the petiole at the base, and hardly prominent there, becoming impressed distally above and raised below; lateral veins irregular, 10–14 per side, curved and anastomosing before the edge, impressed above, prominent beneath as are the smaller veins which are distinct and reticulate towards the leaf margin; dark green and glossy above, paler and dull beneath, deeply puckered in both the fresh and dry state. Petiole 25–50 x 2.5–3.5mm, densely stellate-scaly initially. Immature buds c.20 x 20mm, bracts ovate, the outer ones sub-acuminate, the inner ones obtuse, with long appressed hairs on both sides and scaly outside. Corolla (immature) densely scaly on the tube outside, glabrous at the lobes. Fruit pedicel densely scaly, c.25 x 1.5mm. Young fruit 25mm, fusiform, densely covered with scales and pale coarse hairs, as is the style, of which only the lower part (for c.3cm) is known. Twisted valves of the mature fruit 30–55mm.
Habitat: Undershrub or tree in transitional zone of Castanopsis to Nothofagus forest
Distribution: Indonesia, New Guinea (W), Arfak Mts, Mt Sarumot, Anggi Gigi Lake, once collected.
Altitude: 2050-2100m
Latin – bullatus – puckered; folium – leaf. Alluding to the leaves being deeply puckered.
Still apparently known only from the very imperfect type specimen and the collectors’ field notes.
Type: Sleumer & Vink 4444, 26 Jan. 1961. Indonesia, W New Guinea, Arfak Mts, Mt Saru-mot near Iray, Anggi Gigi Lake (A, CANB, G, K, L, LAE, P, PNH, UC).
Occurs in Countries: ID Altitude Ranges: 2,000 - 3,000m Subgenus: Vireya Habit: Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:77
Erect, straggling shrub up to 1-6 m. Leaves (8-)12—21 X 4-7(-8) mm, elliptic or oblong-elliptic, apex rounded, obscurely mucronate, usually emarginate, base broadly cuneate, undersurface pale with tan speckling, with irregularly contiguous or slightly discontiguous colourless, straw or buff scales with some larger, darker scales dispersed among them. Inflorescence l-3(-5)-flowered, pedicel pubescent and lepidote, 1-2 mm. Calyx lobes l-2(-4) mm, triangular to irregularly rounded, outer surface lepidote, margin lepidote and with a few cilia. Corolla pinkish purple, magenta, deep violet or occasionally white, pubescent in the throat and rarely so on the outer surface, (9.5-)10.5-13(-17) mm, tube 2-5—3(—5) mm, lobes with pale scales on the outer surface. Stamens (8-)10. Ovary lepidote, style 12-17 mm, usually exceeding the stamens, usually pubescent and with a few scales towards the base. Capsule ovoid, lepidote, c. 5 mm.
Habitat: Open woodland, scrubby and wooded hillsides
Distribution: China (S Sl SW Xizang—Tsangpo valley)
Altitude: 3000-3800m
The Philipsons (1975, p. 47) record a natural hybrid with R. nivale subsp. nivate
Type: SE Tibet Lusha, 3050 m, 19 v 1924, Kingdon Ward 5686 (holo. E)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: magenta, purple, white
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):104
Shrub, l-3(-6)m. Leaves elliptic, 4.5-12 x 2-7cm, 1.7-3 X as long as broad, apex acuminate, base rounded or cuneate, lower surface with a dense unistrate lanate ramiform tomentum, salmon-pink when young, becoming rich rusty red; petioles l-2cm, densely tomentose. Inflorescence 10-20-flowered; rhachis 2-3mm; pedicels 10-20mm, densely pilose and glandular. Calyx 5-10mm, lobes fleshy or membranous, densely pilose and glandular. Corolla white flushed pink to pink, sometimes with purple flecks, 25-40mm. Ovary densely stipitate-glandular, sometimes also tomentose; style usually glandular, at least near the base. Capsule c.15 x 9mm.
Habitat: Open pine forests, Rhododendron thickets
Distribution: China (N Yunnan)
Altitude: 3350-4250m
R. cruentum is described as differing from R. bureavii in its smaller flowers and fleshy calyx. There is, however, a complete intergradation in these characters.
Type: China, Yunnan, ad collum Yen-tze-hay, prope Lankong, 3200m, 1 v 1886, Detavay 2213 (iso. E, K).
Synonymy: R. cruentum Leveille, Feddes Repert. 12: 284 (1913). Type: China, Yunnan, brousse du plateau de Ta-Hai-Tse, 3200m, v 1912, Maire (holo. E)
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: pink, purple
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):338
Much branched spreading shrub to 15 cm. Leaves 8-12 x 3-6 mm, elliptic to ovate, apex obtuse, mucronate, base broadly cuneate, undersurface bicolorous, densely covered with pale golden scales mixed with darker, amber scales. Inflorescence 3-8-flowered, pedicel lepidote and minutely pubescent, (l-)2-3-5 mm. Calyx lobes rounded to triangular, c. 0-5 mm, lepidote, margin ciliate. Corolla rosy violet, narrowly funnel-shaped, 12-15 mm, tube 5-7 mm, pubescent in the throat. Stamens (5-)7(-10), shorter than corolla, filaments pubescent towards the base. Ovary lepidote, style 3-4 mm, shorter than the stamens. Capsule ovoid, lepidote, c. 6 mm.
Habitat: Moist places in Larch forests.
Distribution: USSR (eastern Sajan mountains to the west of the southern end of Lake Baikal)
Type: USSR, Montes Sajanenses orientales, alpes Kito-jenses, fl. Saghan-Sajir, 20 vi 1958, Malyschev (holo. LE—n.v.)
Occurs in Countries: RU Subgenus: Rhododendron Habit: Non-Tree
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):106
Shrub to 2 m. Young growth with a dense indumentum of loriform setae which is soon deciduous. Leaves obovate, tapering to the base, obtuse at the apex, 50-55 X 20-24 mm, upper surface dark green, rather densely lepidote with flat, somewhat dried-out scales, margins loriform-ciliate when young, somewhat crenate in the upper part, lower surface densely lepidote with overlapping to contiguous scales producing a brownish colour; petioles densely lepidote and sparsely loriform-setose. Inflorescence 4-6(-10)-flowered, pedicels densely lepidote. Calyx disc-like, undulate, lepidote, loriform-ciliate. Corolla greenish yellow, funnel-campanulate, 30-35 mm, tube 18-20 mm, the base of the tube pilose outside, the whole conspicuously lepidote, tube glabrous inside. Stamens 10, filaments densely pubescent in the lower part. Ovary densely lepidote; style impressed, lepidote in the lower part. Fruit unknown.
Habitat: Fringes of forest
Distribution: C Burma (Mt Victoria)
Altitude: 2700-2900m
Originally described from cultivated material, later refound in the wild. A distinct and easily recognised species.
Type: a cultivated specimen (holo. K)
Occurs in Countries: MM Altitude Ranges: 2,000 - 3,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):43
Shrub to 80cm. Twigs smooth, green or reddish, very finely hairy and laxly scaly. Leaves 5–8 in tight pseudowhorls, with a variable number of smaller reduced scale leaves. Blade 18–28 x 9–12mm, obovate; apex broadly pointed to rounded; margin entire, slightly recurved; base tapering; laxly scaly above and with a few simple hairs but quickly glabrescent; below laxly and more persistently scaly but without hairs. Scales stellate, flat, with a broad marginal flange and small slightly impressed centre. Mid-vein impressed above, raised below; lateral veins 2–3 per side, faint or obscure. Petiole 4–5 x 1–2mm, hairy and scaly, weakly grooved at the junction with the lamina, green. Flower buds to 8 x 4mm, ellipsoidal, green, tips of the bracts stiffly erect, hairy outside and with marginal brown scales. Inflorescences often lateral as well as terminal, of 1–2 occasionally up to 4 flowers, hanging vertically. Pedicels 17 x 1mm, red, with long, white, spreading hairs. Calyx a low green disc with a hairy margin. Corolla 23 x 26mm, bright-red, without scent; tube c.17 x 8 x 6mm, swollen just above the base and then narrowed slightly, becoming parallel sided and straight, long-hairy and with a few scales outside, hairy only near the base inside; lobes 10 x 6mm, wide-spreading, not overlapping. Stamens spreading all round the mouth of the flower; filaments 18mm, white, passing to pink distally, broadened and hairy in the proximal 4mm; anthers 1.4 x 0.8mm, brown. Ovary c.4 x 3mm, shortly cylindrical, densely hairy, with white semi-appressed hairs and brown scales covered by the hairs; style 5 x 0.5mm, green with a few hairs near the base only; stigma green, 1mm in diameter. Fruit 16 x 5mm, cylindrical, white-hairy and with brown scales, the valves spreading widely after opening. Seeds 3.3mm, without tails 1mm, the longest tail 1.2mm.
Habitat: Epiphytic in mossy sub-montane forest.
Distribution: Malaysia (Borneo), Sarawak, Mt Murud, Mt Lawi. Sabah, Mt Lotung, Crocker Range and in the area of the River Rekong Waterfall near Long Pasia. Erroneously reported from Kinabalu although it could easily be on that mountain.
Altitude: 1500-1600m
Named after B.L. Burtt, botanist at Edinburgh, who made a series of expeditions to Sarawak and who first collected this species with Adam Martin on Gunong Murud.
Type: Burtt & Martin B.5549, 16 Oct. 1967, (cultivated specimen April 1970). Sarawak, 5th Div., G. Murud (E, L, SAR).
Occurs in Countries: MY Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:200
Shrub to 3.5m. Twigs 3–4mm in diameter, rounded, laxly appressed-scaly, often whitish; internodes 3–16cm. Leaves 4–6 together in lax pseudowhorls with 1–2 additional ones on the internodes. Blade 70–160 x 4–75mm, ovate-elliptic to elliptic; apex shortly acuminate, obtuse; margin very slightly or not revolute; base broadly tapering, sometimes nearly rounded, glabrescent above when mature, laxly persistently scaly beneath. Scales small, marginal zone variously lobed, fragile and disappearing, leaving dark spots; centre small, shallowly impressed. Mid-vein grooved above, obtusely prominent beneath; lateral veins 8–12 per side, straight below, curved and anastomosing before the margin, minutely impressed above, distinctly raised beneath, reticulation lax, faintly prominent beneath. Petiole 10–20 x 1.5–2mm, slightly flattened, rugose, often white. Inflorescence 7–10-flowered. Pedicels 20–33 x c.1mm, laxly scaly and hairy. Calyx 4–5mm in diameter, obliquely disc-shaped, scaly and with some short hairs outside. Corolla 40–50mm, broadly funnel-shaped, tubular below, white; tube 20–26 x 5–6 x 7–8mm, distinctly 5-pouched at the base, straight, with some scattered scales, (almost glabrous), outside, shortly hairy inside; lobes 12–23 x 12–20mm, spreading, broadly obovate to sub-circular. Stamens unequal, exserted to c.6mm; filaments linear and sub-densely patently hairy in the proximal 1⁄3–½, filiform and glabrous distally; anthers 3–4 x 1mm, oblong, the base slightly thickened. Disc prominent, glabrous or shortly hairy on the upper margin. Ovary 6–7 x 2.5–3mm, sub-cylindrical, densely covered with sub-patent short hairs which cover small scales, abruptly contracted distally; style densely hairy and laxly scaly to the lower 2⁄3, glabrous distally; stigma rounded.
Habitat: Terrestrial on loamy limestone soil
Distribution: Indonesia, Maluku, Buru, Mt Toga and between Leksula and Mnges Waen.
Altitude: 1290-1900m
Named after the island from which it was collected.
Not recollected recently.
Type: Stresemann 38. Moluccas, Buru, G. Toga, 1900m (L).
Synonymy: R. lompohense var. grandifolium J.J.Sm., Fedde Rep. 1932. 30: 169.
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:292
Shrub or tree to 5m. Twigs c.3mm in diameter, initially laxly covered with scales and sometimes with very fine papillose hairs, later glabrescent but with thick raised leaf scars; internodes 1–4cm. Leaves 5–8 in dense pseudowhorls. Blade 10–35 x 6–25mm, broadly elliptic, ovate- or obovate-elliptic or sub-circular; apex obtuse, often rounded-obtuse, sometimes slightly emarginate, with an inconspicuous apical gland; margin slightly recurved, distinctly crenulate; base rounded, cordate, or broadly tapering, sub-densely to laxly scaly on both sides initially, early glabrescent with minute pits above; more persistently scaly beneath. Scales irregularly crenate or lobed with a narrow marginal zone; centre often large, swollen and persistent, deeply impressed. Mid-vein narrow and slightly impressed above, broad and obtusely prominent beneath; lateral veins 5–6 per side, somewhat irregular, spreading, slightly impressed above in old leaves, inconspicuous beneath, reticulation lax and faintly impressed above, obscure beneath. Petiole 1.5–3 x 1–3mm, grooved above, flattened, rugose. Flower buds (see p.327) to 17 x 11mm, ovoid, green, with the points of the bracts standing erect away from the bud. Outer bracts ovate-acuminate, the dorsal mid-vein tapering to a short subulate acumen, hairy and laxly scaly outside, hairy inside, margins ciliate near the apex only; inner ones ovate-obtuse to spathulate. Bracteoles to 20 x 1mm, linear below, sub-spathulate distally. Inflorescence of 5–10 flowers in open umbels. Flowers semi-erect to half-hanging. Pedicels 12–24 x 1–2mm, sub-stellately scaly. Calyx 3–4mm in diameter, a low scaly disc, often revolute. Corolla 26 x 37mm, broadly funnel-shaped or sub-campanulate, pink to deep red, strongly honey-scented; tube 15–18 x 4–5 x 12–15mm, sub-densely scaly outside, glabrous inside, straight, the base pouched; lobes 15–18 x 13–15mm, spreading, slightly reflexed, overlapping c.½, obovate-spathulate. Stamens sub-equal, at the mouth of the tube; filaments c.13mm, linear, glabrous, pink; anthers c.3mm, oblong, pale-brown, cells obtuse or narrowed into a short distinct basal apiculus. Disc prominent, glabrous. Ovary c.4–4.5 x 2–3mm, sub-ovoid-conical, apex obtuse, abruptly contracted distally, densely scaly and occasionally with some very sparse hairs; style 9 x 1mm, glabrous, or scaly at the base for c.1mm, red, as long as the stamens; stigma c.2mm in diameter, red, rounded. Fruit 14–18 x 7–8mm, ovoid-fusiform, brown-scaly. Seeds 1.7mm, without tails c.1mm, the longest tail 0.4mm.
Habitat: In forest above 3100m, but more frequent in shrubberies and in open places amongst the granite rocks, up to 3900m.
Distribution: Malaysia (Borneo), Sabah, Mt Kinabalu.
Altitude: 3100-3900m
Latin – Buxus – Buxus sempervirens – ‘the European box’; folium – leaf. An allusion to the similarity of the leaves to that of this shrub.
The variety robustum recognised by Sleumer (1960) has little significance, except to indicate the effects of exposure: the type specimen is from the upper end of the range from an exposed site and thus has small leaves compared with the plants lower down. It is one of the most magnificent botanical sights on Mt Kinabalu when in full flower on a fine sunny day.
Type: Low s.n., March 1851. North Borneo, Mt Kinabalu, 2745–4096m, top (K, CGE, L).
Synonymy: R. buxifolium var. robustum Sleumer, Reinwardtia 1960. 5: 173.
Occurs in Countries: MY Altitude Ranges: 3,000 - 4,000m Subgenus: Vireya Habit: Tree Fl. Colour: pink, red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:202
Shrub to 2m. Twigs 2–3mm in diameter, scaly at first with stalked scales, warty with persistent scale bases after the scales have gone; internodes 0.5–1.5cm. Leaves in tight to loose pseudowhorls, 2–5 together or spirally arranged. Blade 10–30 x 4–14mm, broadly obovate to elliptic; apex obtuse, to rounded, often emarginate; margin strongly and broadly revolute, sometimes crenulate with impressed scales; base tapering, decurrent; densely and persistently scaly on both sides. Scales large, thick, rounded, entire, strongly impressed; the narrow margin tending to disintegrate, the centre persistent. Mid-vein impressed above, raised below; lateral veins 3–4 per side, obscure to strongly raised below at least when dry, reticulation obscure. Petiole 1.5–2mm. Bracts c.5mm, obovate, densely scaly and white-hairy distally outside and with a ciliate margin. Inflorescence 2–4 flowers in an open umbel, hanging vertically. Pedicels 6–14 x 0.5–0.6mm, slender, densely scaly, without hairs. Calyx obliquely disc-shaped, obscurely lobed or undulate, densely scaly. Corolla tubular, red; tube 13–15 x 3–4 x 4–7mm, completely very densely covered in thick rounded scales, glabrous inside; lobes 3–4 x 3–4mm, erect, obovate, spathulate, or sub-circular, scaly in the central part outside. Stamens exserted to c.3mm; filaments linear, glabrous; anthers 1.5 x 1mm, obovoid. Disc glabrous. Ovary c.2.5 x 1.5mm, conical, densely scaly, gradually tapering distally; style scaly at the base only, glabrous distally, about as long as the corolla; stigma slightly broadened, obliquely truncate. Fruit 7–9 x 3–4mm, shortly cylindrical, deeply grooved. Seed 1.2–1.5mm, without tails c.1mm, the longest tail to 0.4mm, mostly broadly triangular at one end with a short narrow tail at the other.
Distribution: Malaysia (Borneo), Sarawak, Mt Murud, Mt Mulu and Batu Lawi
Altitude: 1800-2300m
Like the ‘European box’ Buxus sempervirens, the leaves being superficially similar.
Flowers Apr, Oct.; probably continuously.
Sleumer (1973) commented that this species was ‘close to’ R. perakense but differed in the slightly crenulate leaves, red corolla and the bracts being both hairy and scaly outside. It is usually a much larger plant with bigger leaves and flowers. This species is not known to have been cultivated. In its small, dull red, densely scaly flowers it very much parallels R. inconspicuum and R. yelliotii from New Guinea. The almost tail-less seeds are like those of other species from the highest points on high mountains.
Type: Nooteboom & Chai 1973, 6 April 1970. Borneo, Sarawak, 5th Div., Mt Murud, towards the top (L, K, SAR).
Occurs in Countries: MY Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:46
Shrub, 1-2 mm. Young growth sparsely lepidote. Leaves subdeciduous, flat or rarely slightly revolute, ± oblong-elliptic or rarely oblong-ovate, 30-42 x 13-18 mm, apex subacute or rounded, base rounded or somewhat cuneate, the lower surface with an indumentum of distant, straight or slightly curved loriform setae, which also occur on the margins and petioles, the surface white-papillose and with distant, equal, golden scales, upper surface glabrous and elepidote. Inflorescence (l-)2-3-flowered, pedicels 12-15 mm, sparsely lepidote. Calyx obscurely lobed, lobes 1-2 mm, sparsely lepidote and loriform-ciliate. Corolla yellow, c. 18 mm, tube 9-10 mm, lepidote and glabrous outside. Ovary lepidote, glabrous. Capsule cylindric, c. 10 mm
Habitat: Rocky slopes
Distribution: China (SW & C Yunnan)
Altitude: 2450-3050m
Type: a cultivated plant said to be from seed of Forrest 26798 (holo. K, iso. E)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Rhododendron Habit: Non-Tree
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):152
Prostrate, cushion-forming, low shrub, forming vertical patches up to 2cm in depth and 20cm in diameter, extending by prostrate, elongate, not, or sparsely, branched stoloniform shoots which root freely into the substrate. These eventually become erect and branch freely. Twigs c.1mm in diameter, covered in shortly stalked sub-stellate, brown scales at first, these falling and leaving a minutely warty surface with scale stalks up to 0.2mm high. Leaves spirally arranged along the elongate shoots, densely crowded towards the erect branch tips. Blade 3–6 x 2–3mm, elliptic; apex shortly acuminate, broadly acute to obtuse or rounded; margin entire or sub-crenulate with a broad and only faintly demarcated sub-cartilaginous edge; base tapering, laxly to sub-densely scaly at first on both sides but these scales disappearing quickly from the upper surface. Scales orange-brown, with a broad and deeply incised marginal zone. Mid-vein only visible when fresh, all veins obscure after drying. Petiole 1–2 x c.0.5mm, weakly grooved above when fresh. Flower buds brown, 5–6 x c.3mm. Bracts long acuminate, the tips standing away from the bud, glabrous outside but with scales along the margins. Bracteoles c.4mm, filiform. Flowers solitary, horizontal to half-hanging. Pedicels 2–3 x c.1mm, densely scaly. Calyx a low disc, densely white-scaly. Corolla 12 x 7mm, pale pink; tube 7 x 5 x 4mm, cylindrical but contracted just below the lobes, densely scaly outside, glabrous inside; lobes 3 x 3.5mm, without scales, semi-erect to horizontally spreading, overlapping to c.2⁄3. Stamens 6mm, curving distally so that the anthers fill the upper part of the tube; filaments white, glabrous; anthers 1–1.1mm, brownish-purple. Disc glabrous. Ovary 5 x 3mm, densely white-scaly, abruptly contracted distally; style 2–2.5mm, glabrous, reddish-brown; stigma c.1mm in diameter, dark pink. Fruit 11 x 5mm, erect, broadly fusiform and densely brown-scaly, the pedicels elongating to 5–6mm, on ripening the outer layer irregularly peeling back and then the valves splitting to c.45°. Seeds 1.8–2.2mm, without tails to 0.8mm, the longest tail to 0.7mm.
Habitat: Growing in the high open valleys dominated by tree-ferns and forming cushions on their trunks. Probably protected from frost and with optimal shading by growing usually about mid-way up the tree-fern trunks (Argent et al. 1999).
Distribution: Indonesia, New Guinea (W), Mt Trichora (Mt Wilhelmina), Lake Habbema vicinity.
Altitude: 2400-3500m
Latin – caespitosus, growing in tufts like grass, generally of low growing plants.
Type: Brass 9039, Aug. 1938. New Guinea, Mt Wilhelmina, Habbema Lake (A, L).
Occurs in Countries: ID Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: pink
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:141
Shrub or small tree to 10m tall, usually non-rhizomatous; young twigs reddish brown, sparsely to densely covered with unicellular hairs and multicellular eglandular hairs. Vegetative bud scales glabrous abaxially; margin unicellular-ciliate. Leaf blade membranaceous, ovate or obovate to elliptic, (4.5-)5.6-7.7(-9.1) x (1.3-)1.8-2.6(-3.3)cm; base acute to oblique; apex acute to obtuse, often mucronate; adaxial surface sparsely covered with multicellular eglandular and unicellular hairs or with only multicellular eglandular hairs, or glabrous; the midvein densely covered with unicellular hairs; abaxial surface sparsely to densely covered with multicellular eglandular hairs or glabrous; the midvein densely covered with unicellular and multicellular eglandular hairs,rarely densely covered with unicellular hairs and multicellular eglandular hairs, or with only unicellular hairs; margin entire, ciliate with multicellular eglandular hairs; petiole 0.3-0.6(-0.7)cm long, sparsely to densely covered with unicellular hairs and multicellular eglandular hairs. Flower bud scales chestnut brown; abaxial surface glabrous, rarely very sparsely covered with unicellular hairs; margin glandular. Flowers appearing before or as the leaves expand; inflorescence a shortened raceme of 5 to 9 flowers. Pedicels (0.7-)0.8-L2(-1.4)cm long, sparsely to densely covered with unicellular hairs and densely covered with multicellular gland-tipped hairs, or with multicellular eglandular hairs, or both. Sepals (0.1-)0.2-0.3cm long, often varying in length on the same flower; margins glandular-fimbriate, frequently setose; abaxial surface sparsely to densely covered with unicellular hairs and multicellular gland-tipped hairs, rarely with unicellular hairs and multicellular eglandular hairs or with only unicellular hairs. Corolla orange to flame-coloured, fragrance acrid, the tube longer than the limb and abruptly expanding into it; upper corollalobe (1.4-)1.6-2.2(-2.3) x (1.2-)1.5-2.2(-2.5)cm; lateral lobes 1.8-2.6(-3.0) x (0.9-)1.0-1.4(-l .5)cm; corolla tube (1.6-) 1.8-2.2(-2.4)cm long, (0.2-)0.3-0.4(-0.5)cm wide at base; outer surface of corolla sparsely to densely covered with unicellular hairs and densely covered with multicellular gland-tipped hairs which often continue up the corolla lobes; inner surface of corolla sparsely to densely covered with unicellular hairs. Stamens (5.2-)5.7-6.7(-7.2)cm long, with dense terete or flattened unicellular hairs on proximal (1.9-)2.3-3. l(-3.2)cm of filament, exserted (3.4-)3.7-4.8(-5.4)cm beyond throat of corolla. Style (5.5-)5.9~6.8(-7.2)cm long, exserted (3.8-)4.2-5.3(-6.0)cm beyond throat of corolla, with dense unicellular hairs on proximal (0.0-) 0.3-1.3(-1.7)cm; stigma 0.1-0.2(-0.3)cm wide. Ovary 0.3-0.4(-0.5)cm long, (0.1-)0.2-0.3cm wide at the base, densely covered with multicellular eglandular hairs and dense unicellular hairs, rarely with multicellular gland-tipped hairs and unicellular hairs, or with all three types of hairs. Capsules (1.5-)1.8-2.6(-2.9) x (0.5-)0.6-0.8(-0.9)cm, ovate, sparsely covered with unicellular hairs and sparsely to moderately covered with either multicellular eglandular hairs or less often eglandular hairs. Seeds pale to dark chestnut brown, ovate or elliptic to fusiform, (1.7-)2.4-3.9 (-4.2) x (0.6-)0.9-1.5(-1.9)mm, body (0.8-)l.l-1.7(-2.1) x (0.2-)0.4-0.7(-0.8)mm, the testa expanded and dorsiventrally flattened, surrounding the body, the cells elongate, with transverse end-walls.
Habitat: Found in open, dry sites on southern and western exposures of hills and mountain-sides.
Distribution: USA: Northern West Virginia, south through the mountains of Virginia, North Carolina, Tennessee and Georgia. Generally restricted to the Ridge and Valley Province and Southern Appalachians, with occasional populations in the Cumberland Mountains and in the eastern edge of the Cumberland Plateau in Ohio and Kentucky. Not known west of die Tennessee River Valley in Tennessee. Extending into the Upper Piedmont in North and South Carolina and as far soutii as Meriwether Co., Georgia. Collections from Tarrytown, New York that are R. calendulaceum have been suggested as native in the past (Barnhart, 1895). However, all of the collections are nearly a century old and this is well north of the range of the species. Most likely these were cultivated plants that had persisted.
Altitude: 180-1000m
Illustrations:
The morphological characters which are the most useful in distinguishing R. cumberlandense from R. calendulaceum are outlined in Table 6. These characters are most useful in the field. Identification can be made with much more confidence when a population is Investigated, as opposed to an isolated specimen. Individuals may be further identified by taking into consideration the geographic location and the altitude in combination with the height and habit of the plant. Rhododendron cumberlandense is primarily a plant of the higher elevations of the Cumberland Plateau and Mountains where it flowers well after the leaves have expanded (this is one of the most useful characters). It is usually of smaller stature and glaucous leaves are much more common in populations of R. cumberlandense than in R. calendulaceum. The results of this study show that R. calendulaceum is morphologically separable from R. cumberlandense when a combination of characters is used in conjunction with geographic location. These two species can be most easily identified in the field where populations can be examined for variability in pedicel indumentum and sepal margin condition, and where phenological conditions can be clearly discerned. It is still difficult to identify some individual specimens because the range of morphological variation in R. calendulaceum may occasionally obscure the differences between the two species. However, difficulty in identification is not necessarily a valid reason to consider R. cumberlandense as conspecific with R. calendulaceum (Willingham, 1973). Rhododendron calendulaceum was once thought to be the red-orange-flowered taxon in the hybrid swarm on Gregory Bald, Blount Co., Tennessee. However, Li (1957) showed that all individuals sampled from that locality were diploid, and thus the red-orange species is the diploid, R. cumberlandense. However, a few specimens from Gregory Bald are indistinguishable morphologically from R. calendulaceum, and this species Ukely occurs on the bald in small populations. Although of low probability, hybrids with the tetraploid are not impossible since unreduced gametes are fairly frequent in the Ericaceae (Li, 1957; Goldy & Lyrene, 1984). The putative hybrids listed in the Appendix exhibit a combination of characters that occur where R. cumberlandense is not known to occur, and with species whose blooming times overlap with that of R. calendulaceum, but not R. cumberlandense. As such, these plants are most likely the result of hybridization by unreduced gametes.
Several specimens previously classified as 'intermediates'fit best Into the natural range of variation of R. calendulaceum and are best classified as the tetraploid, based upon morphological Information. Rhododendron cumberlandense is less morphologically variable than R. calendulaceum, in that the pedicels and sepal margins are almost always eglandular, and only occasionally one or the other will be somewhat glandular. From the R. cumberlandense populations examined, the only individuals with both completely glandular pedicels and sepal margins occurred In Alabama, in a population of hybrids between R. arborescens and R. cumberlandense. By contrast, this character combination occurs frequently in R. calendulaceum. Field-work In Virginia and North Carolina confirms the generally eglandular nature of R. cumberlandense and the glandular nature of R. calendulaceum.
Principal component analysis of 39 OTUs and up to 40 floral, bud-scale and vegetative characters were performed. Most of the characters were so variable that they only resulted in adding a great amount of 'noise'to an akeady complex problem. Therefore a series of analyses was performed, and from these, six characters (see Table 5) were chosen for an additional analysis. These six characters consistently recurred In each of the previous analyses as characters which were heavily weighted In the first and second principal components. The results of this analysis, using 39 OTUs and six characters, are shown In Fig. 25. Some definite trends are evident. Using the character of flowering time (which was not used In the principal component analysis) tentative assignment of specimens to either R. cumberlandense or R. c(ilendulaceum was made. There Is a trend towards Increasing floral size from the diploids to the tetraploids. However, there is no morphological gap in corolla size. The variation In the Indumentum of the pedicels and In the sepal margins from eglandular to glandular Is an Important trend. In the R. cumberlandense specimens, the pedicels and sepal margins are usually both eglandular, while in most specimens of R. calendulaceum the pedicels and sepals are glandular. Leaf pubescence appears to be highly variable. There is only a weakly defined trend towards densely unicellular pubescent leaves in R. calendulaceum.
The tetraploid flame azalea, R. calendulaceum, has long been noted for its morphological variation (Bartram, 1791; Rehder, 1921; Skinner, 1955, 1961; Galle, 1968, 1985). This species is found throughout the Blue Ridge and into the Ridge and Valley and Piedmont provinces. The closely related R. cumberlandense is diploid and has a more discontinuous occurrence within Its geographic range than the tetraplold, occurring primarily In the Cumberland Plateau and Mountains. While these two taxa are distinct biological entities, they are often very difficult to separate on the basis of morphology. This Is due to the great range of morphological variation In R. calendulaceum (WEEngham, 1973; personal observation) and also in part to the natural variation found in populations of R. cumberlandense. The characters which have been used to distinguish between these two species (besides chromosome number) include flavonoid chemistry (King, 1977a, 1980), flowering time and leaf expansion (Lemmon, 1938; Braun, 1941; Skinner, 1955, 1961; Galle, 1968, 1985), size of the corolla (Braun, 1941; Skinner, 1955, 1961; Galle, 1968, 1985), pubescence of the abaxial surface of the leaves (Skinner, 1955, 1961; Galle, 1968, 1985), and habit (Braun, 1941; Skinner, 1955, 1961; Galle, 1968, 1985). Rhododendron calendulaceum is characterized in the Eterature as tall usually non-stoloniferous shrubs possessing flowers which open before or as the leaves expand, and are up to 4cm across. In addition, R. calendulaceum is cited as possessing unicellular pubescent abaxial leaf surfaces (Rehder, 1921; Braun, 1941; Skinner, 1955,1961; Galle 1968,1985). By contrast, R. cumberlandense has been described as a low-growing stoloniferous shrub, with smaller, redder flowers, and more glabrous leaves than R. calendulaceum(Bmw, 1941; Skinner, 1961). The primary difference which has been emphasized in the literature has been the flowering of R. cumberlandense after the leaves have fully expanded. Difficulties in identification arise because there are no gaps in the flower size and colour or in leaf size or pubescence, and the phenologlcal differences are sometimes difficult to discern from herbarium material. Both R. cumberlandense and the 'early' and late'-blooming forms of R. calendulaceum have been studied in the Nantahala Mountains and nearby areas In North Carolina and Georgia by Willingham (1973,1974, 1975,1976). No morphological or phenological gaps were found between the early and late forms of R. calendulaceum. To distinguish between the two species WElingham used the following characters: growth habit, leaf expansion, flower colour, flower size, presence or absence of a blotch, pollen size (tetrad), pollen viability, cuticular ridging of the epidermis, stomata size and flavonoid compounds. Of these characters, only flavonoid compounds, pollen size and pollen viability were considered reliable characters in distinguishing between the two species by Willingham. He did note the difficulty in distinguishing the later-blooming individuals of R. calendulaceumfmm Individuals of R. cumberlandense, as late-blooming R. calendulaceum often has most of its leaves unfolded (however, there are usually some vegetative bud scales remaining on the plant). These late-blooming individuals almost always possess multicellular gland-tipped hairs on the pedicels and the sepal margins, whereas R. cumberlandense has eglandular pedicels and sepal margins. Earlier-blooming individuals of R. calendulaceum appear to be more variable in pedicel and sepal margin condition, with either the pedicel or sepal margins being eglandular. Plants of R. calendulaceum with both eglandular pedicels and sepal margins are usually clearly blooming before or with the expansion of the leaves. In Kentucky the pedicels and sepal margins of R. calendulaceum are more often eglandular than in West Virginia where they are usually glandular.
Chromosome number: 2n = 52 (Sax, 1930; Janaki-Ammal et al., 1950; Li, 1957)
Flowering from May to July
Occurs in Countries: US Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Pentanthera Habit: Tree
Kron, K.A. (1993) A Revision of Rhododendron Section Pentanthera. Edinburgh Journal of Botany 50(3):296
Small, straggling, much-branched shrub to 50cm. Twigs 1–2mm in diameter, slender, rounded, tips densely scaly with brown, stellate scales, the older parts glabrescent, smooth; internodes 1–8cm. Leaves 4–7 together in tight pseudowhorls, often noticeably different in size in the same pseudowhorl. Blade 10–70 x 1–6mm, linear or occasionally very narrowly ovate or narrowly elliptic; apex sub-obtuse; margin entire or slightly revolute; base very broadly tapering or rounded, very densely red-brown scaly on both sides initially. Scales deeply stellately divided, sub-sessile or shortly dendroid, each on top of a minute epidermal tubercle, becoming glabrous and smooth above, persistently red-brown scaly beneath. Mid-vein faintly impressed above, as thick as the petiole and prominently raised beneath; lateral veins obscure. Petioles 2–5 x 1–1.5mm, weakly grooved distally, densely brown-scaly. Flower buds to 12 x 7mm, densely brown-scaly when young, becoming green just before opening, narrowly elliptic, sharply acute at the apex. Outer bracts subulate, inner ones ovate-subulate to ovate-acuminate, densely stellate-scaly in a patch on the outer upper part, glabrous otherwise, margin fringed with scales. Bracteoles to 8mm, linear to very narrowly obovate, margin laxly fringed with scales. Inflorescence of solitary flowers or up to 3 together. Flowers hanging vertically downwards. Pedicels 6–12mm, slender, densely stellately scaly. Calyx c.2.5mm in diameter, small, disc-like, densely stellate-scaly externally. Corolla 30–35mm, white to cream, sometimes very pale pink, without scent, tubular below, slightly expanded at the mouth, a little curved, zygomorphic; tube 20–25 x 4–6 x 6–10mm, densely stellately scaly and without hairs outside, glabrous inside; lobes 7–9 x 6–9mm, broadly obovate to sub-circular, spreading horizontally and overlapping to c.¼, scaly at the base outside. Stamens clustered on the upper side of the flower, unequal, exserted to c.10mm; filaments white, linear, glabrous or sparsely hairy in the proximal ½; anthers c.2 x 1mm, brown. Disc glabrous below, densely stellate-scaly on the upper margin. Ovary sub-ovoid, gradually tapering to the style, very densely stellate-scaly and conspicuously 5-ribbed, c.7 x 3.5mm; style greenish-white, on the upper side of the tube, slender, scaly throughout the proximal 1⁄3, glabrous distally or with sparse white hairs almost to the top, equalling the corolla in length when receptive; stigma white or green, club-shaped to globose, obscurely 5-lobed. Fruit fusiform, the valves ultimately curling right back, the placentae breaking away at the base and irregularly splaying apart.
Habitat: Open sub-montane shrubberies, cliffs and on fallen logs.
Distribution: Indonesia, New Guinea (W), Koruppun Valley (139°38'E 4°28'S). Papua New Guinea, West Sepik Province, Hindenburg Range, Mt Amdutakin; Victor Emanuel Range, Mt Womtakin. Enga Province, Laiagam–Porgera Divide, Mt Maip. Western Highlands District, Mt Sigal Mugal; Waghi–Sepik Divide, Mt Manduil.
Altitude: 2400-2900m
Latin – caligo – of mist or fog, the type collection being made from plants that seemed perpetually enshrouded in mist.
A striking species owing to its linear leaves which are densely covered with dark brown, dendroid scales when immature and its apparent association with limestone outcrops. Similar to R. hooglandii from which it is best distinguished by its subulate bracts which are densely scaly outside. For a discussion of other differences see under R. hooglandii.
Type: Kores WEI 1600, 7 Aug. 1976. Papua New Guinea, West Sepik Province, Victor Emanuel Range, Mt Womtakin, 2850m (LAE, BISH, E, L).
Occurs in Countries: ID, PG Altitude Ranges: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: cream, green, pink, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:78
Shrub, 0.6-2(-3)m; young shoots shortly stipitate-glandular. Leaves broadly ovate to orbicular, 3.5-7 x 3-5cm, 1-1.5 X as long as broad; apex rounded, acuminate, base cordate, upper surface glabrous, lower surface glaucous, with minute red punctate glands, sometimes also stipitate-glandular at base, especially on midrib; petioles 1.2-2cm, stipitate-glandular, at least when young. Inflorescence 4-8-flowered; rhachis c.3mm; pedicels c.l5mm, stipitate-glandular. Calyx c.2mm, stipitate-glandular. Corolla campanulate, white to rose-pink, sometimes with purple flecks and a faint basal blotch, 30-40mm. Ovary stipitate-glandular; style glabrous or with a few glands at base. Capsule 15-20 x 3-4mm, curved.
Habitat: Stony slopes, thickets, etc.
Distribution: China(W Yunnan)
Altitude: 3000-4000m
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: purple, rose, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):262
Flowers pink
Illustrations:
Type: China, W Yunnan, Shweli/Salween divide, 25°20'N, 10000ft, Forrest 12019 (holo. E; iso. K)
Synonymy: R. cyclium Balfour f. & Forrest, Notes R.B.G. Edinb. 13:39 (1920). Type: China, W Yunnan, N'Maikha/Salween divide, vi 1919, Forrest 18044 (holo. E; iso. K). R. hedythamnum Balfour f. & Forrest, ibid. 13:261 (1922). Type: China, Mid W Yunnan, Tali Range, W flank, 11000ft, vi 1913, Forrest 11601 (holo. E; iso. K). R. hedythamnum Balfour f. & Forrest var. eglandulosum Handel- Mazzetti, Anz. Akad. Wiss. Wien 79: 3 (1923). Type: China, Yunnan, in lateris orient, montis Dzang-shan prope urbem Dali, 3900-4250m, Handel-Mazzetti 8712, n.v.
Cowan & Davidian maintain R. myiagrum at specific rank while admitting that the only significant difference between it and R. callimorphum is the flower colour, a distinction that certainly does not merit more than varietal rank.
Synonymy: R. myiagrum Balfour f. & Forrest, Notes R.B.G. Edinb. 13: 52 (1920). Type: China, W Yunnan, N'Maikha/Salween divide, 10000ft, vi 1919, Forrest 17793 (holo. E; iso. K).
Tree, (2-)5-12m. Leaves oblong-oblanceolate, 14-30 x 4-7.2cm, 3.5-6 x as long as broad, apex cuspidate to acuminate, base cuneate, lower surface glabrous when mature, or with vestiges of juvenile indumentum persisting along the midrib; petioles 1 -2 cm, stout, glabrous or with a thin indumentum. Inflorescence 5-30-flowered; rhachis 12-20 mm; pedicels 30-55 mm, glabrous. Calyx c. 1 mm, glabrous. Corolla 5-7-lobed, open-campanulate, glabrous, pinkish white with purple flecks and a basal blotch, 40-60 mm. Stamens 15-20, filaments puberulent below. Ovary and style glabrous; stigma discoid. Capsule 25-33 x 6-12 mm.
Habitat: Forests, etc.
Distribution: China (C & E Sichuan, NE Yunnan)
Altitude: 1800-4000m
Occurs in Countries: CN Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: pink, purple, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):228
Leaves 18-30 cm long, apex acuminate; inflorescence 15—30-flowered
Illustrations:
Type: China, Sichuan,Moupine, 4000 m, 1870, Pere David (iso. E)
Illustrations:
Type: China, W Sichuan, Yung Ching hsien, Wa Wu shan, 2300-2800 m, 18 ix 1908, Wilson 3414 (holo. A; iso. K)
Synonymy: R. openshawlanum Rehder & Wilson in PI. Wilsonianae 1: 543 (1915)
Shrub, c.40cm. Twigs slender, at first laxly sub-stellate, the older parts glabrescent, smooth, 1–2mm in diameter; internodes 1.5–2.5cm. Leaves 4–6 in loose pseudowhorls. Blade 20–25 x 5–9mm, narrowly elliptic; apex sub-acutely tapering or sub-acuminate; margin sub-crenulate with impressed scales at first in the crenulations or sub-entire; base tapering, initially laxly scaly on both sides, slowly glabrescent above, sub-persistently scaly beneath. Scales with the thin marginal zone sub-stellate; centre small, impressed. Mid-vein hardly impressed above or flat, thick and obtusely prominent beneath; lateral veins inconspicuous. Petiole 2–3 x 0.7–1mm. Bracts to 20 x 10mm, membranous, red, glabrous and shining outside, ovate; outer ones acuminate-apiculate, inner ones obtuse. Inflorescence of solitary or paired, hanging, flowers. Pedicels 15–20mm, slender, densely stellately scaly. Calyx c.2.5mm in diameter, obliquely disc-shaped, often covered by the basal lobed part of the corolla tube, hardly lobed, scaly outside. Corolla 30–35mm, weakly zygomorphic, red, thin; tube 20–25 x 5–6 x 8–10mm, straight, laxly sub-stellately scaly outside, otherwise glabrous; lobes c.10 x 5–8mm, half-spreading, broadly obovate-oblong. Stamens very unequal, the longest reaching the mouth, hardly exserted; filaments linear, glabrous; anthers 1.5–1.8 x 1mm, obovate-oblong, base obtuse. Disc prominent, glabrous. Ovary 4 x 1.5mm, sub-obliquely cylindrical, densely covered with sub-stellate, brown scales but without hairs, tapering distally; style slender with some scales at the base, glabrous distally; stigma rounded, shortly 5-lobed.
Habitat: In alpine or semi-alpine shrubby vegetation. Rare.
Distribution: Indonesia, New Guinea (W), Star Mts, Mt Antares.
Altitude: 3000-3200m
Greek – kalos – beautiful; anthos – flowers. The rhododendron with beautiful flowers.
Sleumer (1961) commented that it was related to R. rubrobracteatum but differed in having smaller leaves and a larger corolla.
Type: Kalkman 454227, July 1959. New Guinea (C), Star Mts, Mt Antares, 3000–3200m (L).
Occurs in Countries: ID Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:233
Prostrate, matted or erect intricate shrub, 0.05-1-5 m. Young growth densely lepidote, not loriform-setose, or if so the setae quickly deciduous. Leaves suborbicular to oblong-ovate, rarely oblong-obovate, 11-33 x (2-)4-20 mm, upper surface matt with persistent, dried-out scales, rarely elepidote and somewhat shining, margins sparsely loriform-ciliate, lower surface with dense, overlapping scales arranged in 3-4 tiers, those of the outermost tier with long stalks and cup-shaped discs. Inflorescence 1 -5-flowered, pedicels lepidote with usually many long-stalked scales with cup-shaped discs. Calyx with frequently unequal, oblong to ovate lobes, rounded at the apex, variably lepidote and filiform-acicular pubescent on the surface, margins loriform-setose, inner surface puberulent. Corolla magenta, more rarely pink or purple, often with darker spots on the upper lobes, 18-28 mm, tube 7-12(-14) mm, pilose outside, occasionally somewhat lepidote also. Stamens 10. Ovary lepidote, glabrous. Capsule 6-9 mm, lepidote.
Occurs in Countries: CN, IN, MM Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: pink, purple
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):115
Leaves ± obtuse, lepidote above, (7-)9-20 mm broad; decumbent or erect shrubs. Scales on the undersurface clearly borne in 3-4 tiers; leaves 12-22 mm long. Flowers 1-2 in each inflorescence; pedicels 16-27 mm
Habitat: Stony alpine meadows and cliffs
Distribution: N Burma, China (W Yunnan)
Altitude: 3300-4250m
Illustrations:
Type: NE Burma, ridge of the Naung chaung/Nwai Divide, 16 vii 1914, Kingdon Ward 1790 (holo. E)
Leaves ± acute, elepidote above, 2-7(-9) mm broad; prostrate shrublet
Habitat: Stony alpine slopes
Distribution: NE Burma, China (NW Yunnan, SE Xizang)
Altitude: 4250-4550m
Illustrations:
Subsp. keleticum is found only in the area of overlap between R. calostrotum and R. saluenense subsp. chameunum, at the highest altitudes; it grades into subsp. riparium below c. 4200 m.
Synonymy: R. keleticum Balfour f. & Forrest, Notes R.B.G. Edinb. 13:50 (1920). Type: China, SE Tibet, Tsarong, Salween/Kiu chiang Divide, viii 1919, Forrest 18918 (holo. E). R. radicans Balfour f. & Forrest, op. cit.: 290 (1922). Type: China, SE Tibet, Tsarong, Salween/Kiu chiang Divide, Forrest 19919 (holo. E)
Leaves ± obtuse, lepidote above, (7-)9-20 mm broad; decumbent or erect shrubs. Scales on leaf undersurface ± flat, the tiers indistinct; leaves 22-33 mm long.
Habitat: Alpine meadows, cliffs, slopes
Distribution: China (NW Yunnan)
Altitude: 3650-4450m
Very similar to subsp. riparium but differing in its larger leaves and flowers, and the scales on the leaf undersurface not being so clearly tiered, presenting a smooth, almost felted appearance. Restricted to the mountains around Weixi (Wei hsi), where R. saluenense subsp. chameunum also occurs. It may be a stabilised hybrid between R. calostrotum and subsp. chameunum.
Type: China, Yunnan, on the Shui-lu-shan W of Wei hsi, 13000 ft, Forrest 25503 (holo. E)
Leaves ± obtuse, lepidote above, (7-)9-20 mm broad; decumbent or erect shrubs. Scales on the undersurface clearly borne in 3-4 tiers; leaves 12-22 mm long. Flowers 2-5 in each inflorescence; pedicels 10(-15) mm
Habitat: Open rocky slopes and hillsides, often beside streams or in swamps, 3050-4550 m
Distribution: India (Arunachal Pradesh), ne Burma, China (NW Yunnan, S & SE Xizang)
A northerly vicariant of subsp. calostrotum, occupying quite a wide distribution area. The small-leaved variants, described as R. nitens and R. calciphilum are in many ways intermediate to subsp. keleticum.
Synonymy: R. rivulare Kingdon Ward, Gard. Chron. 86:503 (1929) non Handel-Mazzetti (1921). Type: as for R. riparium. R. riparium Kingdon Ward, Notes R.B.G. Edinb. 16:180 (1931). Type: China, S Tibet, Doshong La, 10-11000 ft, Kingdon Ward 5828 (holo. BM, iso. E). R. calciphilum Hutchinson & Kingdon Ward, Notes R.B.G. Edinb. 16:179(1931). Type: Upper Burma, Seinghku Wang, 11-14000 ft, on limestone, Kingdon Ward 6984 (iso. E). R. nitens Hutchinson, Gard. Chron. 99:135 (1936). Type: a cultivated plant (holo. K). R. kingdonii Merrill, Sunyatsenia 3:256 (1937). Type: as for R. riparium. R. calostrotum var. calciphilum (Hutchinson & Kingdon Ward) Davidian, R.H.S. Rhodo. Yearbook 8:87 (1954)
Shrub, 1 -2.5m; young shoots shortly stipitate-glandular, also with a detersile dendroid indumentum. Leaves elliptic to ovate, 6—10 x (2.5-)3.2—4cm, 1.5-2.5(-3) x as long as broad, apex rounded, apiculate, base rounded, upper surface glabrous except for a thin veil of indumentum over the midrib, lower surface with a few stipitate glands and a thin detersile indumentum that is sometimes restricted to near the midrib at the base; petioles l-2cm, glandular and with a sparse indumentum. Inflorescence lax, c.5-flowered; rhachis c.5mm; pedicels 15-28(-35)mm, shortly stipitate-glandular. Calyx 2-3mm, glandular. Corolla funnel-campanulate, white flushed rose, with a few crimson markings, c.35mm. Ovary densely glandular, also with a varying proportion of rufous dendroid hairs; style glabrous. Capsule c.15 x 4mm, curved.
Habitat: Conifer forests, scrub, open rocky places
Distribution: China (SE Xizang, NW Yunnan)
Altitude: 3350-4550m
Var. duseimatum may be a chance hybrid between R. selense and var. calvescens, especially since it has only been collected once and then from a well-known locality. R. calvescens is closely allied to R. dasycladoides, sharing with it the rufous dendroid-hairy ovary, but differing in the lack of bristles and in the more persistent leaf indumentum.
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: crimson, rose, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):275
Leaves 3.2-4cm wide, 1.5-2.5 X as long as broad; pedicels 15-20mm
Type: China, SE Xizang, Tsarong, on Dokar La, 11000ft, vii vii 1917, Forrest 14331 (holo. E; iso. K)
Leaves 2.5-3.2cm wide, c.3 x as long as broad; pedicels 20-28(—35) mm
Synonymy: R. duseimatum Balfour f. & Forrest, Notes R.B.G. Edinb. 13: 41 (1920). Type: China, SE Xizang, Dokar La, Mekong/Salween divide, 12000ft, vii 1917, Forrest 16464 (holo. E; iso. K). R. selense Franchet subsp. duseimatum (Balfour f. & Forrest) Tagg in Stevenson (ed.), The Species of Rhododendron 722 (1930). R. selense Franchet var. duseimatum (Balfour f. & Forrest) Cowan & Davidian, Rhododendron Yearbook 6: 152 (1952).
Shrub to 2 m, epiphytic or growing on rocks. Young growth lepidote. Leaves narrowly elliptic to oblong-elliptic, bluntly acute at the apex, tapering to a shortly rounded base, (53-)60-90(-105) x (16-)20-30(-37) mm, shining dark green above with few, dried-out scales, pale green to brownish beneath with a dense covering of almost contiguous, broadly rimmed scales of which a few are larger and darker than the rest. Inflorescence 1-2-flowered, pedicels densely lepidote. Calyx lobes oblong, rounded at the apex, 5-8 mm, lepidote or not on the surface, fringed with scales. Corolla waxy, with a short, broad tube, white to deep rose, rarely with a whitish or yellowish zone within at the base, lepidote outside, villous within, 14-18(-20) mm, tube 8-10 mm. Ovary 5-10-locular, lepidote, style usually shorter than the stamens. Capsule ovoid, lepidote, tapered to the apex, 7-11(-13) mm
Habitat: Forest and forest margins, cliffs
Distribution: Nepal, India (Sikkim), Bhutan
Altitude: 2750-3650m
Illustrations:
R. lucidum Nuttall, Hooker's Kew Journ. 5: 363, 1853 (Type: On the mountains of Bootan (i.e. India, Arunachal Pradesh, cf, Ludlow, loc. cit.), beyond the Bhorelli, Booth—holo. K) is based on a plant without flowers or fruits. It is probable that it is merely a variant of R. camelliiflorum.
Type: Sikkim Himalaya, 9-10000 ft, fl. vii, fr. xii, Hooker (holo. K)
Synonymy: R. sparsiflorum Nuttall in Hooker's Kew Journ. 5:363 (1853). Type: 'Bootan'(i.e. India, Arunachal Pradesh, cf. Ludlow, Trans. Bot. Soc. Edinb. 41:362, 1972), Booth (holo. K). R. cooperi Balfour f., Notes R.B.G. Edinb. 10:91 (1917). Type: Bhutan, Ridang, Angduphorang, 9000 ft, 8 vi 1915, Cooper 3959 (holo. E)
Occurs in Countries: BT, IN, NP Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: rose, white, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):138
Shrub or small tree, 1.3-4.5m; young shoots glabrous. Leaves ovate to broadly elliptic, 7-14 x 3.8-7.5cm, 1.9-2.5 x as long as broad, apex ± rounded, apiculate, base rounded to cordate, upper surface glabrous when mature, lower surface with a dense fulvous lanate tomentum composed of capitellate to ramiform hairs; petioles 1.5-2.5cm, glabrous. Inflorescence 8-15-flowered; rhachis up to 25mm; pedicels 15-25mm, glabrous. Calyx c.lmm, glabrous. Corolla open-campanulate, white to pale mauve or pink, with ± pronounced purple flecks, 30-50mm. Ovary glabrous. Capsule 20-30 x c.5mm, usually curved.
The following natural hybrids occur in the wild: i. R. campanulatum x R. arboreum-a specimen from Chankali Lagma, Nepal (Polunin, Sykes & Williams 4113) is presumed to be a hybrid of this parentage. ii. R. campanulatum subsp. aeruginosum x R. mghtii. Shrub, 0.6-2m. Leaves coriaceous, 7-10 x 3.2-5cm,c.2 x as long as broad, apex rounded, base rounded to sub-cordate, upper surface glabrous, lower surface with a compacted reddish-brown indumentum composed of radiate hairs; petioles 0.8-lcm, densely tomentose. Inflorescence 10-12-flowered; rhachis up to 12mm; pedicels 10-15mm, very sparsely tomentose to glabrescent. Calyx c.lmm, glabrous. Corolla campanulate, white to purplish-pink, 30-35mm. Ovary glabrous. Fruit not known. Occurs where the ranges of the two parents overlap, especially in C Bhutan. iii. R. campanulatum subsp .campanulatum x R. w/gM/-a smgle specimen with leaves 11 x 6.2cm but otherwise as in 'ii.? is presumed to be a hybrid with this parentage (Sharma E 219, from Nepal).
Occurs in Countries: BT, IN, NP Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: lilac, mauve, pink, purple, rose, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):372
Leaves 7-9.5cm long (wild specimens), coriaceous, opening with a bluish metallic bloom on the upper surface; corolla lilac or purple.
Habitat: Alpine slopes
Distribution: N India (Sikkim), Bhutan, ? E Nepal
Altitude: 3800-4500m
All specimens seen of subsp. aeruginosum have small coriaceous leaves and in this respect agree well with the type specimen. However, the characteristic bloom on the upper surfaces of the leaves is usually lost on drying so it cannot be observed on most herbariaum material. I have not seen any specimens from C and E Sikkim or from Bhutan that match W Himalayan specimens in the size of their leaves but there is a series of fruiting specimens, presumed to have been collected in Sikkim (Cave 6719, 6726, 6983; Watt 5245, 5295, 5296), with leaves 7.5-9cm long, but subcoriaceous and with a less thick indumentum than is usual in subsp. aeruginosum. These may be considered as being intermediate between the two subspecies. There is also a series of intermediate plants in cultivation from E Nepal (Spring-Smythe 7, 8, 9, 11, 17, 41, 44). On present evidence therefore, subsp. aeruginosum apparently replaces subsp. campanulatum in the east but there is a zone of overlap.
Synonymy: R. aeruginosum Hooker f., Rhododendrons Sikkim Himalaya 23, t.22 (1849). Type: Sikkim Himalaya, Laochun, Lachung, Hooker (E). R. campanulatum D. Don var. aeruginosum [Hooker f. ex] Cowan & Davidian, Rhododendron Yearbook 4: 168 (1949).
Leaves 9.5-14cm long, subcoriaceous, without a metallic bloom; corolla whitish to pale rose or lilac.
Habitat: Mixed forest, scrub, etc.
Distribution: N India (Kashmir to W Sikkim), Nepal, Bhutan
Altitude: 2700-3500m
Illustrations:
Type: C Nepal, Gossaingsthan, Wallich 756a (iso. E)
Synonymy: R. nobile Wallich, pro parte, nomen nudum.
Shrub or small tree, 1—4(—6.5)m; young shoots usually with a few short stipitate glands. Leaves orbicular to elliptic, 3.2-10 x 1.5-5cm, 1.1-2.5 x as long as broad, apex rounded and apiculate, base ± cordate, upper and lower surfaces glabrous when mature, rarely with a few glands at base below; petioles 0.5-2.2cm, stipitate-glandular, at least when young. Inflorescence 3 —10(—15)-flowered; rhachis 3-5mm, rarely up to 20mm; pedicels 10-35mm, stipitate-glandular. Calyx 3-5mm, stipitate-glandular, lobes rounded. Corolla campanulate, pale to sulphur yellow, sometimes tinged with red in bud, with or without a basal blotch, 25-40mm. Ovary densely stipitate-glandular; style glabrous or glandular for up to one third of its length. Capsule 13-20 x 4-7mm, curved.
Occurs in Countries: BT, CN, IN, MM, NP Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: red, yellow
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):263
Habitat: Forest margins, Rhododendron thickets, open places
Distribution: NE Upper Burma and adjacent provinces of China (SE Xizang & W Yunnan)
Altitude: 3000-4300m
Apparently intergrading with subsp. campylocarpum though probably entirely replacing it in the eastern part of the range of the species. Some forms of subsp. caloxanthum have a marked glaucous bloom on the lower surface of the leaves. These have been referred to R. telopeum. This character is difficult to see in dried material and there are plants from the western part of the range of subsp. campylocarpum that also have glaucous leaves. It therefore seems likely that they are no more than local habitat forms, perhaps showing a response to more exposed conditions. A specimen from SE Xizang, Ludlow, Sherriff & Elliot 13756, is a hybrid of R. campylocarpum, possibly with R. stewartianum as the other parent. R. campylocarpum also hybridises with R. wardii (q.v.) where the ranges of the two species overlap.
Synonymy: R. telopeum Balfour f. & Forrest, Notes R.B.G. Edinb. 13: 61 (1921) Type: China, SE Xizang, Tsarong, Salween/Kiu-chiang divide, vii 1919, Forrest 18963 (holo. E; iso. K). R. caloxanthum Balfour f. & Farrer, Notes R.B.G. Edinb. 13: 238 (1922). Type: NE Burma, Chimili, 12000ft, 18 v 1919, Farrer 837 (holo. E). R. campylocarpum Hooker f. subsp. telopeum (Balfour f. & Forrest) Chamberlain, Notes R.B.G. Edinb. 36: 116 (1978).
Habitat: Open forests, stony slopes
Distribution: Nepal, N India (Sikkim, Arunachal Pradesh), Bhutan, China (S Xizang)
Altitude: 3000-4600m
Illustrations:
Several specimens from Fuchuan, SW of Weixi in NW Yunnan are technically referable to subsp. campylocarpum though they have leaves that are relatively small and which sometimes have rounded bases. These might be part of a stabilised hybrid population with subsp. caloxanthum and R. selense s.l. as putative parents, especially as this locality is outside the normal range of subsp. campylocarpum. These specimens are as follows: McLaren D 231; Rock 16980, 16996, 17011, 17012, 17019, 18353, 18373, 18393.
Type: Sikkim, 11 —14000ft, Hooker (holo. K; iso. E)
Creeping, prostrate or decumbent shrublet up to 60 cm (-1 m), more rarely an erect or ascending shrub. Young growth sparsely lepidote, glabrous or pubescent. Leaves obovate or narrowly elliptic, obtuse or rarely subacute at the apex, tapered to the base, (10-)14-25(-34) x (4-)7-12 mm, dark green and sparsely pubescent along the midrib above, papillose and often whitish or silvery beneath, glabrous and with distant, deciduous scales. Inflorescence l-2(-3)-flowered, pedicels sparsely lepidote and pubescent, 25-50 mm, up to 70 mm in fruit. Calyx lobes oblong or obovate, sometimes obscure, usually 4-7 mm, glabrous and usually elepidote. Corolla pink to red or purple, (10-)13-20(-23) mm, tube 7-12 mm, glabrous, elepidote and pruinose outside, sparsely pubescent within the tube. Capsule borne on the accrescent and rigid pedicels, ovoid-cylindric, 7-9 mm, sparsely lepidote.
Habitat: On cliffs and ledges and in moorland and scrub, 2750-4250(-4900) m
Distribution: India (Arunachal Pradesh), ne Burma, China (N, NW, W, C & SW Yunnan, S & SE Xizang)
Illustrations:
A variable species as to leaf size and shape and corolla colour and size. None of the variation is either correlated or geographically significant.
Type: China, Yunnan, in rupibus graniticis montis Tsang chan supra Tali, 14 vi 1884, Delavay (holo. P.—n.v.)
Synonymy: R. caeruleo-giaucum Balfour f. & Forrest, Notes R.B.G. Edinb. 13:34 (1920). Type: China, SE Tibet, Tsarong, Salween/Kiu chiang Divide, vii 1919, Forrest 19181 (holo. E). R. cremastum Balfour f. & Forrest, op. cit.: 39. Type: China, NW Yunnan, Mekong/Salween Divide, vii 1917, Forrest 14266 (holo. E). R. glauco-aureum Balfour f. & Forrest, op. cit.: 46. Type: China, Yunnan, Shweli/Salween Divide, vii 1918, Forrest 17544 (holo. E). R. charopoeum Balfour f. & Forrest, op. cit.: 245 (1922). Type: NE Burma, Chawchi pass, 11-13000 ft, Farrer 1670 (holo. E). NOTES RBG EDINB. 39 (1) R. damascenum Balfour f. & Forrest, op. cit.: 254. Type: China, NW Yunnan, Se la, Soutie (holo. E). R. myrtilloides Balfour f. & Kingdon Ward, Notes R.B.G. Edinb. 13:276 (1922). Type: NE Burma, ridge of Naung chaung in Nwai Divide, 15000 ft, 15 vii 1914, Kingdon Ward 1785 (holo. E). R. cerasiflorum Kingdon Ward, Gard. Chron. 93:277 (1933) nomen nudum. R. rubriflorum Kingdon Ward, Rhodo. Assoc. Yearb. Suppl. 240 (1934) nomen nudum. R. campylogynum var. celswn Davidian, Rhodo. Yearbook 8:83 (1954). Type: China, Yunnan, eastern flank of Tali range, 11-12000 ft, Forrest 4151 (holo. E). R. campylogynum var. charopoeum (Balfour f. & Forrest) Davidian, loc. cit. R. campylogynum var. cremastum (Balfour f. & Forrest) Davidian, loc. cit. R. campylogynum var. myrtilloides (Balfour f. & Kingdon Ward) Davidian, op. cit.: 84.
Occurs in Countries: CN, IN, MM Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: purple, red
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):145
Prostrate or low shrub (usually less than 20cm high), much branched, deciduous or evergreen, the dry bud-scales ± persistent. Leafy shoots from separate buds below the inflorescences; leaves ± sessile, obovate or spathulate, 10-60 x 4-22 mm, base cuneate, apex rounded with a glandular apiculum, serrulate, with marginal cilia and pubescent on the veins below, reticulation of veins evident. Inflorescence buds terminal, opening to produce a 1-3-flowered raceme, the peduncle bearing leafy bracts, often with glandular hairs as well as cilia. Calyx lobes oblong, 8-18 X 4-5 mm, obtuse, margins and back with cilia and glandular hairs. Corolla rose-purple (rarely white) with darker spots, ± rotate, pubescent outside or glabrous, c.20-25 mm long, tube c.7 mm long, the division between the lower pairs of lobes reaching to the base of the tube. Stamens 10, unequal in length, the largest ± equalling the corolla; filaments hairy below. Ovary ovoid, c.6 mm long, pubescent, 5-locular; style curved, pubescent near the base. Capsule ovoid, c.lOmm long, pubescent.
Occurs in Countries: JP, RU, US Subgenus: Therorhodion Habit: Non-Tree Fl. Colour: white
Philipson, W.R. & Philipson, M.N. (1986) A Revision of Rhododendron III. Subgenera Azaleastrum, Mumeazalea, Candidastrum and Therorhodion. Notes from the Royal Botanic Garden Edinburgh 44(1):19
Foliage on vegetative shoots without glandular hairs (or these very sparse); corolla lobes pubescent on the outside and with ciliate margins.
Distribution: Japan (N Honshu, Hokkaido), USSR (S & E Kamtschatka, Kuriles Islands), USA (Aleutian Islands and S Alaskan coast).
A lower growing plant with narrower corolla lobes. The leaves of the vegetative shoots are distinctly glandular-hairy and the outer surface of the corolla lobes is glabrous (or virtually so) and margins are not ciliate.
Distribution: USSR (Siberia north of Okhotsk to the Bering Strait), USA (W Alaska - Seward Peninsula and lower Yukon River valley)
Over most of the range of the species these two subspecies are morphologically distinct and have separate geographical distributions, However, intermediate forms occur in the zone where the two subspecies meet (see Hulten, op. cit.).
Synonymy: Therorhodion glandulosum Small, N. Amer. Fl. 29(1):45 (1914). Type: USA, Alaska, foot of Kigluiak Mountain, nr Ooglak Bay, Imurak Basin, n.v. Rhododendron glandulosum (Small) Hutchinson in Stevenson (ed.), The Species of Rhododendron 190 (1930).
Rhizomatous shrub to lm tall; bark reddish brown to grey, smooth to very slightly longitudinally grooved and flaking; young twigs pale to reddish brown, often with a pink tinge, usually glaucous, sparsely covered with multicellular eglandular and shorter gland-headed hairs, moderately to densely covered with short unicellular hairs; new foliage shoots arising from axillary buds associated with foliage leaves of previous year's shoot (i.e. below terminal bud), and some terminal buds. Vegetative bud scales moderately to densely unicellular-pubescent abaxially and often with scattered multicellular gland-headed and eglandular hairs, especially near apex or along midvein, moderately to densely unicellular-pubescent adaxially; margin fringed with unicellular hairs, the lowermost scales often with aristate apices or rudimentary blades. Leaves deciduous, dull bluish green (glaucous) to rarely dark green adaxially, pale to whitish green abaxially, turning red in autumn, alternate (with internodes becoming more closely spaced towards tip of shoot). Blade membranaceous to char-taceous, elliptic or oblong to obovate, 1-8.3 x0.4-3cm; base cuneate or acute to rounded, apex acute to rounded, usually with a short mucro; midvein strongly raised and prominent abaxially, the secondary veins flat to slightly raised abaxially; adaxial surface, including midvein, sparsely to moderately covered with short unicellular hairs and multicellular eglandular and gland-headed hairs; abaxial surface, including midvein and higher order veins, moderately to densely covered with short unicellular hairs and moderately covered with multicellular eglandular and gland-headed hairs, the eglandular hairs of midvein larger than those of higher order veins and lamina; margin entire, revolute to less commonly plane, fringed with multicellular eglandular hairs and with inconspicuous unicellular hairs; petiole l-12mm long, moderately to densely unicellular-pubescent, and with scattered multicellular eglandular and gland-headed hairs, the base of petiole slightly expanded at point of attachment. Flower buds terminal (rarely also from axillary buds just below terminal bud), larger than, but otherwise ± similar to, vegetative buds, more frequently densely unicellular-pubescent. Flowers appearing before or occasionally with the leaves; inflorescence an umbellate raceme of 3-9 flowers. Pedicels 3-10mm long, usually glaucous, usually sparsely covered with multicellular gland-headed hairs, and lacking to densely covered with unicellular hairs. Calyx lobes broadly subovate to triangular-ovate, 0.4-1.5 x 0.7-1.6mm; apex rounded; margin fringed with multicellular gland-headed and/or eglandular hairs, and unicellular hairs; adaxial surface glabrous; abaxial surface usually glaucous, glabrous to densely unicellular-pubescent, often with scattered multicellular gland-headed hairs. Corolla rose-purple to pink, or rarely white, unspotted to red-spotted on upper 3 lobes, fragrant, strongly zygomorphic, clearly 2-lipped due to the very extensive fusion of the upper 3 lobes contrasting with the 2 elongate and widely divergent lower lobes, the tube essentially lacking due to deep division between 2 lower lobes and between lateral and lower lobes; upper corolla lobe 0.3-0.8 x 0.25-0.5cm; lateral lobes 1.2-2.2 x 0.25-0.4cm (closely fused with upper lobe); lower lobes 1.2-2.2 x 0.25-0.6cm (± free); outer and inner surfaces of corolla glabrous to occasionally with few scattered multicellular gland-headed hairs. Stamens 10, slightly declinate to ± straight, variable in length, 0.9-2cm long, exserted (due to deeply cut corolla); filaments glabrous distally, becoming densely covered with flattened unicellular hairs proximally. Ovary L7-3mm long, densely covered with multicellular gland-headed and eglandular hairs and unicellular hairs; style slightly declinate, 1.1-2.2cm long, glabrous to unicellular-pubescent near base, often glaucous. Capsules ovoid to nearly cylindrical and curved near the base, slightly grooved, 0.7-1.7x0.3-0.6cm, often glaucous, moderately covered with multicellular gland-headed and eglandular hairs and densely covered with short unicellular hairs. Seeds brown, flattened ellipsoid, 1-2.7x0.4-1.3mm; testa tightly appressed to body, with cells at each end elongated and expanded, forming a flat tail 0.3-0.9mm long, the cells covering central portion of body elongate and non-bulging, those along margin expanded and flattened (in plane parallel to compression of seed body), forming an irregular wing-like fringe connecting the tails. Cotyledons lacking multicellular hairs and with venation represented by rnidvein and one (or very few) poorly developed secondary veins. 2´ = 52 (Sax, 1930).
Habitat: In moist to dry coniferous or deciduous forests, thickets, open rocky areas, lake margins, bogs, and swamps
Distribution: Distributed from Newfoundland and Quebec, south to eastern Pennsylvania and northern New Jersey.
Altitude: 0-1900m
Illustrations:
Rhododendron canadense is a very distinctive species most closely related to R. vaseyi; see discussion following the latter species. Although originally described as the genus Rhodora (Linnaeus, 1762), its close relationship to Rhododendron has long been recognized (see Rehder, 1921a; Sleumer, 1949, 1980; Wood, 1961).
The artificial (and infertile) hybrid between Rhododendron canadense and R. molle (Blume) G. Don subsp. japonicum (A. Gray) K. Kron is referred to as R. fraseri W. Watson (Gard. Chron., ser. 3, 67: 225, 1920). Representative specimens of this entity include: Fraser s.n., 1929 (A); C.E.K. C.K.A., Arnold Arbor. #15359 (A); Rehder s.n., 29 iii 1920 (A); E.J.P., Arnold Arbor. #15359-1 (A).
Occurs in Countries: JE Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Pentanthera Habit: Non-Tree Fl. Colour: pink, red, white
Judd, W.S. & Kron, K.A. (1995) A Revision of Rhododendron VI. Subgenus Pentanthera (Sections Sciadorhodion, Rhodora and Viscidula). Edinburgh Journal of Botany 52(1):30
Shrub or small tree to 6m tall, usually non-rhizomatous; young twigs red-brown, sparsely to densely covered with unicellular hairs and multicellular eglandular hairs, occasionally with only unicellular hairs, or with unicellular hairs and multicellular gland-tipped hairs, rarely glabrous. Vegetative bud scales densely covered with unicellular hairs abaxially; margin unicellular-ciliate or glandular. Leaf blade membranaceous, ovate or obovate to elliptic, (4.7-)5.9-8.5(-9.8) x (1.4-)1.9-2.8(-3.6)cm; base acute to oblique; apex acute to obtuse, often mucronate; adaxial surface sparsely to densely covered with unicellular hairs, or also with multicellular eglandular hairs, occasionally only with multicellular eglandular hairs, rarely with unicellular hairs and multicellular gland-tipped hairs, the midvein densely covered with unicellular hairs; abaxial surface sparsely to densely covered with unicellular hairs, rarely also with multicellular eglandular hairs, or glabrous, the midvein densely covered with unicellular hairs and multicellular eglandular hairs, or rarely with multicellular gland-tipped hairs or only unicellular hairs; margin entire, rarely minutely serrulate, ciliate with multicellular eglandular hairs, rarely with a few multicellular gland-tipped hairs at the base of the blade; petiole (0. l-)0.2-0.4(-0.5)cm long, sparsely to densely covered with unicellular hairs and multicellular eglandular hairs, occasionally with unicellular hairs and multicellular gland-tipped hairs, rarely with only unicellular hairs. Flower bud scales chestnut brown; abaxial surface densely covered with unicellular hairs; margin unicellular-ciliate, occasionally with both unicellular hairs and glands. Flowers appearing before or with the leaves; inflorescence a shortened raceme of 6 to 19 flowers. Pedicels (0.4-)0.5-l .0(-l .3)cm long, sparsely to densely covered with unicellular hairs and multicellular eglandular hairs, occasionally with unicellular hairs and multicellular gland-tipped hairs, rarely with all three types of hairs. Sepals less than 0.1-0.2(-0.4)cm long, often varying in length on the same flower; margins setose, occasionally also with multicellular gland-tipped hairs, or only glandular-fimbriate; abaxial surface densely covered with unicellular hairs, or also with multicellular eglandular hairs, occasionally with unicellular hairs and multicellular gland-tipped hairs, rarely with all three types of hairs. Corolla pink, or the tube pale to deep pink and the lobes pale pink to white, occasionally white or rose to deep pink throughout, fragrance musky-sweet, the tube longer than the limb and gradually expanding into it; upper corolla lobe (0.7-)0.8-l .3(-l .5) x (0.6-)0.7-l .0(-l .4)cm wide; lateral lobes (0.8-)1.0-1.5(-2.0) x (0.3-)0.5-0.8(-1.0)cm; corolla tube (1.3-)1.5-2.0(-2.6) long, (0. l-)0.2-0.3(-0.4)cm wide at base; outer surface of corolla densely covered with unicellular hairs and sparsely to densely covered with multicellular gland-tipped hairs that occasionally continue up the corolla lobes; inner surface of corolla sparsely to densely covered with terete or rarely flattened unicellular hairs. Stamens (3.1-)4.4-5.7(-6.4)cm long, with dense terete or flattened unicellular hairs on proximal (0.0-)2.0-3.1(-4.1)cm of filament, exserted (1.7-)2.5-3.6(-4.5)cm beyond throat of corolla. Style (3.7-)4.4-5.7(-6.8)cm long, exserted (2.0-)2.7-3.9(-4.8)cm beyond throat of corolla, with dense unicellular hairs on proximal (0.0-)0.7-2.0(-3.3)cm; stigma 0. l-0.2cm wide. Ovary 0.3-0.4(-0.5)cm long, 0. l-0.2(-0.3)cm wide at the base, densely covered with unicellular hairs and multicellular eglandular hairs, occasionally also with multicellular gland-tipped hairs, or with unicellular hairs and multicellular gland-tipped hairs; the multicellular hairs may cover the unicellular hairs or may only occur on the ribs of the ovary; the nectary is crowned with a dense ring of unicellular hairs. Capsules (1.2ó)1.5ó2.1(ó2.5) x 0.3-0.5cm wide, narrowly ovate to cylindric, moderately to densely covered with unicellular hairs and sparsely to moderately covered with multicellular eglandular hairs. Seeds pale to dark chestnut brown, ovate or elliptic to fusiform, (1.2-) 1.6-2.5(-3.0) x (0.3-)0.5-0.8(-l.l)mm, body (0.6-)0.8-1.2(-1.4) x (0.1-)0.3-0.5(-0.6)mm; testa expanded and dorsiventrally flattened, surrounding the body, with both elongate and short cells scattered throughout the testa, the short eels more common in the expanded portion of the testa, with tapering end-walls
Habitat: River bottoms and stream banks, low flatwoods, dry clearings and open woods.
Distribution: Tennessee and southern North Carolina, south along the Coastal Plain and Piedmont to peninsular Florida, west to eastern Texas and Oklahoma, north to Union Co., Illinois (Fig. 27).
Altitude: 0-500m
Chromosome number: In = 26 (Janaki-Ammal et al., 1950; Li, 1957)
Flowering from March to April; occasionally as late as June or July.
Rhododendron canescens is similar morphologically toR.prinophyHum mAR. periclymenoides, and these three variable species have been considered difficult to identify by previous workers (Rehder, 1921; Skinner, 1955,1961; King, 1977a, b, 1980; Galle, 1985). In addition, hybridization can occur where the habitats and geographic ranges of these species overlap. All three species have pink-white corollas, and flower before or with the leaves in the spring. In general, the corolla tube expands gradually into the limb, but in R. canescens the limb is slightly more abruptly expanded than in R. periclymenoides orR. prinophyllum. This character is difficult to measure on herbarium material, and, in this group, is continuously variable. In the past, the characters used to distinguishR. canescens fmmR. periclymenoides were primarily those of the indumentum of the corolla tube (Rehder, 1921; Skinner, 1955,1961). Rhododendron canescens has multicellular gland-tipped hairs on the outer surface of the corolla tube, whereas most populations of R. periclymenoides have multicellular eglandular hairs. However, there are glandular forms of R. periclymenoides. These were attributed to hybridization by Skinner (1961). Other characters used to distinguish R. canescens from R. periclymenoides include the following: dense unicellular pubescence of the abaxial surface of the leaves (Porter, 1889a; Rehder, 1921; Skinner, 1961) and dense unicellular pubescence of the abaxial surface of the bud scales (Rehder, 1921; Lawrence, 1954; Skinner, 1961; Galle, 1968). Galle (1968) noted that R. periclymenoides is rarely white, while R. canescens often has at least some white on the corolla limb, if not also on the corolla tube. The gradually expanding corolla tube and the less dense unicellular pubescent condition of the leaves of some individuals of R. prinophyllum have led to some confusion in separating it from R. periclymenoides. These two species are more northern in their distribution than R. canescens and are sympatric throughout much of their range. Although Rehder (1921) recognized these as distinct species, Weigand (1924) commented that one species graded into the other, and thus recognized R. prinophyllum as a variety of R. periclymenoides [ R. nudiflorum (L.) Torrey var. roseum (Lois.) Weigand]. Lawrence (1954) discussed the differences between the two species, and distinguished R. prinophyllum from R. periclymenoides on the following characters: unicellular pubescent bud scales vs. usually glabrous bud scales, blue-green adaxial leaf surface vs. bright green surface, 'spicy9 fragrance vs. sweet fragrance, multicellular gland-tipped hairs on the surface of the corolla vs. multicellular eglandular hairs, shorter stamens and the fruit with multicellular glandular hairs vs. longer stamens and the fruit with multicellular eglandular hairs. Skinner (1961) also reported that plants of R. prinophyllum were generally non-stoloniferous, whereas those of R. periclymenoides were often stoloniferous. 306 EDINB. J. BOT. 50(3) Fig. 27. Distribution of Rhododendron canescens. The results of principal component analysis of 117 OTUs using 26 floral characters (see Table 5, Fig. 28) show that R. prinophyllum is morphologically the most distinctive of the three pink to white early flowering species. The characters which influenced the first principal component were primarily those of floral indumentum and size. Among the floral characters influencing the first component, sepal margin and pedicel pubescence were the most heavily factored. In R. canescens and R. periclymenoides the sepal margin is usually setose, whereas the sepals of R. prinophyllum usually have at least some multicellular gland-tipped hairs along the margin. In addition, the pedicels of R. prinophyllum are more often glandular than those of R. canescens or R. periclymenoides. It is interesting to note that when these indumentum characters are considered individually, R. prinophyllum is usually more distinct from R. periclymenoides, with which it is often sympatric, than it is from the allopatric R. canescens. Even though the range of morphological variation within each species overlaps to some extent, the overlap is consistently less between R. prinophyllum and R. periclymenoides than between R. prinophyllum and R. canescens. The delimitation of R. periclymenoides and R. canescens is less definite. These two species are generally allopatric but their geographic ranges overlap as R. canescens extends into the Piedmont and R. periclymenoides is found on the northern Atlantic Coastal Plain. The results of principal component analysis of 88 OTUs using 30 floral and bud-scale characters (see Table 5, Fig. 29) show that these two species are indeed very similar morphologically. The first component is most heavily influenced by corolla size, while the second is influenced most by the stamen length and sepal margin. Rhododendron periclymenoides has a greater percentage of individuals with pedicels lacking unicellular hairs than R. canescens, which always has pedicels with unicellular hairs. While the pedicels of R. canescens and R. periclymenoides usually have multicelluar eglandular hairs, R. canescens also often possesses at least some multicellular gland-tipped hairs on the pedicel. Since the indumentum of the corolla tube has been stressed in previous treatments this character was investigated with respect to its geographical distribution and its occurrence in the principal component analysis plot. The occasional glandular condition of the corolla tube of R. periclymenoides does not correlate with overlap of the geographic ranges of R. canescens and R. periclymenoides. Instead, it occurs sporadically in populations throughout the range of R. periclymenoides, often where R. canescens does not occur. Therefore the glandular condition of some individuals of R. periclymenoides reflects natural variation within the species, and usually does not indicate hybridization with R. canescens. However, the morphological similarity between these two species, whose ranges are primarily allopatric, raises the question of whether they should be considered to be geographical subspecies. This can best be answered by the results of the cladistic analysis (see Phylogenetic Analysis). Rhododendron periclymenoides and R. canescens form a paraphyletic group and therefore it would be phylogenetically misleading to lump both taxa into a single species. Therefore two partially sympatric species are recognized: Rhododendron periclymenoides and R. canescens. The most variable characters of R. canescens are the density of the pubescence of the leaves, flower colour, and, to a lesser extent, bud-scale margins. Plants in southern Georgia, Arkansas and Oklahoma tend to be very densely unicellular pubescent, whereas those individuals in Louisiana and Mississippi tend to be more sparsely unicellular pubescent. The flower colour varies from completely white to dark pink, but these variations do not show any geographical or ecological pattern. The margin of the bud scales is almost always ciliate, except for some populations in central Georgia and South Carolina. In these populations the bud-scale margins are hiixed unicellular-ciliate and glandular. Whereas R. canescens and R. prinophyllum are almost completely allopatric, the geographic range of R. canescens overlaps with that of R. periclymenoides. Rhododendron canescens is generally found in wetter habitats than R. periclymenoides, but this is not always the case, especially in the upper Piedmont. Rhododendron canescens hybridizes with several species that occur within its geographic range.
Synonymy: Azalea canescens Michaux, Fl. Bor.-Amer. 1: 150 (1803). Type: juxta rivulos Carolinae inferioris. A. Michaux s.n. (lecto. designated here, P-MICHX; IDC #6411,36.1.4). Azalea nudiflora var. bicolor Aiton, Hort. Kew. 1: 203 (1789). A. bicolor (Aiton) Pursh, Fl. Am. Septentr. 1: 153 (1814). Rhododendron bicolor (Aiton) Sweet, Hort. Brit. 344 (1830). Type: n.v. Azalea rosea Lois, in Duhamel, Traite Arb. Arbust. ed. 2, 224: 64 (1812), nom. illeg.; Rhododendron roseum (Lois,) Rehder, Monogr. Azaleas 138-139 (1921), nom. illeg.; R. nudiflorum (L.) Torr. var. roseum (Lois.) Weigand in Rhodora 26:1-5 (1924), nom. illeg. Type: as for A. canescens Michaux. Azalea Candida Small in Bull. Torrey Bot. Club. 28: 360 (1901). Rhododendron candidum (Small) Rehder, in Bailey, Stand. Cycl. Hort. 5: 2945 (1916). R. canescens (Michaux) Sweet var. candidum (Small) Rehder, Monogr. Azaleas. 146 (1921). Azalea canescens var. Candida (Small) Ashe in J. Elisha Mitchell Sci. Soc. 38: 91 (1922). Type: Georgia, Lowndes Co.: along Withlacoochee River, about Valdosta. 6-12 vi 1895. /. K. Small s.n. (holo. NY; iso. A, NY). Rhododendron canescens f. subglabrum Rehder, Monogr. Azaleas 145 (1921). Type: Mississippi, Hinds Co.: Jackson, 15 iv 1915. T. G. Harbison 16 (lecto. A; isolecto. NCU).
Altitude Ranges: 0 - 1,000m Subgenus: Pentanthera Habit: Tree Fl. Colour: pink, rose, white
Kron, K.A. (1993) A Revision of Rhododendron Section Pentanthera. Edinburgh Journal of Botany 50(3):302
Terrestrial, erect, branching shrub, c.50cm. Twigs erect, slender, rounded, 1–2mm in diameter, tips laxly scaly, glabrescent below. Leaves crowded especially at the tips of the new shoots. Blade 8–15 x 3–6mm, elliptic or obovate; apex abruptly acuminate; margin thickened and a little paler than the lamina, sub-crenulate where impressed scales are, or have been, slightly or not revolute; base acutely tapering, dark green above, lighter green below, sub-densely scaly on both sides initially, glabrescent and shiny above at maturity, persistently scaly below. Scales the marginal zones entire and somewhat irregular, impressed with thickened centres. Mid-vein impressed above, raised beneath; lateral veins obscure. Petiole 2–3mm, slender, flattened, laxly scaly. Outer bracts 6–10mm, ovate-acuminate, subulate or apiculate, laxly scaly and very laxly hairy; inner bracts broader, obovate, apiculate and very laxly scaly outside. Inflorescence of solitary flowers or in twos. Flowers half-hanging to hanging. Pedicels 12–15mm, slender, scaly. Calyx membranous, with 5 broadly triangular lobes 0.5–1mm. Corolla 25–30mm, tubular, slightly dilated near the mouth, bright red, glabrous inside; tube cylindrical, 17–20 x 3–4 x 5–7mm, slightly curved, laxly scaly outside, glabrous inside; lobes 6–7 x 4–6mm, half-spreading, broadly obovate, scaly proximally outside. Stamens almost equal in length, exserted to c.3mm; filaments linear, laxly hairy in the proximal ¼, glabrous distally; anthers obovate, c.1.5 x 1mm. Disc glabrous except for a minutely hairy upper margin. Ovary cylindrical-conical, densely covered with long white hairs and sub-densely scaly, c.5 x 1.5mm, tapering distally; style just shorter than the corolla tube with a few hairs at the base, glabrous distally; stigma club-shaped-globose.
Habitat: Sub-alpine shrubbery
Distribution: Papua New Guinea, West Sepik Province, Star Mts, summit region of Mt Capella
Named after the mountain on which it was found.
Transferred from Pseudovireya (sensu Sleumer 1966) as the bract margins are scaly, not hairy. At present known only from the type collection and not in cultivation. Said to be closely related to R. pulleanum (Kores 1978) but R. capellae has much less warty twigs, much longer, subulate outer bracts and an ovary which is both hairy and scaly. It would appear to be closer to R. womersleyi but differs in the more slender subulate bracts in addition to the characters used in the key.
Type: Croft & Hope LAE 68056, 29 May 1975. Papua New Guinea, W Sepik Province, Star Mts, summit region of Mt Capella (LAE, A, BRI, CANB, CANU, E, K, L).
Occurs in Countries: PG Subgenus: Vireya Habit: Non-Tree Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:150
Compact and rounded shrub to 1-5 m. Leaves (7-)10-18(-22) x(3-)5-9 mm, elliptic or oblong-elliptic, apex rounded, emucronate, base broadly cuneate, undersurface pale brown with darker speckling, the bicolorous scales contiguous or discontiguous, colourless to straw-coloured with pale golden centres and tan to dark amber with darker centres, usually either equal in number or the pale scales predominating. Inflorescence 3-5-flowered, pedicel 1-3 mm, pilose or lepidote. Calyx variable, often with unequal membranous lobes up to 6 mm, pilose or lepidote at base, margins ciliate. Corolla pale lavender to bluish purple or deep purple, broadly funnel-shaped, pubescent in the throat and sometimes minutely so on the tube outside, 10-15 mm, tube 3-5 mm. Stamens 10, filaments pubescent towards the base. Ovary lepidote, style 6-13 mm, usually slightly exceeding the stamens, glabrous or pubescent towards the base. Capsule ovoid, 5-6 mm, lepidote.
Habitat: Forests, mountainsides, moist meadows
Distribution: China (N Sichuan, Quinghai, Gansu, Shaanxi)
Altitude: 3000-4300m
Similar to R. nitidulum (p. 98), with which it possibly intergrades (cf. Philipson & Philipson, 1975, p. 58)
Type: China, Kansu, Przewalski 22 (holo. LE)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: lavender, purple
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):107
Free-growing shrub up to 1 m. Young growth not loriform-setose. Leaves narrowly elliptic, rarely obovate, tapered to the base and the acute apex, 50-110 x 30-40 mm, dark green and persistently lepidote above, brownish or greyish beneath with scales about their own diameter apart. Inflorescence 2-4-flowered; pedicels lepidote. Calyx unequally 5-lobed, lepidote, the margins loriform-ciliate. Corolla pink all over (sometimes very faintly so), funnel-shaped, 40-50 mm, the tube c. 30 mm, pubescent at the base and moderately lepidote all over the surface outside. Stamens 10, filaments pubescent towards the base. Ovary densely lepidote, tapering into the lepidote style. Capsule lepidote, oblong, up to 20 mm.
Distribution: Know only in cultivation
From the available material, which is all cultivated, R. carneum appears to be reasonably distinct. However, its status must remain doubtful until wild material is collected.
Type: Described from a plant cultivated at Kew, said to originate in the northern Shan States of Burma (holo. K)
Subgenus: Rhododendron Habit: Non-Tree
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):55
Shrub. Twigs rounded, tips glabrous or very laxly scaly; internodes 2.5–9cm. Leaves 3–4 together in pseudowhorls at the upper 3–4 nodes. Blade 40–60 x 25–55mm, ovate to sub-ovate-rounded; apex broadly and shortly acuminate, obtuse; margin entire, flat; base distinctly sub-auriculate, cordate, sessile or nearly so, superficially glabrous, but laxly covered with minute irregularly stellate scales beneath leaving a minute spot where the slightly impressed centre was. Mid-vein flat or slightly impressed above, grooved in the proximal ½, thick and very prominent beneath proximally, less so distally; lateral veins c.10 per side, 2–3 of them from the base of the blade, the others from the mid-vein, all curved-ascending and anastomosing near the edge, prominent on both sides, reticulation dense and clearly visible especially beneath. Petiole c.1 x 1.5mm. Bracteoles linear. Inflorescence a 4–5-flowered umbel. Pedicels 13–25mm, thick, sub-densely to laxly thin-scaly, thickened at apex. Calyx c.2mm in diameter, oblique, membranous, shortly, obtusely 5-lobed to 1mm, shortly fringed. Corolla trumpet-shaped, white; tube 55–60 x c.3.5 x c.7mm, slightly curved, dilated gradually upwards, laxly sub-stellately scaly outside, with dense retrorse hairs proximally, distally more laxly so with spreading hairs, glabrous below the mouth; lobes 12–15 x 10–15mm, spreading, rounded-obovate, glabrous on both sides. Stamens a little exserted; filaments narrow-linear, densely hairy at the base, more laxly and patently so in the middle, glabrous distally; anthers 2.8–3 x 1mm, oblong, base obtuse. Disc densely short-hairy especially above. Ovary c.10 x 2mm, elongate-conical, densely covered with appressed yellowish hairs and laxly with scales which tend to be hidden by the hairs, gradually tapering distally; style 55–65mm, exserted, laxly hairy and scaly at the base for c.5mm only, glabrous distally; stigma thick-conical, crenulate.
Distribution: Papua New Guinea, Mt Victoria, NW of ‘The Gap’. Epiphytic on an open hillside
Altitude: Around 2440m
Named after the collector, Cedric Carr, orchid enthusiast and prolific plant collector who spent many years in SE Asia.
Type: Carr 15266, 27 Jan. 1936. New Guinea (SE), Central District, ascent to Mt Victoria, Main Range NW of ‘The Gap’, 2440m (BM, A, K, SING).
Occurs in Countries: PG Altitude Ranges: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:178
Shrub to 5m. Twigs c.4mm in diameter, rounded, tips densely covered with thin brown scales; internodes 2–3cm. Leaves 3–5 together in tight pseudowhorls, sometimes with one or two much smaller leaves, also recorded as spiral. Blade 40–80 x 25–45mm, obovate to elliptic-obovate, apex rounded or obtuse; margin slightly or not recurved; base broadly tapering but the extreme base rounded or truncate; glabrescent above when fully mature, sub-densely to laxly scaly beneath. Scales thin, marginal zone persistent, shallowly and irregularly dentate; centre small, impressed. Mid-vein raised above but grooved proximally for a few millimetres, impressed distally, strongly prominent beneath, but less so towards the apex; lateral veins 6–8 per side, often forked before the edge, anastomosing both among each other and with the stronger veins, laxly reticulate, prominent on both sides. Petiole 2–6 x 2–5mm, somewhat flattened and weakly grooved above, scaly. Flower buds to 40 x 20mm, elongate-ovate, imbricate, yellow-brown, smooth. Bracts to 25 x 15mm, sub-circular to obovate-spathulate, scaly outside and not or only laxly shortly hairy. Inflorescence at first an erect umbel of 5–6 flowers, the tubes closely held together by the bracts, later the flowers spreading and the umbel becoming open. Bracteoles linear. Pedicels c.2 x 5–8mm, sub-densely scaly. Calyx c.2mm in diameter, rim-like, membranous, irregularly and very shortly 5-dentate, fringed. Corolla trumpet-shaped, white, powerfully and sweetly scented; tube 50–70 x 4–4.5 x 5.5–6mm, cylindrical, slightly curved, sub-densely scaly outside, inside with short spreading hairs proximally becoming glabrous above the middle; lobes 10–15 x 6–13mm, obovate to broadly elliptic- circular, spreading, very laxly scaly outside, glabrous inside. Stamens exserted to 8mm, arranged all round the mouth; filaments linear, densely covered with spreading hairs below, these gradually thinning to become glabrous distally; anthers 5–7 x 1–1.2mm, sub-obovate-oblong, base of each cell with a distinct spur-like point. Disc densely hairy. Ovary c.10 x 1.5mm, narrowly cylindrical, slightly tapering towards the base, densely covered with yellowish or whitish, forwardly pointing hairs which cover numerous scales, gradually tapering distally; style 55–65mm, hairy and densely scaly apart from the distal 6mm; stigma conical. Fruit narrowly cylindrical, shortly tapering at both ends, with 5 grooves, sub-densely hairy and scaly, c.50 x 6mm. Seeds with very narrow appendages.
Habitat: On open hillsides, along rocky river banks and gorges, mostly terrestrial but occasionally epiphytic.
Distribution: Papua New Guinea, Owen Stanley Range; Central District: Mt Obree, Mt Victoria; Milne Bay District: Mt Dayman, Mt Suckling.
Altitude: 1830-2440m
Named after Lady Carrington, wife of the British representative in New Guinea, for her interest in the plants of the colony.
Type: Cuthberson & Sayer s.n. New Guinea (SE), Central District, Mt Obree, 1830–2135m (MEL, K).
Occurs in Countries: PG Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:179
Shrub. Twigs sub-angular, whitish, smooth, early glabrescent; internodes 7–10cm. Leaves 3–4 together in pseudowhorls. Blade 65–100 x 40–55mm, broadly elliptic, elliptic to obovate-elliptic; apex obtuse to rounded; margin entire, flat; base shortly and broadly tapering, glabrescent above at maturity, sub-densely scaly beneath. Scales small, marginal zone irregularly dentate; centre a little impressed. Mid-vein somewhat impressed above, strongly prominent beneath; lateral veins 8–10 per side, irregular, straight below, curved-anastomosing before the margin, slightly impressed above, hardly prominent beneath, smaller veins laxly reticulate, raised beneath only. Petiole 10–15 x c.2mm, grooved above. Bracts to 40 x 18mm, obovate-elliptic, hairy outside in the middle and with longer and appressed hairs in the lower part on both sides. Bracteoles 30–50mm, filiform, hairy. Inflorescence 6–9-flowered. Pedicels c.5mm, thick, scaly. Calyx minute, oblique, circular, obscurely 5-lobed. Corolla 65–70mm, trumpet-shaped; tube 50–60 x c.3 x c.6mm, cylindrical, hardly widened upwards, glabrous outside, densely hairy inside in the proximal ½; lobes c.17 x 14mm, obovate-sub-circular, glabrous. Stamens somewhat exserted from the mouth; filaments linear, densely hairy to 4/5, glabrous distally; anthers c.6 x 1mm, each cell with a tail-like appendage (1–1.5mm) at the base. Disc sub-glabrous. Ovary c.7 x 1.8mm, elongate-cylindrical, very densely covered with yellowish hairs, gradually tapering distally; style yellowish hairy in the proximal 1⁄3, glabrous distally; stigma thick-obconical.
Distribution: Indonesia, New Guinea (W), Mt Jaya (Mt Carstensz), once collected
Altitude: 1675-2040m
Named after the mountain on which it was collected.
Not so far recollected and never cultivated. Very similar to R. syringoideum, differing chiefly in the much smaller flowers; it is the older name and would take precedence if the species were amalgamated.
Type: Kloss B. s.n., 26 Jan. 1913. New Guinea (W), Ascent to Mt Carstensz, 1675–2040m (BM).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:172
Shrub, 1.3—3m; young shoots fulvous-tomentose, setae very few or entirely lacking. Leaves obovate, 8-10 x 4.2-5.5 cm, 1.6-2 x as long as broad, apex rounded, apiculate, base broadly cuneate, upper surface glabrous, lower surface densely fulvous-tomentose, indumentum bistrate, the upper layer loose, dendroid, the lower whitish and compacted; petioles 1-1.5cm, tomentose. Inflorescence 6-9-flowered; rhachis 5-10mm; pedicels 25-35mm, floccose-tomentose. Calyx 15-20mm, cupular, glabrous except for the ciliate margin, lobes shallow. Corolla fleshy, tubular-campanulate, crimson, c.45mm. Ovary densely tomentose. Capsule 20-25 x c.l2mm.
Habitat: Forest margins, rocky slopes
Distribution: China (SE Xizang, NW Yunnan)
Altitude: 3650-4400m
Closely allied to R. haematodes but generally with larger leaves and calyces. One specimen, Forrest 20908, has the leaf shape and indumentum of R. catacosmum but the setulose young shoots and petioles of R. haematodes subsp. chaetomallum. This may be a hybrid. A specimen, Rock 17016, is intermediate between R. catacosmum and R. coelicum, with the sparsely stipitate-glandular petioles of the latter and the tomentose ovaries and the large calyx of the former. R. catacosmum apparently hybridises with R. citriniflorum (q.v.) and R. temenium.
Type: China, SE Xizang, Tsarong, Salween/Kiu-chiang divide, NW of Si-chi-to, 13000ft, vi 1922, Forrest 21727 (holo. E).
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: crimson
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):389
Shrub, 2—3m; young shoots tomentose though soon glabrescent. Leaves broadly elliptic to obovate, 6.5-11.5 x 3.5-5cm, 1.9-2.3 x as long as broad, apex ± obtuse, base rounded, upper and lower surfaces glabrous when mature though with persistent hair bases below; petioles 2-3cm, ± lanate at first, soon glabrescent. Inflorescence dense, 15-20-flowered; rhachis 20-25mm; pedicels 30-35mm, with a sparse dendroid indumentum. Calyx c.lmm, ± glabrous. Corolla funnel-campanulate, usually lilac-purple, with faint flecks, 30-45mm. Ovary densely rufous-tomentose; style glabrous. Capsule c.20 X 4mm.
Habitat: Rocky slopes, etc.
Distribution: Eastern USA (N Carolina & Virginia)
Altitude: 50-1000m
Illustrations:
Map in Little, Atlas United States Trees 4: map 118 (1977)
Closely allied to R. ponticum despite the surprising disjunction. Large flowered, large-leaved plants from eastern N Carolina have been referred to forma insularis Coker (in J. Elisha Mitchell Sci. Soc. 34: 76 et sec, t.19, 1919).
Type: USA in montibus excelsis Carolinae septentrionalis, juxto origine-amnis Catawbe, n.v.
Occurs in Countries: US Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: lilac
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):316
Dwarf shrub, 0.3-lm; young shoots sparsely tomentose. Leaves obovate to elliptic, 4-7.5 x 1.3-3cm, 2.2-3 X as long as broad, apex blunt to apiculate, base cuneate, upper surface glabrous, lower surface with a compacted fawn to brownish tomentum; petioles 0.5-lcm, sparsely velutinous. Inflorescence lax, 6-15-flowered; rhachis up to 35mm; pedicels pilose, 25-30mm in flower, up to 60mm in fruit; perulae usually persistent. Calyx 1 —2mm, pilose. Corolla broadly campanulate, whitish to yellow, sometimes flushed with pink, with greenish flecks, 30-35mm. Ovary densely dendroid-pilose; style glabrous. Capsule 15-20 X c.8mm.
Distribution: NE Turkey & adjacent parts of USSR (Caucasia)
Illustrations:
A distinctive species though apparently hybridising with R. ponticum (q.v.) and R. smirnowii. The plate accompanying the type description gives a false impression of the species as described here and may be disregarded as there is no direct reference to any of the type specimens cited. Plate 3422 in Bot. Mag. 62 (1835) is a reliable representation of the species as treated here.
Type: USSR, altere septentrionale Caucasi, in Ossetia inter Tschin et Tschinaga meridiem versus; postea in Caucaso australiore in alpinis elatioribus (? BM)
Synonymy: R. caucasicum Pallas var. stramineum W. Hooker, Bot. Mag. 62: t.3422 (1835). Type: a plant or the plate drawn from it (cited above), grown in Glasgow and flowering in iv 1835
Occurs in Countries: RU, TR Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: green, pink, yellow
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):312
Shrub to 5 m high, young branches glabrous. Leaves glabrous; blade narrowly obovate to oblanceolate, 75-150 x 35-40mm, base and apex attenuated, thinly coriaceous; petiole 8-12 mm long. Inflorescence buds lateral, at the ends of leafy shoots, 3- or more-flowered; bud scales glabrous or with minute cilia on the margins, caducous; pedicels 25-30 mm long, laxly or densely pubescent. Calyx of 5 minute lobes, glabrous or ciliate. Corolla white to rose, tube 12-I5mm, lobes 20-24 x 10-12mm. Stamens 10, filaments hairy on lower part (? sometimes glabrous). Ovary cylindric, 7 mm high, pubescent; style glabrous. Capsule c.40-50 mm long.
Distribution: China (Guizhou, Guangxi).
Illustrations:
The inflorescences with several flowers and hairy pedicels recall R. henryi, but the hairs of the pedicels form a fine pubescence in contrast to the glandular patent hairs of R. henryi. Also the leaves are longer and narrower than those of R. henryi.
Type: China, Guizhou, sous prefecture de Tou-chan, v 1899, Cavalerie 2633 (holo. E).
Occurs in Countries: CN Subgenus: Azaleastrum Habit: Non-Tree Fl. Colour: rose
Philipson, W.R. & Philipson, M.N. (1986) A Revision of Rhododendron III. Subgenera Azaleastrum, Mumeazalea, Candidastrum and Therorhodion. Notes from the Royal Botanic Garden Edinburgh 44(1):12
Shrub to 1.5m; roots sometimes swollen and tuber-like. Twigs rounded, 1.5–3mm in diameter, sub-densely sub-stellately scaly, older stems glabrescent, smooth, often red; internodes 1.5–6cm. Leaves 3–7 together in distinct but loose pseudowhorls. Blade 30–70 x 15–30mm, elliptic to narrowly ovate-elliptic; apex shortly acuminate, sub-acute or obtuse; margin entire, narrowly cartilaginous, flat when fresh, slightly and narrowly revolute when dry; base broadly tapering; glabrescent and slightly rugose above at maturity, sub-densely scaly beneath. Scales small, flat or impressed, marginal zone thin, pale, silvery, large, angled or sub-stellately lobed; centre small, brown. Mid-vein narrow and slightly impressed above, strong and prominent beneath; lateral veins 5–7 per side, sub-patently spreading, anastomosing, faintly impressed above, very slightly or not raised beneath, without clear reticulation. Petiole 4–12 x 1–1.5mm, flattened, red, shallowly grooved above, scaly. Flower buds to 15 x 6mm, ellipsoid, smooth, except for low protuberances at the apices of the bracts, minutely pale-brown scaly outside and along the bract margins. Bracts 5–12 x 4–7mm, ovate to obovate, minutely pale-brown scaly outside or glabrous; margin with brown, stellate scales. Bracteoles c.15 x 1–2mm, linear below, sub-spathulate, dilated and irregularly impressed distally, glabrous. Inflorescence 3–8-flowered, an open umbel, the flowers hanging vertically downwards. Pedicels 15–20 x c.1mm, slender, densely stellate-scaly and papillose, not properly hairy. Calyx 2.5–3mm in diameter, disc-shaped, oblique, shortly obtusely 5-lobed, densely scaly outside. Corolla 35–46 x 20–25mm, tubular, pink to red, without scent; tube 30–35 x 6–8 x 9–11mm, cylindrical, straight, often angular and strongly pouched at the base, laxly to very laxly scaly outside, glabrous inside; lobes 8–11 x 6–10mm, sub-circular, mostly not overlapping, half-spreading to almost horizontal. Stamens irregularly spread around the mouth of the flower, or exserted to 8mm; filaments pink, glabrous; anthers 2–2.5 x 1mm, dark, brown, pores up to ½ the length of the anthers. Disc green, prominent, glabrous. Ovary 5–6 x 2mm, sub-cylindrical, pink, very densely silvery stellately scaly, tapering gradually distally; style glabrous or scaly at the base, as long as the corolla; stigma thick-globose. Fruit 25–38 x 35mm, fusiform-cylindrical, scaly. Seeds 7–8mm, without tails c.1mm, the longest tail to 4.5mm, the tails strongly crimped.
Habitat: Epiphytic in mossy forest
Distribution: Indonesia, Sulawesi, Minahasa: Mt Klabat, Lake Poso area, Mt Rantemario, Mt Gambuta.
Altitude: 1800-2600m
Named after the island on which it was found, Celebes (now Sulawesi).
Type: Reinwardt s.n., 1821. Celebes, Menado: Mt Klabat, top, 1800–2000m (L, P).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: pink, red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:287
Variably sized, often contorted and sometimes prostrate shrub, 0-1-1.2 m, often with very thick lower stem. Leaf-bud scales persistent and very conspicuous. Leaves broadly elliptic to suborbicular, 15-47 x 7-23 mm, base usually rounded, apex obtuse or rounded, rarely emarginate, upper surface dark, glossy green, usually elepidote, lower surface fawn to brown, rarely dark brown or rusty with dense, overlapping scales in 2-3 tiers, those of the lower tier golden, paler than those of the upper tiers. Inflorescence dense, many-flowered; pedicels short, lepidote. Calyx lobes oblong, (3-)4-7 mm, lepidote or elepidote outside, margins usually ciliate with loriform cilia (rarely margined with scales), inner surface glabrous or slightly puberulent. Corolla white or pink, rarely yellowish, tube 6-5-14 mm, lobes (3-)4-8 mm, tube elepidote and glabrous outside, lobes often bearing a few scales on their backs, mouth of the tube densely pilose inside. Stamens 5(-7). Ovary lepidote. Capsule scarcely exceeding the calyx
Two subspecies, differing mainly in size, can be recognised
Occurs in Countries: CN, IN, MM Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: pink, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):161
Habitat: Open meadows, moorland, rocky slopes
Distribution: India (Arunachal Pradesh), N Burma, China (N, NW & C Yunnan, S & SE Xizang)
Altitude: 3050-4500m
Illustrations:
Type: China, Yunnan, in cacumine montis Koua-la-po prope Hokin, 26 v 1884, Delavay 59 (holo. P—n.v., iso. E)
Synonymy: R. chamaetortum Balfour f. & Kingdon Ward, Notes R.B.G. Edinb. 9:218 (1916). Type: China, Tibeto-Yunnan frontier, Ka-gwr-pu (Ka kar po) glacier valley, 15000 ft, vi 1913, Kingdon Ward 431 (holo. E). R. crebreflorum Hutchinson & Kingdon Ward, Notes R.B.G. Edinb. 16:173 (1931). Type: Assam, Delei valley, 13000 ft, Kingdon Ward 8337 (holo. BM, iso. E). R. nmaiense Hutchinson & Kingdon Ward, op. cit.: 252. Type: E Upper Burma, ridge of Naung chaung, Nwai Divide, 12-13000 ft, 16 vii 1914, Kingdon Ward 1791 (holo. E). R. cephalanthum var. crebreflorum (Hutchinson & Kingdon Ward) Cowan & Davidian, Rhodo. Yearbook 2:70 (1947). R. cephalanthum var. nmaiense (Hutchinson & Kingdon Ward) Cowan & Davidian, op. cit.: 71.
Habitat: Cliffs and ledges
Distribution: NE Burma, China (NW & C Yunnan)
Altitude: 3050-3350m
Subsp. platyphyllum is, essentially, a large-sized variant of subsp. cephalanthum, reasonably distinct both morphologically and geographically. Cytological observations on the two taxa would be interesting, but subsp. platyphyllum is not available in cultivation.
Synonymy: R. cephalanthum var. platyphyllum [Franchet ex] Diels, Notes R.B.G. Edinb. 7:211 (1912) nomen nudum. Type: China, Yunnan, in cacumine montis Tsang chan supra Tali, 27 vi 1887, Delavay (holo. P—n.v., iso. E). R. platyphyllum [Franchet ex] Balfour f. & W. W. Smith, Notes R.B.G. Edinb. 9:259(1916)
Shrub, 1.2-3.7m; young shoots glabrescent. Leaves narrowly obovate to elliptic, 4.5-7 x 1.8-4cm, 1.7-2.5 x as long as broad, apex rounded, apiculate, base rounded, upper and lower surfaces glabrous, lower cuticle shortly papillate with some red sessile hair-bases; petioles 0.7-1.5cm, with sparse, well-developed, rufous, dendroid hairs that extend up the midrib on the upper surface of the leaves. Inflorescence 4—7-flowered; rhachis up to 5mm; pedicels 15-25mm, sparsely glandular. Calyx c.1.5mm, shortly stipitate-glandular, at least on the lobe margins. Corolla campanulate, crimson to scarlet or white with a deep pink border, nectar pouches darker, 35-45mm. Ovary shortly stipitate-glandular; style glandular to tip. Capsule c.20mm.
Habitat: Coniferous forests
Distribution: NE Upper Burma, China (SE Xizang)
Altitude: 3200-3800m
Illustrations:
Type: N Burma, Seingku Wang, vi 1936, Kingdon-Ward6923 (holo. K; iso. E).
Occurs in Countries: CN, MM Altitude Ranges: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: crimson, pink, scarlet, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):418
Shrub to 1m. Twigs spreading, tips reddish-brown-scaly; internodes 1.5–8cm. Leaves 4 together in pseudowhorls. Blade 40–90 x 10–17mm, narrowly elliptic; apex shortly, to long acuminate; margin slightly revolute when dry; base tapering, glabrescent above with age, the remaining scales flat and not impressed, densely and persistently scaly beneath. Scales flat, with many touching or slightly crenate overlapping, forming a continuous layer, the marginal zone wide in relation to the small darker centre, deeply and irregularly to moderately lobed; centres impressed. Mid-vein impressed above, thick and prominent beneath; lateral veins 6–8 per side, straight and spreading, sometimes minutely depressed above, obscure beneath. Petiole 6–15 x c.1.5mm, semi-rounded, scaly. Outer bracts to 8 x 5mm, ovate to sub-spherical, abruptly subulate-tapering at the apex, densely scaly outside; inner ones ovate to sub-spathulate, obtuse. Bracteoles to 6mm, filiform, laxly scaly. Inflorescence c.5-flowered, an open umbel, the flowers half-hanging. Pedicels 10–15mm, slender, densely scaly. Calyx c.2.5mm in diameter, sub-oblique, almost cup-shaped, the margin spreading or reflexed, irregularly, shortly and obtusely 5-lobed. Corolla 10–12mm, broadly campanulate, yellow; tube c.8 x 2–3 x c.10mm, sub-densely scaly outside; lobes 5–6 x 4–5mm, broadly obovate, shortly retuse or irregularly crenate distally, scaly outside except near the margins. Stamens nearly as long as the corolla; filaments linear, long patently hairy in the proximal 1⁄3, glabrous distally; anthers 1.7mm. Disc prominent, very shortly hairy at the upper margin, glabrous below. Ovary c.2.5 x 1.7mm, ovoid-conical, densely patently hairy and scaly, abruptly contracted distally; style 4–5mm, scaly at the extreme base, glabrous distally; stigma large, 5-lobed.
Habitat: Reported growing on a dry sulphur-stone slope
Distribution: Indonesia, S Sumatra, near Bengkulu (Benkulen): Mt Kaba (Mt Belirang). Mt Belirang does not appear on modern maps. Belerang is the Indonesian for sulphur, and the local people harvest sulphur on Mt Kaba and often call it Mt Belerang. It seems most likely that Belirang and Kaba are one and the same place.
Altitude: Around 1500m
Latin – cernuus – slightly drooping, presumably alluding to the habit of the flowers.
Apparently known from only two specimens, not recently recollected or ever cultivated.
Type: Rappard 63, 12 Aug. 1963. Sumatra, Benkulen, Mt Belirang (BO, L).
Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:130
Dwarf shrub, 0.1 -lm; young shoots stipitate-glandular or sparsely tomentose, perulae ± deciduous or persistent. Leaves broadly obovate to elliptic, (2-)4-6 x (1.3-)1.8-3.2cm, 1.5-2.1 x as long as broad, apex rounded or retuse, base rounded to broadly cuneate, shortly decurrent, upper surface glabrous, lower surface glabrous or with a sparse whitish adpressed indumentum, epapillate; petioles 0.5-lcm, tomentose and/or stipitate-glandular. Inflorescence (1 -)2-5-flowered; rhachis c.5mm; pedicels 10-20mm, sparsely stipitate-glandular, sometimes also villous-tomentose. Calyx l-7(— 15)mm, minute or with well-developed, sometimes coloured, glandular-ciliate lobes. Corolla fleshy, campanulate, pink to deep crimson, usually unmarked, 25—45mm. Ovary densely to very sparsely rufous-tomentose with varying proportions of stipitate glands. Capsule c. 15 x 4mm.
Habitat: Amongst boulders, damp rocky slopes
Altitude: 4000-4600m
Closely allied to and apparently hybridising with R. forrestii (q.v.).
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: crimson, pink
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):406
Corolla carmine to crimson; calyx lobes to 7(- 15)mm; ovary sparsely hairy, sometimes glandular. Leaves with a thin discontinuous indumentum when mature; petioles and young shoots eglandular.
Synonymy: R. repens Balfour f. & Forrest var. chamaedoron Tagg & Forrest, Notes R.B.G. Edinb. 16: 206 (1931). Type: China, SE Xizang, Tsarong, Salween/Kiu-chiang divide, W of Chamatong, 14500ft, vi 1922, Forrest 21768 (holo. E). china (SE Xizang & adjacent NW Yunnan).
Corolla pale to deep pink; calyx minute, 1mm or less; ovary densely hairy.
Synonymy: R. repens Balfour f. & Forrest var. chamaethauma Tagg, Notes R.B.G. Edinb. 16: 206 (1931). Type: China, SE Xizang, Doshong La, 12-13000ft, vi 1924, Kingdon-Ward 5847 (E, K). china (S Xizang, Doshong La & Deyang La).
Corolla carmine to crimson; calyx lobes to 7(- 15)mm; ovary sparsely hairy, sometimes glandular. Leaves glabrous; petioles and young shoots glandular.
Distribution: China (SE Xizang & adjacent NW Yunnan)
Synonymy: R. repens Balfour f. & Forrest var. chamaethomsonii Tagg & Forrest, Notes R.B.G. Edinb. 16: 206 (1931). Type: China, SE Xizang, Tsarong, Salween/Kiu-chiang divide, NW of Si-chi-to, 14-15000ft, vi 1922, Forrest 21723 (holo. E).
Shrub or small tree to 8 m high, young branches densely covered with glandular bristly hairs. Leafblade elliptic or obovate 70-150 x 25-50 mm, base cuneate, apex acuminate, chartaceous, upper surface sparsely short setose, increasing towards the margin, lower surface loosely bristly, especially on the mid-rib and principal veins, often also pubescent, margin ciliate; petiole c. 10-12 mm, with dense spreading bristles. Inflorescence buds lateral, clustered at the ends of leafy shoots, about 5-flowercd; bud scales viscid; pedicels c. 18-20 mm long, densely covered in coarse spreading glandular hairs. Calyx of 5 variable lobes, up to 12 mm long, narrow, densely ciliate. Corolla at first pink becoming white with yellow markings on upper lobe, glabrous, tube c. 12-15 mm, lobes c.40-45 x 25-30 mm. Stamens 10, filaments hairy on the lower part, Ovary cylindric, c.7mm long, densely bristly; style glabrous. Capsule narrowly cylindric, coarsely setose, c.35-40 mm long.
Distribution: China (Guangxi, Guangdong, Fujian, Zhejang, Hunan, Jiangxi), Hongkong.
The leaf margins of a number of species of section Choniastrum bear ciliate hairs in juvenile (or sucker) plants, but R. championae is the only species in which the adult leaf has marginal cilia. R. championae var. ovalifolium Tam (Survey Genus Rhododendron S. China 112, 1981) has bullate leaves, white flowers and some basal puberulence on the style.
Occurs in Countries: CN Subgenus: Azaleastrum Habit: Tree Fl. Colour: pink, white, yellow
Philipson, W.R. & Philipson, M.N. (1986) A Revision of Rhododendron III. Subgenera Azaleastrum, Mumeazalea, Candidastrum and Therorhodion. Notes from the Royal Botanic Garden Edinburgh 44(1):9
Shrub to 1 -5 m. Leaves elliptic to obovate, cuneate at the base, apex very bluntly rounded to almost retuse, 30-55 x (14—)18—30 mm, upper surface dark green, elepidote or very sparsely lepidote, lower surface with very marked veins, and scales of varying density. Inflorescence (3-)4-5-flowered, pedicels lepidote, (18-)20-27 mm, rachis very short, pubescent with at least some loriform hairs which, in some specimens, tend to be dendritic. Calyx lobes ovate, rounded at the apex, (3-)5-7(-9) mm, somewhat glaucous, tepidote at the base and around the margins. Corolla campanulate, (15-)20-25 mm, tube (8-)9-12 mm, pink to purplish, sometimes spotted, elepidote or very sparsely lepidote outside. Capsule ovoid, c. 10 mm.
A variable species, which can be divided into two intergrading subspecies
Occurs in Countries: CN, MM Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: pink
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):141
Habitat: On cliffs, among boulders and on rocky slopes, rarely in scrub
Distribution: NE Burma, China (NW Yunnan)
Altitude: 3200-4250m
Illustrations:
A natural hybrid between subsp. charitopes and R. campylogynum (p. 145) has been collected by Farrer (NE Burma, Chawchi pass, 3350 m, 16 vii 1920, Farrer 1726)
Type: NE Burma, Shing Hong pass, 10500-12000 ft, 18 vi 1920, Farrer 1627 (holo. E)
Habitat: Slopes, rocks, open mountainsides
Distribution: China (S Xizang)
Altitude: 2450-4100m
Subsp. tsangpoense is a northern vicariad of subsp. charitopes; though they do not overlap geographically, they approach very closely, and there is no very clear morphological separation between them. The name curvistylum has been applied to a plant collected at the locus classicus of tsangpoense, which is in no way different from the type of the latter. However, material cultivated as R. tsangpoense var. curvistylum (often as Kingdon Ward 5843) is different—it is a plant with very small, narrowly elliptic, acute leaves, and is probably a hybrid between subsp. tsangpoense and R. campylogynum.
Synonymy: R. tsangpoense Kingdon Ward, Gard. Chron. 86:504 (1929). Type: China, SE Tibet, Doshong La, 12-13000 ft, 24 vi 1924, Kingdon Ward 5844 (holo. BM, iso. E). R. curvistylum Kingdon Ward, Plant Hunting on the Edge of the World 375 (1930) nomen nudum. R. tsangpoense var. curvistylum [Kingdon Ward ex] Cowan & Davidian, Rhodo. Yearbook 3:90 (1948). Type: China, SE Tibet, Doshong La, Kingdon Ward 5843 (holo. BM, iso. E)
Shrub to 2m. Twigs 2–2.5mm in diameter, smooth, rounded and at first densely brown scaly; internodes 3–5mm. Leaves in moderately tight pseudowhorls, 4–5 together, apparently rigidly held semi-erect. Blade 40–50 x 13–24mm, elliptic to narrowly obovate, very shortly acuminate to a broadly acute or obtuse apex; margin entire, flat to slightly revolute distally distinctly revolute in the proximal 1⁄3, especially when dry; base tapering and decurrent, glabrescent above, densely scaly beneath. Scales rounded, with a moderately large centre but broad, paler flange, lightly impressed. Mid-vein narrowly impressed above in the proximal ½–2⁄3, then flat; narrowly raised beneath throughout its length, sometimes terminating in an indistinct terminal gland. Petiole 4–10 x c.2mm, weakly grooved above, densely brown-scaly, often flushed pink. Bracts to 20 x 8mm, ovate, acute, with a few brown scales outside distally and along the margins, glabrous inside. Bracteoles 6 x 1mm, narrowly triangular, with a few teeth on the margin, glabrous. Inflorescence 1–4-flowered, the flowers held semi-erect. Pedicels 8–10 x 1–1.5mm, densely scaly, without simple hairs. Corolla 20–23 x 35–49mm, bright to pale yellow, without scent; tube 6–12 x 4–5 x 10–12mm, glabrous outside; lobes 15 x 12mm, half-spreading. Stamens spreading round the mouth of the flower, exserted to 7mm; filaments glabrous or with a few hairs at the base; anthers c.4 x 2mm. Disc glabrous. Ovary 5 x 25mm, with patent white hairs and brown scales; style 6 x 1mm, glabrous, bent to the lower side of the tube. Fruit 15–18 x 5–6mm, erect, prominently hairy and scaly.
Habitat: Evergreen forest dominated by Fokienia and Phyllostachys.
Distribution: Vietnam, (S) Prov. Khanh Hoa (Nhatrang) massif de Hon-ba; Lam Dong, Lac Duong, Bi Doup peak area.
Altitude: 1000-2100m
Named after the collector, Auguste Chevalier, who made many important collections in what is now Vietnam and Cambodia.
Type: Chevalier 38709, 1 Sept. 1928. S. Annan, forêt vierge du Honba (P).
Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:191
Small tree, 4m; young shoots setulose-glandular, also with a loose tomentum. Leaves coriaceous, oblong, 19-23 x 5-7cm, 4-4.5 x as long as broad, apex rounded, base rounded to sub-cordate, margin with minute deciduous setulae below, lower surface with an evanescent pubescence; petioles 1.5-2cm, glandular-setulose. Inflorescence c. 8-flowered; rhachis c. 20mm; pedicels c. 10mm, brown-pilose, eglandular. Calyx c. 2mm, fimbriate. Corolla 7-lobed, broadly infundibular-campanulate, colour unknown, c. 40mm. Stamens c. 15. Ovary densely stipitate-glandular; style glandular to tip. Capsule not known.
Distribution: China (Guangxi)
Altitude: Around 850m
Allied by the original authors to R. strigillosum and R, monosematum but the 7-lobed corolla and glandular style suggest a closer affinity with R. auriculatum.
Type: China, Guangxi, Lungsheng Hsien, Pingshui Hsiang, Hung Tan, Pichia Shin, 850m, 13 iv 1955, KwangfuExped. 56 (holo. Herb. Inst. Bot. Guangzhou)
Occurs in Countries: CN Altitude Ranges: 0 - 1,000m Subgenus: Hymenanthes Habit: Tree
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):241
Shrub, 0.6-lm; young shoots ± densely setose, eglandular. Leaves obovate, 6-7.5 x 2.2-2.8cm, c.2.5 x as long as broad, apex rounded, acuminate, base broadly cuneate, glabrous above when mature, with a discontinuous floccose tomentum beneath; petioles 0.5-lcm, setose. Inflorescence 4-6-flowered; rhachis c.5mm; pedicels 15-20mm, sparsely setulose-glandular. Calyx 2-3mm, lobes ciliate. Corolla tubular-campanulate, white, c.35mm. Ovary densely rufous-tomentose. Capsule not known.
Habitat: Rocky slopes
Distribution: ne Upper Burma, China (W Yunnan)
Altitude: Around 4400m
Allied to, or a hybrid of, R. haematodes subsp. chaetomallum but differing in the white flowers and discontinuous indumentum.
Type: NE Upper Burma, western flank of the Salween/Kiu-chiang divide, 27°18'N, 98°40'E, 14000ft, vii 1924, Forrest25592 (holo. E).
Occurs in Countries: CN, MM Altitude Ranges: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):390
Small shrub to 1.2m. Twigs 1.5–2mm in diameter, rounded, laxly scaly, becoming glabrescent, smooth; internodes 4–11cm. Leaves 2–4 together in tight pseudowhorls at the upper 2 or 3 nodes, sub-sessile. Blade 40–110 x 25–65mm, ovate; apex shortly or long-acuminate; margin entire, flat, slightly recurved when dry; base cordate to rounded; laxly scaly initially, glabrescent above, persistently scaly beneath. Scales flat, small, the thin marginal zone large, irregularly and deeply divided; centre darker, small, slightly impressed. Mid-vein narrow and deeply grooved above, strong and prominent beneath; lateral veins 4–6 per side, curved-ascending and joining, weakly or not impressed above, slightly prominent beneath; densely reticulate. Petiole 1–2 x 1–2mm, flattened, scaly. Flower buds to 20 x 12mm, ovate, smooth. Bracts to 20 x 8mm, outer ovate, the apex abruptly subulate or mucronate, very shortly appressed hairy outside and with a few scales distally in the central area; inner ones ovate, apiculate or obtuse, appressed-hairy in the upper part outside, margin minutely irregular and with fragile scales. Bracteoles to 20 x 5mm, linear below, spathulate towards the apex, laxly hairy, often with a few irregular teeth apically and with a few stalked scales on the margins. Inflorescence an open umbel of 2–5 flowers. Pedicels 15–25 x c.2mm, red, densely patently hairy, with few or no scales. Calyx 3–4mm in diameter, disc-shaped, densely hairy outside, with 5 short, obtuse ciliate lobes or occasionally longer up to 5mm. Corolla 30–45 x 25–35mm, tubular below, expanded and oblique at the lobes, bicoloured with a yellow tube and orange lobes, without scent; tube 20–25 x 6–7 x 12–18mm, yellow at the base or throughout, orange distally, densely long-hairy both inside and out, without scales; lobes 13–18 x 10–18mm, obovate-spathulate or sub-circular, hairy outside. Stamens exserted to 12mm, clustered on the upper side, unequal; filaments linear, densely patently hairy in the proximal ¼–1⁄3, glabrous distally; anthers 2–2.5mm, obovoid, apex truncate. Disc densely hairy in the upper ½. Ovary 5–7 x 2.5–3mm, cylindrical, continuous with the style, shortly hairy; style as long as the stamens, densely hairy to nearly the top; stigma oblique, rounded or weakly lobed. Fruit 30–35 x c.5mm, sub-cylindrical, widest in the upper 1⁄3, slightly curved, laxly hairy, valves thin, becoming twisted. Seeds 6–7mm, without tails 0.8mm, the longest tail 3.5mm.
Habitat: Mostly epiphytic in mossy forest and on grassland tree-ferns, or terrestrial in open forest or rock faces on cliffs
Distribution: Papua New Guinea, New Guinea (E), Mt Saruwaged and vicinity; Eastern, Western and Southern Highlands; Simbu District; Wharton Range; Finisterre Mts (Madang District). Indonesia, New Guinea (W), Wamena R.; Ibele valley.
Altitude: 1200-3000m
Named after Konrad H. Christ, Swiss fern specialist who was professor of botany at Basel.
The records from near Wamena are a surprising extension to the range of this species which had previously been known only from Papua New Guinea; some of these plants differ in having broadly tapering leaf bases but others are quite typical with cordate bases. Those with tapering leaf bases could be hybrids with R. curviflorum. It is reported hybridising with R. beyerinckianum (van Royen & Kores 1982), these hybrids having uniformly pink flowers (see R. x schoddei).
Type: Keysser s.n., Oct. 1912. New Guinea (NE), Morobe District, Mt Saruwaged, Bolan, 2400–3000m (B†); ibid. Keysser 176 (BM, neotype).
Synonymy: R. christi var. loniceroides Schltr., Bot. Jahr. 1918. 55: 155. R. aff. wentianum Stonor, Rhod. Yearbook 1951. 6: 50, f.54. R. christii Foerster orth. var., Chamberlain et al., The Genus Rhododendron 1996. 17, 103.
Occurs in Countries: ID, PG Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: orange, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:301
Shrub to 3m. Twigs 2–3mm in diameter, rounded, sparsely scaly when young; internodes 2–12cm. Leaves 3–5 together in tight pseudowhorls. Blade 40–75 x 30–45mm, broadly elliptic or sub-obovate-elliptic, apex abruptly and shortly or gradually acuminate, obtuse, sometimes rounded or slightly emarginate, terminal gland thick, not protruding; margin flat; base broadly tapering or tapering; laxly scaly on both sides when young, glabrescent above, persistently laxly scaly beneath. Scales small, marginal zone variously lobed; centre slightly impressed. Mid-vein slightly or faintly impressed above, bluntly prominent in the proximal ½ beneath; lateral veins 5–7 per side, spreading, divided and curved-anastomosing before the margin, obscure above, a little raised beneath, reticulation inconspicuous. Petiole 5–10 x 1–1.5mm, grooved above, somewhat rugose, glabrous. Outer bracts to 15 x 8mm, ovate to obovate, innermost ones elliptic-spathulate, hairy on the outer middle line and at the apex, margin with fragile scales. Bracteoles c.15mm, linear-sub-spathulate to filiform, laxly hairy. Inflorescence 2–5-flowered, an open umbel. Pedicels 10–27 x c.1mm, densely, shortly hairy, laxly scaly at both ends. Calyx c.4mm in diameter, oblique, disc-shaped, shortly obtusely 5-lobed, scaly and hairy outside. Corolla tubular, yellow shading to orange, especially at the lobes, and yellow or green on the tube; tube 25–35 x 7–10 x 15–20mm, straight, the base lobed, sparsely scaly outside, laxly hairy in the proximal 1⁄3 inside; lobes 15–25 x c.20mm, broadly obovate or sub-circular. Stamens unequal, regularly arranged around the flower, short ones at or a little beyond the mouth, longer ones exserted to c.12mm; filaments linear, yellow, densely and very shortly hairy in the proximal 1⁄3, glabrous distally; anthers 3–5 x c.1mm, blackish-purple, narrow-oblong, base with two short points. Disc slightly prominent, white-hairy on the upper margin. Ovary c.6 x 2.5mm, sub-cylindrical, abruptly contracted distally, white-hairy and scaly (scales hidden by the hairs); style 30–40mm, as long as the corolla tube, densely hairy and scaly proximally, becoming laxly so distally, glabrous for the 5–7mm below the stigma; stigma thick, 5-lobed. Fruit 30–34 x c.6mm, persistently appressed hairy, fusiform with longitudinal grooves.
Habitat: Compact terrestrial shrubs on precipitous rock faces or cliffs, overhanging deep gorges, in full sun. Locally abundant.
Distribution: Papua New Guinea, Milne Bay District, Daga country; Mt Simpson area, Mt Dayman area.
Altitude: 600-1525m
Named after Canon Cruttwell’s mother Christian Cruttwell, who went out to New Guinea to work as a missionary at the age of 55 and remained there for some 25 years.
‘When in flower (probably about June), it is a mass of orange and a conspicuous sight for miles, even from an aeroplane’ (Cruttwell 1971).
Type: Cruttwell 410, 8 May 1954. New Guinea (SE), Milne Bay District, Kanasura, c.775m (E, K, L).
Occurs in Countries: PG Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: green, orange, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:306
Deciduous or semi-evergreen shrub, to 2m; densely branched, branchlets with dense coarse flat, yellowish-brown, adpressed hairs. Leaves persistent coriaceous, dimorphic, lanceolate to oblanceolate; spring leaves 1.5-6 x 0.5-1.5cm, apex acute, base cuneate, margin slightly crenulate, upper surface lustrous, glabrous except for a few coarse flat adpressed hairs on the midrib, net-veins conspicuously impressed, lower surface with few and similar hairs; summer leaves 5-10 x 3-5mm, otherwise as for spring leaves; petioles 3-5mm, covered with adpressed flat yellowish-brown hairs. Inflorescence (3-)6-12~flowered; pedicels 10-15mm, densely hairy. Calyx minute, hairy. Corolla tubular-campanulate, rose, 20-30mm, glabrous; tube 7-15mm, 3mm wide at base. Stamens 5, longer than corolla, papillate below middle. Ovary densely hairy, hairs coarse, lustrous, yellowish-red, adpressed; style glabrous. Capsule ovoid, densely hairy.
Habitat: Thickets
Distribution: China (Guizhou, N Guangxi, W Hubei, SE Sichuan)
Altitude: Around 700mm
Type: Kouy-Tcheou (Guizhou), route de Mou-you-se a Tchen-Lin, vi 1904, Cava-lerie 2059 (E); Pin-Fa bord des ruisseaux, 25 iv 1904, Cavalerie 1796 (E).
Synonymy: R. spinigerum Levi, Bull. Acad. Geog. Bot. 24: 251 (1914). Type: Kouy-Tcheou (Guizhou), Hot a Pia Quay-Ho, 700m, 2 v 1912, Esquirol 3560 (holo. E). R. kouytchense Levi., Fl. Kouy-Tcheou 152 (1914), nom. nud., pro syn. sub. R. chrysocalyx. R. xiushanense Fang in Acta Phytotax. Sin. 21: 461 (1983). Type: China, Sichuan, Xiushan, Baigeqiao, 370m, 17 v 1978, S.X. Tan 354 (holo. SZ).
Occurs in Countries: CN Altitude Ranges: 0 - 1,000m Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: rose
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):107
Shrub, perhaps epiphytic, attaining 1 m or more in cultivation. Young shoots bristly with deciduous loriform setae. Leaves oblong-elliptic, up to 88 X 45 mm, obtuse at the apex, rounded at the base, loriform-ciliate when young, the lower surface papillose with close, golden yellow scales slightly sunk in pits. Inflorescence 3-4-fIowered, pedicels very short, densely lepidote. Calyx obscurely lobed, lobes 2-3 mm, lepidote, loriform-ciliate. Corolla campanulate, yellow, 29-30 mm, tube c. 15 mm, lepidote and pubescent at the base of the tube outside, pilose within the tube. Ovary lepidote. Capsule unknown.
Habitat: Scrub, 2450 m
Distribution: ne Burma (Adung valley)
Illustrations:
This species, which is known from only two wild-collected specimens and material in cultivation, is peculiar in several respects. It was described from cultivation and said to be raised from seed of Forrest 25446—a flowering specimen from Yungchang in Yunnan belonging to subsection Maddenia, and here identified as R. yungchangense (p. 53). The cultivated material is certainly not yungchangense, but appears to combine most of the characteristics of subsection Boothia with a few of subsection Maddenia, particularly scale type, calyx form, the large size of the flower and the presence of indumentum at the base of the corolla tube outside. On the basis of this evidence the plant might well have been regarded as a natural hybrid between yungchangense and sulfureum. However, in the same year that the plant first flowered in cultivation (1931), Kingdon Ward collected a specimen in the Adung valley on the Burmese/Chinese frontier, which matches it in every respect. The Adung valley is about 240 km north of Yungchang and was not visited by Forrest, so this does not explain the origin of the material in cultivation. It is possible that chrysodoron is distributed between the Adung valley and Yungchang, or that it is the result of occasional hybridisation between members of subsections Maddenia and Boothia, thus explaining the scattered distribution as we know it today. The description above has been drawn up from wild material; in cultivation the flowers may be larger (up to 40 mm) and, apparently, of a deeper yellow.
Type: a cultivated specimen, said to derive from Forrest 25446—see below {holo. K, iso. E)
Synonymy: R. butyricum Kingdon Ward, nomen nudum.
Occurs in Countries: MM Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):135
Small shrub, to 2m; young shoots covered with adpressed flattened strigose red-brown hairs. Leaves monomorphic, coriaceous, persistent, elliptic to oblong-ovate, 1-2 x 0.5-0.9cm, 2 x as long as broad, apex acuminate, base broadly cuneate, margin entire, upper surface strigose, lower surface paler, strigose, especially on midrib; petiole 2-3mm, strigose. Inflorescence 2-3-flowered; pedicels 5-7mm, densely brown-strigose. Calyx strigose; lobes l-2mm, oblanceolate. Corolla funnel-shaped, lilac-purple, upper lobes flecked, 9-10mm; tube c.6 x 3mm, with 5 rows of glands on outer surface, also glandular within. Stamens 5, sub-equal, filaments minutely hairy below. Ovary densely covered in fine brown hairs; style covered with fuscous setose hairs and glands in lower half. Ripe capsule not known.
Habitat: Wooded slopes and ravines
Distribution: China (N Guangdong)
Tan describes the leaves as being dimorphic, the spring leaves 38-40 x 10-15mm; specimens seen by us do not confirm this.
Type: China, Guangdong, Kock-Kiang (Qujiang), Chut-Hsin Tun, 18 iv 1930, X.P. Gao (S.P. Ko) 50411 (holo. SYS; iso. E, PE)
Occurs in Countries: CN Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: lilac
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):133
Shrub to 2 m. Young growth loriform-setose, the older branches with the bases of the setae remaining. Leaves elliptic to narrowly elliptic, dark green and somewhat rugose above, paler green or brownish beneath, acute or obtuse at the apex, (44-)55-70(-90) x (21-)24-34 mm, the upper surface loriform-setose to some extent, particularly along the lower part of the midrib, the lower surface with scattered, rather unequal scales. Inflorescence 2-5-flowered, pedicels lepidote and rather densely loriform-setose. Calyx conspicuous, somewhat unequally 5-lobed, the lobes usually herbaceous, oblong-ovate, obtuse, lepidote near the base, loriform-ciliate, the largest 6-9 mm. Corolla white or white flushed pink, campanulate to funnel-campanulate, (32-)36-45 mm, the tube (19-)21-29 mm, glabrous and elepidote outside. Stamens 10, filaments pubescent towards the base. Ovary lepidote, style impressed, glabrous and elepidote. Capsule oblong-globose, c. 10-16 mm, lepidote.
Habitat: Hillsides, rocky places, forests
Distribution: Nepal, India (Sikkim), Bhutan, China (S Xizang)
Altitude: 2400-4000m
Illustrations:
Type: Sikkim Himalaya, Lachen and Lachung valleys, 9000-10000 ft, Hooker (holo. K)
Occurs in Countries: BT, CN, IN, NP Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: pink, white
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):41
Free-growing shrub. Young growth loriform-setose, the setae usually persistent. Leaves elliptic or narrowly elliptic, tapering to the base, acute at the apex, 70-110 x 26-40 mm, brownish beneath with rather dense but not contiguous scales. Inflorescence (2-)3-5-flowered. Calyx small, undulately lobed, persistently loriform-ciliate. Corolla white or pink, 50-60 mm, tube 25-34 mm, the tube pubescent but not lepidote outside, the lobes sparsely lepidote. Capsule ovoid-cyhndric, c. 20 mm
Habitat: Hillsides
Distribution: China (N & C Yunnan)
Altitude: Around 2400m
Illustrations:
R. ciliicalyx is a reasonably uniform species. R. missionarum is in no way different and probably comes from the same general area (the localities given by Maire have not been precisely identified). R. pseudociliicalyx was described from a cultivated specimen; it is also identical to R. ciliicalyx and is likely to have originated in Yunnan rather than Sichuan as surmised by Hutchinson (loc. cit.)
Type: China, Yunnan, prope Mo-so-yn, 2400 m, Delavay 736 (holo. P—n.v., iso. E)
Synonymy: R. missionarum Leveille, Bull. Geogr. Bot. 24:20 (1915). Type: China, Yunnan, Tong-koua-pur, 3000 m, 1911, Maire (holo. E). R. pseudociliicalyx Hutchinson, Notes R.B.G. Edinb. 12:54 (1919). Type: a cultivated specimen (holo. E)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: pink
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):51
Erect shrub. Twigs rounded, sub-densely covered with reddish sessile or sub-sessile scales, without simple hairs. Leaves in a loose pseudowhorl, or spirally arranged several together at the tips of the stems. Blade 12–20 x 5–10mm, obovate; apex very shortly retuse, rarely rounded; margin very shortly revolute proximally, otherwise flat; base tapering, laxly scaly above, glabrescent with age and becoming a little rough, sub-densely scaly beneath. Scales sub-circular, sessile, marginal zone narrow and thin, sub-entire, centre large, thick and distinctly impressed. Mid-vein slightly impressed above, obtusely raised beneath, disappearing distally; lateral veins obscure above, weakly or not visible beneath. Petiole 2–3mm, rounded, scaly. Bracts to 6 x 3mm, ovate to obovate-spathulate, apiculate, with silky hairs and scaly in the upper outer part, densely white-fringed along the margins. Bracteoles to 5mm, filiform, hairy at the apex. Inflorescence of solitary or paired flowers, hanging vertically. Pedicels 6–10mm, slender, densely to laxly scaly with shortly stalked scales, and sometimes laxly short-hairy. Calyx c.2mm in diameter, minute, wavy and spreading, or with the narrow margin reflexed, scaly and very shortly hairy outside, with very short and obtuse lobes. Corolla 20mm, tubular; tube c.18 x 3 x 5mm, laxly scaly outside, glabrous inside; lobes c.4 x 3–4mm, ovate to sub-circular, erect at first, later spreading, distinctly irregularly-denticulate and ciliate at the apex. Stamens as long as the corolla on opening, finally slightly exserted; filaments filiform, glabrous; anthers 1.3mm. Disc glabrous. Ovary c.2.5 x 1.5mm, sub-ovoid-cylindrical, very densely scaly, gradually tapering distally; style c.17mm, thick-filiform, glabrous; stigma club-shaped, irregularly lobed. Fruit c.13 x 3.5mm, obliquely sub-cylindrical, deeply 5-grooved.
Habitat: In heath vegetation or Leptospermum forest
Distribution: Indonesia, New Guinea (W), Wissel Lakes region; Mt Kobre near Manokwari.
Altitude: 1755-2000m
Latin – cilium – a hair-like outgrowth; lobus – a rounded flattened organ. Referring to the characteristic cilia on the margin of the corolla lobes.
A form without hairs at the calyx and corolla lobes is known from the Balim Valley at 1600m.
Type: Eyma 4787, 29 March 1939. New Guinea (W), Wissel Lake Region, Enarotali-Kugapa, Egogitoagapa (L, BO).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:61
Shrub of 1-3-1-6 m. Young growth loriform-setose. Leaves narrowly ovate to elliptic, rounded at the base, ± acuminate towards the apex, 50-70 x 30-35 mm, upper surface dark brownish green, lower surface brownish with rather lax scales; petiole loriform-setose. Inflorescence 3-4-flowered, pedicels lepidote. Calyx rather conspicuous, undulately 5-lobed, the lobes broadly triangular, obtuse, loriform-ciliate, lepidote, c. 4 mm. Corolla white with a greenish blotch at the base, 55-60 mm, tube c. 30 mm, pilose near the base, laxly lepidote all over the outside. Ovary lepidote. Capsule unknown
Habitat: Cliffs and boulders,
Distribution: China. (N & NW Yunnan)
Altitude: Around 3000m
Another obscure species. The paratype cited by Hutchinson with the original description [Forrest 25484) is very different from the type, and is here placed in R. pseudociliipes (p. 50). R. ciliipes is very similar in foliage to R. roseatum, also from the Shweli/Salween Divide, but it has an impressed style.
Type: China, Yunnan, Shweli/Salween Divide, v 1925, Forrest 26384 (hoio. E)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: green
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):48
Erect shrub. Twigs slender, rounded, tips scaly; internodes 2–11cm. Leaves 4–6 together in tight pseudowhorls, not aromatic. Blade 30–60 x 30–40mm, ovate-elliptic or mostly elliptic; apex shortly obtusely acuminate, sometimes apiculate with a small gland; margin entire, slightly revolute; base sub-truncate, rounded or cordate, sub-densely scaly above but quickly glabrescent, densely and persistently scaly beneath. Scales nearly round, wavy at the margin, very distinctly impressed, the scale pits becoming blackish with age. Mid-vein impressed above, strongly prominent beneath; lateral veins 3–4 per side, very slightly impressed above in fully mature leaves, somewhat prominent in younger ones, mostly not easily visible, especially beneath, reticulation obscure. Petiole 1.5–3 x 1–1.5mm, scaly, grooved above. Bracts to 10 x 7mm; outer bracts ovate, acute; inner ones obovate, scaly above along the middle line. Bracteoles c.6 x 1mm, linear. Pedicels 5–8mm, slender, densely reddish-brown scaly. Calyx c.2.5mm in diameter, disc-like, scaly outside, glabrous inside, the margin undulate and shortly 5-lobed, spreading or reflexed at flowering. Corolla 32 x 14mm, (dry), white, trumpet-shaped; tube 25–30 x 2.5–3 x 2.5–3mm, nearly straight, 5-pouched at the base, very densely scaly outside, glabrous inside; lobes 10–12 x 8–9mm, spreading horizontally, obovate-elliptic, sparsely scaly outside, glabrous inside. Stamens unequal, not or slightly exserted from the throat; filaments filiform, laxly hairy; anthers 2–2.5mm, broadly oblong. Disc low, densely white-hairy. Ovary c.4 x 2mm, cylindrical-conical, densely and exclusively scaly, abruptly narrowed to the style, slightly 5-ribbed; style c.23mm, scaly and shortly patently hairy in the proximal 1⁄3, gradually becoming glabrous distally; stigma shortly obconical, minutely crenulate.
Habitat: In open montane shrubberies especially in disturbed areas at roadsides.
Distribution: Indonesia, New Guinea (W), Wissel Lakes, 2400m, and on the southern side of Mt Jaya (Carstensz).
Latin – Cinchona – a South American plant in the Rubiaceae from which was derived the antimalarial ‘quinine’; florum – pertaining to the flower. The flowers are reminiscent of those of the quinine plant.
Type: Eyma 5264, 11–17 Oct. 1939. Papua, Wissel Lake Region, Look-out Perai, 2400m (BO, L).
Occurs in Countries: ID Subgenus: Vireya Habit: Non-Tree Fl. Colour: white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:66
Shrub to 2m. Twigs rounded, slender, grey, tips laxly scaly; internodes 2.5–10cm. Leaves 4–6 together in pseudowhorls. Blade 40–55 x 12–23mm, elliptic to obovate; apex shortly obtusely acuminate, rarely rounded; margin entire, flat; base tapering; sub-densely scaly initially on both sides finally glabrescent above, persistently scaly beneath. Scales thin, flat, irregularly lobed; centre small, impressed. Mid-vein shallowly impressed above, prominent beneath, especially proximally; lateral veins 6–8 per side, inconspicuous. Petiole 6–10 x c.1.3mm, grooved above, flattened, scaly initially. Bracts to 15 x 7mm, ovate to obovate-spathulate, laxly scaly outside and with hairs apically, glabrous internally, ciliate and with scales at the margin. Bracteoles 10–15 x 1mm, filiform to sub-spathulate. Inflorescence 5–7-flowered. Pedicels 9–20 x 0.5mm, densely scaly, laxly and very shortly hairy. Calyx very oblique, a thin, wavy, irregularly 5-dentate rim, one or more teeth elongate to 2–4mm. Corolla 50–60mm, trumpet-shaped, white; tube 37–50 x c.2.5 x 3–3.5mm, cylindrical, straight or slightly curved, densely scaly, not hairy outside, laxly hairy inside in the proximal 1⁄3 only; lobes c.10 x 6–7mm, spreading, spathulate-obovate, laxly scaly outside, glabrous inside. Stamens well exserted from the corolla tube; filaments filiform, hairy in the proximal ½ only; anthers c.2.5mm, oblong, base obtuse. Disc shortly hairy at the upper margin. Ovary c.5 x 1.2mm, elongate-cylindrical, sub-densely scaly and sub-appressed-hairy, gradually narrowed distally; style exserted for c.10mm, scaly and sub-patently hairy for 30mm above the base, otherwise scaly only, nearly to the top; stigma shortly obconical-globose.
Habitat: Secondary forest amongst Sphagnum
Distribution: Indonesia, New Guinea (W), Wissel Lakes area. Two collections.
Altitude: Around 1750m
Latin – cinerascens – becoming ash-grey, alluding to the colour of the twigs.
An anomalous collection from the Vogelkop (van Royen & Sleumer 7836) keys out to this species but is from much lower altitude (700m). Never cultivated.
Type: Eyma 4854, 11 April 1939. New Guinea (W), Wissel Lake region, Upper Ennaro Valley and Puraida ridge, 1755m (L, A, BO, K, SING).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:173
Straggling shrub up to 7 m in favourable locations. Young growth lepidote and often glaucous or with a pruinose bloom. Leaves mostly evergreen, sometimes deciduous, broadly to narrowly elliptic, rounded to the ± obtuse apex, tapered to cordate at the base, 30-90 x 27-50 mm, lepidote or elepidote above, lepidote beneath with rather fleshy, narrowly rimmed equal or unequal scales. Inflorescences all terminal, 2-7-flowered, pedicels lepidote. Calyx disc-like or undulate, lepidote. Corolla tubular to campanulate, variable in colour: yellow, orange (sometimes with a purple flush), red, red and yellow, or purple; usually with a waxy, pruinose bloom, 25-36 mm, the tube 15-22 mm. Stamens 10, filaments pubescent towards the base, rarely entirely glabrous. Ovary lepidote and sometimes puberulous at the apex. Style glabrous or sparsely pubescent or rarely lepidote at the base. Capsule lepidote, cylindric, c. 10 mm.
A very variable species, divisible into three vicariating subspecies
Occurs in Countries: BT, CN, IN, MM, NP Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: orange, purple, red, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):123
Corolla lobes elepidote outside; most leaves evergreen; corolla variable in colour, rarely purple. Leaves relatively narrow, length/breadth ratio 2.2 or more, usually elepidote above; corolla usually ± tubular-campanulate
Habitat: Hillsides, forest and forest margins
Distribution: Nepal, India (W Bengal, Sikkim), Bhutan, China (S Xizang)
Altitude: 2750-3950m
Illustrations:
The corolla of subsp. cinnabarinum is usually somewhat tubular, and varies in colour from dull red, through coppery red to red and yellow or orange.
Type: Sikkim Himalaya, Hooker (holo. K)
Synonymy: R. roylei Hooker, Rhodo. Sikkim Himalaya t. 7 (1849). Type: Sikkim Himalaya, Hooker (holo. K). R. blandfordiiflorum W. J. Hooker, Bot. Mag. 82: t. 4930 (1856). Type: Sikkim Himalaya, (J. D.) Hooker (holo. K). R. cinnabarinum var. roylei (Hooker) Hort. R. cinnabarinum var. blandfordiiflorum (Hooker) Hort.
Corolla lobes lepidote outside; most leaves deciduous; corolla purple.
Habitat: Thickets and forest margins
Distribution: N Burma
Altitude: 2750-3200m
Geographically disjunct from the rest of R. cinnabarinum, but clearly sustaining the W-E trends in various characters shown by the other subspecies. Its corolla is campanulate and purple.
Synonymy: R. tamaense Davidian, Rhododendrons (RHS) 1972:54-55 N Burma, N Triangle, Tama Bum, 10000-10500 ft, 20 vi 1953, Kingdon Ward 21021 (holo. BM)
orolla lobes elepidote outside; most leaves evergreen; corolla variable in colour, rarely purple. Leaves relatively broader, length/breadth ratio less than 2.2, usually persistently lepidote above; corolla usually campanulate
Habitat: Hillsides, forests, forest margins
Distribution: India (Arunachal Pradesh), Bhutan, China (S Xizang)
Altitude: 3050-3950m
Illustrations:
The corollas of subsp. xanthocodon are campanulate and vary in colour from clear yellow to apricot, yellow flushed with purple (either when young, when old, or permanently), or purple. The subspecies intergrades with subsp. cinnabarinum in Bhutan, where many intermediates occur.
Synonymy: R. xanthocodon Hutchinson, Gard. Chron. 95:409 (1934). Type: a cultivated specimen derived from Kingdon Ward 6026 (holo. K). R. concatenans Hutchinson, ibid. 97:374 (1935). Type: a cultivated specimen derived from Kingdon Ward 5874 (holo. K, iso. E). R. cinnabarinum var. pallidum W. J. Hooker, Bot. Mag. 80: t. 4788 (1854). Type: a cultivated specimen (holo. K). R. cinnabarinum var. purpurellum Cowan, Notes R.B.G. Edinb. 21:147 (1951). Type: Tibet, Natrampa, Chayul Chu, 10000 ft, 27 iv 3936, Ludlow & Sherhff 1354 (holo. E, iso. BM)
Leaves elliptic to oblong, up to 11 x 3.5cm, lower surface with a thin mid-brown crisped indumentum.
Differs from R. lanatum in its predominantly glandular ovary that only has a few lanate hairs.
The only specimen seen is very poor and only has old corollas; the flower colour is therefore not known. In the absence of adequate material, the status of this taxon is unclear.
Type: China, S Xizang, Bimbi La, 13-14000ft, 12 vii 1935, Kingdon-Ward 11964 (iso. E).
Subgenus: Hymenanthes Habit: Non-Tree
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):370
Dwarf shrub, 0.2-l(-1.5)m; young shoots glabrous or with a white ± floccose tomentum. Leaves obovate to elliptic, 4-6(-7.5) x 1.5—2.3cm, 2.2-2.7(-3.3) x as long as broad, apex rounded, apiculate, base ± cuneate, glabrous above when mature, with a dense thick grey-brown ramiform tomentum beneath; petioles 0.5-lcm, usually ± winged, glabrous or with a white floccose tomentum when mature. Inflorescence 2-6-flowered; rhachis 2-3mm; pedicels 10-20mm, stipitate-glandular or with a mixture of long-branched hairs and glands. Calyx 2-12mm, when well-developed ± cupular, lobes ciliate or glandular-ciliate, otherwise glabrous. Corolla not fleshy, tubular-campanulate, yellow or orange to carmine, 32-45mm. Ovary stipitate-glandular and/or densely rufous-tomentose. Capsule 8-12 x 4-6mm.
Habitat: Cliffs, rocks, moorland, occasionally in thickets
Distribution: China (SE Xizang, NW Yunnan)
Altitude: 4000-4600m
The two extremes, var. citriniflorum with yellow flowers, a short calyx and glandular ovary, and var. horaeum with red flowers, a well-developed calyx and a tomentose, eglandular ovary, are distinct. There is however a range of intermediates (var. horaeum as recognized here includes plants with flowers that are orange or tinged with red). The intermediates fall into two groups. The first, with yellowish-red flowers and glandular ovary, includes plants referred to R. citriniflorum subsp. rubens Cowan (Notes R.B.G. Edinb. 20: 14, 1940, type: Rock 23245, E) and the following: Forrest 21859; Rock 10109, 10111, 23669. The second group, with yellow flowers and an eglandular ovary, include: Forrest 25595; Rock 10106, 22189, 22277.
A number of plants are intermediate between, and apparently part of hybrid swarms involving R. catacosmum, R, citriniflorum and R. temenium: i.R, x xanthanthum Tagg & Forrest in Notes R.B.G. Edinb. 15:308 (1927). Type: China, SE Xizang, Tsarong, Salween/Kiu-chiang divide, NW of Si-chi-to, 14000ft, vi 1922, Forrest 21275 (holo. E). Shrub, 0.5-1.5m; young shoots densely setulose. Leaves obovate, 9-10 x c.4cm, 2.3-2.5 x as long as broad, lower surface with a loose, brown lanate, ± continuous tomentum. Calyx 10-15mm, cupular. Corolla creamy yellow flushed crimson, 47-60mm. ii. R. x hillieri Davidian, Rhododendrons with Magnolias and Camellias 47 (1974). Type: China, SE Xizang, Tsarong, Salween/Kiu-chiang divide, NW of Si-chi-to, 13-14000ft, vi 1922, Forrest 21736 (holo. E). Shrub, 0.3-1.8m; young shoots densely tomentose, sometimes also with a few setae. Leaves obovate, 4.5-7 x 2-3cm, 2-2.5 x as long as broad, indumentum arachnoid-floccose, sparse and discontinuous. Calyx 7-10mm, cupular. Corolla rose-pink to deep crimson, 30-50mm. iii. 1R. citriniflorum x R. temenium, Shrub, 0.6-1.3m; young shoots tomentose and often densely setulose. Leaves 5-8 x 2.3-3(-4)cm, indumentum greyish to fawn, tomentose, dense to continuous. Calyx c.7mm. Corolla 35-40mm, yellow flushed rose to crimson. The setose indumentum on the young shoots and petioles of some of these plants (assumed to be derived from R. temenium), is like that of R. haematodes subsp. chaetomallum, a taxon that might also be involved in this hybrid complex. At Si-chi-to there are plants referable to all three hybrids as well as to the three putative parents. It is perhaps significant however that subsp. chaetomallum does not occur there.
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: carmine, orange, yellow
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):392
Corolla yellow; calyx 2-5(-10)mm; ovary and usually pedicels stipitate-glandular.
The following fruiting specimens with glandular capsules are probably referable to var. citriniflorum: Forrest 15294, 22680; Rock 10905, 119, 124.
Type: China, W NW Yunnan, Mekong/Salween divide, 28°12'N, 13000ft, vii 1917, Forrest 14271 (holo. E; iso. K)
Synonymy: R. chlanidotum Balfour f. & Forrest, Notes R.B.G. Edinb. 13: 38 (1920). Type: China, SE Xizang, Tsarong, Ka-gwr-pu, 13-14000ft, vii 1918, Forrest 16714 (holo. E; iso. K).
Corolla yellowish-red to carmine; calyx (2—)7 —12mm; ovary and pedicels eglandular.
The following fruiting specimens are probably referable to var. horaeum: Forrest 14752, 22862, 25901, 25913; Rock9099, 11203, 11206.
Synonymy: R. horaeum Balfour f. & Forrest, Notes R.B.G. Edinb. 13: 264 (1922). Type: China, SE Xizang, Tsarong, Salween/Kiu-chiang divide, ix 1921, Forrest 20287 (holo. E). R. citriniflorum Balfour f. & Forrest subsp. aureotum Cowan in Notes R.B.G. Edinb. 20: 75 (1940). Type: China, SE Xizang, Tsarong, on Ka-gwr-pu, 14000ft, vii 1917, Forrest 14503 (holo. E).
Latin – citrinus – lemon yellow, alluding to the colour of the flowers.
Type: Hasskarl s.n. Indonesia, Java, Mt Gedeh Tjibureum, not preserved. Lectotype: Docters van Leeuwen 8245, the same locality (BO).
Synonymy: Azalea citrina Hassk., Flora 1842. 25(2): 30. R. zippelii Blume, Fl. Jav. Pl. inéd. 1863–83. t.4. R. jasminiflorum (non Hook.) Koord., Junghuhn Gedenkb. 1910. 184.
Occurs in Countries: ID Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Fl. Colour: orange, red, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:197
Small, spreading shrub, to 2m. Twigs 1–2mm in diameter, rounded, densely covered with flat pale-brown scales at first, glabrescent with age; internodes 1–5cm. Leaves 4–5 together in pseudowhorls, very unequal. Blade 20–60 x 10–30mm, elliptic, broadly-elliptic, rarely obovate-elliptic; apex broadly acute, obtuse to rounded, sometimes with a very small terminal gland; margin narrowly revolute in dry specimens, flat when fresh; base tapering; densely to sparsely scaly, quickly glabrescent above, more persistently scaly beneath. Scales flat, small, variously obtusely angled or more deeply indented in the marginal area which often decays leaving the small, dark, slightly impressed centres. Mid-vein slightly impressed above, prominent beneath, often conspicuously purplish-red for most of its length; lateral veins 5–8 per side, widely spreading, anastomosing, faintly raised beneath, often inconspicuous. Petiole 5–12 x c.1mm, scaly, slender, distinctly grooved above when fresh. Flower buds ovoid, to 10 x 5mm, smooth, green with a strong reddish-purple flush, often with a few spreading to recurved bracts around the base. Outer bracts triangular to ovate-acuminate, with pale brown scales at the tips outside and also minutely and densely, shortly hairy; inner ones ovate to spathulate, minutely and densely shortly hairy outside, fringed along the margin with scales, these inner ones with a highly irregular margin. Bracteoles to 8mm, filiform, almost glabrous. Inflorescence 1–4-flowered, the flowers half-hanging to hanging vertically downwards, without scent or sometimes reported as a little fragrant. Pedicels 15–20mm, red, slender, shortly hairy and sparsely scaly below, more densely so distally. Calyx 3–4mm in diameter, oblique, disc-shaped, or shortly and obtusely 5-lobed sometimes with one lobe a little longer than the others, scaly outside. Corolla 15–19 x 10–14mm, campanulate, pale-yellow to yellowish-white, lobed nearly halfway; tube 10–12 x 4–5 x 8–9mm, laxly scaly to almost glabrous outside in the Javanese, but more densely scaly in the Balinese specimens; glabrous inside; lobes c.9 x 10mm, semi-erect, obovate-spathulate, apex rounded or very slightly retuse, overlapping to ¾. Stamens 5, loosely clustered on the lower side of the flower, the anthers exserted to c.5mm; filaments 12–15mm, linear, glabrous, pale yellow, red or orange; anthers 2.2–2.6 x c.1mm, oblong, deeply emarginate at both ends, yellow or orange. Disc prominent, glabrous. Ovary 3–4 x c.1.5mm, green, obliquely oblong-ellipsoid, somewhat 5-angled, papillose-scaly mostly at the base, occasionally all over, abruptly contracted distally; style 6–8mm, red or orange, glabrous, slightly expanded upwards; stigma rounded-sub-globose, on the lower side of the mouth. Fruit 15–27 x c.4mm, obliquely cylindrical, shortly tapering at both ends, slightly curved, red, deeply 5-grooved, glabrous, on opening the valves reflexing and often twisting, the placentae breaking away from the base and weakly spreading. Seeds 5.5–6mm, without tails c.1.2mm, the longest tail to 2.6mm, the tails crimped, sometimes strongly so.
Habitat: In very humid primary forest, sub-alpine forest or forest margins
Distribution: Indonesia, W Java, Mt Salak, Mt Gedeh, Mt Galunggung, Mt Patuha, Mt Gegerbintang, Mt Masigit, Mt Pangrango and Mt Malabar. Also reported for C Java and possibly growing on Mt Diëng but no specimens have been preserved. Bali, Mt Abang.
Altitude: 1000-2900m
Collected in Java by Mr Henshall for Rollisons Nursery and flowering in May 1854 from which material it was figured in Curtis’s Botanical Magazine (t.4797).
Corolla mostly orange, bright red, rarely pale yellow. Ovary completely or almost entirely covered in scales.
Habitat: In mossy forest, on ridges
Distribution: Indonesia, Sumatra, Atjeh, West Coast, Palembang and Lampong.
Altitude: 1220-2500m
Latin – discolor – of another colour, alluding to the usually red or orange flowers of this variety.
The fact that pale yellow flowers are recorded from Sumatra makes this variety of doubtful significance as some Javan specimens have the ovaries entirely covered with scales.
Type: Meijer 4871. Sumatra, Mt Sago near Pajakumbuh, summit region, 1800–2000m (L, BM, SING).
Synonymy: R. magniflorum Forbes, Wand. 1885. 208 nom. nud. R. citrinum (non Hassk. s.str.) Miq., Fl. Ind. Bat. 1860. Suppl. 1: 251, 586. R. multicolor (non Miq.) Moore, J. Bot. 1925. 63: 57.
Shrub, l-3m. Leaves ovate-lanceolate, (6.5-)9-14 x (3-)4.5-8cm, 1.5-2 x as long as broad, apex rounded, obtuse, base + cordate, lower surface with a thick whitish to buff bistrate indumentum, the upper layer ramiform, lanate-tomentose, the lower compacted; petioles 1.5—2cm, glabrous when mature. Inflorescence 10-15-flowered; rhachis up to 12mm; pedicels 15—30mm, glabrous, stout. Calyx c.lmm, glabrous, lobes rounded. Corolla 7-lobed, campanulate, white to deep rose, with purple flecks, 40-50mm. Ovary and style glabrous. Stamens 12-14. Capsule c.20 x 10mm.
Habitat: Open forests, among boulders
Distribution: China (NW Yunnan, SW Sichuan)
Altitude: 3350-3950m
Illustrations:
A distinctive species, the only one in subsection Taliensia with a consistently 7-lobed corolla. A specimen from S Xizang, Ludlow, Sherriff & Taylor 3868, is technically referable to R. clementinae on account of its 7-lobed corolla but it has an apiculate leaf with a thin white indumentum beneath and white-tomentose petioles. Without further material, the taxonomic significance of these differences remains uncertain but the locality is considerably further west of the present known range of the species.
Type: China, Yunnan, on the mountains of the Chungtien Plateau, 11000ft, vii 1915, Forrest 10857 (holo. E; iso. K).
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: purple, rose, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):358
Dwarf shrub, 0.3-1.3m. Leaves oblanceolate to elliptic, 4-6.5 x 1-1.8cm, 3.5-4.5 x as long as broad, apex acute, base cuneate, lower surface with a sparse reddish sub-ramiform indumentum intermixed with stipitate glands, persistent on the midrib, detersile on the lamina; petioles c.0.5cm, tomentose. Inflorescence c.6-flowered; rhachis minute; pedicels 25-30mm, sparsely stipitate-glandular. Calyx 2-4mm, glandular-ciliate, lobes rounded. Corolla campanulate, bright yellow with crimson spots, c.30mm. Ovary stipitate-glandular; style glandular to tip. Capsule not known.
Habitat: Stony slopes
Distribution: China (NW Yunnan)
Altitude: 3650-4250m
A poorly known species, apparently without close allies
Type: China, NW Yunnan, Mekong/Salween divide, E of Yeh-chih, 8 viii 1921, Forrest 19810 (holo. E)
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: crimson, yellow
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):337
Small shrub; young shoots sparsely stipitate-glandular. Leaves obovate, 6-8.5 X 3.1-4.4cm, 1.6-2 x as long as broad, apex rounded, apiculate, base rounded, upper surface glabrous, lower surface with a thick fulvous dendroid tomentum; petioles 1 — 1.5cm, sparsely short stipitate-glandular. Inflorescence c. 10-flowered; rhachis c.5mm; pedicels 7-10mm, shortly stipitate-glandular, often also with remnants of the juvenile tomentum. Calyx 5-7mm, lobes rounded, glandular-ciliate, otherwise glabrous. Corolla fleshy, tubular-campanulate, crimson, 38—45mm. Ovary shortly stipitate-glandular and tomentose. Capsule 15-18 x c.5mm, curved.
Habitat: Shaded screes, cliffs
Distribution: NE Upper Burma and adjacent parts of China (W Yunnan)
Altitude: 2750-4400m
Illustrations:
Closely allied to R. pocophorum but differing in its broader leaves and non-tomentose petioles. One plant, Kingdon-Ward 13150, is intermediate between and may be a hybrid of R. coelicum and R. haematodes subsp. chaetomallum. It not only has the stipitate glands of the former but also the setae on the young shoots and petioles of the latter.
Type: NE Upper Burma, Chawchi Pass, 11000ft, 15 x 1920, Farrer 1548 (holo. E; iso. K)
Occurs in Countries: CN, MM Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: crimson
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):389
Tree, 4-8m. Leaves oblanceolate, 7.5-12 x 2.5-4cm, 3-3.5 x as long as broad, apex acuminate, sometimes with extreme tip blunt, base cuneate, lower surface with a dense bistrate indumentum, the upper layer rufous, ramiform-tomentose, persistent or evanescent, the lower whitish, adpressed, scurfy; petioles 1—2cm, densely rufous-tomentose. Inflorescence 6-9-flowered; rhachis c.3mm; pedicels 7- 15mm, densely rufous-tomentose. Calyx c.2mm, tomentose. Corolla funnel-campanulate, pink or purplish, 40-45mm. Ovary densely rufous-tomentose; style glabrous. Capsule not known.
Distribution: China (SE Sichuan)
Distantly allied to R. rufum and R. wiltonii
Type: China, E Sichuan, Nan Chuan, Met'u-Wan, 1891, Bock von Rosthorn 929 (photo. E)
Occurs in Countries: CN Subgenus: Hymenanthes Habit: Tree Fl. Colour: pink
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):361
Prostrate shrub to 15cm. Twigs c.1mm in diameter, covered with stalked stellate scales, becoming glabrescent, laxly warty. Leaves spirally arranged, not aggregated into pseudowhorls. Blade 6–12 x 4–8mm, ovate or elliptic; apex broadly acute to obtuse, sometimes with a protruding gland; margin entire to sub-crenulate, cartilaginous, narrowly revolute; base broadly tapering to rounded; quickly glabrescent above, more persistently but laxly scaly beneath. Scales irregularly obtusely stellate-lobed, slightly or not impressed. Mid-vein impressed above and raised beneath, or almost smooth; lateral veins obscure. Petiole c.1–1.5 x 1mm, grooved above, scaly. Flower buds to 13 x 7mm, ovate, acute with the bract tips spreading out, almost glabrous. Bracts to 10 x 5mm, ovate, glabrous outside except for a few scales near the acute points outside. Flowers 1–2, horizontal to hanging. Pedicels 10–17 x 0.5mm, sub-densely stellate-scaly, with or without hairs. Calyx c.2.5mm in diameter, disc-shaped, obscurely 5-lobed. Corolla 25–30 x 14–18mm, pink to red, without scent; tube 20–25 x 4–5 x 10–12mm, tubular, slightly expanded upwards, very sparsely scaly outside, glabrous inside, oblique; lobes 5–7 x 5–7mm, sub-circular, half-spreading. Stamens unequal, exserted to c.3mm; filaments linear, glabrous; anthers sub-orbicular, c.1.5mm. Disc prominent, glabrous. Ovary sub-cylindrical, densely scaly, c.3–6 x 2mm, gradually tapering distally; style glabrous, nearly as long as the corolla; stigma obconical-globose. Fruit 18–22 x c.2.5mm, fusiform.
Distribution: Indonesia, New Guinea (W), Mt Jaya (Carstensz), Lake Habbema
Altitude: 2600-3810m
Latin – caelestis – heavenly; no doubt an impressive plant.
Still a poorly known species but distinctive in its prostrate habit and spirally arranged leaves. Sleumer (1973) commented that it might have to be united with R. schizostigma and R. disterigmoides but both of these species have a much more vigorous erect habit.
Type: Kloss s.n. New Guinea (S), Mt Carstensz, 3200–3810m (BM).
Occurs in Countries: ID Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: pink, red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:144
Shrub to 1 m. Leaf-bud scales deciduous. Leaves ± elliptic, 30-40 X 13-17 mm, rounded to the base, tapered to the acute, mucronate apex, pale green and elepidote above, pale greenish brown to brown with dense, overlapping and ± plastered scales all of the same golden brown colour beneath. Inflorescence somewhat elongate, c. 16-20-flowered, pedicels short, lepidote. Calyx lobes 5-5-5 mm, sparsely lepidote outside, margins lacerate-ciliate with loriform setae, inner surface puberulent. Corolla white (often pink in bud), funnel-hypocrateriform, tube 10-13 mm, lobes 6-8 mm, glabrous and elepidote outside, tube pilose within. Stamens 8-10. Ovary lepidote. Capsule lepidote, c. 5 mm, scarcely exceeding the calyx
Habitat: Steep rocky and stony slopes
Distribution: Afghanistan, Pakistan
Altitude: 3050-3900m
Illustrations:
Type: Described from Afghanistan (Shendtoi to ridges of Sikaram 10-13000 ft)
Occurs in Countries: AF, PK Altitude Ranges: 3,000 - 4,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: pink
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):158
Dwarf shrub, 0.6-1m. Leaves elliptic to obovate, 3-5 X 1.2-1.5cm, 2.5-3.5 X as long as broad, apex apiculate, base cuneate, lower surface with a dense bistrate indumentum, the upper layer red-brown, loosely lanate-tomentose, the lower compacted; petioles c.0.5cm, brown-tomentose. Inflorescence 6-10-flowered; rhachis c.5mm; pedicels c.lOmm, brown-tomentose. Calyx c.0.5mm, brown-tomentose. Corolla deep rose, with a few flecks, c.35mm. Ovary rufous-tomentose. Capsule not known.
Habitat: Open pasture, stony slopes
Distribution: China (SE Xizang, NW Yunnan)
Altitude: 3950-4250m
The shape of the corolla is not clear in the herbarium specimens available so the affinities of this species are not certain. It does, however, resemble R. proteoides in its vegetative characters.
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: rose
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):346
Compact, stiff, often flat-topped shrub, to 6m. Sometimes forming a thick woody basal burl from which numerous epicormic shoots arise. Twigs c.3mm in diameter, rounded or angular, green or red, stellate-scaly and minutely short-hairy; internodes 1.5–4.5cm. Leaves spirally arranged, or in very loose pseudowhorls, clustered more densely in the upper part of the internodes. Blade 10–43 x 8–22mm, elliptic to obovate-elliptic, narrowly obovate or in the high altitude forms almost circular; apex obtuse to rounded with a conspicuous apical gland which is sometimes extended into a down-turned point; margin flat or slightly revolute, cartilaginous and distinctly crenulate; base broadly tapering; shiny green and glabrescent above although the scales often leaving blackish pits; beneath, paler-green sub-densely brown scaly. Scales rounded to lobed, with small centres, impressed into the leaf surface and leaving distinct pits where they have fallen off. Mid-vein impressed above, broad and obtusely prominent in the lower ½ beneath, less so distally; lateral veins 4–6 per side, irregular, curved ascending, slightly impressed above in fully mature leaves, faintly raised or hardly visible beneath, reticulation inconspicuous. Petiole 2–4 x 1–2mm, grooved above and slightly flattened, scaly and obscurely shortly hairy. Flower buds to 15 x 12mm, green, the bract apices standing out as short points. Bracts to 15 x 11mm, the outer ones subulate, intermediate ovate-acuminate, abruptly subulate in the upper ¼–½, innermost ones obovate-spathulate, shining, glabrous or scaly along the dorsal midline and at the apex (never hairy!), fringed with scales. Bracteoles to 12 x 1mm, linear. Inflorescence of 4–6-flowered open umbels. Flowers half-hanging to semi-erect. Pedicels 8–18 x c.1.5mm, laxly to densely brown-stellate-scaly, without hairs or with minute papillose hairs between the scales and sometimes some longer hairs just under the calyx. Calyx c.4mm in diameter, oblique, scaly at the base, deeply 5-lobed, lobes narrowly triangular or sometimes linear-subulate up to 10mm, glabrous, or occasionally long-hairy at the apex, irregular in both shape and length, sub-persistent. Corolla 20–35 x 27mm, tubular, oblique and curved, (rarely straight), deep red to purplish, pink, pale yellow or white; tube 25–30 x 6–7 x 10–12mm, laxly to sub-densely stellately scaly outside, glabrous or shortly hairy inside, swollen at the base and conspicuously grooved in the proximal ½; lobes 10–11 x 9–10mm, sub-spathulate-circular, spreading to reflexed and overlapping to c.1⁄3. Stamens exserted to 10mm, loosely arranged in the upper ½ of the flower; filaments linear, purplish-pink, glabrous or laxly shortly papillose-hairy; anthers obovate-oblong, 2–2.3 x 1mm. Disc prominent, glabrous. Ovary 4–5 x 2–3mm, conical to sub-cylindrical, densely covered with short slightly distally directed, silvery hairs which cover small scales; style glabrous or with some hairs for the basal 5mm, ultimately as long as the stamens, on the upper side of the tube, moving to a central position as the stigma becomes receptive; stigma obliquely globose. Fruit 10–20 x 6–8mm, ellipsoid, standing erect, sub-densely short-hairy and scaly. Seeds c.3mm, the tails included.
Habitat: Terrestrial in grassland at the edge of Papuacedrus forest, in open semi-swampy places, also on crests of high ridges, stony ground. Becoming very small-leafed at high altitudes.
Distribution: Indonesia, New Guinea (W), Mt Jaya. Papua New Guinea, Star Mts, Yobobos, Mt Sugarloaf, Sirunki, Yogonda, Mt Hagen area, Tomba, Kubor Mts, Mt Wilhelm lakes area, Mt Michael, Finisterre Mts, Sarawaket Mts.
Altitude: 1800-4000m
Said to be named after the author’s wife!
Van Royen & Kores (1982) reduced R. pseudonitens to this species on the basis of field work which showed the size difference between them was untenable. They also recorded wild hybrids with R. culminicola and R. womersleyi in the Finisterre Mts and with R. macgregoriae in the Tari Gap.
Type: Keysser s.n. Papua New Guinea, Morobe District, Mt Saruwaged, (‘Bolan’) (B†, BM).
Synonymy: R. stonori Sleumer, Reinwardtia 1960. 5: 155. R. nitens Sleumer, Reinwardtia 1960. 5: 162, non Hutchinson, 1936. R. pseudonitens Sleumer, Blumea 1961. 11: 124.
Occurs in Countries: ID, PG Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: pink, red, white, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:219
Shrub or small tree to 3m, growing with dense-packed, slender stems. Twigs 2–4mm in diameter, rounded, densely covered with sub-stellate reddish-brown scales when young; internodes 3–12cm. Leaves 2–5 together in pseudowhorls. Blade 80–170 x 20–55mm, elliptic; apex elongate, sometimes abruptly acuminate, sub-acute; margin flat or very slightly revolute; base broadly and acutely tapering, (never rounded), sometimes the sides unequal, sub-persistently scaly above, minutely rugose by inflated epidermis cells, persistently laxly to sub-densely scaly beneath. Scales minute, marginal zone sub-stellately lobed; centres small and slightly impressed. Mid-vein very narrow and distinctly depressed above, as thick as the petiole, and strongly prominent beneath, often more densely scaly than the surrounding leaf; lateral veins 10–14 per side, spreading at almost 90°, straight below, curved and obscurely anastomosing before the margin, with additional less distinct veins, parallel, faintly impressed above, minutely raised or inconspicuous beneath, reticulation dense, visible above only. Petiole 10–15 x 1.5–2mm, flattened and grooved above, densely scaly. Bracts to 20 x 7mm; outer bracts narrowly ovate-acuminate, extended at the apex into a fine sharp point, scaly along the outside middle line distally, glabrous at the margin, inner bracts much narrower, nearly linear. Bracteoles c.15mm, filiform, laxly scaly. Inflorescence 3–5-flowered, an open umbel, the flowers semi-erect. Pedicels 10–20 x c.1mm, laxly sub-stellately scaly, not hairy. Calyx c.4mm in diameter, obliquely disc-shaped, shortly and bluntly 5-lobed, densely scaly outside. Corolla 50–65mm, funnel-shaped, bright red with purplish-pink flushed throat, lobed to c.1⁄3; tube 30–40 x 4–5 x c.15mm, lobed at the base, laxly minutely sub-stellately scaly outside, laxly short-hairy in the proximal ½ inside; lobes 20–27 x 15–24mm, half-spreading, broadly obovate-spathulate or sub-circular. Stamens unequal, exserted to c.10mm; filaments linear, sub-densely papillose-hairy proximally, papillose in the middle, glabrous in the distal 1⁄3; anthers 3–3.5 x c.1mm, oblong. Disc glabrous below, shortly hairy on the upper margin. Ovary 7–8 x c.2mm, sub-cylindrical, greyish long-hairy with distally directed hairs and densely scaly (the scales covered by the hairs), abruptly contracted distally; style thick, densely sub-patently hairy nearly to the top, less densely scaly, nearly as long as the corolla; stigma thick-rounded. Fruit c.80 x 4mm, narrowly cylindrical, curved, laxly hairy and densely scaly.
Habitat: Mostly terrestrial in swampy jungle or white sand podsols at low elevations in shaded habitats.
Distribution: Malaysia (Borneo), Sarawak and Sabah. Brunei.
Latin – commutatus – change, presumably an allusion to the changed status of the original collection.
Type: Beccari P.B. 2322. Borneo, Sarawak, Lundu (FI, A, K, P, S).
Synonymy: R. gracile (non Low ex Lindl.) Beccari, Malesia 1878. I: 203.
Occurs in Countries: MY Subgenus: Vireya Habit: Tree Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:271
Erect shrub to 2m. Twigs 2–4mm in diameter, semi-rounded, laxly and deciduously sub-stellately scaly when young, sometimes whitish; internodes 2–11cm. Leaves 4–5 together in pseudowhorls. Blade 35–90 x 25–50mm, elliptic to sub-obovate-elliptic; apex broadly tapering or very shortly sub-abruptly acuminate, obtuse, sometimes rounded; margin narrowly but distinctly revolute; base broadly tapering, glabrescent above when mature, laxly, sub-persistently scaly beneath. Scales minute, marginal zone irregularly sub-stellately lobed; centre slightly impressed. Mid-vein narrowly impressed above, thick and obtusely prominent beneath; lateral veins 5–9 per side, spreading, sometimes irregular, often divided before the margin, mostly sub-parallel to each other and distinctly curved-anastomosing, slightly impressed above, somewhat raised beneath, reticulation faintly impressed above in old leaves, often inconspicuous. Petiole 10–23 x 1–2mm, semi-rounded, grooved above. Bracts to 20 x 15mm; outer bracts ovate, sub-acuminate, or circular, scaly along the midline distally outside; inner bracts obovate to spathulate, glabrescent or glabrous apart from marginal scales. Bracteoles 15 x 0.5–1.5mm, linear-spathulate, glabrous. Inflorescence an open 8–13-flowered umbel. Pedicels 20–30 x c.1mm, densely sub-stellately scaly. Calyx c.3mm in diameter, obliquely disc-shaped, shortly and bluntly 5-lobed, scaly outside. Corolla 40–48 x 50mm, funnel-shaped, white, scented; tube c.25 x 5–6 x 8–12mm, straight, sub-cylindrical, lobed at the base, laxly to sub-densely covered with minute sub-stellate scales outside, shortly hairy inside; lobes 15–20 x 15–20mm, broadly obovate or sub-circular, spreading. Stamens sub-equal, exserted; filaments linear and laxly patently hairy in the lower 2⁄3, more filiform and glabrous distally; anthers 3–3.5 x 0.8mm, narrowly oblong. Disc low, glabrous. Ovary 5–6 x c.2mm, sub-cylindrical, densely covered with forwardly directed hairs which cover the scales, tapering distally; style slightly shorter than the stamens, densely hairy and scaly for the proximal ¾, scaly at the apex; stigma deeply 5-lobed. Fruit 30–35 x 5–6mm, sub-cylindrical. Seeds very narrow, 4–5mm including the long tails.
Habitat: Scattered in stiff scrub on the summit and on cliffs.
Distribution: Papua New Guinea, Milne Bay District, Sudest I., on Mt Riu
Altitude: 600-800m
Latin – comparandus – worthy of comparison, alluding to its supposed relationship with R. lochae (see below).
Sleumer (1966) noted: ‘Much related to R. lochae F. v. M. from NE Queensland (the only Rhododendron in Australia [at that time]), which, however, has red corollas, laxly hairy ovary (the scales thus clearly visible) and 2–5 (rarely up to 7) flowers per umbel’. It would be interesting to know if DNA analysis supported this view.
Type: Brass 27861, 27 Aug. 1956. New Guinea, SE, Milne Bay District, Sudest Isl., Mt Riu, summit, 800m (L, A, K, LAE, PNH, S, US).
Occurs in Countries: PG Altitude Ranges: 0 - 1,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:299
Fastigiate or rounded, much branched shrub, 8-60 cm. Leaves 3.5-11 x I -8-6 mm, broadly or narrowly elliptic to ovate, apex obtuse or rounded, mucro small or absent, base cuneate or truncate, undersurface uniformly ferrugineous with contiguous scales. Inflorescence 3-4(-5)-flowered, pedicels lepidote, 0-5-7.5 mm. Calyx obsolete to less than 1 mm, rarely to 2 mm, lobes deltoid, rounded or strap-shaped, margin lepidote and/or ciliate. Corolla pale lilac to rosy purple, usually narrowly funnel-shaped, 9-13 mm, tube 4-6 mm, pubescent inside and occasionally outside. Stamens 5-6(-8), filaments pubescent towards the base. Ovary lepidote, style usually short (up to 3 mm), rarely longer (6-8 mm), glabrous or slightly pubescent towards the base. Capsule c. 5 mm, ovoid to subrotund, lepidote.
Habitat: Alpine screes, rocks and stony slopes
Distribution: China (N Yunnan)
Altitude: 3400-4600m
Type: China, Yunnan, Chungtien plateau, 3350-3650 m, Forrest 12520 (holo. E, iso. K)
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: lilac, purple
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):99
Latin – comptus – adorned, presumably alluding to the plant being covered with flowers.
Type: Giulianetti s.n., 1896. New Guinea, Owen Stanley Range, Mt Scratchley (K).
Occurs in Countries: PG Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Vireya
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:137
Low erect shrub with several branches arising independently from subterranean stems. Twigs 2–3mm in diameter, firm, angular and longitudinally striate, densely covered with sessile scales initially, glabrescent and smooth with age, often with conspicuous lateral buds; internodes 2–8cm. Leaves loosely spirally arranged, mostly in the upper ½ of the internode, sometimes over the whole length, semi-erect. Blade 18–30 x 5–9mm, narrowly elliptic to elliptic or obovate-elliptic; apex shortly tapering, sub-apiculate, or sometimes nearly rounded; margin minutely crenulate by impressed scales, not revolute; base tapering, densely scaly on both sides initially, glabrescent and shining above with age, below more persistently scaly. Scales very dense, touching and often overlapping each other, flat, thin, small, brown initially, becoming silvery with age; centre impressed, leaving a pitted surface when the scales have gone. Mid-vein a little impressed above, and slightly and obtusely raised beneath, obscure apically; lateral veins not visible. Petiole 0.5–2 x c.1.5mm, flattened and grooved above, scaly. Outer bracts to 20 x 10mm, ovate-elliptic, sub-acuminate, inner ones elliptic to elliptic-obovate, scaly on a broad midline outside, glabrous elsewhere. Bracteoles linear, glabrous, c.15mm. Inflorescence 3–5-flowered, the flowers hanging vertically. Pedicels very densely scaly, without hairs, 12–18 x 1–1.5mm. Calyx c.3.5mm in diameter, shortly cup-shaped, oblique, forming an angle with the pedicel, densely scaly outside, obscurely and bluntly lobed, sometimes with one lobe more distinct. Corolla tubular below, campanulate distally, c.28 x 20mm, bright red; tube 15–18 x 4–5 x 6–7mm, laxly scaly outside, glabrous inside; lobes 7–9 x 7–9mm, sub-circular, spreading. Stamens within the mouth; filaments linear, light yellow, glabrous; anthers 1.3–1.5mm, inwardly curved, light brown, obovate to sub-orbicular. Disc glabrous. Ovary 3–4 x 2.5–3mm, very densely scaly, conical, tapering or somewhat abruptly contracted distally; style as long as the corolla, thick, scaly proximally for ¼–1⁄3, glabrous distally; stigma large, 5-lobed. Fruit c.15 x 6mm, ovoid.
Distribution: Papua New Guinea, Owen Stanley Range: Mts Scratchley, Victoria and Albert Edward
Altitude: 3000-4000m
The species is fairly distinctive, with its scattered elliptic leaves with no obvious lateral veins but often drying with oblique lateral folds on the undersides of the blades. This has been confused with R. giulianettii but that species has much broader leaves in relation to length, with rounded rather than tapering bases. Rhododendron giulianettii also commonly (but not always) has leaves with 1–2 lateral veins per side, visible.
Differing only in that the ovary is hairy, as well as densely scaly. Described with bright red flowers. Fruit 10–12 x 6–7mm, becoming erect with persistent styles. Seeds 20–25mm, without tails 0.9mm, the longest tail 0.9mm.
Distribution: Papua New Guinea, Mt Albert Edward, cliffs in open grassland and terrestrial on a steep, boggy slope
Altitude: 3600-3800m
Greek – tricho – hairy, alluding to the hairy ovary which distinguishes this from the type variety.
Type: Brass 4346. New Guinea, Central Dist., Mt Albert Edward (L, A, BO).
Very similar to R. monanthum, differing essentially only in its purple corolla. INDIA (Arunachal Pradesh)
Known only from the type collection, this species is a purple-flowered equivalent of R. monanthum. Its distinctness is dubious (purple/yellow corolla colour variation is known in other species, e.g. R. lepidotum, see p. 149) and further material is necessary before its status can be settled.
Type: Assam, Delei valley, 8000-11000 ft, Kingdon Ward 8578 (iso. E)
Subgenus: Rhododendron Habit: Non-Tree
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):61
Shrub, 0-5-2 m. Leaves ovate or elliptic, 35-60 x 18-32 mm, rounded to cordate at the base, acute to slightly acuminate at the apex, upper surface lepidote (scales sometimes deciduous), puberulent along the midrib, lower surface grey or brownish with numerous contiguous or almost contiguous large, flat, broadly rimmed scales with a tendency to dimorphism in colour—golden and brown. Inflorescence 2-4-flowered; pedicels (5-)7-13 mm, lepidote. Calyx minute, variably lobed, ciiiate with loriform and filiform-acicular hairs, rarely glabrous. Corolla purple or reddish purple, rarely pale, 20-30 mm, tube 8-15 mm, lepidote on the tube outside, pubescent within the tube. Stamens 10, filaments pubescent towards the base. Ovary lepidote, sometimes minutely pubescent at apex. Style glabrous or puberulent. Capsule lepidote, 8-14 mm
Habitat: Forests and thickets
Distribution: China (NW, SW, C & E Sichuan, W Hubei)
Altitude: 2300-4500m
Illustrations:
A rather variable species known from material that is, for the most part, poor. Leaf shape and size vary, as does the colour of the leaf undersurface. It is, however, reasonably distinct on the basis of its broad leaves and lepidote, purple corolla. R. apiculatum was based on a poor specimen collected by Wilson, and is identical with R. concinnum except that the extant fragment of the corolla is not lepidote. The varieties recognised by Davidian have no significance other than in horticulture. I have seen no material of R. hutchinsonianum Fang, Acta Phytotax. Sinica 2:83, 1953 (type: Szechuan, Erh-lang-shan, Tien chuan hsien, Hu & Ho 10148, holo. CHENGDU). From the description, it is merely a variant of R. concinnum.
Type: China, Szechuan, summit of Mt Omei, Faber (holo. K)
Synonymy: R. yanthinum Bureau & Franchet, Journ. de Bot. 5:94 (1891). Type: China, Szechuan, sur les montagnes au sud du Tatsienlu, Henri d'Orleans (holo. P—n.v., iso. E). R. benthamianum Hemsley, Gard. Chron. 47:4 (1910). Type: China, Szechuan, Wilson 1878 (holo. K). R. coombense Hemsley, Bot. Mag. 135: t. 8280 (1909). Type: a cultivated specimen (holo. K). R. apiculatum Rehder & Wilson, PI. Wils. 1:519 (1913). Type: China, Szechuan, west and near Wen chuan hsien, Wilson 3422 (iso. K). R. yanthinum var. lepidanthum Rehder & Wilson, Ioc. cit. Type: China, Szechuan, west and near Wen chuan hsien, 2500 in, vii 1908, Wilson 3419 (n.v.). R. laetevirens [Balfour f. ex] Hutchinson, The Species of Rhododendron, 781 (1930) in syn. R. pseudoyanthinum [Balfour f. ex] Hutchinson, op. cit.: 783. Type: as for R. yanthinum var. lepidanthum. R. concinnum var. benthamianum (Hemsley) Davidian, R.H.S. Rhodo. Yearbook 17:194 (1963). R. concinnum var. pseudoyanthinum (Balfour ex Hutchinson) Davidian, loc. cit.
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: purple, red
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):75
Shrub or small tree, 2-7.5m. Leaves oblanceolate, (12-) 16-25 x 4.8 -6.2cm, 2.5-4 x as long as broad, apex rounded, minutely apiculate, base cuneate, upper surface glabrescent, smooth, lower surface covered with a dense bistrate indumentum, the lower layer compacted, the upper whitish or fawn to pale cinnamon, composed of scarcely fimbriate, broadly cup-shaped hairs; petioles 2-3cm, terete, sparsely whitislj-tomentose. Inflorescence 15-20-flowered; rhachis 10-15(-30)mm; pedicels 20-30mm, sparsely brown-tomentose. Calyx c.lmm, lobes minute. Corolla (5-)7-lobed, funnel-campanulate7; white, sometimes flushed with rose, with a crimson basal blotch, sometimes also with flecks, 35-40mm. Stamens (10-)14. Ovary densely rufous-tomentose. Capsule 18-25 x 4mm, straight or curved.
Habitat: Conifer forests, Rhododendron thickets
Distribution: China (NW Yunnan, SE Xizang)
Altitude: 3000-4000m
Illustrations:
R. coriaceum is allied to R. rex but may be distinguished from subsp. rex, which also has a pale leaf indumentum, by its more slender leaves and its more westerly distribution. Some forms of subsp. fictolacteum approach R. coriaceum in the size of their leaves but have a consistently darker indumentum.
Type: China, NW Yunnan, environs de Tsekou, Soulie 1021 (E, K), 1022 (E, K), 1024 (E)
Synonymy: R. foveolatum Rehder & Wilson in Sargent (ed.), PL Wilsonianae 1: 537 (1913). Type: China, NW Yunnan, Tsekou, Mombeig 3 (E)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: crimson, rose, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):258
Small straggling shrub to 2m. Twigs c.1mm in diameter, rounded, tips flattened and densely covered with reddish-brown, sub-stellate scales; internodes 2–4cm. Leaves 4–6 together in pseudowhorls. Blade 25–40 x 8–14mm, obovate-elliptic to obovate; apex broadly tapering, obtuse or rounded; margin slightly recurved; base tapering, scaly on both sides at first, quickly glabrescent above, persistently sub-densely scaly beneath. Scales large, flat, irregularly stellately divided in the marginal zone; centre slightly impressed. Mid-vein grooved above, prominent beneath; lateral veins 3–4 per side, inconspicuous, often obscure beneath. Petiole 2–4mm, scaly. Bracts to 8 x 5mm, broadly ovate to ovate-elliptic, obtuse, glabrous outside, except for the marginal scales. Bracteoles c.5mm, filiform, laxly scaly. Inflorescence 2–3-flowered. Pedicels 10–14 x 0.5–0.7mm, slender, sub-densely stellately scaly and sparsely, shortly patently hairy. Calyx c.2.5mm in diameter, disc-shaped, oblique, scaly and shortly hairy outside, indistinctly 5-lobed. Corolla c.25 x 20mm, obliquely tubular-funnel-shaped, pink to red; tube 12–14 x 4–5 x 6–8mm, sub-densely to laxly covered with reddish-brown sub-stellate scales outside, laxly hairy inside, slightly curved; lobes 9–10 x 6–7mm, spreading, obovate-spathulate. Stamens exserted to c.5mm, sub-equal; filaments filiform, laxly patently hairy for the proximal 2⁄3, glabrous distally; anthers c.1.6mm, broadly oblong. Disc prominent, glabrous. Ovary c.5 x 2mm, sub-cylindrical, densely short-hairy and scaly, the scales covered by the hairs, tapering distally; style oblique, laxly patently hairy in the proximal ½, without scales, glabrous distally, nearly equalling the corolla in length; stigma sub-globose. Fruit (sub-mature) 22 x 4mm, sub-fusiform-cylindric, curved, densely hairy and scaly.
Habitat: Reported to be common in mossy forest and shrubberies
Distribution: Indonesia, New Guinea (W), Waigeou I., (W of Vogelkop), top of Mt Nok (Buffelhoorn)
Altitude: Around 860m
Latin – cornu – horn; bovis – an ox. After the Dutch name of Mt Nok where it was collected.
Type: Cheesman 1192, 17 June 1938. New Guinea, Weigeo I., top of Mt Nok (Buffelhoorn), E shore of Majalibit Bay, c.860m (BM).
Occurs in Countries: ID Altitude Ranges: 0 - 1,000m Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:219
Shrub with erect branches, to 4m. Twigs round to angular, at first densely covered with scales, which give a grey appearance; internodes 1–8cm often with conspicuous rounded lateral buds. Leaves either scattered in loose, or crowded in distinct 5–7-leafed, pseudowhorls. Blade 20–35 x 8–17mm, elliptic or sub-obovate, rarely ovate-elliptic; apex broadly obtusely tapering, sometimes rounded, apiculate with a small terminal gland; margin thickened and crenulate by impressed scales; base very broadly tapering to rounded, densely scaly initially on both sides, glabrescent later above and then with a pitted surface; very densely and more persistently scaly beneath. Scales overlapping with broad transparent, lobed marginal zones which eventually disappear and small to moderately sized centres which are impressed, leaving pits. Mid-vein slightly impressed above, bluntly raised beneath especially in the proximal part, disappearing distally, or sometimes entirely inconspicuous; lateral veins 3–5 per side, curved-ascending, faintly impressed or often obscure above, indistinct beneath. Petiole 3–12 x c.2mm, semi-rounded, grooved above, densely scaly. Buds 15–20 x 8–11mm, narrowly ovate with a slender acute apex and with spreading tips. Bracts to 20 x 10mm; outer bracts ovate-acuminate, sub-acute with a few scales outside near the midline and margins, glabrous elsewhere but often with a greyish waxy deposit; inner ones narrowly ovate to obovate-spathulate, membranous and shiny, glabrous. Bracteoles 10–15mm, linear-sub-spathulate, glabrous. Inflorescence an open, 3–5-flowered umbel, the flowers hanging vertically, occasionally half-hanging. Pedicels 10–20 x c.1mm, very densely scaly, without hairs, forming an angle with the calyx. Calyx 2.5–3mm in diameter, very shortly cup-shaped, oblique, densely scaly outside, obscurely lobed. Corolla 20–32 x 20–25mm, tubular below, slightly dilated distally, yellow or orange, without scent; tube 12–22 x 4–8 x 6–12mm, sub-densely or laxly scaly outside, glabrous inside; lobes 6–11 x 8–9mm, broadly elliptic to sub-circular, semi-erect, overlapping to halfway, scaly outside away from the margins. Stamens unequal, irregularly clustered around the mouth of the flower; filaments linear, glabrous; anthers 2–2.5 x 1.3–2mm, broadly obovate-oblong. Disc glabrous. Ovary c.4 x 2.5–3mm, conical, densely scaly; style thick, scaly at the very base, glabrous otherwise, as long as the corolla, becoming exserted; stigma thick, 5-lobed. Fruit c.15–20 x 4–5mm, sub-cylindrical, apex long-tapering, base shortly tapering, becoming erect before maturity. Seeds 4–4.8mm, without tails 1mm, the longest tail c.2.1mm, one tail often much broader than the other.
Habitat: Sub-alpine forest, marginal forest shrubberies and in open vegetation, also on ridge crests, commonly on mossy or peaty soil, locally abundant
Distribution: Indonesia, New Guinea (W), the Main Range from Mt Jaya (Carstensz), Hubrecht and Orange Mts to Mt Trichora (Wilhelmina).
Altitude: 3100-4300m
Resembling Correa, Australian trees in the Rutaceae.
Introduced into cultivation in 1993 by Paul Smith, it grows weakly as a leggy shrub in Edinburgh although flowering regularly. It is one of the species used in the Mt Jaya mine to recolonise disturbed ground and spoil heaps as it grows well at high altitude. It is not a spectacular plant, the flowers being rather small. It comes in two colour forms, yellow and orange, although intermediates may occur.
Type: Pulle (Versteeg) 2435, 7 Feb. 1913. W New Guinea, Hubrecht Mts (lectotype) (L, BO, K, U).
Synonymy: R. coniferum Wernham, Trans. Linn. Soc. London, II, Bot. 1916. 9: 97.
Occurs in Countries: ID Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: orange, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:135
Shrub or small tree, 2.5—6m. Leaves elliptic to oblanceolate, 8.5—16 x 2.2-4cm, c.4 x as long as broad, apex acute to acuminate, glabrous above, lower surface with a thin compacted silvery to fawn unistrate indumentum embedded in a surface film and intermixed with a few stipitate glands; petioles 1.5—2cm, floccose, with a few shortly stipitate glands. Inflorescence 20-30-flowered; rhachis 15-30mm; pedicels 30-35mm, sparsely dendroid-hairy and glandular. Calyx 2-3mm, lobes triangular, glandular. Corolla funnel-campanulate, whitish with crimson flecks, 25—30mm. Ovary glabrous or with a few whitish simple hairs; style glabrous. Capsule 20-25 x 4-6mm, cylindrical, curved to ± circinnate.
Habitat: Fir forests. Rhododendron thickets
Distribution: China(NW Yunnan & adjacent SE Xizang)
Altitude: 3650-4400m
The ± glabrous ovary and many-flowered inflorescence distinguish this from the remaining species of the subsection.
Type: China, SE Xizang, Salween/Kiu-chiang divide, NW of Si-chi-to, vi 1932, Forrest 21693 (holo. E); Forrest 22889-Iater collection (fruiting) (E)
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: crimson
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):324
Deciduous shrub, 0.3-2.3 m. Shoots pale brown, glabrous, ± elepidote. Leaves thin, oblong-elliptic, broadly elliptic or obovate, 42-65 X 22-30 mm, margins loriform-ciliate, upper surface dark green, lepidote, filiform-acicular pubescent along the veins, lower surface pale green, lepidote with distant, pale brown, broadly rimmed scales. Inflorescences 3-5-flowered, pedicels 10-20 mm, lepidote and sparsely puberulent. Calyx lobes reddish, lepidote, glabrous or rarely with a few short loriform cilia, 4-6 mm. Corolla purplish pink, 14-20 mm, very sparsely lepidote outside. Stamens 10. Ovary lepidote. Capsule ovoid-cylindric, lepidote, 8-11 mm
Habitat: Open slopes in forest
Distribution: Nepal
Altitude: 3200-3950m
Illustrations:
A distinct species of rather uncertain affinities. It was originally placed in subsection Trichoclada (Trichocladum series) because of its deciduous leaves, but it differs from that group in scale type and inflorescence, and is more closely allied to R, lepidotum.
Type: Nepal, Langtang lateral valley, 3650 m, Polunin 175 (holo. BM, iso. E)
Occurs in Countries: NP Altitude Ranges: 3,000 - 4,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: pink
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):150
Latin – crassus – thick; folium – leaf. Alluding to the thick leaves.
Type: Low s.n. North Borneo, Mt Kinabalu, 1525–2745m (K).
Synonymy: R. crassinervium Ridl., J. Str. Br. R. As. Soc. 1912. 63: 61. R. brevitubum J.J.Sm., Ic. Bog. 1914. 4: 253, t.381.
Occurs in Countries: ID, MY Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Fl. Colour: orange, pink, red, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:257
Shrub to 2.5m. Twigs 3–5mm in diameter, sparsely scaly, quickly glabrescent; internodes 1.5–15cm. Leaves spirally arranged or in lax pseudowhorls of 3–4 together. Blade 80–140 x 40–80mm, elliptic, or broadly elliptic, occasionally obovate-elliptic; apex obtuse or rounded, sometimes shortly obtusely acuminate; margin entire, flat; base broadly tapering, rounded or truncate, sometimes slightly cordate; initially scaly on both sides, glabrescent and blackish punctate above when mature, scaly for longer beneath. Scales lax, small, flat, irregularly lobed; centre minute, faintly or not impressed. Mid-vein very strongly raised above for the proximal ½–2⁄3, smooth near the apex, only weakly raised beneath or completely smooth; lateral veins 8–12 per side, sub-parallel, broadly spreading to almost a right angle, anastomosing before the margin, slightly raised above and smooth below when fresh, raised on both sides when dry, the surface smooth or distinctly rugosely puckered above, reticulation dense. Petiole 7–15 x 5–8mm, somewhat flattened, not grooved, sparsely scaly. Flower buds to 45 x 25mm, ovate, acute to obtuse, pale translucent pink or whitish, with the outer bracts standing vertically away from the buds or appressed. Bracts ovate-acuminate, glabrous, to 25 x 10mm. Bracteoles to 20mm, linear, glabrous. Inflorescence 8–20-flowered in a complete umbel, semi- erect to half-hanging. Pedicels 20–60 x c.2mm, sparsely scaly. Calyx 3–4mm in diameter, a fleshy ring, glabrous. Corolla 25–30 x 25–45mm, shortly funnel-shaped, pink, red or more rarely orange or white; tube 12–15 x 6–10 x 12–15mm, glabrous outside, sparsely hairy inside, distinctly 5-pouched at the base; lobes 12–22 x 13–19mm, obovate-elliptic, not, or overlapping up to ½, often with the lateral margins revolute. Stamens dimorphic, 12–20mm, regularly arranged around the mouth, only the longest slightly exserted up to 2mm; filaments linear, densely sub-patently hairy in the proximal ¼–1⁄3, filiform and glabrous distally; anthers 2.5–3 x 1.3mm, sub-elliptic. Disc prominent, glabrous. Ovary 5–6 x 2.5–3mm, glabrous, or with some minute scales depressed into pits in the surface, abruptly contracted distally; style 3–4mm, centrally placed, glabrous; stigma 2–3mm in diameter, dark red, 5-lobed. Fruit 18–25 x 5–6mm. Seeds 4–5mm, without tails 0.8mm, the longest tail 2.8mm.
Habitat: Epiphytic in deep shade of mossy forest but also terrestrial on open landslides, locally common and widespread
Distribution: Malaysia (Borneo), Sabah, Kinabalu, Crocker Range, Mt Trus Madi. Sarawak, Mt Mulu, Mt Murud, Mt Dulit, Upper Limbang R., Mt Derian. Indonesia, Kalimantan (Borneo), C Mt Liang Gagang, Mt Mili.
Altitude: 1200-2200m
Rhododendron crassifolium is a variable but nevertheless very distinct species. Hybrids with R. stenophyllum have been recorded and are very similar to R. nervulosum. Rhododendron x planecostatum is the hybrid with R. bagobonum. Rhododendron brevitubum was reduced to synonymy by Argent et al. (1988). It differed by the hairs inside the corolla tube being in 5 distinct vertical stripes. The hairs inside the corolla of R. crassifolium are commonly in 5 indistinct stripes and in other ways the plants are very similar: at best R. brevitubum could be considered as a local variant.
Differing only in the glabrous filaments.
Habitat: Common epiphyte in primary forest.
Distribution: Indonesia, Central East Borneo, Mt Kemul. Malaysia (Borneo), Sarawak, Mt Murud
Altitude: 1600-1850m
Latin – pseudo – false; murudense – of Mt Murud. The original Smith collection having been from Mt Murud.
Type: Endert 4323, 18 Oct. 1925. Borneo, Central East, W Kutei, Mt Kemul (BO, L).
Synonymy: R. murudense (non Merr.) J.J.Sm., Bull. Jard. Bot. Buit. III, 1935. 13: 449. R. murudense Merr., Sarawak Mus. J. 1928. 3: 542. R. pseudomurudense Sleumer, Reinwardtia 1960. 5: 189.
Shrub to 1 m. Young branches loriform-setose, the setae persistent. Leaves oblong-elliptic, (25-)30-40 x (12-)15-20 mm, cuneate at the base, rather abruptly narrowed to the acute apex, upper surface with the veins puberulent, margins crenulate, lower surface densely lepidote. Inflorescence 3-4-flowered, pedicels densely lepidote. Calyx 5-lobed, the lobes ± ovate, obtuse, c. 2 mm, densely lepidote, loriform-ciliate. Corolla pale yellow, c. 30 mm, tube 15 mm, lepidote and pilose near the base outside. Stamens 10, pubescent towards the base. Ovary densely lepidote, style impressed, lepidote for most of its length, densely so at the base, more laxly so above. Capsule broadly oblong, 10-13 mm, lepidote.
Distribution: Laos
Known only from the type collection.
Type: Laos, prov. Tranh-Ninh, Pu Bia (103° 7' 19° 01'), summit c. 2800 m, 14 iv 1932, Kerr 21044 (holo. K; iso. BM, P-ult. n.v.)
Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):43
Shrub, c.1.5m; young shoots adpressed-strigose at first, soon glabrescent. Leaves dimorphic, chartaceous; spring leaves ovate, 4-5 x 2-2.3cm, c.2 x as long as broad, apex acute to shortly acuminate, base cuneate, margin ciliate towards base, upper surface initally adpressed-strigose, soon glabrescent, lower surface adpressed brownish-strigose especially on midrib; summer leaves 12-18 x 10mm, otherwise as for spring leaves; petioles 2-4mm, strigose. Inflorescence 5-6-flowered; pedicels 3-5mm, reddish strigose. Calyx densely strigose, lobes c.3mm. Corolla funnel-campanulate, white with red flecks, c.l6mm; tube c.9mm long, 5mm wide at base, hairy on outer surface, tapering. Stamens 5, filaments glabrous. Ovary densely reddish-brown-stri-gose; style strigose at base. Capsule not known.
Habitat: Woodland
Distribution: China (Guangdong)
Superficially resembling R. mariae but differing in the short, hairy corolla tube
Only known from the type
Type: China, Guangdong, Rhuyuan Xian, 12 iv 1934, X.P. Gao (S.P. Ko) 54106 (holo. IBSC)
Occurs in Countries: CN Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: red, white
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):106
Shrub or small tree, l-5m; young shoots with a sparse covering of shortly stipitate glands. Leaves subcoriaceous, obovate to oblanceolate, (7—)10—17 x (2.3-)3-4.2cm, 3-4 x as long as broad, apex cuspidate, base rounded, margin not ciliate, upper surface glabrous when mature, lower surface with a dense (occasionally sparse) matted fawn to red-brown tomentum composed of ramiform hairs, intermixed with stipitate glands, especially towards the base; petioles l-2cm, densely stipitate-glandular. Inflorescence 8-14-flowered; rhachis 10-15mm; pedicels 25-30mm, densely stipitate-glandular, also very sparsely hairy. Calyx 5-10mm, densely stipitate-glandular, lobes irregular, Ungulate, rounded. Corolla campanulate, white flushed pink, with at least a few purple flecks and a basal blotch. Ovary stipitate-glandular; style glabrous or glandular at base. Capsule c.15 x 6mm.
Habitat: Open pine forests, rocky slopes
Distribution: China (NW Yunnan, SE Xizang), NE Upper Burma
Altitude: 3350-4000m
R. crinigerum is less setose that the remaining species of this subsection and in this respect approaches some members of subsection Taliensia. However, in leaf shape and in leaf characters, it is closer to the remaining members of subsection Glischra.
Occurs in Countries: CN, MM Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: pink, purple, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):288
Type: China, NW Yunnan, Tsekou, environs de Thrana, 15 v 1895, Soulie 1011 (holo. P, n.v.)
Synonymy: R. ixeunticum Balfour f. & W. W. Smith, Notes R.B.G. Edinb. 9: 240 (1916). Type: China, NW Yunnan, Kari Pass, Mekong/Yangtze divide, 12000ft, viii 1914, Forrest 12944 (holo. E).
The leaves of all the specimens of var. euadenium are more glandular than those of var. crinigerum and most are less densely hairy. The type, however, is more densely tomentose. The following specimens are intermediate between the two varieties in that the lower surface of the leaves is densely tomentose but also with many stipitate glands: Rock 10967, 22504.
Type: China, NW Yunnan, Salween/Kiu-chiang divide, vii 1924, Forrest 25619 (holo. E).
Tree to 6m. Twigs semi-rounded, laxly to densely scaly; internodes 2.5–14cm. Leaves 5–7 together in tight pseudowhorls, with some much smaller than the others. Blade 50–100 x 20–40mm, obovate-elliptic or elliptic to broadly elliptic; apex shortly gradually acuminate, obtuse to broadly acute, sometimes with a small terminal gland; margin entire, flat; base broadly tapering, dark green above, paler and dull beneath, glabrescent above, laxly to sub-densely scaly beneath. Scales with a broad, thin marginal zone variously dentately divided; centre small, somewhat impressed and more persistent. Mid-vein raised and grooved for a few millimetres proximally otherwise slightly depressed above, raised beneath; lateral veins 8–10 per side, lower ones irregular, distinctly grooved above in the basal part, upper ones more straight and sub-parallel, curved-anastomosing with each other, smooth when fresh, prominent on both sides when dry, reticulation dense and visibly raised on both sides when dry, very distinct underneath when fresh. Petiole 6–12 x 1.5–2mm, grooved above, slightly flattened, scaly. Flower buds to 25 x 15mm, imbricate, green, smooth with the bracts appressed. Bracts to 15 x 10mm, ovate-acuminate, laxly scaly in the middle outside, also with hairs all over the outer and undersurface, glandular-ciliate. Bracteoles to 15mm, narrowly linear, glabrous. Inflorescence 4–9-flowered in erect to spreading umbels. Pedicels 10–15 x 1–1.5mm, laxly patently hairy and scaly especially in the distal 1⁄3, obliquely thickened below the calyx. Calyx c.2.5mm in diameter, membranous, indistinctly 5-lobed, laxly scaly and hairy. Corolla 60–70 x 25–30mm, trumpet-shaped, pure white, scented; tube 50–60 x 4–5 x 8–10mm, slightly curved, a little lobed at the base, sparsely scaly outside, densely hairy in the proximal ½ and glabrous distally inside; lobes 10–13 x 7–12mm, spreading, broadly obovate to sub-circular, glabrous. Stamens exserted to 10mm; filaments linear, hairy in the proximal ½, glabrous distally; anthers 2–2.3 x c.1mm, oblong, base obtuse. Disc low, glabrous. Ovary 6–7 x c.1.5mm, cylindrical, gradually narrowed distally, densely covered with sub-patent white or greyish hairs, and some obscure scales; style c.60mm, patently hairy and scaly for over ½ its length, becoming scaly only, glabrous for the distal 6–10mm; stigma exserted to 10mm, conical-globose, crenulate. Fruit (immature) to 30 x 5mm, fusiform, often curved.
Habitat: In open evergreen forest, margins of valley forest, on moss-covered ground among non-calcareous rocks in shade.
Distribution: Papua New Guinea, Maneau Range: Mt Maneao, Mt Yauama and Mt Simpson. Central Province: Mt Albert Edward. Eastern Highlands District: Mt Gahavisuka.
Altitude: 1860-2600m
Named after the collector, the Reverend Canon Norman Cruttwell, for most of his life a missionary in Papua New Guinea but also a keen botanist who collected many vireyas.
Type: Cruttwell 525, 11 June 1954. New Guinea (SE), North-eastern District, Mt Maneao, 2590m (K, E).
Occurs in Countries: PG Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Tree Fl. Colour: white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:180
Shrub of uncertain height. Stem swollen and tuber-like at the base. Young growth lepidote. Leaves rather narrowly elliptic, acuminate at apex 100-125 x 30-40 mm, upper surface brownish green, sparsely lepidote, lower surface pale green, lepidote with distant, golden scales; petiole iepidote and with a few sparse loriform setae. Inflorescence c. 5-flowered, pedicels lepidote and sparsely pubescent. Calyx unequally 5-lobed, the longest lobe c. 7 mm, all oblong-ovate, foliaceous, lepidote and sparsely pubescent outside, fringed with loriform setae. Corolla funnel-campanulate, white with a yellow blotch inside, 55-65 mm, the tube 22-35 mm, pubescent outside at the base, sparsely lepidote all over, tube glabrous inside. Stamens 10, filaments pubescent towards the base. Ovary densely lepidote, style impressed, lepidote in the lower half, pubescent near the base. Capsule unknown.
Distribution: Known only in cultivation
Illustrations:
This is an obscure species in many ways. There is no herbarium material from the wild and it is known only from cultivated material. Young plants were reputedly collected by Lady Cuffe on Mt Victoria in Burma and grown on at Glasnevin, Dublin. The notes with the type description in the Botanical Magazine suggest that the place of origin was Sindaung on the edge of the Shan plateau, but this was later altered to Mt Victoria by Hutchinson. The swollen stem base, which is illustrated in the Botanical Magazine plate appears to be unique in this group of rhododendrons. Hutchinson's two descriptions (Bot. Mag.y cited above, and Notes R.B.G. Edinb. 12:52, 1919) do not agree entirely with material at Edinburgh said to come from the type plant and determined by him: for instance, in this material the corolla is sparsely lepidote all over, not 'not lepidote except towards the 5 lobes which are sparingly so towards the middle'; and thestyle is pubescent and lepidote at the base, not just lepidote. I have not been able to trace a type specimen, so this matter cannot be resolved.
Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: white, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):45
Latin – culmen – summit; cola – inhabiting. Summit-dwelling.
Type: MacGregor s.n., 1889. New Guinea (E), Mt Victoria (MEL).
Synonymy: R. culminicolum F.Muell., Trans. R. Soc. Vict. n.s. 1889. 1(2): 23 (orthographic variant). R. nodosum C.H.Wright, Kew Bull. 1899. 103. R. keysseri Foerster, Fedde Rep. 1914. 13: 223. R. angiense J.J.Sm. in Gibbs, Phyto. Fl. Arfak Mts, 1917. 169, non J.J.Sm. (1914). R. convexum Sleumer, Reinwardtia 1960. 5: 218. R. gregarium Sleumer, Reinwardtia 1960. 5: 221.
Occurs in Countries: ID, PG Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Vireya Habit: Tree Fl. Colour: pink, purple, red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:308
Differs from var. culminicola in having smaller more rounded scales, corollas 25–35mm and smaller fruits, 4–5mm in diameter.
Habitat: In disturbed Nothofagus/Tristania forest or forest margins and open summit areas, locally common, but often sterile, mostly terrestrial.
Distribution: Indonesia, New Guinea (W), Vogelkop Peninsula, Arfak, Nettoti and Tohkiri Mts. Papua New Guinea, Star Mts, Tel Basin.
Altitude: 900-2300m
Named after the lakes where the type specimen originated.
Type: Gjellerup 1217. New Guinea (W), Arfak Mts, Anggi Lakes, 1900m (BO, L).
Shrub or tree to 8m. Twigs 2–5mm in diameter, scaly but early glabrescent; internodes 2–10cm. Leaves 3–7 together in tight pseudowhorls. Blade 25–80 x 1–45mm, elliptic, broadly elliptic, obovate or more rarely ovate; apex obtuse to rounded, sometimes abruptly sub-acuminate; margin revolute; base broadly tapering, rounded to sub-cordate; at first densely covered on both sides with flattish, pale scales, glabrescent above at maturity, laxly scaly beneath. Scales small, flat, shallowly and irregularly lobed with a broad flange and small slightly impressed centre. Mid-vein narrowly impressed above, broadened, wrinkled, and prominent in the proximal part; lateral veins 4–8 per side, curved-spreading and indistinctly anastomosing before the margin, slightly impressed above, somewhat raised beneath, reticulation sub-dense, obscure above, slightly raised beneath. Petiole 2–9 x 1–3mm, grooved above, scaly. Flower buds to 25 x 15mm, ovoid or broadly ovoid, smooth with all bracts appressed. Outer bracts sub-circular to ovate, sometimes with a short narrow point, inner ones ovate to obovate, laxly scaly and sometimes hairy at the base outside, glabrous or laxly to sub-densely hairy inside. Bracteoles filiform to linear, glabrous, to 20 x 3mm. Inflorescence 4–9 flowers in an open umbel, curving downwards. Pedicels 15–24 x c.1mm, laxly to sub-densely scaly, sometimes also hairy. Calyx obliquely disc-shaped, wavy, obtusely and shortly lobed, c.4mm in diameter, scaly outside, occasionally fringed with hairs. Corolla 35–45 x 12–25mm, obliquely tubular, red to purple, sometimes pink; tube 25–40 x 4–6 x 8–15mm, distinctly curved, laxly to sub-densely scaly outside, sparsely to sub-densely hairy in the lower part of the tube inside; lobes 8–18 x 8–15mm, broadly obovate to sub-circular, sub-erect or spreading, overlapping 1⁄3–2⁄3. Stamens sub-equal, not or only weakly exserted; filaments linear, laxly to sub-densely hairy in the lower ½, glabrous distally; anthers 2–3.5 x 1–1.5mm, obovate to broadly oblong, base often minutely apiculate. Disc prominent, shortly hairy at the upper margin. Ovary 5–7 x 2–3mm, sub-cylindrical, white or yellowish hairy, and densely (but obscurely) scaly, gradually tapering distally; style slender, mostly with some sparse hairs and scales at the base, rarely so up to the proximal 1⁄3, becoming exserted; stigma round. Fruit 25–40 x 6–8mm, sub-cylindrical, tapering at both ends, scaly and laxly hairy.
Habitat: Low mossy forest or the margins of sub-alpine shrubberies, open slopes or summit vegetation, also found in alpine pasture, in both primary and secondary communities, often as part of the forest undergrowth, locally plentiful.
Distribution: Indonesia and Papua New Guinea. Widespread on the island of New Guinea on the Main Range, from Mt Jaya (Carstensz) to the Southern and Western Highlands and in the Owen Stanley Range, also in the Mt Saruwaged–Rawlinson Range area.
Altitude: 2400-4000m
Rhododendron culminicola is conceived here in the broad sense of Sleumer (1966) with the exception that the variety nubicola has been reinstated as a good species. Specimens from the upper montane forest (at the lower elevations from c.2400m) tend to have larger flowers and tapering leaf bases. Forms at higher elevations (3200–4000m) have smaller flowers and smaller, stiffer, short-petioled or sub-sessile leaves with rounded or sub-cordate bases. It is one of the small number of variable species which are distributed all over the mountainous part of New Guinea.
Shrub or small tree to 2m tall, usually rhizomatous; young twigs reddish brown, sparsely to densely covered with unicellular hairs and multicellular eglandular hairs, rarely glabrous or with only multicellular eglandular hairs. Vegetative bud scales glabrous abaxially; margin unicellular-ciliate. Leaf blade membranaceous, ovate or obovate to elliptic, (3.1-)4.6-7.0(-8.1) x (1.3-)1.8-2.9(-3.5)cm; base acute to oblique; apex acute to obtuse, often mucronate; adaxial surface glabrous, occasionally with sparse multicellular eglandular hairs, the midvein densely covered with unicellular hairs; abaxial surface glabrous, or very sparsely covered with multicellular eglandular hairs usually also glaucous, the midrib sparsely to densely covered with unicellular hairs and multicellular eglandular hairs, rarely with only multicellular eglandular hairs; margin entire, ciliate with multicellular eglandular hairs; petiole (0.2-)0.3-0.5cm long, sparsely to densely covered with unicellular hairs and multicellular eglandular hairs, rarely with only unicellular hairs. Flower bud scales chestnut brown; abaxial surface glabrous; margin ciliate at the apex and glandular below, rarely glandular to the apex. Flowers appearing after the leaves have expanded; inflorescence a shortened raceme of 3 to 7 flowers. Pedicels (0.4-)0.5-0.7(-Q.9)cm long, sparsely to densely covered with unicellular hairs and multicellular eglandular hairs, rarely with multicellular gland-tipped hairs and then the sepals eglandular. Sepals less than 0.1-0.2(-0.3)cm long, often varying in length on the same flower; margins setose with multicellular eglandular hairs, rarely with multicellular gland-tipped hairs and then the pedicels eglandular; abaxial surface sparsely to densely covered with unicellular hairs and multicellular eglandular hairs, rarely with only multicellular eglandular hairs. Corolla red, fragrance acrid, the tube longer than the limb and abruptly expanding into it; upper corolla lobe 1.3ó1.8(ó2.1) x l.l-1.6(-2.0)cm; lateral lobes 1.4-1.9(-2.5) x 0.7-1,2cm; corolla tube (1.4-)1.6-2.1(-2.4)cm long, 0.2-0.3cm wide at base; outer surface of corolla densely covered with unicellular hairs and sparsely covered with multicellular gland-tipped hairs that continue up the corolla lobes; inner surface of corolla densely covered with unicellular hairs. Stamens (4.2-)4.9-6. l(-6.2)cm long, with dense terete or flattened unicellular hairs on proximal (1.7-)2.3-3.0(-3.1)cm of filament, exserted (2.7-)3.1-4.1(-4.3)cm beyond throat of corolla. Style (3.9-)4.5-6.5(-7.2)cm long, exserted (2.8-)3.0-4.9(-5.5)cm beyond throat of corolla, densely covered with unicellular hairs on proximal 0.1-1.7(-2.8)cm; stigma 0. l-0.2cm wide. Ovary 0.2-0.3(-0.4)cm long, 0. l-0.2cm wide at the base, densely covered with multicellular eglandular hairs over dense unicellular hairs, nectary with a crown of dense unicellular hairs. Capsules (1.2-) 1.4-2.3(-2.8) x 0.5-0.7(-0.8)cm, ovate to broadly ovate, sparsely to moderately covered with unicellular hairs and sparsely to densely covered with multicellular eglandular hairs. Seeds pale to dark chestnut brown, ovate or elliptic to fusiform, (1.8-)2.1-3.4 (-4.5) x (0.5-)0.7-l.l(-1.4)mm, body (0.8-)l.l-1.6(-1.9) x (0.2-)0.4-0.6(-0.8)mm; testa expanded and dorsiventrally flattened, surrounding the body, the cells short, end-walls transverse.
Habitat: Ridge-tops above 900m, but also occasionally at lower elevations, in mixed mesophytic forests.
Distribution: Western most Virginia and eastern Kentucky in the Cumberland Mountains and Plateau, south through Tennessee to northern Alabama, and east of the Tennessee River Valley in the southern Blue Ridge, along the border of Tennessee and North Carolina, south to northern Georgia. Isolated populations occur in Talladega, Cleburne and Randolph counties in Alabama
Altitude: Around 900m
Illustrations:
The name R. bakeri (Lemmon, 1938) has been used for this diploid flame azalea since Skinner (1955) considered R. bakeri to be the same taxon as R. cumberiandense. Since R. bakeri, was an earlier name, it was properly used over R. cumberiandense. However, the type specimen of Azalea bakeri (= R. bakeri) is not at all similar to the type of R. cumberiandense. The specimen, which is labelled Azalea bakeri by Lemmon, has young expanding leaves, which are densely pubescent on the abaxial surface. In addition, the margins of the floral bud scales are all unicellular-ciliate, and the corolla possesses both glandular and eglandular multicellular hairs. None of the above characters is found in R. cumberiandense, which flowers well after the leaves have expanded and usually has glabrous leaves (never densely pubescent). In addition, the floral bud-scale margins and the outer surface of the corolla are consistently glandular in R. cumberiandense. Therefore Lemmon's specimen is probably a hybrid between R.flammeum and R. canescens (see hybrid names, p. 362). Thus, the correct name for the diploid flame azalea is Rhododendron cumberiandense.
Chromosome number: 2n = 26 (Li, 1957; WEEngham, 1973).
Rhododendron cumberiandense is most closely related to R. calendulaceum (see Phylogenetic Analysis) and can be distinguished from the latter by its flowering well after the leaves have expanded, and by the eglandular condition of the pedicel and sepal margins. In addition, the leaves are very glaucous abaxially, and often are bluish green to dark olive-green in colour, especiaMy upon drying. This species is primarily restricted to the Cumberland Mountains and Plateau, where it is morphologically and phenologically distinct from R. calendulaceum. In the southern Blue Ridge, however, R. cumberiandense can hybridize with R. arborescens or R. viscosum. It can also occupy the same kinds of habitats as high-altitude late-flowering individuals of R. calendulaceum. In these areas it is more difficult to distinguish R. cumberiandense from R. calendulaceum (see discussion under R. calendulaceum). See Appendix for citation of representative hybrid specimens.
Synonymy: Azalea cumberlandense (E. L. Braun) Copeland, Am. Midi. Nat. 30: 533-625 (1943). Type: Kentucky, McCreary Co.: Yahoo Ridge, 15 vi 1935, E. L. Braun 971 (holo. Herb. Braun, n.v.; iso. A).
Altitude Ranges: 0 - 1,000m Subgenus: Pentanthera Habit: Tree
Kron, K.A. (1993) A Revision of Rhododendron Section Pentanthera. Edinburgh Journal of Botany 50(3):309
Shrub, l-2(-4) m. Leaves densely lepidote, 11-70 x 5-26 mm, narrowly to broadly elliptic, apex acute, obtuse or rounded, strongly mucronate, base cuneate, undersurface uniformly fawn to deep rust or occasionally with darker spots, the scales contiguous or overlapping. Inflorescence up to 6-flowered, pedicels 2-13 mm, lepidote. Calyx (2-)5-8(-12) mm, lobes usually oblong, apex rounded to acute, with pale scales forming a central band, margin long-ciliate, sometimes with a few scales. Corolla deep purple to rose-lavender, often with darker markings, rarely almost white, funnel-shaped, (12-)22-31 mm, tube (5-)10-16 rmn, pubescent within and often ouside also, lepidote or elepidote outside. Stamens 10, pubescent in the lower part, varying in length. Ovary lepidote, style declinate, longer than or rarely equal to stamens, pubescent towards the base. Capsule lepidote, ovoid, up to 14 mm
Distribution: China (N & W Yunnan, SW Sichuan)
A distinctive species, in many ways similar to the species of subsection Heliolepida (p. 87), from which it differs mainly in the possession of a large, deeply Iobed calyx. It is in many ways (large, zygomorphic flower, type of scaling, etc.) aberrant in subsection Lapponica, and stands in an intermediate position between Lapponica and Heliolepida. The Philipsons (1975, p. 16) note the occurrence of natural hybrids with R. hippophaeoides and other, undetermined, species.
Type: China, Yunnan, eastern flank of Lichiang range, 3650 m, x 1910, Forrest 6738 (holo. E)
Synonymy: R. ravum Balfour f. & W. W. Smith, Notes R.B.G. Edinb. 9:270 (1916). Type: China, Yunnan, mts. in NE of the Yangtze bend, 11000 ft, vii 1913, Forrest 10423 (holo. E). R. cinereum Balfour f. in Millais, Rhododendrons 145 (1917) nom. nud. R. cheilanthum Balfour f. & Forrest, Notes R.B.G. Edinb. 11:32 (1919). Type: China, Yunnan, mts in NE of Yangtze bend, 10-11000 ft, vii 1913, Forrest 11736 (holo. E). R. sclerocladum Balfour f. & Forrest, op. cit. 11:133 (1919). Type: China, Yunnan, mts of Chungtien plateau, 11000 ft, vii 1914, Forrest 12665 (holo. E)
Occurs in Countries: CN Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: purple, rose, white
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):95
Latin – cuneus – a wedge; folium – leaf. Alluding to the wedge-shaped leaf base.
Type: Haviland 1180. North Borneo, Mt Kinabalu, 1650–2745m (K, SAR).
Synonymy: R. quadrasianum S.Vidal var. cuneifolium (Stapf) H.F.Copel., Phil. J. Sc. 1929. 40: 145.
Occurs in Countries: MY Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:47
Shrub to 2m. Twigs smooth apart from some raised leaf scars, red or green passing to brown, minutely shortly hairy and sparsely scaly. Leaves spirally arranged, or only weakly grouped into loose pseudowhorls. Blade 10–30 x 3–7mm, narrowly obovate to spathulate; apex retuse to rounded; margin entire or sometimes crenulate in the distal ½; base tapering, laxly silvery scaly becoming glabrescent above, laxly and more persistently impressed scaly beneath. Scales circular with a moderately broad flange which is often marked with radial furrows and a broad centre. Mid-vein deeply impressed above and raised below but obscure in high altitude forms; lateral veins obscure, rarely 1 or 2 per side. Petiole 2 x 1mm, without a conspicuous groove, sparsely scaly and often very finely hairy. Flower buds c.6 x 3mm, ellipsoid, brown, with a few scales outside distally and a broad fringe of white hairs. Bracts ovoid. Inflorescence of mostly solitary flowers, occasionally up to 3-flowered, flowers half-hanging, occasionally horizontal or vertically hanging. Pedicels c.5 x 1mm, green with white scales but no hairs. Calyx of 5 equal ovate-triangular lobes to 1.5mm or sometimes with 2 longer lobes to 2mm. Corolla 15–20 x c.8mm, pale red to orange-red, without scent, sub-cylindrical or narrowly funnel-shaped; tube c.15 x 6 x 7mm, densely scaly outside, glabrous inside; lobes c.5 x 4mm, semi-erect to spreading, overlapping ½–2⁄3, scaly outside except near the margin. Stamens in a loose cluster on the lower side of the mouth, exserted to 8mm; filaments c.18mm, pale pink, glabrous, tapering from just above the base; anthers c.1 x 0.75mm, dark brown. Ovary c.2.5 x 2mm, green, densely covered with silvery scales but no hairs; style 16–20 x c.1mm, glabrous apart from a few scales at the base, pale yellow, lying on the lower side of the corolla but curving upwards; stigma circular. Fruit 7–11 x 4–5mm, the valves curving back on opening. Seeds c.1.9mm, without tails 0.7mm, the longest tail 0.6mm.
Habitat: Mostly terrestrial, sometimes epiphytic. Common on Mt Kinabalu from 1500 to 2800m, where it occupies a zone between that of R. borneense and R. ericoides.
Distribution: Malaysia (Borneo), Sabah, Mt Kinabalu and Mt Alab. Reported from Sulawesi but this has not been properly substantiated (Monod de Froideville 187 from Makale, Makale-Bi(n)tuang, Rante Karua, (Rantepao), SW Central Sulawesi, 1200m).
Altitude: 1500-2800m
Flowers Jan.–Dec. but apparently not continuously, having rest periods between flushes of flowers.
Differing from the type mainly in the following. Twigs prominently grooved with leaf supports and covered in scales but without hairs. Blade 5–8 x 1.5–2.5mm, narrowly obovate; lateral veins always obscure. Ovary 1.5–2 x 1.5–2mm. Fruit 4–4.5 x 3mm. Seeds 0.8–0.9mm, without tails 0.4mm, the longest tail 0.3mm.
Greek – micro – little or small; carpus – fruit. Alluding to the very small fruit of this variety.
An extreme form of R. cuneifolium known only from Mt Trus Madi, Sabah, E Malaysia.
Type: Collenette 646b, 7 Jan. 1961. Sabah, Mt Trus Madi, Crest of main ridge, 2300m (K).
Shrub to 2.5m. Twigs semi-rounded, 2.5–4mm in diameter, tips sub-densely sub-stellately scaly, older parts glabrescent; internodes 4–17cm. Leaves 4–7 together in tight pseudowhorls. Blade 100–130 x 50–70mm, ovate to ovate-elliptic; apex shortly apiculate, broadly acute; margin entire or slightly sinuate, flat or weakly recurved; base rounded or occasionally broadly tapering, dark green and glabrescent above, sub-densely brown-scaly beneath. Scales dense, small, irregularly and deeply stellate; centre dark brown, finally blackish, faintly impressed but with occasional long-stalked scales from the flat surface. Mid-vein narrowly impressed above, strongly raised below; lateral veins 5–8 per side, spreading at a wide angle, straight below, curved upwards and anastomosing, slightly impressed above, prominent beneath, reticulation dense, faintly impressed or raised above, much more distinct and prominent beneath at least when dry. Petiole 7–17 x 2–3mm, grooved above, densely brown scaly but becoming glabrescent. Flower buds to 40 x 25mm, ovate, smooth with all the bracts appressed, dull pale green except for brown marks at the apices of the bracts, minutely hairy outside and with areas of small brown scales towards the bract apices. Outermost bracts broadly ovate and apiculate; central bracts to 20mm, hemispherical to broadly ovate, shortly emarginate, minutely hairy outside, scaly distally near the apex and fringed with small brown scales, glabrous inside; innermost bracts spathulate. Bracteoles 36 x c.1mm, linear becoming slightly broadened towards the apex, white hairy throughout and with slender, brown, long-stalked scales near the apex. Inflorescence an open 5–11-flowered umbel, the flowers mostly horizontal but the mouth facing downwards due to the curvature of the tube. Pedicels 20–35 x 2–3mm, densely shortly hairy, without scales, except for a few distally just under the calyx. Calyx 4–6mm in diameter, disc-shaped, patently white hairy outside but fringed on the margin with scales, the lobes c.1mm, shortly triangular, obtuse. Corolla 60–65 x 40–50mm, tubular, oblique, unequally 5-lobed, yellow (or mauve; see note below), without scent; tube 35–40 x 9–11 x 11–17mm, cylindrical but sulcate and 5-angled in the proximal ½, slightly compressed laterally in the upper ½, densely shortly patent hairy outside and without scales, hairy in the lower ½ of the tube inside; lobes 22–25 x 18–20mm, hairy outside except near the margins, all lobes spreading to the horizontal, the three upper lobes overlapping to halfway, the two lower lobes not overlapping. Stamens clustered on the upper side of the mouth, exserted to c.12mm; filaments linear, densely to sparsely patently hairy below, more slender and glabrous towards the top; anthers c.4 x 1.8–2mm, brown, broadly oblong, the base obtuse. Disc prominent, deeply lobed, densely hairy above, less so below. Ovary 6–7 x 4–5mm, elongate-conical, tapering distally, densely hairy with slightly forward-pointing white hairs; style deep within the tube on the flower opening, becoming exserted to 15mm, green, densely patently hairy nearly to the top; stigma thick, lobed, reddish-brown. Fruit 40–50 x 6–7mm, fusiform, often curved and longitudinally grooved. Seeds 60–70mm, without tails c.1mm, the longest tail 3.8mm.
Habitat: Epiphytic or terrestrial in secondary forest or landslips.
Distribution: Indonesia, New Guinea (W), Keyts Mts and Bele R. around Pabililo and the Ibele valley, near Wamena.
Altitude: 1900-2700m
Latin – curvi – curved; florum – with flowers. Alluding to the curved flowers.
Sleumer (1966) notes: ‘The size of the corolla in Smith’s description of 1914 differs from that in t.36 B; unfortunately, the type material, conserved in formaline at Bogor, is practically useless. I have drawn a new description of it based on good and apparently conspecific specimens (BRASS 11215 AND 11536) from the Bele R., which have yellow flowers instead of “lilac” as said of the type material, which came from the Keyts Mts. Also the description of the perulae [bracts], not given in the original diagnosis, is made after the BRASS collections’. I have followed Sleumer’s interpretation of this species; the anatomical characters certainly agree closely with Smith’s descriptions but I cannot find the discrepancy in measurements that he mentions. Rhododendron curviflorum was common around the village of Pabilio above Wamena and was all very uniform yellow in colour. It would be odd for this species to occur in the lilac mentioned in the original type description. This may have been an error in the field descriptions or we may still be dealing with two different species. Further collecting in the Keyts Mts will need to be done to resolve this.
Type: Cocq d’Armandville 233, Dec. 1912. New Guinea (SW), Johannes Keyts Mts (BOG†). Neotype: Brass 11215. New Guinea (W), Bele R., c.18km NE of Lake Habbema (L).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: mauve, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:303
Terrestrial shrub to 1.5m. Twigs 3–6mm in diameter, rounded, scaly becoming glabrescent; internodes 8–17cm. Leaves 4–7 together in tight pseudowhorls of very variably sized leaves at the same node. Blade 70–200 x 20–70mm, narrowly ovate or elliptic; apex acuminate, with long sub-caudate points, acute; margin entire, very narrowly slightly revolute; base broadly tapering, rounded to sub-cordate; glabrescent above, laxly and more persistently scaly beneath. Scales small, marginal zone irregularly sub-stellately lobed; centre darker and slightly impressed. Mid-vein narrowly impressed above, strongly raised below, becoming gradually more slender from base to apex; lateral veins 8–10 per side, wide-spreading, straight below, indistinctly curved-anastomosing before the margin, faintly raised on both sides, sometimes inconspicuous especially beneath. Petiole 3–6 x 2–3mm, grooved above, scaly. Flower buds 35 x 25mm, sub-orbicular-ovoid. Bracts to 35 x 23mm; outer bracts ovate, apex very shortly subulate, the inner ones larger, ovate, obtuse, innermost ones spathulate, all laxly sub-stellately scaly and very shortly hairy outside and along the margin. Bracteoles to 30 x 4mm, linear to linear-sub-spathulate, shortly hairy. Inflorescence a 9–12-flowered complete umbel. Pedicels 25–60 x c.1mm, laxly scaly, without hairs. Calyx c.3mm in diameter, disc-shaped, wavy and obscurely lobed, densely scaly outside. Corolla 35–45 x c.35mm, tubular-funnel-shaped, orange or orange-yellow; tube 15–20 x 5–6 x 15–17mm, straight, 5-angular, lobed at the base, sub-densely to laxly sub-stellately scaly outside, sparsely or very sparsely hairy proximally inside; lobes 23–27 x 15–22mm, broadly obovate-spathulate or sub-circular. Stamens c.25mm, sub-equal, slightly exserted; filaments linear and densely patently hairy in the proximal ½, glabrous distally; anthers c.4 x 1mm, oblong. Disc hairy. Ovary 5–6 x c.2.5mm, cylindrical-conical, white-hairy and scaly, abruptly contracted distally; style nearly equalling the stamens, hairy and distinctly scaly in the proximal 1⁄3–2⁄3; stigma deeply 5-lobed.
Habitat: Secondary forest, locally common.
Distribution: Indonesia, New Guinea (W), Wissel Lakes region; Armina, Sjuga-Wagura area, Babo District.
Altitude: 150-1900m
Latin – cuspis – a sharp rigid point; ellum – diminutive. The leaves being sharply pointed.
Very similar to R. baenitzianum but said to differ by the smaller flowers; more collections are badly needed to evaluate this.
Type: Versteeg BW 3008, 20 March 1959. New Guinea (W), Wissel Lakes, Enarotali, 1900m (L, E).
Occurs in Countries: ID Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:319
Shrub or small tree, l-3.8m; bark rough; young shoots glabrous. Leaves broadly elliptic to orbicular, 6.5-12.5 x 4.2-9cm, 1.2-1.6 x as long as broad, apex and base rounded, upper surface glabrous, lower surface ± glaucous with epidermis mammillate, glabrous or with a few scattered hairs on the midrib towards the base; petioles 1 -3cm, often shghtly winged, glabrous. Inflorescence 6-11-flowered; rhachis 5-10mm; pedicels 10-20mm, glabrous. Calyx (2-)7-15mm, cupular, greenish, glabrous, lobes truncate. Corolla ± campanulate to funnel-campanulate, white or cream to clear pink, with dark nectar pouches, flecks lacking, (40—)50—60mm. Ovary glabrous or rarely with a few glands, style glabrous. Capsule 15-20 x 8-10mm, usually with a glaucous bloom.
Habitat: Open pasture, forest margins
Distribution: China (W Yunnan)
Altitude: 3000-4000m
Superficially close to R. thomsonii but differing in the paler flowers and the mammillate leaf epidermis. Var. eriphyllum, which is only known from the type and differs only it its sparsely glandular ovary, is not worthy of formal recognition.
Type: China, Yunnan, rochers de Tsang-chan, Delavay 3947, 4166 (K). R. hedythamnum Balfour f. & Forrest var. eglandulosum Handel-Mazzetti, Akad. Wiss. Wien Math.-Naturwiss. Kl., Anz. 19: 3 (1923). Type: China, Yunnan, orient, montis Dsang-schan, prope Dali, 3900-4050m, 13 v 1910, Handel-Mazzetti 8712, n.v. R. cyanocarpum (Franchet) W. W. Smith var. eriphyttum [Balfour f. & W. W. Smith ex] Tagg in Stevenson (ed.), The Species of Rhododendron 738 (1930). Type: China, Yunnan, western flank of the Tali Range, 11000ft, vii 1913, Forrest 11593 (holo. E; iso K)
Synonymy: R. thomsonii Hooker f. var. cyanocarpum Franchet, J. Bot. (Morot) 9: 389 (1895)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: cream, pink, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):423
Shrub. Twigs thick, c.2mm in diameter, rounded, the tips densely covered with sessile or very shortly stalked roundish scales, lower parts glabrescent, becoming smooth; internodes 2–4cm. Leaves 3–5 together in loose pseudowhorls at the upper nodes, sometimes spiral. Blade 25–32 x 12–19mm, elliptic or ovate-elliptic; apex gradually tapering, obtuse, apiculate; margin strongly revolute in the distal 2⁄3, hardly at all proximally; base rounded or sub-truncate, sub-densely to laxly scaly on both sides initially, slowly glabrescent above, persistently scaly beneath. Scales round, entire, marginal zone narrow; centre thick, little or not impressed. Mid-vein slightly impressed above, very prominent beneath; lateral veins 5–6 per side, irregular, spreading, a little raised above, more distinctly so beneath, reticulation obscure. Petiole 2–3 x c.0.8mm, thick, scaly. Bracts to 10 x 6mm, ovate, obtuse, glabrous except for some scales near the top outside, shortly patently hairy inside. Inflorescence a 5–8-flowered umbel. Pedicels 7–12mm, slender, scaly. Calyx oblique, obscurely 5-lobed, c.2.5mm in diameter. Corolla c.35mm, pinkish-red, tubular below, dilated upwards; tube 25–30 x 4 x 7–10mm, very densely scaly outside, glabrous inside, curved; lobes c.8mm, spreading, rounded. Stamens c.25mm; filaments linear, sparsely hairy proximally, glabrous upwards; anthers 2.5mm, broadly oblong. Disc glabrous. Ovary c.5 x 2mm, densely scaly and laxly patently short-hairy; abruptly contracted distally; style 20mm, glabrous.
Distribution: Indonesia, New Guinea (W), Mt Jaya (Carstensz), along the Utakwa R.
Altitude: 2520-3050m
Greek – kryptos – hidden; phyllon – leaf. A somewhat obscure allusion!
Not yet recollected and remaining poorly known. Very distinctive in the unusual feature of the leaves being more revolute distally than proximally which is the reverse of the usual situation.
Type: Kloss s.n. New Guinea (S), Mt Carstensz (BM).
Occurs in Countries: ID Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:60
Shrub; young shoots becoming glabrous. Leaves coriaceous, oblong-lanceolate, 2.8-3.8 x 1.3-1.7cm, apex slightly acute, upper surface greenish, opaquely brown when dry, lower surface paler below, covered with thin lanate indumentum, with the midrib setulose; petioles 3-4mm, densely brownish, strigose with some longer setose hairs. Inflorescence 1-flowered; pedicels 6-8mm, densely strigose. Calyx densely brown-strigose, lobes crenulatc, 5mm. Corolla obliquely funnel-campanulate, rose, c.25mm, lobes 20-22mm, obovate-oblong. Stamens 10, filaments puberulent. Style glabrous. Fruit not known.
Distribution: China (Fujian)
Known only from the type. Allied to R. farrerae but differing in several distinctive characters.
Type: China, Fujian, Dehua Xian, prope Catervam Daiyuan, 20 iv 1975, L.K. Ling 3040 (holo. Fujian Normal Univ.)
Synonymy: R. daiyuenshanicum P.X.Tan, Survey Gen. Rhododendron S. China 96, f.22, 3 (1983). Type as above.
Occurs in Countries: CN Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: rose
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):145
Epiphytic or more rarely free-growing shrub. Young shoots loriform-setose. Leaves mostly narrowly elliptic, more rarely tending to obovate, (75-)100-170 x 35-70 mm, tapered to the base and to the ± rounded apex, petioles variably loriform-ciliate, lower surface greyish or brownish green with small, slightly unequal, reddish scales more than their own diameter apart; margins often crenulate. Inflorescence 2-3-flowered, pedicels 15-20 mm, lepidote and pubescent, accrescent in fruit. Calyx conspicuous, deeply 5-lobed, the lobes oblong or oblong-triangular, rounded at the apex, 10-15 x 5-10 mm, lepidote at the base, the middles of the lobes with few to many filiform-acicular hairs. Corolla narrowly funnel-campanulate to funnel-campanulate, white or cream, often yellowish inside, sometimes with 5 red lines running from the base of the tube to the apices of the lobes, 85-105 mm, tube 60-75 mm, very sparsely lepidote to elepidote outside. Stamens 10, filaments pubescent in the lower part. Ovary lepidote, tapered into the style which is lepidote in the lower part. Capsule cylindric-fusiform, 40-50 x 15-20 mm, lepidote, rather strongly 5-ridged.
Occurs in Countries: BT, CN, IN, NP Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: cream, red, white, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):37
Corolla without 5 longitudinal red lines
Habitat: Epiphytic on trees, or on rocks and cliffs in forest and scrub
Distribution: Nepal, India (Sikkim, W Bengal), Bhutan, China (S Xizang)
Altitude: 1800-2450m
Illustrations:
Type: Sikkim Himalaya, 7000-9000 ft, Hooker (holo. K)
Corolla with 5 longitudinal red lines
Habitat: Epiphytic in forests or free-growing on hillsides
Distribution: India (Arunachal Pradesh), China (S Xizang)
Altitude: 1500-2600m
Illustrations:
The red-striped flower is the only distinguishing feature of var. rhabdotum.
Synonymy: R. rhabdotum Balfour f. & Cooper, Notes R.B.G. Edinb. 10:141 (1917). Type: Bhutan, Punakka, 8000 ft, 29 v 1915, Cooper 3987 (holo. E)
Shrub or small tree, 2-5m; young shoots densely glandular-setose. Leaves ovate to obovate, 4.5-9 x 2.9-4cm, 2-3.5 x as long as broad, apex rounded, apiculate, base rounded, margin glandular-ciliate at base, upper surface glabrous when mature or with traces of hairs at base, lower surface with lamina glabrous and midrib glandular-setose; petioles 1-1.5cm, glandular-setose and floccose-tomentose. Inflorescence 5-8-fIowered; rhachis c.2mm; pedicels c.l5mm, tomentose and stipitate-glandular. Calyx 2-7mm, stipitate-glandular, lobes rounded. Corolla funnel-shaped, pale to deep purplish rose, with darker flecks, 35-40mm. Ovary dendroid-tomentose; style glabrous. Capsule up to 30 X 5mm, curved.
Habitat: Forests, etc.
Distribution: China (SW Sichuan, adjacent NW Yunnan)
Altitude: 3000-4850m
Doubtfully distinct from R. selense subsp. dasycladum but apparently with no intermediates and a more easterly distribution. Kingdon-Ward 5201 is a mixed gathering containing both taxa.
Type: China, S Sichuan, in montibus supra Molien, c.4000m, 26 v 1914, Schneider 4083 (iso. E)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: rose
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):277
Much branched shrub to 75 cm. Leaves 8-15 x 3-7.5 mm, elliptic or oblong-elliptic, apex obtuse or rounded, mucronate, base broadly cuneate, sometimes with a few simple cilia near the base and on the petiole, undersurface uniformly tawny brown, densely covered with contiguous scales. inflorescence 2-flowered, pedicels lepidote and puberulous, 3-4 mm. Calyx 3 mm, lobes broadly strap-shaped, rounded, pubescent and lepidote, margin ciliate. Corolla bright purplish rose, broadly funnel-shaped, 12-15(-18) mm, lube 4—5(—8) mm, pubescent inside, pilose outside. Stamens 10, filaments pubescent towards the base. Ovary lepidote, style exceeding stamens, pubescent at base. Capsule ovoid, c. 5 mm, lepidote.
Habitat: Open stony pasture, 3500 m
Distribution: China (NW Yunnan)
Known only from one collection
Type: China, Yunnan, Li-ti-ping, 3500 m, vi 1917, Forrest 13905 (holo. E, iso. K)
Occurs in Countries: CN Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: rose
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):100
Shrub to 50cm. Body of the plant sparsely scaly. Lower branches creeping, curved, the upper spreading, grey-brown. Leaves in pseudowhorls of 3–5 near the apices of the branches. Blade 20–40 x 10–20mm, elliptic to narrowly obovate or elliptic-obovate; apex bluntly acute; margin entire but distinctly revolute; base narrowed, often decurrent; shiny dark-green above, paler below. Mid-vein and lateral veins impressed above when dry, the laterals quickly becoming obscure beneath. Petiole 3–5mm, flattened. Flower buds rounded-ovate, bracts ovate or ovate-spathulate, ciliate on the margins. Inflorescence a terminal umbel with 4–7 flowers. Pedicels 7–12mm. Flowers yellow, the calyx small; lobes reflexed, obtuse-crenulate. Corolla 8–10 x c.12mm, shortly campanulate; tube 4–5 x 3–4mm, with white hairs within the upper part; lobes 5 x 4mm, rounded-ovate; apex broadly rounded. Stamens 6mm; filaments cylindrical above, flattened below the middle, glabrous at the base, white hairy below the middle. Ovary 3mm, ovate-rounded; style shorter than the stamens, c.3mm, club-shaped, downwardly curved; stigma flattened rounded, to 5-lobed. Fruit 10–13 x 6mm, elongate-ellipsoid.
Distribution: China, Guangdong, Xinyi, Datianding. Epiphytic.
Named after Datianding, the place of the original collection.
Flowers June, Fruit Oct.
Said to be similar to R. rupivalleculatum but differing in the oblong-elliptic leaves, 2–4 x 1–2cm; the leaf apex obtuse, not recurved; the inflorescence of a 4–7- flowered umbel; the stamens and pistil much shorter, and the ellipsoidal capsule. Very reminiscent of R. rushforthii in the umbellate inflorescence. The much smaller vegetative measurements may be accounted for by differences between growing in cultivation and in a harsh wild environment but the lack of description of the indumentum on the ovary and style leaves doubt about the identity of this species. Only an examination of the type specimen will settle the matter of whether these two species are truly different. Rhododendron datiandingense is the older name by a few months and would take precedence if they are found to be conspecific.
Type: Z.J. Feng 54123, 10 June 1990. Datianding, Xinyi, Guangdong, China (CANT).
Occurs in Countries: CN Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:35
Straggling shrubs, 0.5-1.5 m. Young growth lepidote and puberulous. At least some of the leaves overwintering, coriaceous, glabrous except for the shortly puberulent upper surface of the midrib, obtuse to retuse at the apex, densely lepidote beneath, 10-36 x 5-20 mm. Pedicels very short, obscure. Calyx very small, rim-like, densely lepidote. Corolla 14-21 mm, tube 5-11 mm, 20-35 mm in diameter, pink or violet-pink, pilose outside near the base, ± elepidote. Stamens 10, exserted, filaments pubescent towards the base, anthers grey. Ovary lepidote, style glabrous. Capsule ovoid, lepidote.
Distribution: USSR (eastern Siberia, Altai mountains, Angara-Sayan region, Ussuri region, Dahuria, region around the river Lena), MONGOLIA, China (northern part, adjacent to Mongolia), Japan (Hokkaido)
Illustrations:
R. dauricum is a widely distributed and variable species. Two variants have been described as separate species in the Russian literature, but I have not seen enough material to judge their distinctness. They are: R. ledebourii Pojarkova in Komarov (ed.) Fl. S.S.S.R. 18:722, t. 2 f. 3 (1952), Type: USSR, Altai, nr mouth of river Kainzci, on stony slopes, 11 vii 1915, Krylov (LE); and R. sichotense Pojarkova, loc. cit., t. 2 f. 1, Type: USSR, Reg. Ussuri, around the Olga bay, 28 iv 1913, Bjeloussov (LE)
Type: Habitat in Dauria'
Occurs in Countries: CN, JP, MN, RU Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: pink
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):112
Shrub or tree,3-8m. Leaves oblanceolate, 9.5-15.5 x 2-3cm,3.5-5.2 x as long as broad, apex long-acuminate to shortly cuspidate, base cuneate, lower surface glabrous; petioles 1.5-2.5 cm, glabrous. Inflorescence 7-12-flowered; rhachis 25-60 mm; pedicels 15-20 mm, stipitate-glandular. Calyx 1 -2 mm, stipitate-glandular. Corolla 7-8-lobed, open-campanulate, sparsely glandular outside, glabrous within, pink to rose-purple, with darker flecks, 40-55 mm. Stamens 14-16, filaments glabrous. Ovary stipitate-glandular; style glabrous or with a few glands and then usually only at the base, only occasionally for up to two-thirds of its length, stigma capitate. Capsule unknown.
Habitat: Open places, bamboo thickets
Distribution: China (C & S Sichuan, NE Yunnan)
Altitude: 1900-4000m
Illustrations:
Allied to R. huianum but lacking the well-developed calyx of that species. The style is usually ± glabrous though even the type has some glandular styles.
Type: China, Sichuan, Moupine, 3000-4000 m, ii-iv 1869, PireDavid (iso. E, K)
Occurs in Countries: CN Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: pink, rose
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):228
Shrub, 0-6-5 m. Young growth greenish or brownish. Leaves 3 or more x longer than broad, (27-)30-62 x 11-20 mm, acute at the apex, cuneate at the base, often ± V-shaped in section, lower surface densely lepidote with small brown scales with narrow rims, the darker centre making up more than Vi the diameter of the scale, 1-2 x their own diameter apart. Inflorescence open, few-flowered, pedicels lepidote, (8—)11—15 mm. Calyx disc-like or undulate, sometimes ciliate. Corolla (21-)23-27 mm, pink, pinkish lavender or lavender, ± elepidote outside. Capsule 11-13 mm
Habitat: In thickets and on forest margins
Distribution: China (SW & C Sichuan)
Altitude: 2000-3300m
Illustrations:
Type: China, W Szechuan, southeast of Tachienlu, 2000-2500 m, v & x 1908, Wilson 1275 (iso. E)
Synonymy: R. charianthum Hutchinson, Bot. Mag. 142: t. 8665 (1916). Type: a cultivated specimen (holo. K)
Occurs in Countries: CN Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: lavender, pink
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):66
Shrub or small tree; young shoots soon glabrous. Leaves broadly rhombic, 2-3(-6) x 2~4cm, apex acuminate, upper surface with glands, especially on midrib and veins, also with a few scattered hairs, lower surface with scattered villose hairs and glands; petioles 10-15mm, sparsely glandular, also with villose hairs. Inflorescence 1-3-flow-ered, flowers appearing before leaves; pedicels 5-8mm, villose, densely so at base, also with glands. Calyx minute, glandular, lobes ciliate. Corolla open funnel-campanulate, 25-28mm, magenta, spotted; lobes c.20mm, narrowly oblong. Stamens 10, unequal, filaments glabrous. Ovary glandular, with a few villose hairs; style glabrous. Capsule 8-15mm, curved.
Habitat: Forested hillsides
Distribution: Japan (S Honshu, Shikoku)
Altitude: Around 800m
Illustrations:
R. dilatatum var. satsumense is described as differing from R. decandrum in its dilatate-ovate leaves, shining above, in the involucre being lightly reflexed before anthesis, in the glabrescent floral buds and in the glandular-punctate, usually not ciliate, capsules. We assume that this taxon has ten stamens since it has been allied by the original author to R. decandrum; we have not however seen any material of it.
Occurs in Countries: JP Altitude Ranges: 0 - 1,000m Subgenus: Tsutsusi Habit: Tree Fl. Colour: magenta
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):147
Shrub or small tree, 1-6 m. Leaves oblanceolate to elliptic, (5.5—)7—15 x (2.2-)3-6.8 cm, (2-)2.3-3 x as long as broad, apex ± rounded, mucronate, base rounded, lower surface glabrous when mature except for punctulate hair bases; petioles 1.5-4 cm, glabrous. Inflorescence 7-10-flowered; rhachis 15-30 mm; pedicels 15-30 mm, stipitate-glandular. Calyx 1-3 mm, lobes minute, rounded, stipitate-glandular. Corolla 6-7-lobed, funnel-campanulate, usually sparsely glandular outside, often more densely so within, white to pale pink, with or without green or crimson flecks, 45-55(-62) mm. Stamens 14-16, filaments puberulent below. Ovary and style stipitate-glandular, glands whitish. Capsule 20-30 x c. 12 mm, usually slightly curved.
Habitat: Dry situations, in open forests and amongst scrub
Distribution: NE Burma, China (Yunnan, Sichuan, W Guizhou)
Altitude: 1800-3600m
Illustrations:
The colour of the stylar glands is not clear in all herbarium specimens. The pubescent stamens have therefore been used for differentiating R. decorum from the closely related R. vernicosum. Some ± intermediate plants occur in one or two localities, suggesting local hybridisation (Rock 24619, 25172, etc.). Some specimens (e.g. Forrest 11916ScFarrer979) approachR. diaprepesm the size of their corollas or leaves; these apparently occur at lower altitudes than is usual for R. decorum. One specimen (Rock 16474), assumed to be a hybrid of R. decorum, differs in its sparsely dendroid-tomentose ovary and style base with glands extending only half way up the style.
Type: China, Sichuan, Moupine, 3000 m, Pere David (n.v.); ad montem Tsong Chan, 2200 m, Delavay 1123 (n.v.); supra Ta-pin-tze, 22 v 1886, Delavay, s.n. (E,K)
Synonymy: R. franchetianum Leveille, Bull. Soc. Agric. Sarthe 39: 45 (1903). Syntypes: China, Yunnan, environs de Yunnan-sen, 11 xi 1896, Bodinier (E) & 28 iii 1897, Ducloux (E). R. spooneri Hemsley & Wilson, Kew Bull. 1910: 110 (1910). Syntypes: China, W Sichuan, nr Tatsien-lu, 2650-3650 m, vi 1904, Wilson 3975 (A); NW Yunnan, Tsekou, Monbeig (K). R. giraudissii Leveille, Feddes Repert. 18: 340 (1914). Type: China, E Yunnan, mont de Siao-ou-long, 2700 m, vi 1913, Maire (holo. E)
Occurs in Countries: CN, MM Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: crimson, green, pink, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):230
Very similar to R. sulfureum, differing as follows: leaves broadly ovate-oblong, 45-50 x 27-30 mm, the scales beneath contiguous, markedly unequal, flat, borne above the surface, not obviously sunk in pits; corolla c. 25 mm, tube 16 mm
Habitat: Rhododendron and bamboo forest
Distribution: China (S Xizang)
Known only from the type collection. A specimen hitherto identified as R. sulfureum (Burma, Kaw-ji pass, 10500 ft, Farrer 1550) has scales which match those of dekatanum; in other respects it is typical of sulfureum, and its status is uncertain.
Type: China, SE Tibet, Chayul Chu, Natrampa, Ludlow & Sherriff 1360 (holo. BM, iso. E)
Occurs in Countries: CN Subgenus: Rhododendron Habit: Non-Tree
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):136
Latin – delicatulus – delicate, alluding to the delicate or dainty nature of the specimen.
Type: Brass 11876, Jan. 1939. New Guinea (W), Northern part, 15km SW of Bernhard Camp, Idenburg River, mossy forest (A).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Fl. Colour: yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:79
Shrub to 50cm. Twigs 1–2mm in diameter, very slender, rounded, laxly leafy, the tips densely stellate-scaly, glabrescent below; internodes 3–6cm. Leaves 3–4 together in pseudowhorls at the upper nodes. Blade 30–65 x 4–7mm, very narrowly ovate-elliptic to almost linear, mostly widest below the middle; apex gradually acuminate and somewhat curved, sub-acute; margin slightly revolute; base broadly tapering to nearly rounded; very young leaves densely covered on both sides with deeply stellately divided or shortly dendroid scales, which are on top of persistent epidermal tubercles, early glabrescent and rough to the touch above, slowly so beneath. Mid-vein impressed above, prominent beneath; lateral veins obscure. Petiole c.2 x 0.5–0.7mm, scaly. Bracts to 20 x 6mm; outer bracts subulate; inner ones ovate, with a subulate acumen for the ultimate 3–10mm, densely stellately scaly outside, glabrous internally, fringed with scales. Bracteoles to 15 x 1mm, linear-sub-spathulate, very laxly hairy. Inflorescence c.3-flowered. Pedicels c.12mm, slender, densely reddish-brown stellately scaly. Flowers hanging or half-hanging. Calyx c.2mm in diameter, small, oblique, circular or obscurely lobed, thin, stellately scaly, shortly fringed. Corolla c.27mm, tubular below, widened at the mouth, zygomorphic, pink; tube 15–18 x 3 x 6mm, sub-densely, shortly, whitish hairy (but not scaly) outside, laxly hairy inside; lobes 5–7 x 5–6mm, spreading, broadly obovate-spathulate or sub-circular. Stamens almost equalling the corolla in length; filaments filiform, very laxly hairy proximally, glabrous distally; anthers 1.3 x 0.8mm, broadly oblong. Disc very shortly yellowish hairy at the upper margin, glabrous below. Ovary c.5 x 1.8mm, conical-cylindric, densely dark-brown stellately scaly, gradually tapering distally; style slender, as long as the corolla and covered with spreading yellowish hairs to the top; stigma sub-globose.
Habitat: Mossy forest
Distribution: Indonesia, New Guinea (W), Bernard Camp, Idenburg R.
Altitude: Around 1800m
Known only from the type collection.
Differing from the type in that the leaves are wider, 25–50 x 7–12mm, and the pedicels shorter, 5–7mm.
Habitat: On peaty soil
Distribution: Indonesia, New Guinea (W), Star Mts, 1km E of the mouth of the Minam R. in the Bon R.
Altitude: Around 1500m
Latin – lanceolatus – spear-shaped, the leaves being lanceolate in shape.
Once collected.
Type: Kalkman 4400 (A, L).
Epiphytic or free-growing shrub. Young growth rarely loriform-setose. Leaves narrowly elliptic to narrowly obovate, tapered to the base, rather abruptly acute or with a short drip-tip, 70-120 x 30-48 mm, undersurface with a covering of scales of variable density. Calyx disc-like or very obscurely lobed, not loriform-ciliate. Corolla white, often with a yellow, orange or greenish blotch and/or flushed pink, lepidote outside, pilose at the base of the tube. Ovary lepidote, usually waisted towards the apex. Capsule up to 20 mm.
Distribution: India (Arunachal Pradesh), ne Burma, China (NW, W & C Yunnan, SE Xizang). Rocks, cliffs, etc., or epiphytic, 1200-1400 m
Illustrations:
A very variable species in terms of indumentum, density of scales and corolla colour; all this variation is, however, continuous. Its distribution is rather disjunct, with one main mass of records in the Taron valley (c. 28° N), the other further south in the Salween valley (c. 25-26° N). In spite of this, no clear distinction into two units can be made.
Type: N Burma, Nwai valley, 11 v 1914, Kingdon Ward 1538 (holo. E)
Synonymy: R. atentsiense Handel-Mazzetti, Anz. Akad. Wiss. Wien 18:14 (1921). Type: China, Yunnan bor.-occid., in monte inter pagum Atentse et fluvium Mekong sito, versus .4000 m, 1914, Gebauer (holo. WU—n.v., iso. E). R. notatum Hutchinson, Notes R.B.G. Edinb. 16:177 (1931). Type: Upper Burma, Seinghku Wang, 5000-5500 ft, Kingdon Ward 6711 (holo. E). R. taronense Hutchinson, op. cit.: 178. Type: China, Yunnan, Taron valley, 4000-5000 ft, Kingdon Ward 5501 (holo. E)
Occurs in Countries: CN, IN, MM Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: green, orange, pink, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):48
Very similar to R. moupinense, differing as follows: shrub to 0-7 m; leaves 13-17 x 6-10 mm; calyx lobes up to 3 mm, ± elepidote; corolla rose pink, 20-22 mm, tube 10-13 mm; style shorter than stamens. Capsule unknown.
Habitat: On old logs
Distribution: China (C Sichuan)
Altitude: 2600-3000m
Illustrations:
Type: China, Mupin, ad truncos putridos, in sylvis regionis altissimae, v 1869, David (holo. P—n.v., iso. E)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: pink
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):58
Shrub to 1.3m. Twigs c.1.5mm in diameter, red or green, densely covered with warty scale bases and brown scales; internodes 3–10mm. Leaves in loose pseudowhorls, 7–15 together, 5–15mm apart, when in exposed places, clustered at the ends of the twigs. Blade 6–12 x 3.5–5mm, obovate, spathulate; apex emarginate and mucronate with a small gland at the apex; margin entire and revolute; base tapering; upper surface green shiny and glabrescent; lower surface paler green, sparsely but persistently scaly. Scales small, brown, circular or slightly lobed with large centres. Mid-vein slightly impressed above, raised below; lateral veins obscure. Petiole 2–3 x 0.7–1mm, faintly grooved above, sparsely scaly. Flower buds to 6 x 2.5mm, ovate, green, turning brown before opening, smooth, glabrous except along the margins of the bracts. Outer bracts ovate, glabrous with shortly ciliate margins. Inflorescence of solitary flowers held horizontally to half-hanging. Flowers 6–7 x 15–18mm. Pedicels 9–14 x 1mm, sparsely scaly, without hairs. Calyx shallowly 5-lobed, lobes c.1.5–2 x 1.5mm, scaly outside. Corolla 8–10mm, campanulate, yellow, without spots or visible markings; tube c.5 x 4 x 4mm, sparsely scaly outside, hairy inside, lobes 6–7 x 3.5–4.5mm, elliptic, spreading to the horizontal or slightly reflexed, not or only slightly overlapping. Stamens exserted to c.5mm, arranged all round the mouth, filaments hairy; anthers brown. Ovary ovoid, densely scaly and hairy; style 2–4mm, curved downwards; stigma globose. Fruit 7–11 x 3–4mm, with a persistent style. Seeds 4mm, without tails c.1mm, the longest tail 1.5mm.
Habitat: In mixed forests on the ground in light shade or exposed on ridges on rocky sometimes limestone mountains
Distribution: China, SE Yunnan, Malipo and Xichou.
Altitude: 1000-1800m
Latin – densus – dense; folium – leaf. Alluding to the densely leafy stems.
Flowers Sept.–Oct., although one plant was flowering in June. The fruit said to be ripe Sept.–Oct. of the following year.
Very similar to R. emarginatum but with consistently smaller, narrower leaves which gradually broaden upwards to near the apex. It also has hairs on the ovary as well as scales. It might be thought to be a high altitude form of R. emarginatum except that this species is reported at even higher altitudes than R. densifolium. These two species do grow together in the wild and are clearly distinct on leaf size. The marginal hairs on the bracts are exceptionally short, barely reaching 0.1mm. Recently introduced into cultivation but not yet known to have flowered.
Type: K.M. Feng 12815, 3 Nov. 1947. Yunnan, Mar-li-po: Chung-dzai, 1600–1800m (KUN)
Occurs in Countries: CN Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:33
Shrub, 2-3m. Leaves sub-coriaceous, elliptic, 12.5-20 X 4-7cm, 2.5-3 x as long as broad, apex apiculate, upper surface glabrous, with impressed veins, lower surface with a bistrate indumentum, the lower layer whitish, compacted and adpressed, the upper yellow to cinnamon, even when mature, lanate, ± detersile, hairs ramiform, sometimes lacking on the older leaves, veins prominent and ± glabrous; petioles 1— 2cm, tomentose. Inflorescence 8—10-flowered; rhachis up to 7mm; pedicels 10-15mm, densely tomentose. Calyx c.lmm, tomentose, lobes minute. Corolla campanulate, rose to wine-red, probably with interior markings, c.40mm. Ovary densely whitish-tomentose; style glabrous. Capsule not known.
Habitat: Mountains
Distribution: China (C & S Sichuan, NE Yunnan, NW Guizhou)
Altitude: 3100-3300m
Closely allied to R. floribundum and doubtfully distinct. The" leaves are apparently thinner and also differ in the detersile yellowish upper layer of the indumentum.
Type: China, Yunnan, rochers de Tien Sin, iv 1911, Maire (holo. E; iso. K).
Synonymy: R. xanthoneuron Leveille, ibid. 13: 340 (1914). Type: China, Yunnan, Mont Ta-Pe-Lou, 3200m, v 1911, Maire (holo. E)
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: rose
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):321
Dwarf shrub, 0.3- lm; perulae persistent. Leaves oblanceolate to elliptic, 4-5 x 1.5-1.8cm, c.2.7 x as long as broad, apex acute, base cuneate, upper surface with impressed veins so appearing bullate, lower surface with a unistrate red-brown detersile lanate ramiform indumentum; petioles c.0.5cm, densely tomentose. Inflorescence c.lO-flowered; pedicels c.lOmm, densely glandular-hirsute. Calyx c.3mm, densely hairy and stipitate-glandular, lobes ligulate, rounded. Corolla campanulate, pinkish, 25-30mm. Ovary glandular-pilose; style glandular in the lower half. Capsule not known.
Habitat: Rocky slopes
Distribution: China (E Sichuan)
Altitude: Around 2500m
Only known from material collected by Farges near the type locality. The bullate leaves and leaf indumentum suggest a distant affinity with R. mltonii but the glandular ovary and well-developed calyx suggest that it is closer to R. adenogynum and its immediate allies.
Type: China, E Sichuan, rochers de Touan tchen, s.p. de Ta-lin-hien, 2500m, Farges 1382 (iso. E,K).
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: pink
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):337
Rigidly erect shrub to 1.5m. Twigs with shortly stalked scales, later rough and minutely warty after the scales have fallen. Leaves densely spirally arranged. Blade 10–15 x 2–4mm, elliptic to spathulate; apex broadly acute to obtuse, margin narrowly revolute, sub-crenulate with scale attachments; base narrowly tapering, decurrent, laxly scaly above but quickly glabrescent, below sub-densely and persistently scaly. Scales with a narrow marginal flange and thick rounded and partly impressed centre. Mid-vein impressed above, slightly raised below; lateral veins and reticulation not visible. Petiole c.1mm, scaly. Bracts to 4mm, ovate sub-acuminate to apiculate, outside scaly along the middle line, without hairs except for the ciliate margins. Inflorescence of 1–3 vertically hanging flowers. Pedicels 6–8mm, slender, densely scaly but without hairs. Calyx c.2.5mm in diameter, shortly 5-lobed, densely scaly. Corolla c.12mm, red, cylindrical; tube c.10 x 3 x 4mm, densely scaly outside, glabrous inside; lobes c.3 x 3mm, sub-circular, semi-erect, scaly outside, without hairs but with a denticulate margin. Stamens as long as the corolla tube; filaments c.10mm, glabrous; anthers 1.5mm, broadly oblong. Disc glabrous but with scales on the upper side. Ovary c.2 x 1mm, cylindrical, vertically striate, densely round-scaly; style c.8mm, slender, densely scaly for the proximal 1mm, glabrous distally; stigma club-shaped. Fruit 6–7 x c.3mm, sub-cylindrical.
Habitat: In the grassland border with Podocarpus/Papuacedrus forest, and tree fern grassland
Distribution: Papua New Guinea, Central District, Goilala subdistrict, Mt Dickson; Morobe District, above Bakaia, c.15 miles SE of Garaina.
Altitude: 2745-3500m
Dedicated to the memory of H. Detzner, an admirer of New Guinea rhododendrons who was in the Mt Dickson area with the Kaiser Wilhelm Land Boundary Commission in 1914.
Said to be closely related to R. erosipetalum from the Vogelkop Peninsula but that species has bracts and pedicels which are both hairy and scaly outside and also has hairs on the corolla lobes.
Type: Hartley 12959, 10 Feb. 1964. New Guinea (E), Central District, Goilala subdistrict, Mt Dickson, 3500m (L, CANB, K, LAE).
Occurs in Countries: PG Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:58
Shrub to 2m. Twigs slender, densely scaly, early glabrescent and often whitish; internodes 6–16cm. Leaves 3–4 together in pseudowhorls at the upper 2 or 3 nodes. Blade 70–140 x 30–55mm, broadly elliptic or elliptic or slightly obovate; apex broadly acute to obtuse; margin entire, flat, a little recurved when dry; base broadly tapering to rounded, young leaves densely reddish-brown stellate-scaly, mature ones glabrescent, on both sides covered with numerous epidermal tubercles which make them feel rough to the touch. Scales dendroid; marginal zone divided to, or almost to, the centre; centre small, deepened or prolonged into a short stalk. Mid-vein slightly prominent proximally above, gradually becoming flat in the distal part above; below as thick as the petiole in the proximal part, gradually decreasing distally; lateral veins 8–12 per side, irregular, inarched before the margin, slightly prominent on both sides, veins laxly reticulate, not very conspicuous. Petiole 10–15 x 2–2.5mm, densely scaly initially. Bracts 10–35 x 10–15mm, dull red; outer ones ovate, inner ones elliptic-ovate and apiculate, innermost ones broadly spathulate, scaly and/or appressed-hairy. Bracteoles c.20 x 1–2mm, linear, glabrous. Inflorescence a 3–6-flowered open umbel, the flowers held stiffly horizontally or half-hanging. Pedicels 10–15 x 1.5mm, very densely brown stellate-scaly, without hairs. Calyx c.3mm in diameter, obliquely disc-shaped. Corolla 50–70 x c.70mm, pure white, or pink with darker pink edges, with a scent of carnations; tube 25–40 x 6–10 x 12–15mm, tubular, straight, glabrous outside, shortly hairy inside; lobes 6–7 in number, 20–35 x 20–30mm, spathulate, 3 or 4 of them generally smaller than the others, horizontally spreading. Stamens exserted to c.10mm; filaments linear, densely or more laxly hairy in the proximal ¾, glabrous distally; anthers 3.5–4 x c.1mm, elongate-oblong, the base obtuse. Disc glabrous below, hairy at the upper margin. Ovary 8–10 x 2–3mm, sub-cylindrical, covered with whitish to yellowish, distally directed hairs, which cover the scales, tapering gradually; style c.30mm, slender, densely hairy proximally, the hairs becoming laxer distally and completely glabrous in the uppermost ¼, without scales; stigma 2.5–3mm.
Habitat: Epiphytic in primary forest, 800–1400m, descending along ravines to c.500m.
Distribution: Indonesia, New Guinea (W), above Jayapura on the W slope of Mt Dafonsero; Cycloop Mts, Faita R. camp and along path from Ifar to Ormu.
Altitude: 500-1400m
Named after the genus Dianthus because the flowers have a similar perfume.
In cultivation since 1961 when Professor Sleumer sent seed from New Guinea to the USA from where it has been distributed. Probably all genuine materials of this species are from this introduction. Slow growing and fairly compact.
Type: van Royen & Sleumer 5736, 8 June 1961. New Guinea (N), Cycloop Mts, Faita R. camp (L, A, CANB).
Occurs in Countries: ID Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:79
Shrub or tree, 1-14 m. Leaves elliptic-oblong to ovate, 12—19(—30) x 4.4-11 cm, 1.7-3 x as long as broad, apex ± rounded and minutely mucronate, base rounded, lower surface glabrous when mature except for persistent punctulate hair bases; petioles 2-3.5 cm, glabrous. Inflorescence 5-10-flowered; rhachis 15-20 mm; pedicels 15-30 mm, ± stipitate-glandular. Calyx 2-6 mm, lobes shallow to well-developed, stipitate-glandular. Corolla 7—8-lobed, open- to funnel-campanulate, ± glandular outside, puberulent within, white, sometimes flushed rose, (65-)80-100 mm. Stamens 18-20, filaments puberulent below. Ovary and entire style with white-stipitate glands. Capsule 30-60 x 12 mm, curved
Distribution: NE Burma, China (W Yunnan), Laos
Illustrations:
Closely allied to R. decorum but with larger leaves and corollas, also close to R.faithae(q.v.)
Further material seen since the completion of the manuscript suggests that R. diaprepes is best treated as a subspecies of R. decorum as several intermediate specimens are now known from the extreme western part of Yunnan, within the range of R. diaprepes. The necessary combination is R. decorum Franchet subsp. diaprepes (Balfour f. & W. W. Smith) T. L. Ming, based on R. diaprepes as cited above.
Type: China, W Yunnan, Shweli/Salween Divide, 9000 ft, vi 1913, Forrest 11958 (holo. E; iso. K)
Synonymy: R. rarile Balfour f. & W. W. Smith, ibid. 10: 139 (1917). Type: China, W Yunnan, hills around Tengyueh, 6000-7000 ft, v 1912, Forrest 7940 (holo. E)
Occurs in Countries: CN, MM Subgenus: Hymenanthes Habit: Tree Fl. Colour: rose, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):233
Dwarf shrub, 0.3-2.3m; young shoots with a white floccose indumentum, sometimes also glandular- or eglandular-setose; perulae deciduous. Leaves oblanceolate to elliptic, 4—9.5 X 2-4cm, 1.9-3.2 x as long as broad, apex apiculate, base ± rounded to cuneate, glabrous above, with a continuous silvery to fawn, ± loose to compacted rosulate indumentum beneath; petioles 0.5-lcm, indumentum white, floccose. Inflorescence 3-6-flowered; rhachis 5(-8)mm; pedicels 15-25mm, rufous-tomentose or stipitate-glandular. Calyx 3-15mm, coloured, cupular when well-developed, though usually irregular, glabrous except for the rounded, glandular-ciliate lobes. Corolla fleshy, tubular-campanulate, orange-red, occasionally yellow flushed red or even carmine, 35-50mm. Ovary rufous-tomentose, with or without stipitate glands. Capsule 10-15 x 4-6mm.
Habitat: Open rocky slopes, cliff ledges, cane brakes, etc.
Altitude: 2750-4550m
A variable species showing some geographical variation; closely allied to R. sanguineum. A specimen, Forrest 27071, with yellow flowers flushed rose, sparsely hairy leaves and persistent perulae, is almost certainly a hybrid between R. dichroanthum and R. aperantum.
Occurs in Countries: CN, MM Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: carmine, orange, red, yellow
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):393
Ovary lacking stipitate glands, rarely with one or two towards the base; young shoots with eglandular setae or setae absent. Leaves 1.9-2.4(-2.5) x as long as broad; silvery to fawn.
Distribution: China (W Yunnan), ne Upper Burma
Illustrations:
Synonymy: R. apodectum Balfour f. & W. W. Smith, Notes R.B.G. Edinb. 10: 83 (1917). Type: China, Yunnan, western flank of the Tali Range, 25°20'N, 10-11000ft, viii 1912, Forrest mi (holo. E; iso. K). R. jangtzowense Balfour f. & Forrest, Notes R.B.G. Edinb. 13: 271 (1922). Type: China, W Yunnan, Shweli/Salween divide, Jangtzow Shan, 11000ft, vi 1919, Forrest 18167 (holo. E; iso. K). R. liratum Balfour f. & Forrest, ibid. 13: 274 (1922). Type: China, W Yunnan, Shweli/Salween divide, Jangtzow Shan, 11000ft, vi 1919, Forrest 18153 (holo. E; iso. K).
Ovary lacking stipitate glands, rarely with one or two towards the base; young shoots with eglandular setae or setae absent. Indumentum silvery, compacted; leaves 2.5-3 x as long as broad.
Illustrations:
Type: China, Yunnan, E flank of the Tali Range, 9-10000ft, vii 1916, Forrest 4138 (holo. E; iso. K)
Ovary with a number of stipitate glands; young shoots often glandular-setose. Leaves 1.9-2.5(-2.7) x as long as broad.
Distribution: NE Upper Burma, China (W Yunnan)
Synonymy: R. scyphocalyx Balfour f. & Forrest, Notes R.B.G. Edinb. 13: 291 (1922). Type: NE Upper Burma, western flank of the N'Maikha/ Salween divide, 26°25'N, v 1919, Forrest 18050 (holo. E). R. herpesticum Balfour f. & Kingdon-Ward, Notes R.B.G. Edinb. 10:114 (1917). Type: E Upper Burma, Mwai divide, Ridge of Naung Chanung, 12-13000ft, 16 vii 1914, Kingdon-Ward 1793 (holo. E; iso. K). R. torquatum Balfour f. & Farrer, Notes R.B.G. Edinb. 13: 303 (1922). Type: NE Upper Burma, Maguchi Pass, 11-12000ft, 31 vii 1920, Farrer 1775 (holo. E). R. dichroanthum Diels subsp. herpesticum (Balfour f. & Kingdon-Ward) Cowan, Notes R.B.G. Edinb. 20: 87 (1940).
Ovary with a number of stipitate glands; young shoots often glandular-setose. Leaves 3-3.3 x as long as broad. Indumentum whitish to fawn, leaves 3-3.3 x as long as broad.
Type: NE Upper Burma, western flank of the Salween/Kiu-chiang divide, 27°18'N, 98°40'E, 13-14000ft, vii 1924, Forrest 25750 (holo. E).
Named after Friedrich L.E. Diels, 1874–1945, a German botanist.
Type: Schlechter 17770. New Guinea (NE), Kani Mts, Above Bolobo, c.1400m (B†, P).
Synonymy: R. laureola Schltr., Bot. Jahr. 1918. 55: 151.
Occurs in Countries: PG Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:80
Shrub to 1.5m. Twigs rounded, 1.5–3mm in diameter, the tips densely brown with stellate scales which give an almost hairy appearance; older parts glabrescent, smooth, brown; internodes 1.5–8cm. Leaves mostly 3–4 together in tight pseudowhorls at the upper 2–3 nodes. Blade 30–55 x 8–25mm, elliptic; apex shortly acuminate, apiculate, sub-acute; margin flat or slightly revolute; base broadly tapering, or rarely almost rounded; densely scaly on both sides initially, quickly glabrescent above, more persistently scaly beneath especially near the mid-vein, finally glabrescent and a little rough to the touch on both sides. Scales small, deeply stellately divided, sessile or shortly dendroid and on top of low, persistent, epidermal tubercles. Mid-vein somewhat impressed above, raised beneath; lateral veins c.6 per side, very faintly impressed above and raised beneath, inconspicuous on both sides. Petiole 2–5mm, grooved above, slender, densely scaly. Flower buds to 18 x 6mm, slenderly ellipsoid or ovate, the apex acute, the bract tips appressed or only slightly spreading. Bracts to 15 x 6mm; the outer subulate, often with the point as long as the broad part; inner ones ovate-subulate to ovate-apiculate, stellate-scaly in the upper ½ and shortly fringed with stalked scales. Bracteoles to c.10mm, filiform, laxly scaly. Inflorescence of mostly solitary or paired flowers, hanging or half-hanging, rarely in up to 5-flowered open umbels. Pedicels 10–13mm, slender, densely brown-stellate-scaly. Calyx c.2.5mm in diameter, often slightly oblique, disc-shaped, densely stellately scaly, very shortly obtusely 5-lobed. Corolla 25–35 x 11–14mm, tubular to c.4⁄5 of its total length, slightly curved and zygomorphic, pale pink; tube 12–20 x 8–10 x 6–8mm, slightly laterally compressed, narrowest about the middle, weakly pouched at the base, sparsely scaly outside, glabrous or sparsely hairy inside; lobes c.6–8 x 5–7mm, broadly spathulate to sub-circular, spreading. Stamens clustered on the upper side of the flower, unequal, the longest exserted from the mouth to c.6mm, shorter ones at the mouth; filaments red, linear to filiform, glabrous or very slightly hairy; anthers c.2 x 1mm, brown. Disc prominent, glabrous. Ovary 5–6 x c.1.5mm, sub-cylindrical, densely stellate-scaly, gradually tapering distally; style slender, glabrous or scaly at the very base only, becoming slightly exserted from the mouth when receptive; stigma sub-globose, slightly 5-lobed. Fruit 17–30 x 3–5mm, cylindrical, grooved longitudinally and often curved. Seeds 40–52mm, without tails 10–11mm, the longest tail c.25mm, irregularly crimped.
Habitat: Epiphytic on tall trees in ravines and wooded slopes, in dense shade, terrestrial in secondary grassland and along roadsides
Distribution: Papua New Guinea, Upper Sepik R. region; Kani, Finisterre and Saruwaged Mts. Common in the Eastern Highlands, also in the Simbu and Western Highlands. Possibly in W New Guinea; see notes under R. bryophilum.
Altitude: 1200-1940m
Slender erect shrub to 3m. Corolla pink. Differs from var. dielsianum by the style which is laxly shortly hairy with spreading hairs in its lower ½.
Habitat: Hillside secondary grasslands locally common.
Distribution: Papua New Guinea, Eastern Highlands: Upper Dunantina Valley, the road between Kami and Lufa and Mt Kesegete, Namaro, Benabena District.
Altitude: 1700-2000m
Latin – stylus – the style; trichoma – hair. Alluding to the hairs at the base of the style which distinguishes this variety from the type one.
Type: Hoogland & Pullen 5307. Papua New Guinea, Eastern Highlands, Goroka subdistrict, Upper Dunantina valley, near Sosomepari village (LAE, B, BRI, CANB, K, L).
Shrub or small tree, 0.6-6m. Leaves elliptic to obovate-lanceolate, 7.5-18 x 4-6.5cm, 1.8-2.7 x as long as broad, apex acute to apiculate, base cordate to ± rounded, lower surface with a thin discontinuous unistrate brown indumentum composed of the scattered remains of hairs and glands; petioles 0.5-2cm, sparsely floccose or glabrescent. Inflorescence 5- 15-flowered; rhachis c.lOmm; pedicels 5-20mm, glabrescent or sparsely floccose. Calyx 0.5-3mm, lobes rounded, usually glandular-ciliate. Corolla campanulatc to funnel-campanulate, white to yellow, sometimes flushed pink, with or without purple flecks and basal blotch, 25-45mm. Ovary glabrous or with a brownish-red floccose indumentum, sometimes interspersed with glands; style usually glabrous, occasionally glandular below. Capsule not known.
Habitat: Forests, open stony slopes
Distribution: China (E Xizang)
Altitude: 3350-4550m
A variable species. Specimens from open habitats are significantly smaller, with shorter corollas and leaves. There also appears to be considerable variation in the amount of indumentum on the ovaries.
Type: China, SE Xizang, Le La (Kyimpu), Chayul Charme, 13000ft, 9 v 1936, Ludlow & Sherriff 1564 (holo. BM; iso. E).
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: pink, purple, white, yellow
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):365
Shrub or small tree; shoots glabrous. Leaves rhombic, 3-5 x 1.5-3.5cm, apex acuminate, both surfaces covered with adpressed pilose hairs when young, at maturity upper surface glabrous, lower surface with sparse pilose hairs; petioles 3~5mm, papillate. Inflorescence 1-3-flowered, flowers appearing before leaves; pedicels 5-8mm, covered with adpressed brown hairs and glands. Calyx minute, glandular, lobes ciliate. Corolla open funnel-shaped, 20-30mm, rose-purple, lobes 15-25mm, oblong. Stamens 5, filaments glabrous. Ovary glandular; style glabrous.
Distribution: Japan (S Honshu)
Altitude: Around 1000m
Illustrations:
Rehder states that the type lacks flowers. Therefore our concept of R. dilatatum follows that of Maximovicz (in Rhododendr. As. Orient. 27, 1870).
Occurs in Countries: JP Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Tsutsusi Habit: Tree Fl. Colour: rose
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):146
Shrub, 1 — 3m. Leaves coriaceous, oblanceolate to elliptic, 6.5—9 X 2.2-3.2cm, c.3 x as long as broad, apex acuminate to apiculate, base ± cuneate, with lamina narrowly decurrent, margin with red sessile glands, entirely glabrous at maturity, lower epidermis epapillate; petioles 0.7-1cm, floccose-hairy at first, soon giabrescent. Inflorescence lax, 8—12-flowered; rhachis c.lOmm; pedicels 7-10mm, dendroid-tomentose. Calyx cupular, up to 10mm, lobes broadly ovate, glabrous except for the gland-fringed margin. Corolla tubular-campanulate, white flushed rose to deep rose-pink, with at least a few purple flecks, papillate-pubescent within towards base, 35-40mm. Ovary densely tomentose, with a few stipitate glands; style tomentose, at least in the lower half. Capsule not known.
Habitat: Open thickets
Distribution: China (W Yunnan, around Dali)
Altitude: 3000-3350m
This species is apparently intermediate between subsections Irrorata and Neriiflora; the corolla suggests an alliance with the former and the well-developed calyx with the latter. R. dimitrium might be a hybrid between R. irroratum and R. neriiflorum, both of which occur in the vicinity of Dali. However, the five specimens seen suggest that a stabilised population has developed thus meriting formal taxonomic treatment.
Type: China, Mid-W Yunnan, western flank of the Tali Range, 25°40'N, 10000ft, v 1917, Forrest 13736 (holo. E; iso. K).
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: purple, rose, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):428
Like a Disterigma, a genus of South American Ericaceae.
Type: Brass 9022, Aug. 1938. New Guinea (N), Mt Wilhelmina, Lake Habbema, 3225m camp (A, L, fragment).
Occurs in Countries: ID, PG Altitude Ranges: 3,000 - 4,000m Subgenus: Vireya Fl. Colour: red, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:147
Erect shrub to 1m. Leaves shiny dark green above, light green with brown scales below, arranged in distinct pseudowhorls. Flower buds to 10 x 4mm, outer bracts broadly elliptic, with long points, inner bracts ovate, acuminate, also with long slender subulate points, completely glabrous except for a dense fringe of scales around the bract margins. Pedicels pink. Corolla deep red with white scales. Stamens pink with white pollen. Ovary brown.
Habitat: Podocarpus–Phyllocladus woodland with Gahnia tussocks dominating the ground layer, locally common.
Distribution: Papua New Guinea, West Sepik District, Telefomin subdistrict, Ridge top W of Tel Basin, 2.5km E of Mt Capella. Indonesia, New Guinea (W), Star Mts, Mt Antares
Altitude: 3380-3800m
Latin – aster – a star; montes – mountains. Alluding to the Star Mountains where it has been collected.
Differing from the type subspecies chiefly in the distinctly pseudowhorled leaf arrangement.
Rhododendron disterigmoides was described from the Lake Habbema area in West New Guinea, not a great distance from the locality of this subspecies. The type of ssp. disterigmoides was described incompletely in that the flower buds were not collected. It is possible that flower bud characters from the type area will show sufficient difference from those of this new subspecies to warrant that this taxon be raised to specific level. Apart from the difference in leaf arrangement there are some other minor differences: the leaves of this subspecies are less revolute, the margins being so only in the proximal 1⁄3, the apices are often obtuse rather than acute to acuminate, and the leaf bases are often broadly tapering rather than rounded or sub-truncate. This subspecies has been confused in the past with R. pulleanum. It is easily distinguished on the marginal bud scale indumentum which is of simple hairs in R. pulleanum, not scales.
Type: Vinas LAE 67036, 7 April 1975. Papua New Guinea, West Sepik District, Telefomin Subdistrict, Ridge-top, west of Tel Basin 2.5km E of Mt Capella, 3800m (LAE, A, BISH, CANB, E, K, L, SYD).
Shrub to 80cm, with strong erect branches. Twigs 1.5–2mm in diameter, when young covered with reddish-brown, stalked, stellate scales, later glabrescent. Leaves sub-densely spirally arranged. Blade 6–10 x 4–6mm, ovate; apex acuminate, apiculate, acute; margin thickened and pale, distinctly revolute, crenulate with impressed scales; base rounded to sub-truncate; glabrescent above, persistently laxly scaly beneath. Scales small, irregularly stellate-incised, weakly or not impressed. Mid-vein obtusely prominent beneath, obscure above; lateral veins obscure. Petiole c.1mm. Inflorescence 2–4-flowered, flowers half-hanging to hanging. Pedicels 8–12mm, slender, densely shortly stalked, stellate-scaly, without hairs. Calyx c.2.5mm in diameter, shortly cup-shaped, shortly obtusely 5-lobed, densely scaly outside. Corolla 22–23mm, tubular, deep red; tube c.17 x 4 x 7mm, laxly to sub-densely scaly outside, glabrous inside; lobes c.8 x 8mm, sub-circular, with a few scales outside. Stamens exserted to c.2mm, unequal; filaments linear, glabrous; anthers c.1.8 x 1mm, broadly obovate-oblong. Disc glabrous. Ovary 4–5 x c.2mm, sub-conical-cylindrical, densely scaly gradually tapering distally; style 8–9mm, glabrous, columnar; stigma club-shaped-globose.
Habitat: A common terrestrial in shrubberies and on peaty ridges
Distribution: Indonesia, New Guinea (W), Lake Habbema.
Altitude: Around 3225m
Shrub, l-2.5m. Leaves obovate to broadly elliptic, 6.5-7.5 x 3-4cm, 1.8-2.2 x as long as broad, apex apiculate to acuminate, base rounded, lower surface with a thin unistrate lanate brown evanescent indumentum; petioles 0.5-1.5cm, glabrescent. Inflorescence 5-10-flowered; rhachis c.5mm; pedicels c.20mm, glandular-tomentose. Calyx 7-10mm, with broad chartaceous, glabrous or glandular-ciliate lobes. Corolla white flushed rose, with purple flecks, c.40mm. Ovary stipitate-glandular; style glabrous. Capsule c. 12 x 6mm, curved.
Distribution: China (NW Yunnan)
A distinctive species on account of its often acuminate leaves and well-developed calyces. The calyx is reminiscent of that found in subsection Thomsonia and it is possible that this taxon is a hybrid.
Type: China, NW Yunnan, Mekong/Salween divide, 14000ft, 27°N, 99°2'E, vii 1924, Forrest 25580 (holo. E)
Occurs in Countries: CN Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: purple, rose
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):338
Latin – Durio, the genus of fruit trees in the family Bombacaceae; folium – leaf. Alluding to the similarity of the scales on the leaf to those of a durian.
Type: Beccari 3230. Malaysia, Sarawak (Borneo), Batang Lupar, Mt Tiang Laju (FI, P).
Occurs in Countries: ID, MY Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Tree Fl. Colour: orange, red, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:113
Shrub or small tree to 3m. Twigs rounded, thick, initially entirely covered in the younger parts with brown to dark golden scales; internodes 3–16cm. Leaves 3–5 in pseudowhorls, in the apical part of the stem. Blade 70–170 x 20–65mm, ovate to ovate-elliptic; apex long-acuminate to shortly caudate; margin flat or narrowly reflexed especially when dry, mostly irregularly wavy, sometimes minutely toothed; base rounded to cordate or auriculate; with very thin silvery scales above which leave small pits as they disappear, entirely and persistently covered with the orange-brown scales beneath. Scales with broad striate flanges and large swollen centres, the largest darker and forming clearly visible spots. Mid-vein distinctly impressed above, very broad and prominent beneath for at least ¾ of its length; lateral veins 6–9 per side, straight and spreading below, curved and anastomosing towards the edge, smooth or slightly impressed above in mature leaves only, indistinct beneath, veins laxly reticulate and mostly minutely impressed on the upper side only; silvery green when dry above turning green when wet, coppery orange-brown beneath. Petiole 1–4 x c.3mm, densely scaly, without a groove when fresh, but mostly very short or almost lacking. Flower buds 20–25 x 12–15mm, smooth, ovoid. Bracts to 20 x 12mm, the outer fully appressed, ovate, obtuse to sub-apiculate, the base truncate, often with minute hairs outside, scaly along the upper outer side near the middle, finely white ciliate along the margins, the inner ones spathulate. Bracteoles to 15mm, filiform, papillose-hairy, often sub-spathulate and very short-ciliate at the apex. Inflorescence an open, or more rarely, a complete umbel of 10–35 flowers. Flowers erect to spreading. Pedicels 10–15 x c.1mm, densely scaly. Calyx a very low, disc-like ring. Corolla 24–30mm, yellow? to orange, or red, tubular to narrowly funnel-shaped; tube c.5 x 5 x 8mm, mostly completely glabrous, rarely with a few (apparently rapidly falling) scales on the lower part of the tube outside, glabrous or slightly hairy at the base of the tube inside, straight, often somewhat pouched at the base; lobes c.12 x 8mm, spreading, obovate to nearly rounded, overlapping in the basal 1⁄3, as long as the corolla tube. Stamens c.20mm, spreading all round the mouth, slightly unequal; filaments linear, flattened and densely whitish hairy in the basal 1⁄3, filiform and glabrous distally; anthers 2.5–3.5 x 0.5–0.8mm, brown, oblong, often curved. Disc glabrous. Ovary 5–8 x c.1.5mm, elongate-conical, densely scaly, gradually tapering distally; style 7–10mm, thick and scaly in the proximal ½, glabrous distally; stigma rounded or slightly 5-lobed, lobes enlarging into separate club-shaped spreading parts as the fruit develops. Fruit 25–45 x 3–4mm, cylindrical, often somewhat curved, densely scaly, slightly 5-ribbed, the valves curling right back. Seeds 6mm, without tails 0.7mm, the longest tail 2.6mm.
Habitat: Widespread, growing both terrestrially and epiphytically in moss forest, low shrubberies and on bare sandstone rocks, locally common
Distribution: Malaysia (Borneo), Sarawak and Sabah. Indonesia, C and SE Borneo.
Altitude: 800-2400m
This species is extremely variable throughout its entire range but may be known amongst the section Malayovireya by its short petioles and the relatively long, tubular, mostly orange-red flowers which are without scales or only slightly scaly at the base and aggregated together into umbels of 10 or more. I have never seen yellow-flowered specimens and this report may be an error although there are occasional purplish-pink-flowered populations which are similar in colour to many of the forms of R. malayanum. A puzzling aspect of this species is the variable shape and size of the flowers. A population in a peat swamp area in southern Sabah had three distinct size classes of flower – large, intermediate and small – which did not appear to intergrade and were all growing together. It is closely related to R. fallacinum, which is maintained in this account although distinguished with difficulty from the complex variation that occurs in R. durionifolium. Rhododendron fallacinum usually has a shorter corolla tube and the flowers are densely scaly outside, with scales occurring right up onto the backs of the corolla lobes. Slender forms of ssp. sabahense approach R. malayanum in form but the petioles do not get quite as long as in that species, the flowers are more numerous from a single flower bud and R. durionifolium never normally produces lateral inflorescences. Rhododendron acuminatum could also be confused but apart from occurring at higher altitude, this species has more strongly puckered leaves with the lateral veins deeply impressed on the upper side and like R. malayanum it has much longer petioles than R. durionifolium.
Differing from the type subspecies in the more slender, narrowly elliptic to elliptic leaves, 90–160 x 20–50mm, with a tapering base; longer petioles: 4–7mm; leaves which are greener and more quickly glabrescent above and flowers predominantly pink or red rather than orange in colour.
Altitude: 900-2400m
Latin – Sabah – the country; ensis – place or origin. Coming or originating from Sabah.
This subspecies occurs above 900m in fairly uniform populations on Mt Lumarku, Mt Lotung and near Long Pasia, in the Sipitang District. With its red or pink flowers and long corolla tubes it would be suitable for bird pollination but this has not been observed. The only hybrid seen is with R. micromalayanum on Mt Lumarku and in the Long Pasia region. This subspecies has been cultivated since 1980. It grows slowly but has most attractive flowers.
Type: A. Phillipps SAN 93169, May 1981. Malaysia, Sabah (Borneo), Sipitang District, Long Pasia Track (SAN).
Shrub, 1 -3(-4.5)m; bark smooth and peeling; young shoots usually sparsely glandular. Leaves obovate-lanceolate (jargonelle-shaped) to elliptic, (4-)6-14.5 x (3-)3.5-5.6cm, 1.9-2.3 x as long as broad, apex rounded, apiculate to retuse, base ± cuneate to rounded, upper surface glabrous, lower surface with epidermis epapillate, glabrous though often with at least some simple straight hairs on either side of the midrib, veins conspicuous; petioles 0.4-3cm, narrowly winged, glabrous or with a few stipitate glands. Inflorescence dense, 6-11-flowered; rhachis 5- 15mm; pedicels 10-25mm, glabrous or sparsely glandular. Calyx 2-15mm, usually cupular, ± glabrous, lobes rounded. Corolla campanulate or widely funnel-campanulate, white or cream to (more usually) deep crimson, with or without purple flecks, (30-)40-50mm. Ovary densely stipitate-glandular; style glabrous. Capsule 15-25 x 6-10mm, often glaucous.
Habitat: Bouldery slopes, thickets, cane brakes
Distribution: China (SE Xizang, NW Yunnan, SW Sichuan), ne Upper Burma.
Altitude: 3000-4000m
R. eclecteum hybridises with R. pocophorum (see under R. x hemigynum). Kingdon-Ward 6900, with leaves typical of R. eclecteum except that they have a floccose but persistent indumentum, may also be of hybrid origin.
Occurs in Countries: CN, MM Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: cream, crimson, magenta, purple, rose, white, yellow
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):425
Petioles 8-30mm; leaf lamina 6-12.5 x as long as petioles, usually lacking simple hairs; corolla usually white to yellow, sometimes flushed with rose
Flowering specimens with relatively long petioles and elliptic leaves almost always have pale flowers but well over half the specimens seen lack flowers or flower colour notes. Therefore, the status of var. bellatulum, which apparently intergrades with var. eclecteum, will remain uncertain until field studies are carried out.
Type: China, Yunnan, Londre Pass, Mekong/ Salween divide, 12000ft, vi 1921, Forrest 19535 (holo. E)
Petioles 4-10mm; leaf lamina 11-18 x as long as petioles, at least some simple straight hairs usually present near the midrib; corolla usually deep magenta-rose to crimson
Cowan & Davidian (loc. cit.) state that var. brachyandrum differs from var. eclecteum in its darker flowers. However, there is no indication of the flower colour of the type of var. eclecteum, or indeed of the majority of the herbarium specimens seen. The type of var. brachyandrum has small flowers, the diagnostic character used by the original authors, although, like Cowan & Davidian, 1 consider that to be of little taxonomic significance. If var. eclecteum is restricted to plants with relatively short petioles and deeply coloured flowers then the following specimens are intermediate between vars. eclecteum and bellatulum: Forrest 18023, 25603; Rock 8748, 8750, 9205, 22222, 22224, 22230, 22661, 22664, 22665.
Type: China, Yunnan, be 1917, Forrest 14804 (holo. E).
Synonymy: R. brachyandrum Balfour f. & Forrest, Notes R.B.G. Edinb. 13: 32 (1920). Type: China, SE Xizang, Tsarong, Salween/Kiu-chiang divide, vii 1919, Forrest 18943 (holo. E). R. eclecteum Balfour f. & Forrest var. brachyandrum (Balfour f. & Forrest) Cowan & Davidian, Rhododendron Yearbook 6: 169 (1951).
Named after Gregorio Edaño, a Philippine collector employed by the Bureau of Science, Manila.
Type: Edaño PNH 153, 13 May 1947. Philippines, Palawan, Mt Mantalingahan, Brook’s Point (A, BM, E, K, L, PNH†).
Occurs in Countries: ID, MY, PH Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Tree Fl. Colour: brown
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:160
Shrub to 40cm. Twigs rounded, densely stellate-scaly; internodes 2–5cm. Leaves 4–6 together in tight pseudowhorls. Blade 25–55 x 15–25mm, elliptic, broadly elliptic or obovate-elliptic; apex obtuse to rounded, often with a pale gland-like spot at the apex; margin entire, narrowly revolute; base broadly tapering to rounded; quickly glabrescent above, densely and sub-persistently scaly beneath. Scales stellate, margin deeply divided; centre very small, each on top of a small persistent epidermal tubercle. Mid-vein impressed above, strongly raised beneath throughout its length; lateral veins 3–6 per side, straight, slightly impressed above, obscure beneath; reticulation not visible. Petiole 5–7 x c.1.5mm, grooved above, densely scaly. Flower buds to 15 x 8mm, slender, ovoid. Bracts broadly subulate with the upper sides rolled and the tips reflexed, green, with a few scales outside and densely scaly along the margins. Bracts to 15 x 7mm, ovate to elliptic to spathulate, densely scaly outside in the upper 1⁄3, glabrous elsewhere. Bracteoles to 15mm, linear to sub-spathulate. Inflorescence 7–15-flowered, an open umbel, flowers white, horizontal to half-hanging, scented. Pedicels 9–15 x c.1mm, densely stellate-scaly and laxly shortly hairy. Calyx disc-like, oblique, sometimes obscurely 5-lobed. Corolla trumpet-shaped, 30–50 x 25–30mm; tube 25–42 x 6–7 x 4–5mm, straight or slightly curved, densely silvery-scaly outside, (the scales turning brown on drying), laxly hairy inside in the proximal 1⁄3, glabrous distally; lobes 14–16 x 9–11mm, spreading to reflexed, with a few scales outside. Stamens irregularly arranged, at different heights well below the mouth of the tube; filaments 24–30mm, linear, sub-densely hairy at the base only, glabrous distally; anthers c.1.5–2.5 x 1mm, oblong, the bases with small points. Disc densely hairy. Ovary 5–6 x 2–2.5mm, cylindrical, densely scaly and shortly hairy, abruptly tapering distally; style c.25mm, becoming exserted up to 7mm, hairy and scaly in the proximal 1⁄3, laxly hairy in the middle, glabrous in the distal ½; stigma to 1.5mm in diameter, rounded, white or red. Fruit 30–40 x c.5mm, the valves splitting away from the base or apex and often spirally twisting, the placentae becoming slightly separated curving outwards. Seeds 3.5mm, without tails 0.9mm, the longest tail 1.5mm.
Habitat: In mossy sub-montane forest.
Distribution: Philippines, Palawan, Mt Mantalingajan, Thumb Peak, Cleopatra Needle
Altitude: 1500-1725m
Shrub or small tree to 3m. Scales blackish-brown. Lateral veins 5–9 per side, straight or curving away from the mid-vein and disappearing before the edge of the leaf, hardly raised but usually distinct both above and below and without visible reticulation. Petiole 1–3 x 3–4mm, dark red, often broader than long and with dark-brown scales, weakly grooved above.
Habitat: Epiphytic in montane mossy forest.
Distribution: Malaysia (Borneo), Sarawak, Mt Lemakok, Mt Lawai, Mt Murut, Mt Murud. Sabah, vicinity of Long Pasia. Indonesia, Mt Kemul, Mt Batu Ajoh, Kayan R.
Altitude: 700-2400m
Greek – pneumon – lungs; anthos – flower. Applying to the inflated-looking corolla tubes, but not particularly apt.
Rhododendron pneumonanthum has been reduced to a subspecies of R. edanoi (Argent 2004). Sleumer (1966) distinguished these two species: ‘Corolla tube more or less manifestly and gradually narrowed from the base upwards. Leaves sub-sessile [R. pneumonanthum] vs. Corolla tube equally wide all over or slightly and gradually widened from the base upwards. Leaves distinctly petioled. [R. edanoi]’. An examination of isotypes of the original collection of R. edanoi showed that the first character is not a valid difference. Several corolla tubes exhibit quite definite narrowing from the proximal to the distal ends. The corollas from cultivated plants from both Palawan and Borneo in the fresh state all quite clearly taper from base to mouth. After pressing, the tube can appear to at least look parallel sided. There is a difference in petiole length between Bornean and Philippine materials but again there is a good deal of variation even on one plant and this alone would not support maintaining these plants as different species. There is also a very small difference in the scales on the leaves from the two islands – those from Bornean materials are darker and more variable in size – but both have essentially the same sub-stellate shape, are tall and are set on pronounced epidermal tubercles. The vegetative habit of the plants in cultivation from the different islands is certainly very different. Both Philippine collections are slow and low growing compared with the tall, ‘leggy’ and much more vigorous Bornean plants. Differences in habit between different populations of the same species are known elsewhere (R. burttii and R. leptanthum). The clinching factor in regarding the Bornean R. pneumonanthum to be, at best, a subspecies and not specifically distinct from R. edanoi is the fact that the distinctive flower bud morphology is identical in plants from both Borneo and Palawan.
Type: Endert 4522, 23 Oct. 1925. SE Borneo, W Kutei, Mt Kemul, c.1700m (L, A, BO, SING).
Synonymy: R. jasminiflorum (non Hook.) Ridl., J. Str. Br. R. As. Soc. 1912. 63: 60. R. pneumonanthum Sleumer, Reinwardtia 1960. 5: 132.
Shrub to 2-5 m, epiphytic or scrambling on rocks. Indumentum dark orange to pale beige brown. Leaves oblong-ovate, oblong-lanceolate or rarely elliptic, 6-15 x 2-5-5 cm, usually acuminate, upper surface strongly bullate and glabrous; scales on the lower surface completely obscured by the indumentum, small, distant, golden. Inflorescence 2-3-flowered, pedicels up to 2 cm, densely tomentose. Flowers usually fragrant. Calyx clearly lobed, the lobes oblong-orbicular, densely tomentose on the margins and also usually on the outer surface, lepidote on the outer surface, the inner surface finely pubescent, 11-14 mm. Corolla funnel-campanulate, (35-)45-60(-66) mm, the tube (19-)25-30(-40) mm, white, sometimes flushed pink and/or with a yellow blotch at the base, glabrous within, lepidote outside. Stamens 10, declinate, filaments densely pilose in the lower part. Ovary densely tomentose. Style about as long as the corolla, declinate, exceeding the stamens, tomentose and/or lepidote for a variable distance above the base. Capsule densely tomentose, oblong-globose, c. 18 x 12 mm.
Habitat: In dense forest.
Distribution: India (Sikkim, W Bengal, Arunachal Pradesh), Bhutan, e Burma, China (N, NW & C Yunnan, S Xizang).
Altitude: 2100-3300m
Illustrations:
Variable in size and habit across a very wide distribution area; the variation, however, is not amenable to taxonomic recognition.
Type: Sikkim Himalaya, in valleys on the inner range, 7000-9000 ft, fl. May-June, fr. November, Hooker (K)
Synonymy: R. bullatum Franchet Bull. Soc. Bot. Fr. 34:281 (1887) China, Yunnan, ad pedem montis Tsang-chan, alt. 2500 m, 20 iv 1886, Delavay 2062 (P) R. sciaphilum Balfour f. & Kingdon Ward Notes R.B.G. Edinb. 10:146 (1917) E Burma, Htawjaw, valley of Naung chaung, Lashi country, 7000-8000 ft, 4 vi 1914, Kingdon Ward 1629 (holo. E)
Occurs in Countries: BT, CN, IN, MM Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: pink, white, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):26
Shrub, 1-1.6m. Leaves elliptic-oblong, 7-13 x 2.4-3.5cm, 3-3.7 x as long as broad, apex acute, base rounded, lower surface covered with a dense unistrate ramiform lanate indumentum, deep pink when young, maturing to a rich rufous brown; petioles 1 —1.5cm, tomentose at first, later glabrescent. Inflorescence 10-20-flowered; rhachis 2-3mm; pedicels c.20mm, rufous-tomentose, at least at first. Calyx c.l2mm, stipitate-glandular, lobes oblong, rounded, glandular-ciliate. Corolla campanulate, pale purplish pink, with crimson flecks, 30-4Omm. Ovary densely stipitate-glandular; style with a few glands at base. Capsule c.15 x 5mm.
Habitat: Among conifers, rocky slopes, meadows
Distribution: China (NW Yunnan, SW Sichuan, nr Yungning)
Altitude: 3650-3950m
Closely allied to R. bureavii and possibly a hybrid between that species and R. adenogynum
Type: China, SW Sichuan, Yung-ning, 13000ft, 7 v 1922, Kingdon-Ward5U (holo. E).
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: crimson, pink
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):339
Small straggling shrub; young shoots stellate-tomentose and stipitate-glandular. Leaves lanceolate to elliptic, 8.5-10 x 3.5-4.2cm,c.2.5 x aslongas broad, apex rounded, apiculate, base rounded, glabrous when mature on both surfaces; petioles 1.5-2.5cm, glabrous. Inflorescence 6—10-flowered; rhachis c.20mm; pedicels c.lOmm, shortly stipitate-glandular. Calyx 3—4mm, glandular, lobes rounded, glandular-ciliate. Corolla funnel-campanulate, rose-purple, with darker flecks, 40-50mm. Ovary densely rufous stellate-tomentose, intermixed with stipitate glands; style tomentose and glandular to tip. Capsule c.15 x 5-6mm.
Distribution: NE India (Nagaland)
Altitude: 2700-3000m
Illustrations:
Allied to R. kyawi and R. facetum but differing from both in its generally smaller leaves and apparently in the shape of the corolla.
Type: NE India, Manipur, Japoo, 9000ft, v 1882, Watt 6893 (holo. K; iso. E).
Occurs in Countries: IN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: rose
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):379
Shrub to 2m. Twigs 1–2mm in diameter, green, with stalked scales, conspicuously rough with the persistent protruding scale bases; internodes 1–4cm. Leaves 4–7 together in tight pseudowhorls. Blade 12–40 x 5–25mm, broadly elliptic to obovate; apex emarginate or rounded, with a small protruding mucronate gland; margin entire, slightly revolute; base narrowly tapering; upper surface green, glabrescent, lower surface sparsely covered with scales, pale green. Scales sub-circular, brown or translucent, mostly pale, variable in size and slightly impressed. Mid-vein impressed above and raised beneath, lateral veins 2–4 per side, weakly impressed above and raised beneath or obscure in smaller leaves. Petiole 2–4mm, grooved above, rounded below, brown scaly and very shortly hairy above. Flower buds 6–8 x 3–4mm, green becoming pale brown, ovate, smooth with broadly acute points. Bracts minutely shortly hairy outside and fringed with longer white hairs, glabrous inside. Bracteoles 1.5mm, filiform with a few white hairs, withering quickly. Pedicels 15–25 x c.1mm, green, moderately to densely scaly from an uneven surface. Inflorescence of solitary, or paired, flowers, semi-erect, horizontal to half-hanging. Flowers 6–8 x 16–22mm, campanulate. Calyx green, densely scaly, wavy to distinctly lobed with rounded or weakly triangular lobes to 3mm. Corolla yellow; tube 4–5 x 4–5 x 4–5mm, moderately densely scaly outside with inconspicuous translucent scales, and with long patent white hairs just below the mouth inside; lobes 6–8 x 5–7mm, the three upper patterned with rows of faint orange-brown spots on the inner side and with a few translucent scales outside, reflexed to the horizontal or a little beyond, overlapping up to 1⁄3. Stamens arranged all round the mouth but with a gap on the lower side where the style is placed, irregularly dimorphic and exserted to 5mm; filaments yellow, tapering to the base in the lower 1⁄3 and also upwards for about 2⁄3, with long patent white hairs in the middle part; anthers 2–2.5 x c.1mm, brown. Disc green, glabrous. Ovary 2.8 x 2.2mm, green, densely covered in silvery scales. Fruit 12–16 x 4–5mm, the pedicel turning to place them erect, green passing to brown, cylindrical with longitudinal grooves and a persistent deflexed style; valves splitting to the base and curving backwards, straight, not twisting, the placentae remaining firmly adherent to the central column. Seeds 4–4.7mm, bright orange-brown, without tails 1.2–1.9mm, the longest tail 1.2–1.5mm, tails mostly straight, sometimes a little crimped usually at just one end.
Habitat: In tropical monsoon forests, often epiphytic on branches of trees
Distribution: China, SE Yunnan, Pingbian, Xichou, Malipo and Mengzi. Guangxi, Daimiaoshan Xian, Pingshixiang, Jiuwandai shan. Vietnam, Province Lao Cai.
Altitude: 1200-2900m
Latin – emarginatus – shallowly notched, alluding to the often emarginate tips to the leaves.
Professor Sleumer compared the types of R. euonymifolium and R. poilanei (Sleumer 1958) and reduced these species to synonymy. These types have also been examined for the present study and their reduction appears logical. Rhododendron leiboense was differentiated in having more slender branches, triangular calyx lobes and flowers in twos. It does not appear to warrant even varietal recognition on these characters. I have reduced R. maguanense after examining the type material. Feng (1983) said this species was close to R. emarginatum but differentiated it on its smaller leaves and longer calyx lobes. Neither of these characters are sufficiently significant. The calyx lobe development is considered variable in R. emarginatum and the smaller leaves with less conspicuous venation appear to be reduction due to exposure.
Type: Henry 9166. China, Yunnan, Mountains SW of Mengtsze (K)
Synonymy: R. euonymifolium H.Lév., Fedde Rep. 1913. 12: 228. R. poilanei Dop, Fl. Gén. I.-C. 1930. 3: 739. R. maguanense K.M.Feng, Acta Bot. Yunnan. 1983. 5(3): 268. R. leiboense Z.J.Zhao, Bull. Bot. Research 1987. 7(3): 57, f.1, 63.
Occurs in Countries: CN Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: orange, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:31
Differing chiefly in that the ovary is both hairy and scaly. The calyx lobes are also well developed, 1.8 x 2mm, with scales along the margins of the lobes. Seeds 2.5–3mm, without tails c.1mm, the longest tail 1.2mm.
Distribution: Known from the type locality in China and Guangxi Province, Daimiaoshan Xian, Pingshixiang, Jiuwandai shan
Altitude: 1200-2180m
Greek – erio – woolly; carpon – fruit. Alluding to the hairy ovary.
Recorded flowering in Aug. and Oct. The hairy ovary is one of the significant characters separating R. emarginatum from R. insculptum. This variety confuses this distinction.
The leaves of var. eriocarpum are quite distinct in being less revolute and more distinctly tapering towards the base than those of R. emarginatum. It might yet warrant specific status.
Type: K.M. Feng 4852, 10 Oct. 1954. China, Yunnan, Pingbian Xian, Daiweishan (KUN)
Shrub to 1.2m. Twigs 5–7mm in diameter, rounded, scaly at first, quickly becoming glabrescent; internodes 4–10cm. Leaves 3–4 together in pseudowhorls, large, sub-sessile. Blade 120–250 x 40–90mm, elliptic, or sub-ovate-elliptic; apex short to long-acuminate, acute or sub-acute; margin narrowly but very distinctly revolute; base broadly tapering, the extreme base truncate-rounded or slightly cordate, glabrescent above when mature, laxly scaly beneath. Scales small, marginal zone irregularly and shallowly lobed; centre slightly impressed. Mid-vein narrow and markedly impressed above, strongly prominent on the underside proximally; lateral veins 8–14 per side, with additional shorter ones between, irregular and ascending, arching inwards before the margin, slightly raised above, more distinctly so beneath, reticulation lax, slightly raised on both sides. Petiole 4–7 x 3–4mm, grooved above, densely scaly. Bracts to 55 x 15mm; outer bracts ovate-lanceolate, long acute hairy and scaly outside; inner ones broadly ovate-acuminate and sub-acute to elliptic-spathulate, also hairy and scaly, glabrous inside. Bracteoles to 30 x 1mm, linear-filiform, scaly and hairy. Inflorescence 4–9-flowered, an open umbel. Pedicels 60–110 x c.1.5mm, erect, laxly scaly, minutely and sparsely hairy. Calyx c.5mm in diameter, rounded or very shortly, obtusely 5-lobed, scaly outside. Corolla c.80 x 100mm, funnel-shaped, orange or reddish to pink, flushed yellow outside; tube 25–30 x 5–8 x 15–20mm, lobed at the base, laxly stellate-scaly outside, laxly hairy inside, with prominent dark veins running lengthwise to the apices of the lobes in the dry state; lobes 50–60 x 30mm, obovate, spreading. Stamens exserted to 25mm; filaments linear and densely hairy in the proximal ½, filiform and glabrous distally; anthers 6–7 x 1mm, linear-oblong, slightly curved. Disc prominent, hairy in the upper ½, glabrous below. Ovary 9–10 x c.3mm, sub-cylindrical, hairy, with numerous minute brown scales between the hairs, tapering gradually distally; style as long as the stamens and covered with short hairs and clearly visible scales in the proximal ½–2⁄3; stigma thick, 5-lobed. Fruit 60–100 x c.5mm, elongate-cylindrical, laxly hairy and scaly.
Habitat: Epiphytic in Agathis forest, or terrestrial in rain forest, 400–600m, also reported from rocks near a river, 1220–2745m.
Distribution: Indonesia, New Guinea (W), Noord R.; Vogelkop, Dalman, near Nabire. Papua New Guinea, Central District, Musgrave Range; Mt Yule.
Altitude: 400-2745m
Named after Victor G.A. Engler (1885–1917).
Very similar to R. baenitzianum but apparently distinct in the clearly revolute margin to the leaf and longer petioles. Baron von Mueller used the invalid name ‘megalostigma’ for this species which has extremely divided stigmatic lobes.
Type: Versteeg 1632, 3 July 1907. New Guinea (SW), Noord R., Bivak, Alkmaar (BO, K, L, U).
Occurs in Countries: ID, PG Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:318
Dwarf shrub, 0.05-0.5m; young shoots ± densely rufous floccose-tomentose; perulae apparently ± persistent. Leaves elliptic to narrowly elliptic, 2.5-4.7 x 0.7-1.7cm, 2.6-5 x as long as broad, apex rounded, apiculate, base ± rounded, upper surface ± glabrous when mature, lower surface purple or green, with the remnants of a floccose ramiform tomentum and often a few stipitate glands, especially on the midrib; petioles c.0.5cm, floccose-tomentose. Inflorescence 1 -3-flowered; rhachis minute; pedicels c. 10mm, sparsely tomentose. Calyx c. 1.5mm, fleshy, ± floccose. Corolla tubular-campanulate, rose-pink, 25-30mm. Ovary with a whitish to rufous tomentum intermixed with stipitate glands. Capsule not known.
Habitat: Rocky meadows
Distribution: China (SE Xizang, NW Yunnan)
Altitude: 3950-4250m
Allied to R. chamaethomsonii and R. forrestii and possibly of hybrid origin. Intermediates between R. chamaethomsonii and R. erastum are as follows: Forrest 16700, 17444, 19491, 20032.
Type: China, W NW Yunnan, Mekong/Salween divide, 28°12'N, 14000ft, vii 1917, Forrest 14373 (holo. E; iso. K)
Synonymy: R. porphyrophyllum Balfour f. & Forrest, Notes R.B.G. Edinb. 11: 108 (1919). Type: China, SE Xizang, Tsarong, on Ka-gwr-pw, 13000ft, vi 1918, Forrest 16695 (holo. E). R. serpens Balfour f. & Forrest, ibid. 11: 135 (1919). Type: China, SE Xizang, Tsarong, on the northern slopes of Ka-gwr-pw, 14000ft, vii 1918, Forrest 16698 (holo. E).
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: rose
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):405
Erect wiry shrub, to 1.5m, dwarfed at its highest localities. Twigs densely leafy, scaly and sometimes minutely hairy on the youngest growth. Stems with protruding leaf-cushions in the younger parts. Leaves spirally and evenly arranged, very dense and imbricate in the upper part of the twigs and held sub-erect. Blade 4–8 x 0.8–1.6mm, ‘ericoid’, linear or very narrowly elliptic; apex acute (with the extreme point rounded), with an obtuse glandular point; margin entire or somewhat indented with irregular crenulations, somewhat thickened and slightly or not revolute; base tapering, glabrescent above, laxly scaly beneath. Scales disc-shaped, entire with the darker centre thick and slightly impressed. Mid-vein very slightly impressed above, swollen underneath; lateral veins obscure. Petiole 0.6–1 x 0.4–0.6mm, scaly and with a few simple hairs, minutely grooved above and with a swollen, bulbous base. Flower buds to 3.5 x 2.5mm, pink, scaly outside. Bracts all appressed, the outermost subulate, inner ovate, scaly in the upper ½ outside, all with a ciliate margin of white hairs. Inflorescence of solitary flowers or paired, rarely up to 4 in an umbel, hanging vertically. Bracteoles c.3 x 0.5mm, linear-spathulate, long-ciliate upwards, falling early. Pedicels 5–8mm, slender, densely scaly, without hairs. Calyx slightly oblique, scaly outside, glabrous inside, with 5 distinct erect lobes, c.2 x 1–1.3mm, initially appressed to the corolla, later spreading, narrowly sub-ovate-triangular, obtuse. Corolla bright red, tubular, not or slightly oblique and curved, c.15 x 11mm; tube c.11 x 6 x 7mm, densely scaly outside, glabrous inside; lobes c.4 x 5mm, scaly outside except near the margins, broadly ovate to rounded, half-spreading and overlapping to c.halfway, the margins irregularly denticulate. Stamens grouped on the lower side of the flower, slightly exserted to c.1mm; filaments glabrous, c.11mm; anthers brown, c.0.9mm. Disc glabrous. Ovary c.1.8mm, conical, green, densely scaly, gradually tapering distally; style red, to 14mm, glabrous, finally exserted, to c.3mm; stigma club-shaped. Fruit oblong-ovoid, often a little oblique and curved, 7–10 x 3–4mm. Seeds 1.5–2mm, without tails 0.75mm, the longest tail to 0.5mm, the tails often with multiple points.
Habitat: In primary mossy forest, abundant terrestrially on the open granite dome in exposed sunny places
Distribution: Malaysia (Borneo), Sabah, Mt Kinabalu, endemic (records from other mountains are all referable to R. borneense).
Altitude: 2700-4000m
Greek – Erica – a genus of mainly South African shrubs; oides – indicating resemblance, the small leaves of this species being very like those of an Erica.
Flower and fruit Jan.–Dec.
Rhododendron x silvicola Sleumer (R. cuneifolium x R. ericoides) Rhododendrons of Sabah, Sabah Parks Publ. 1988. 8: 102. Type: J. & M.S. Clemens 30081, April–June 1932. Borneo, North Borneo, Mt Kinabalu, Tenompok, 5000ft (E, K). Derivation: Latin – silva – wood or forest; cola – inhabitant. An inhabitant of the forest since it was first thought to be a shade form of R. ericoides. Synonyms: R. ericoides var. silvicolum Sleumer, Reinwardtia 1960. 5: 62 (orthographic variant). R. x silvicolum Sleumer, Rhododendrons of Sabah 1988: 102 (orthographic variant). Shrub to 3m. Similar to R. ericoides but with larger leaves, 9–11 x 1.8–2mm, flowers red, usually with elongate calyx lobes. Malaysia (Borneo), Sabah. Fairly common on Mt Kinabalu around the zone of overlap between the two parent species. Recent records are all between 2800 and 3200m although the type collection was recorded at 1525m – this is possibly an error. A large shrub of this hybrid has persisted over more than 20 years beside the main trail up Kinabalu where it is very conspicuous.
Type: Low s.n., March 1851. Borneo, North Borneo, Mt Kinabalu (CGE, K).
Occurs in Countries: MY Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:48
Habitat: Thickets, open woodland
Distribution: Japan (Kyushyu, Ryukyu Islands)
Altitude: Around 300m
Illustrations:
Contrary to Ohwi's most recent statement in the new edition of his Flora of Japan, we are convinced that R. tamurae is a synonym of R. eriocarpum. R. tawadae is described as having small reddish-purple flowers; this agrees better with R. eriocarpum than it does with R. simsii, with which it has been synonymized in the past.
Type: Japan, Liukiu, Nakanoshima, 2 viii 1910, Hayata 96 (holo. TI).
Synonymy: R. indicum Sweet var. eriocarpum Hayata, Icon. PI. Formosan. 3: 134(1913). R. indicum Sweet var. tamurai [sphalm. pro tamurae] Makino in Bot. Mag. Tokyo 18: 102,103, L (1904); R. tamurae (Makino) Masamune, Prelim. Rep. Veg. Yakus. 106 (1929) & Mem. Sci. Agric. Taihoku Imp. Univ. Bot. 11(4): 349 (1934). Type: Japan, Tokyo, cult., vi 1904, Makino, n.v. R. eriocarpum (Hayata) Nakai var. tawadae Ohwi in Bull. Nat. Sci. Mus. Tokyo n.s. 1: 4 (1954); R. tawadae (Ohwi) Ohwi. J. Jap. Bot. 29: 369 (1954). Type: Japan, Ryukyu, vertice Ivi. Uwotsuridake ins. Uwotsuri, 300-320m, 17 iv 1953, Tawada 29, n.v.
Occurs in Countries: JP Altitude Ranges: 0 - 1,000m Subgenus: Tsutsusi
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):118
Erect or spreading shrub to 2m. Twigs densely covered with stalked scales, the lower parts rough where the scales have gone and the stalks remain. Leaves spiral, often somewhat crowded in the upper part of the twigs. Blade 6–13 x 2–4mm, narrowly obovate; apex obtuse or mostly rounded, often slightly retuse; margin revolute; base gradually tapering, dark green above, paler beneath, glabrescent above, laxly scaly beneath. Scales circular, their marginal zone narrow, entire; centre darker, thick, slightly impressed. Mid-vein slightly or not impressed above, raised beneath; lateral veins not visible. Petiole 1–1.5mm. Bracts to 4 x 3mm, ovate, apiculate, hairy and laxly scaly outside, shortly white-ciliate on the margins. Bracteoles to 5mm, filiform. Inflorescence of solitary flowers, hanging vertically. Pedicels 8–10mm, laxly to sub-densely covered with scales and minute white, patent hairs. Calyx small, disc-like, 5-angular or shortly obtusely 5-lobed, scaly. Corolla c.20 x 10mm, tubular, somewhat curved and a little compressed laterally, deep pink to dark red; tube 15–18 x 3–4 x 5–6mm, laxly scaly outside, glabrous inside; lobes c.3–4 x c.3mm, unequal, minutely hairy distally outside, ovate or ovate-elliptic, the apex rounded and minutely irregularly denticulate. Stamens unequal, some slightly exserted from the corolla; filaments narrowly linear, glabrous; anthers c.1.2mm. Disc glabrous. Ovary c.3mm, obliquely conical, longitudinally 5-grooved, densely scaly, tapering distally; style c.13mm, glabrous, somewhat thickened distally to the club-shaped irregularly lobed stigma. Fruit 8–15 x c.3mm, sub-cylindrical, deeply 5-grooved. Seeds 0.15–2mm, shortly tailed at both ends.
Distribution: Indonesia, New Guinea (W), Vogelkop Peninsula, Arfak Mts, Tohkiri, Tamrau and Nettoti Range. Epiphytic or terrestrial, rare on a burnt open summit, mostly on the edge of moss forest, or summit scrub on peaty soil
Altitude: 1400-2650m
Latin – erosus – having an irregular apparently gnawed margin; petalum – of the petals. The corolla lobes having an erose, or raggedly irregular, margin.
Type: Mayr 18, 27 May 1928. New Guinea (W), Arfak Mts, 1800m (BO, lectotype, L, fragment).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:57
Tree, 3.5-6.5m; young shoots with numerous gland-tipped setae. Leaves broadly obovate, 8—10 x 3.7—7cm, 1.5—2.1 x as long as broad, apex and base rounded, upper surface glabrous, lower surface with sparse stout gland-tipped setae and a floccose lanate indumentum, dense at first, becoming thinner with age, midrib with a few bristles; petioles clem, sparsely glandular-bristly. Inflorescence dense, 12-15-flowered; rhachis c.lOmm; pedicels c.lOmm, stipitate-glandular. Calyx reddish, 3-4mm, glabrous, lobes rounded. Corolla tubular-campanulate, rose-pink to crimson, 30-35mm. Ovary densely stipitate-glandular; style glabrous. Capsule c.20 x 6mm, curved.
Habitat: Under Abies, etc.
Distribution: China (SE Xizang)
Altitude: 3000-3800m
Closely allied to R. exasperatum but differing in several minor characters; possibly of hybrid origin.
Type: China, S Xizang, Chayul Chu, Natrampa, Kashong La, 12500ft, 2 v 1936, Ludlow & Sherriff1541 (holo. BM; iso. E).
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: crimson, rose
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):382
Shrub, 1.5-2m; young shoots glabrous or with minute stipitate glands. Leaves coriaceous, ovate to elliptic, 6-12 x 3-4cm, 2(-3) x as long as broad, apex rounded, apicuiate, base + cordate, upper surface glabrous, lower surface with a thin scattered adpressed indumentum, even when mature; petioles l-2cm, glabrous when mature. Inflorescence 8-10-flowered; rhachis less than 5mm; pedicels 15-30(-40)mm, densely stipitate-glandular. Calyx (1-) 4-10mm, lobes broadly ovate and rounded when well-developed, stipitate-glandular. Corolla funnel-campanulate, white flushed rose, with or without purple flecks, 30-35mm. Ovary densely stipitate-glandular, style glandular, at least at base. Capsule c. 20 x 10mm.
Habitat: Thicket margins, bouldcry slopes
Distribution: China (NW Yunnan, SE Xizang)
Altitude: 3000-4250m
The large coriaceous leaves distinguish this species from the remaining members of subsection Selensia. The length of the calyx lobes is variable, even within a single gathering (cf. Rock 11094).
Type: China, E NW Yunnan, Mts NE of Chungtien, vii 1918, Forrest 16581 (holo. E; iso. K)
Synonymy: R. manopeplum Balfour f. & Forrest, Notes R.B.G. Edinb. 13: 275 (1922). Type: China, SE Xizang, Tsarong Province, duplicate of Forrest no.?, 1919, Forrest 18654 (holo. E; iso. K).
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: purple, rose, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):281
Shrub, young branches glabrous. Leaves glabrous; blade elliptic-lanceolate, 35-100 x 12-18 mm, base cuneate, apex acuminate, coriaceous; petiole c.6 mm long. Inflorescence buds lateral, clustered at the ends of leafy shoots, 1-2-flowered; bud scales glabrous and shining on their backs, margins of the upper scales ciliate; pedicels c. 12 mm long, glabrous. Calyx of 5 triangular or sometimes linear, lobes, glabrous. Corolla small (c.25 mm long) with a relatively long tube (c.l2mm long), glabrous. Stamens 10, filaments almost glabrous. Ovary cylindric, c.5mm long, glabrous; style glabrous. Capsule not seen.
Distribution: China (Guizhou)
A rare species, the only specimens seen being those collected by Esquirol and Cavalerie. It has the smallest flowers and the smallest average leaf size of any species of the section. It falls within the group combining glabrous pedicels with (mainly) 1-flowered inflorescences.
Type: China, Guizhou, vi 1905, Esquirol 476 (holo. E).
Synonymy: R. vaniotii Leveille, Feddes Repert. 13:148 (1914). Type: China, Guizhou, Gan-chuan, iv 1912, Cavalerie 3886 (holo. E).
Occurs in Countries: CN Subgenus: Azaleastrum Habit: Non-Tree
Philipson, W.R. & Philipson, M.N. (1986) A Revision of Rhododendron III. Subgenera Azaleastrum, Mumeazalea, Candidastrum and Therorhodion. Notes from the Royal Botanic Garden Edinburgh 44(1):10
Dwarf shrub, up to 0.7m; young shoots floccose-tomentose and stipitate-glandular. Leaves oblanceolate to elliptic, 4.5-7.5 x 1.7-2.3 cm, 2.7-3.3 x as long as broad, apex rounded, minutely apiculate, base ± rounded to cuneate, upper surface glabrous, lower surface with a bistrate indumentum, the upper layer fulvous, ramiform-tomentose, the lower adpressed, whitish, epidermis epapillate; petioles 0.5—lcm, narrowly winged, setulose-glandular, also sparsely floccose-tomentose. Inflorescence 4—5-flowered; rhachis minute; pedicels 7—10mm, densely stipitate-glandular and floccose-tomentose. Calyx 1—2mm, lobes rounded, glandular and tomentose. Corolla fleshy, tubular-campanulate, bright brick-red to scarlet, 25-30mm. Ovary densely stipitate-glandular and stellate-tomentose, tapering into the style which is sparsely tomentose below. Capsule not known.
Habitat: Undershrub in thickets
Distribution: NE Upper Burma
Altitude: 3000-3400m
Apparently allied to R. albertsenianum on account of its bistrate indumentum but differing in its glandular indumentum and smaller leaves.
Type: E Upper Burma, Mwai divide, ridge of Naung-Chaung, 10000ft, 14 vii 1914, Kingdon-Ward 1778 (holo. E; iso. K).
Occurs in Countries: MM Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: brick, scarlet
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):413
Dwarf shrub, 0.3—1.2m; young shoots tomentose, usually also with a few weak setae, rarely ± densely and strongly setose. Leaves elliptic, 3.5-9 x 1—3cm, 2.8—3.5 x as long as broad, apex rounded, apiculate, base rounded, upper surface glabrous, lower surfaces with a thin discontinuous, whitish to brown indumentum and a greenish epapillate epidermis; petioles 0.5-l(—1.5)cm, usually tomentose, sometimes also weakly setose. Inflorescence 2—6-flowered; rhachis c.5mm; pedicels 10-20mm, tomentose, sometimes also glandular. Calyx 2-7mm, cupular when well-developed, lobes rounded, very sparsely tomentose or glandular. Corolla not fleshy (perhaps so in var. mesopolium), tubular-campanulate to campanulate, pink to rose-carmine, 25—40mm. Ovary predominantly glandular to predominantly tomentose. Capsule 15-20 x c.5mm.
Habitat: Cliffs, rocky slopes, thickets, etc.
Distribution: China (border of SE Xizang & NW Yunnan)
Altitude: 3350-4250m
The distinction between var. brunneifolium and var. mesopolium, as implied by the key, is of a fairly trivial nature but, despite this, var. mesopolium may be more distantly allied to var. brunneifolium and var. eudoxum than these two are to one another. Although it cannot be confirmed for certain from herbarium material, the corollas of var. mesopolium do appear to have been more fleshy and more obviously tubular-campanulate than those of the other two varieties. In these respects var. mesopolium is apparently closer to R. sanguineum and its allies.
The following sterile specimens are referable to R. eudoxum s.L: Forrest 14762, 17334, 17336, 20052, 22700.
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: magenta, rose, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):401
Young shoots and pedicels tomentose, with a few weak glandular setae; leaves 7—9cm, with a thin floccose brownish indumentum beneath, not papillate. Inflorescence lax, corolla c.40mm, rose-carmine. Ovary tomentose, eglandular.
Synonymy: R. brunneifolium Balfour f. & Forrest, Notes R.B.G. Edinb. 13: 33 (1920). Type: China, SE Xizang, Tsarong, Kiu-chiang divide, vii 1919, Forrest 19025 (holo. E; iso. K). R. eudoxum Balfour f. & Forrest subsp. brunneifolium (Balfour f. & Forrest) Tagg in Stevenson (ed.), The Species of Rhododendron 549 (1930).
Young shoots and pedicels tomentose, usually also with a few weak glandular setae. Leaves 3.5-7(-8.5)cm, with a thin brownish discontinuous indumentum beneath. Inflorescence lax. Corolla 30(-37)mm, rose-pink to magenta, rarely white. Ovary predominantly stipitate-glandular.
R. fulvastrum var. albipetalum is apparently no more than an albino form of var. eudoxum. The young shoots of the types of both R. trichomiscum and R. trichophlebium are ± densely covered with stout setae as in R. temenium but otherwise are closer to R. eudoxum.
Type: China, NW Yunnan, Mekong/Salween divide, 28°12'N, 11000ft, vii 1917, Forrest 14245 (holo. E; iso. K)
Synonymy: R. trichomiscum Balfour f. Forrest, ibid. 12: A69 (1920). Type: China, SE Xizang, Tsarong, Ka-gwr-pw, 14000ft, 28°24;N, vii 1918, Forrest 16826 (holo. E; iso. K). R. trichophlebium Balfour f. & Forrest, Notes R.B.G. Edinb. 13: 62 (1920). Type: China, SE Xizang, Tsarong, (1917), Forrest 18632 (holo. E). R. eudoxum Balfour f. & Forrest subsp. trichomiscum (Balfour f. & Forrest) Tagg in Stevenson (ed.), The Species of Rhododendron 549 (1930). R. fulvastrum Balfour f. & Forrest subsp. trichomiscum (Balfour f. & Forrest) Cowan and subsp. trichophlebium (Balfour f. & Forrest) Cowan, Notes R.B.G. Edinb. 20: 79 (1940). R. temenium Balfour f. & Forrest subsp. albipetalum Cowan, ibid. 20: 83 (1940). Type: China, SE Xizang, Tsarong, Solo-la, 13000ft, v-vi 1932, Rock 22295 (holo. E). R. temenium Balfour f. & Forrest subsp. rhodanthum Cowan, ibid. 20: 83 (1940). Type: China, NW Yunnan, Mts of Londre, Mekong/Salween divide, 1923, Rock 10285 (holo. E).
Young shoots and pedicels usually floccose-tomentose, eglandular, not strongly setose; leaves 3.5-7cm, with ± prominent veins and a thin whitish discontinuous indumentum beneath; corolla 30-35mm, rose-pink; ovary predominantly tomentose though sometimes also with a few glands.
Synonymy: R. mesopolium Balfour f. & Forrest, Notes R.B.G. Edinb. 13: 57 (1920). Type: China, SE Xizang, Tsarong, Dokar La, 13- 14000ft, vii— viii 1918, Forrest 16751 (holo. E; iso. K). R. asteium Balfour f. & Forrest, ibid. 13: 235 (1922). Type: China, SE Xizang, Tsarong, Salween/Kiu-chiang divide, 28°40'N, 98°15'E, vii 1919, Forrest 18937 (holo. E; iso. K). R. epipastum Balfour f. & Forrest, ibid. 13: 258 (1922). Type: China, SE Xizang, Tsarong, 1919, Forrest 18645 (holo. E; iso. K). R. eudoxum Balfour f. & Forrest subsp. asteium (Balfour f. & Forrest) Tagg, subsp. epipastum (Balfour f. & Forrest) Tagg and subsp. mesopolium (Balfour f. & Forrest) Tagg in Stevenson (ed.), The Species of Rhododendron 549 (1930). R. fulvastrum Balfour f. & Forrest subsp. mesopolium (Balfour f. & Forrest) Cowan & subsp. epipastum (Balfour f. & Forrest) Cowan, Notes R.B.G. Edinb. 20: 79-80 (1940).
Shrub, 1-1.8m; young shoots minutely stipitate-glandular. Leaves 3.5-5.5 x 1.8-2.lcm, 2-2.5 x as long as broad, apex rounded, apiculate, base rounded, upper and lower surfaces glabrous, epidermis epapillate, glaucous beneath; petioles 0.5-0.7cm, glabrous to stipitate-glandular at maturity. Inflorescence 1-3-flowered, lax; rhachis c.3mm; pedicels 12-20mm, sparsely stipitate-glandular. Calyx c.3mm, sparsely stipitate-glandular. Corolla campanulate, creamy white flushed pale rose, with conspicuous flecks, 30-40mm. Ovary and most of style densely stipitate-glandular. Capsule 13-18 x c.6mm, curved.
Habitat: Thickets, etc.
Distribution: China (SE Xizang)
Altitude: Around 4000m
This species has been traditionally allied to R. martinianum (subsection Selensia) but it differs in its campanulate corolla with nectar pouches, a character that excludes it from subsection Selensia. Several sheets cited in the type description are said to be referable to R. stewartianum (Cowan & Davidian, Rhododendron Yearbook 6: 177, 1952), which in some respects it resembles and of which it may be a hybrid.
Type: China, SE Xizang, Tsarong, Salween/Kiu-chiang divide, NW of Si-chi-to, 13000ft, vi 1922, Forrest 21694 (holo. E)
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: cream, rose, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):426
Erect shrub to 2m. Twigs cylindrical, 2–4mm in diameter, densely scaly and warty after the scales have fallen. Leaves erect, in pseudowhorls of 4–6 together, with some cataphylls along the internodes. Blade 20–60 x 10–30mm; apex acute to obtuse, with a hooked point that often falls early to leave a small callosity; margin entire, strongly revolute, the sides often being bent into a tube; base rounded to cordate; upper side at first densely scaly and rough, the scales quickly falling then remaining rough from the scale bases, green; lower side densely and more persistently scaly and warty. Scales orange-brown, irregularly stellate, the centres small from a stalk mounted on an acute persistent protuberance. Mid-vein slightly impressed above and prominent below. Petiole 1–3mm, grooved above, rigid and rugose. External bracts triangular to ovate, caudate to cuspidate at the apex, scaly and rough and shortly hairy outside, scaly on the margin, glabrous inside; internal bracts to 25 x 20mm, obovate-obcordate to broadly spathulate-obcordate, apiculate or mucronate at the apex, glabrous or with a few hairs outside. Bracteoles 15mm, linear, broadened to spathulate distally, sub-glabrous. Inflorescence of 3–7 hanging flowers, without scent. Pedicels 20–30 x c.1.5mm, shortly hairy and densely scaly, rough with papillae. Calyx obliquely discoid, c.4mm in diameter, sub-entire, shortly hairy and densely scaly. Corolla 30–40 x c.25mm, pink, tubular; tube 23–31 x 7 x 12mm, straight or a little curved, sometimes slightly laterally compressed, hairy and scaly outside, distinctly hairy inside; lobes 7–12mm in diameter, half-spreading to spreading, overlapping to c.½, broadly elliptic to sub-circular, rounded or a little retuse at the apex, scaly outside except near the margins. Stamens irregular, exserted to c.5mm; filaments pink, shortly hairy at the base; anthers c.3 x 1.5mm, deep purple, oblong, with rounded bases to the cells. Disc 10-lobed, glabrous except at the top where it is densely short-hairy. Ovary c.5 x 3mm, ovoid, tapering to the style, densely short-hairy and scaly, the white hairs covering the reddish-brown scales; style red or pink, slightly exserted from the mouth of the flower, shortly hairy up to halfway; stigma 5-lobed. Fruit 20 x 8mm, ellipsoid-oblong, grooved, hairy and scaly, the valves a little or not curving on dehiscence. Seeds 4–5mm including the tails.
Distribution: Indonesia, New Guinea (W), at the watershed between Mt Yonowe and Mt Jayawijaya, on the Longimik lateral moraine
Altitude: 3140-3190m
Named after the author’s mother, Evelyne Danet.
Known at present only from the type collection.
Close to R. spondylophyllum but differing chiefly in: the longer petiole, 1–3mm (1mm); the pedicels scaly and hairy (scaly only) and the style shortly hairy in the basal 1⁄3 (hairy and scaly for c.2⁄3).
Type: Danet 4193, 8 Dec. 2002. Indonesia, Papua, Mt Jayawijaya east to Mt Yonowe (LYJB, BO, CANB, E, L, LAE, MAN, P).
Occurs in Countries: ID Altitude Ranges: 3,000 - 4,000m Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:106
Shrub or small tree, 2-5m; young shoots with a dense covering of stout gland-tipped bristles. Leaves broadly obovate to elliptic, 11 — 13.5 x 6-7.5cm, 1.6—2.2 x as long as broad, apex and base rounded, upper surface glabrous, lower surface of lamina with stout gland-tipped setae that intergrade with longer gland-tipped bristles on the midrib; petioles 5- 10mm, with long bristles. Inflorescence dense, 10-15-flowered; rhachis c.5mm; pedicels c.l5mm, sparsely stipitate-glandular. Calyx 4-6mm, reddish, glabrous, lobes broad and rounded. Corolla tubular-campanulate, brick-red, with depressed nectar pouches, 35—45mm. Ovary densely stipitate-glandular; style glabrous.
Habitat: Abies forest, etc.
Distribution: NE India (Arunachal Pradesh), ne Upper Burma, China (SE Xizang)
Altitude: 3000-3700m
A distinctive species on account of its large leaves and characteristic indumentum; allied to R. erosum.
Type: NE India, Arunachal Pradesh, Delei Valley, 11-12000ft, v 1928, Kingdon-Ward 8250 (nolo. E; iso. K).
Occurs in Countries: CN, IN, MM Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: brick
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):382
Shrub of 3 m or more. Leaves oblong-elliptic, tapered to a shortly rounded base and to the obtuse apex, 150-190 x 40-55 mm, the lower surface with slightly unequal scales about their own diameter apart. Inflorescence 3-4-flowered, pedicels c. 20 mm, densely lepidote. Calyx conspicuous, rather deeply 5-lobed, the lobes ± ovate, rounded at the apex, lepidote towards the base, glabrous. Corolla funnel-campanulate, white, c. 100 mm, the tube 75-80 mm, lepidote outside. Stamens (12-)15, much shorter than the corolla lube, filaments pubescent towards the base. Ovary densely lepidote, tapered into the style which is lepidote in the lower part. Capsule unknown.
Distribution: China (SW Yunnan)
Illustrations:
An obscure species, known only from the type collection.
Type: China, Yunnan, south of the Red river from Mengtze, Henry 13666 (holo. K, photo. E)
Occurs in Countries: CN Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: white
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):36
Small tree, c.3.5m. Leaves coriaceous, obovate to oblanceolate, 8—14 x 3-4cm, 2.5-4.5 x as long as broad, apex blunt, base cuneate, margin not undulate, entirely glabrous when mature though with red punctate hair-bases overlying the veins beneath; petioles 2-3cm, glabrous. Inflorescence 6-12-flowered; rhachis 5—15mm; pedicels 20—30mm, stipitate-glandular. Calyx c. 1.5mm, stipitate-glandular, lobes minute. Corolla apparently white, up to c.50mm. Ovary stipitate-glandular; style glandular at base, otherwise glabrous. Capsule c.20 x 8mm.
Habitat: Open forests
Distribution: Vietnam
Altitude: Around 1500m
I have not seen the single reported flowering specimen and therfore hesitate to suggest an affinity for this species. If differs from R. irroratum subsp. kontumense (also from Vietnam), however, in its white flowers and styles glandular only at base.
Type: Vietnam, prov. Nhatrang, massif de Hon-la, 1500m, 2 viii 1918, Chevalier 38707-fr. (holo. P).
Altitude Ranges: 1,000 - 2,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):300
Shrub to 1.2m, with long tortuous branches and leaves only at the extreme ends. Twigs rounded, densely brown scurfy-scaly at the tips, glabrescent and rough below, blackish when dry; internodes 0.8–4cm. Leaves 4–5 together in pseudowhorls, with some much reduced ones scattered along the internodes, stiff, dull light green above, light greenish yellow beneath. Blade 10–16 x 3–7mm, ovate; apex shortly acuminate, sub-acute; margin strongly revolute, often to the mid-vein; base rounded-obtuse; very densely scaly with stellate scales on both sides initially, early glabrescent above, more slowly so beneath, leaving the surface rough. Scales deeply and irregularly narrowly divided, commonly to the minute centre; each scale shortly dendroid and mounted on top of a distinct epidermal tubercle. Mid-vein slightly grooved above, somewhat prominent beneath; lateral veins obscure. Petiole 2–3mm, thick, scaly. Bracts to 15 x 5mm, ovate, acuminate, ciliate and scaly along the outside middle line, otherwise glabrous. Bracteoles to 10mm, linear to linear-sub-spathulate, glabrous. Pedicels c.5 x 1mm, densely reddish-brown scaly. Calyx c.2.5mm in diameter, oblique, disc-shaped, very shortly obtusely 5-lobed, densely scaly. Corolla c.19mm, very pale-yellow, nearly white, broadly funnel-shaped, 5-lobed halfway or slightly more; tube 8–9 x 3–4 x 8–9mm, sub-densely covered with brown scales outside, glabrous inside; lobes c.12 x 12mm, half-spreading, wavy, sub-circular, glabrous except for some scales at the very base outside. Stamens 7–8mm, slightly unequal; filaments linear, slightly dilated above the base, pale green, glabrous; anthers c.1.5mm, red-brown, oblong, dehiscing by distinctly outwardly facing pores. Disc very small. Ovary c.4 x 3mm, ovoid-conical, obtuse, densely stellately scaly, abruptly contracted distally; style to 1mm, very shortly obconical, glabrous; stigma convex, slightly lobed. Fruit c.12 x 6mm, ovoid, densely brown-stellate-scaly.
Habitat: Open slope, also in the saddle between the summits, scattered though common
Distribution: Indonesia, New Guinea (W), Mt Doorman.
Altitude: Around 3500m
Latin – extrorsus – towards the outside, alluding to the distinctive anther dehiscence.
Not recently recollected and never cultivated.
Type: Lam 1668, 18 Oct. 1920. New Guinea (W), Northern part, Doormantop (BO, L, P).
Occurs in Countries: ID Altitude Ranges: 3,000 - 4,000m Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:81
Shrub to 4m. Twigs smooth, green, finely and sparsely scaly only; internodes 2–12cm. Leaves arranged in tight to loose pseudowhorls of 5–8 large and a few smaller. Blade 70–100 x 20–35mm, elliptic to broadly elliptic rarely somewhat obovate; apex acute, sometimes shortly acuminate; margin entire, flat but somewhat irregular; base tapering; obscurely scaly, the scales being very small and quickly disappearing from the upper side of the leaf. Scales sub-stellately lobed with small centres. Mid-vein distinct but smooth, hardly raised above or below; lateral veins 8–10 per side, issuing at an acute angle, very slightly impressed above. Petiole 3–5 x 2–3mm, very weakly grooved above, finely covered in scales. Flower buds (see p.327) to 35 x 15mm, narrowly ovoid, tapering to a very acute point; tips of the bracts only slightly spreading, glabrous, red. Inflorescence 1–3-flowered, an open umbel, the flowers half-hanging, orange becoming red with age, without scent. Pedicels 9 x 2mm, sparsely scaly and occasionally with a few simple hairs. Calyx a low ring, sparsely scaly. Corolla 25–38 x 25–35mm; tube c.20 x 11 x 19mm, straight, very sparsely and inconspicuously scaly outside, glabrous inside; lobes c.19 x 15mm, overlapping for c.½ their length. Stamens arranged all round the mouth of the flower, not exserted, slightly dimorphic; filaments c.15mm, glabrous or with scattered hairs at the base; anthers 5 x 2mm. Ovary 6 x 3mm, densely white-hairy and with a few scales; style c.12mm, glabrous; stigma c.2mm in diameter. Fruit 21 x 6mm, narrowly ellipsoidal. Seeds 5.2mm, without tails 0.8mm, the longest tail 2.6mm.
Habitat: Epiphytic in mossy forest
Distribution: Malaysia (Borneo), Sarawak, Mt Mulu, Mt Murud. Sabah, Mt Kinabalu (Marai-Parai), Mt Trus Madi, Mt Lumarku. Indonesia, W Kalimantan (Borneo), Mt Rajah.
Altitude: 1300-2000m
Latin – exubero – to grow luxuriantly, referring to the wider leaves than those of the related R. nervulosum.
An unusual species confined to very wet mossy forest in the wild. It was introduced into cultivation to the Royal Botanic Garden Edinburgh in 1967 but later lost and reintroduced in 1984. It grows easily and flowers well, usually in March or April in Edinburgh, but often suffers from disfigured contorted leaves and flowers if the humidity drops too low. When grown in poor light the flowers can be yellow.
Type: Anderson 4596, 30 June 1961. Borneo, Sarawak, 4th Div., G. Mulu, path from Sg. Melinau Paku up W ridge, 1430m (L).
Synonymy: R. nervulosum Sleumer var. exuberans Sleumer, Blumea 1963. 12: 113.
Occurs in Countries: ID, MY Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:271
Dwarf shrub to 25cm. Twigs stiffly erect, rounded, c.2mm in diameter, the tips densely covered with pale brown scurfy scales, otherwise rough and dark coloured. Leaves spirally arranged, not in proper pseudowhorls, although some areas of stem are almost bare of normal-sized leaves. Blade 8–13 x 4–7mm, ovate, elliptic or broadly elliptic; apex shortly acuminate, with acute, often mucronate points; margin entire, strongly revolute; base sub-truncate, rounded; young leaves stellate scaly on both sides, mature ones glabrescent above, persistently scaly beneath. Scales scurfy, the margin deeply stellately divided, sub-sessile, the minute centre deepened, each scale on top of a persistent epidermal tubercle. Mid-vein obscure or faintly impressed above, slightly prominent beneath, lateral veins not visible, rigid and very thick and leathery, silvery grey above, brown beneath. Petiole 1–2 x 1–2mm, very shallowly grooved, often broader than long, densely scaly. Flower buds broadly ovoid, 8–10 x c.7mm, the points appressed or slightly spreading. Bracts ovate-acuminate, densely scaly outside and on the margins, glabrous inside, to 10 x 6mm. Bracteoles filiform, glabrous, to 8mm. Inflorescence of paired or solitary flowers, rarely up to 4 together, horizontal to hanging. Pedicels 7–12mm x c.1mm, densely brown scurfy-scaly. Calyx small, densely scaly, irregularly 5-toothed, the teeth broadly triangular, sub-acute, 1mm or one or the other of them elongate to 3mm. Corolla 12–16 x 12–15mm, pale yellow, sometimes with a violet flush and with conspicuous brown scales outside; tube 8–10 x 4–5 x 7–8mm, sub-cylindrical or slightly expanded upwards, very densely brown stellate-scaly outside, glabrous inside; lobes 4–5mm in diameter, sub-erect or a little spreading, sub-spathulate to circular, densely scaly outside except for the margin, glabrous inside. Stamens slightly unequal, clustered round the mouth of the flower; filaments filiform, slightly dilated above the base, glabrous; anthers c.1.5 x 1mm, broadly oblong. Disc low, glabrous. Ovary 3–4 x c.2.5mm, ovoid-conical, very densely stellate-scaly, abruptly contracted distally; style 1.6–2mm, thick-columnar, densely scaly at the base but abruptly becoming completely glabrous; stigma shortly 5-lobed. Fruit 8–10 x 5–6mm, ovoid, shortly contracted distally, densely brown or greyish-brown scaly, with a persistent style; valves not twisted, placentae remaining coherent with the central column. Seeds 1–1.3mm, without tails c.1mm, the longest tail c.0.2mm.
Habitat: Common in the open summit areas.
Distribution: Indonesia, SW Central Sulawesi, Latimodjong Range, Mt Rantemario
Altitude: 3100-3300m
Named after Pierre Joseph Eyma, 1903–1945, who first collected this species. Eyma was a Dutch botanist who made considerable collections in Indonesia, some of which were lost due to the unrest as a result of war.
Type: Eyma 684, 17 June 1937. Indonesia, Celebes, Central, Enrekang, Rante Mario (L, A, BO, K, PNH, SING, U).
Occurs in Countries: ID Altitude Ranges: 3,000 - 4,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: brown, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:73
Shrub, c.2m. Leaves elliptic to ovate-lanceolate, 6-17 x 2.8-8cm, 2-2.5 x as long as broad, apex acuminate to apiculate, base rounded, lower surface with a bistrate indumentum, the upper layer loose, composed of rust-red detersile ramiform hairs that usually do not persist, the lower compacted, whitish, persistent; petioles 0.5-2cm, densely tomentose. Inflorescence 7—20-flowered; rhachis up to 10mm; pedicels (15—)25—30mm, densely glandular. Calyx 7-10mm, sparsely glandular, lobes broad, divided almost to base. Corolla campanulate to funnel-campanulate, white or cream to pink, sometimes with crimson flecks and/or a basal blotch, 30-40mm. Ovary densely stipitate-glandular, sometimes also hairy; style glabrous or glandular at base. Capsule 15-20 x c.5mm.
Distribution: China (C Sichuan)
Altitude: 3050-4400m
At their extremes the two subspecies are very distinct. However there are intermediates, especially from around Tatsien-lu (Kang-ting Xian). These intermediates include the type of R. bureavioides Balfour f. (Notes R.B.G. Edinb. 13:35,1920) from W China, 1904, Wilson 3954 (holo. K; iso. A), with the large leaves of subsp. prattii but a thicker, more persistent upper layer of leaf indumentum than is usual in subsp. prattii. R. faberi resembles R. bureavii and R. nigroglandulosum in its well-developed calyx and glandular ovary but differs from both in its clearly bistrate leaf indumentum which suggests an affinity with R. rufum.
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: cream, crimson, pink, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):359
Leaves 6-11 x 2.8—4.5cm, when juvenile with upper layer of indumentum dense
Illustrations:
Type: China, Sichuan, summit of Mt Omei, Faber (holo. K)
Synonymy: R. faberioides Balfour f., Notes R.B.G. Edinb. 13: 44 (1920). Type: China, W Sichuan, vi 1908, Wilson 3436 (holo. K). R. wuense Balfour f., ibid. 13: 64 (1920). Type: China, SW Sichuan, Mt Wu, Wilson 3960 (A,K)
Leaves 10-17 x 5-8cm, when juvenile with upper layer of indumentum sparse
Illustrations:
Synonymy: R, prattii Franchet, J. Bot. (Morot) 9: 389 (1895). Syntypes: China, Sichuan, aux environs de Ta-tsien-lou, Pratt 58 (A, E, K); Soulie 8 bis, n.v. R. leei Fang, Acta Phytotax. Sin. 2: 82 (1952). Type: China, Sichuan, Hsi-shui-lo, Mow Hsien, 2850-3000m, 21 vi 1951, Lee, T. C. 2210 (holo. SZ)
Shrub or tree, 2-10m; young shoots rufous stellate-tomentose. Leaves oblanceolate to elliptic, 10-18.5 x 3-7.2cm, 2.3-3.2 x as long as broad, apex rounded, apiculate, base cuneate, both surfaces glabrous when mature or with vestiges of indumentum, especially on the midrib towards the base; petioles slender to stout, 2—3cm, stellate-tomentose at first, soon glabrescent. Inflorescence c.lO-flowered; rhachis 10-15mm; pedicels 10-15mm, stellate-tomentose, sometimes also stipitate-glandular. Calyx 3-5mm, stellate-tomentose, lobes broad, rounded. Corolla tubular-campanulate, sparingly floccose-tomentose or glabrous on outer surface, deep rose to scarlet, 0-50mm. Ovary densely rufous stellate-tomentose; style with floccose stellate hairs and glands. Capsule 15-20 x 8 mm, slightly curved.
Habitat: Forests
Distribution: NE Upper Burma, China (W Yunnan)
Altitude: 2700-3350m
Illustrations:
Allied to R. kyawi but lacking the setose glands on the young shoots, also closely allied to R. huidongense (q.v.).
The correlation between stout petioles and glandular pedicels, proposed by Tagg to distinguish between R. eriogynum and R. facetum does not hold for specimens now available. The latter name was chosen rather than the former as it already had a wider acceptance.
Type: E Burma, Fengshui-ling camp, 8-9000ft, 9 vi 1914, Kingdon-Ward 1659 (holo. E)
Synonymy: R. eriogynum Balfour f. & W. W. Smith, Notes R.B.G. Edinb. 10: 101 (1917). Type: China, Mid W Yunnan, Ghi-shan, E of Tali Lake, 9000ft, viii 1914, Forrest 13508 (holo. E).
Occurs in Countries: CN, MM Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: rose, scarlet
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):377
Shrub, c. 4 m. Leaves elliptic, 16-22.5 x 6-8.5 cm, 2.5-3.2 x as long as broad, apex rounded, mucronate, base rounded, lower surface glabrous; petioles 3-4 cm, glabrous. Inflorescence c. 10-flowered; rhachis c. 50 mm; pedicels 25-35 mm, stipitate-glandular. Calyx c. 2 mm, with shallow, stipitate-glandular lobes. Corolla c. 7-lobed, open-campanulate, sparsely stipitate-glandular outside, glabrous within, probably white and lacking flecks, 75-90 mm. Stamens c. 14, filaments glabrous. Ovary and entire style glandular. Capsule not known
Distribution: China (Guangdong, Guangxi)
Closely resembling R. diaprepes but differing in the glabrous filaments, etc. A large-leaved fruiting specimen from Jiangxi, Wilson 'A'1686, may belong to this species.
Type: China, Guangdong, Sunji, Shektung, 21 vii 1931, Koy S. P. 51693 (holo. Herb. Inst. Bot. Guangzhou; iso. E)
Occurs in Countries: CN Subgenus: Hymenanthes Habit: Non-Tree
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):233
Tree, 6-12m. Leaves broadly elliptic to obovate, 18-35 x 8-17cm, 1.4-2.3 x as long as broad, apex rounded, base rounded to cordate, upper surface glabrous or scurfy, rugulose, lower surface with a bistrate indumentum, the lower layer white and compacted, the upper a dense rufous tomentum composed of strongly fimbriate, narrowly cup-shaped hairs; petioles terete, 2.5-5cm, sparsely floccose and stipitate-glandular. Inflorescence 15-20-flowered; rhachis stout; 30-60mm; pedicels 40-55mm, densely stipitate-glandular, viscid. Calyx c.2mm, viscid-glandular. Corolla fleshy, 8(-10)-lobed, obliquely campanulate, whitish to cream, or pale pink with darker tips, purple basal blotch present, 40-50mm. Stamens 12-16. Ovary densely viscid-glandular. Capsule c.40 x 10mm, straight.
Habitat: Deciduous and mixed forests
Altitude: 2700-3750m
Occurs in Countries: BT, IN, NP Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: cream, pink, purple
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):259
Corolla pale pink with darker tips; leaves scurfy above, even at maturity
Distribution: NE India (Arunachal Pradesh)
Illustrations:
Closely allied to subsp. falconeri and apparently replacing it in the east. A fruiting specimen (Ludlow &. Sherriff29S9) from S Bhutan could belong to either subspecies. A specimen from the Subansiri district of Arunachal Pradesh, with relatively narrow leaves, c.2.5 x as long as broad, that are glabrous above and only slightly rugose, but with deep rose-pink flowers (Cox & Hutchison 421), may be a hybrid of subsp. eximium.
Synonymy: R. eximium Nuttall, Hooker's J. Bot. Kew Gard. Misc. 5: 364 (1853). Type: NE India, Arunachal Pradesh, Oola Mountain, 10-11000ft, Booth (holo. K).
Corolla white to cream; leaves glabrous above at maturity
Distribution: E Nepal, N India (Bengal, Sikkim, Arunachal Pradesh), Bhutan
Illustrations:
Three specimens from Duke La & Pele La in C Bhutan (Cooper 3911, 3968; Grierson & Long 1085) with pink to lilac flowers, broad, non-rugulose leaves and a fawn lanate sub-cupular indumentum have almost certainly been derived by hybrisation from R. falconeri. To what extent they are part of a stabilised hybrid population is not certain. Their status therefore remains doubtful. It is however noted that a plant assigned to R. falconeri, with yellow flowers and rugose leaves, but with the same sub-cupular indumentum (Ludlow & Sherriff 3041) originated from Chendebi, not far from Pele La.
Type: N India, Bengal, Tonglu, 10000ft, Hooker(holo. K)
Shrub or small tree to 6m. Twigs rounded, rough with a dense covering of dark brown scales; internodes 2–10cm. Leaves 3–6 in tight pseudowhorls and with small, slender scale leaves arranged along the stems but these soon falling off. Blade 80–160 x 30–55mm, sub-sessile, ovate, or ovate-elliptic; apex shortly to long acuminate or sub-caudate, acute; margin irregularly wavy, flat; base rounded to auriculate; densely silvery scaly above, only disappearing gradually; beneath densely overlapping coppery-brown-scaly. Scales variable in size, strongly lobed, the broad margins striate; the centres large and darker especially those of the largest scales. Mid-vein slightly impressed in the proximal ½ above, strongly raised below for most of its length and especially at the base; lateral veins 8–12 per side, wide-spreading, distinctly indicated but not raised or impressed on the upper surface, slightly raised or very obscure on the lower side. Petiole to 4 x 4mm, very short, rarely longer than broad, densely brown-scaly, not or only weakly grooved above in the fresh state. Flower buds broadly ovoid with the bud scales appressed. Bracts densely scaly in a broad central band on the outer side of each bud scale and conspicuously fringed with white hairs on the margins. Bracteoles to 15mm, filiform and papillose below, spathulate and long hairy above. Inflorescence of 15–35 flowers in a complete or sometimes open umbel. Flowers standing erect to horizontal. Pedicels 15–35 x c.1mm, densely brown-scaly. Calyx a low, scaly ring. Corolla 18–25 x 30–37mm, bright orange, without scent; tube 7–12 x 5 x 5mm, densely scaly outside; lobes 16 x 16mm, widely spreading, overlapping to c.halfway and with a triangular area of scales on the outside. Stamens at first standing erect centrally in the mouth of the flower, later reflexing back away from the stigma against the corolla lobes; filaments 12–16mm, slightly broader proximally and hairy in the basal ½; anthers 3–4mm, brown. Ovary 5.5–7 x 1.5–2mm, densely scaly; style 8–12mm, scaly at the base otherwise glabrous; stigma 5-lobed, to 3mm in diameter. Fruit to 35 x 4mm. Seeds 6mm, without tails 0.9mm, the longest tail 3.5mm.
Habitat: Mostly terrestrial, less commonly epiphytic in mossy forest in damp shady places, but also on open exposed ridges, often common.
Distribution: Malaysia (Borneo), Sabah, Mt Kinabalu, Mt Trus Madi and the Crocker Range. Sarawak, Mt Mulu.
Altitude: 1220-2600m
Latin – fallax – deceptive or fallacious, because of a deceptive resemblance to R. durionifolium which allowed it to go unrecognised for many years.
It was noted by Sleumer (1966) that ‘sterile specimens [were] hardly distinguishable from those of R. durionifolium’. In fact this species is not clearly distinguished from R. durionifolium but is retained here at present. Flower size is extremely variable (see under R. durionifolium) and pedicel length varies enormously as it elongates after the flowers open, even before the corolla has fallen. This leaves only relative scalyness of the corollas and corolla tube length to distinguish between these two species. As conceived here R. fallacinum has flowers with a relatively short and extremely scaly tube, with the scales extending up onto the backs of the lobes, while R. durionifolium
Rhododendron fallacinum has been collected in flower in most months of the year but probably flowers best in the wild from February to April. Pollinators might be expected to be butterflies with the bright display of orange-red flowers with short floral tube and prominently displayed anthers, but Scarlet Sunbirds (Aethopyga mystacalis Temminck) have been seen visiting the flowers. Several hybrids have been recorded with this species in Sabah: x stenophyllum occurs on Mt Alab – it has narrow linear leaves and broad dark scales but has not been seen with flowers; x rugosum occurred on the Mesilau Spur, Kinabalu – it has a mixture of scale types and handsome red flowers; x lamrialianum occurs commonly on Mt Trus Madi and has been seen above the Mesilau Cave – it has intermediate-sized leaves but has not been seen in flower; and x acuminatum, also from the Mesilau Spur, is known only in vegetative form from its intermediate leaves.
Type: Clemens 32714. East Malaysia, Sabah (Borneo), Mt Kinabalu (L, A, BM, BO, E, NY).
Occurs in Countries: MY Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Tree Fl. Colour: brown, orange
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:114
Shrub, 1—5m. Leaves coriaceous, obovate-lanceolate, c.7 x 3cm, 2.3 x as long as broad, apex blunt, ± cucullate, upper surface glabrous, bullate with deeply impressed veins, lower surface with a bistrate indumentum, the lower layer white and compacted, the upper yellowish at first, becoming silvery, lanate-tomentose, hairs ramiform, persistent but with veins exposed; petioles c.lcm, densely tomentose. Inflorescence c.lO-flowered; rhachis c.5mm; pedicels c.lOmm, densely tomentose. Calyx c. 1.5mm, tomentose, lobes minute. Corolla campanulate, white, 30-35mm. Ovary densely tomentose; style glabrous. Capsule not known.
Closely allied to both R. floribundum and R. denudatum but differing from both in its smaller, cucullate-tipped leaves and white flowers, and from R. denudatum (also recorded from lo-chan) in its dense, more persistent leaf indumentum.
Type: China, Yunnan, Flanc de lo-chan, 3200m, v 1913, Maire (holo. E).
Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):321
Dwarf shrub; young shoots becoming glabrous. Leaves ovate, 1.5-3 x l-2cm, apex acute, upper and lower surface with long brown hairs, becoming glabrous; petioles l-3mm, densely villose. Inflorescence 1-2-flowered; pedicels short, hidden by bracts, densely villose. Calyx minute, densely villose. Corolla open-campanulate, pale purple or lilac, upper lobe spotted, 20-30mm, lobes 15mm, broadly oblong. Stamens 10, unequal, glabrous. Ovary densely hairy; style glabrous. Fruit not known.
Habitat: Mixed woodland
Distribution: China (E Guangxi, Guangdong, Fujian, Jangxi, Hunan)
Altitude: Around 600m
Illustrations:
Forms with more or less crenate leaves have been referred to R. cinereoserratum Tan, the type of which has unusually narrow leaves. However, there are specimens with broader but toothed leaves and there are also analagous forms of R. mariesii. We do not therefore consider that there is any justification in maintaining R. cinereoserratum as a distinct taxon.
Type: a plant introduced by Capt. Farrer from China in 1829 (n.v.)
Synonymy: Azalea farrerae (Tate) Koch, Dendr. 2(1): 178 (1872). Rhododendron farrerae Tate var. leucotrichum Franchet, J. Bot. (Morot) 394 (1895). Syntype: China, E Sichuan, aux environs de Tchen-keou-tin. Farges 50, 846, n.v. Azalea squamata Lindley, J. Hort. Soc. Lond. 1:152 & Bot. Reg. t.3 (1847). Type: China, Hongkong, Mt Victoria, 550m, Tate (holo. BM), Rhododendron cinereoserratum P.X.Tan, Bull. Bot. Res. N.E. Forest. Inst. 2(4): 77 (1982). Type: China Fujian, Nanjing Xian, Hexi, Ling hai, Univ. Amoy 20 (holo. Amoy Univ.)
Occurs in Countries: CN Altitude Ranges: 0 - 1,000m Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: lilac, purple
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):144
Prostrate, tufted shrub, or forming a compact cushion, to 1 -5 m. Leaves (4-5-)7-14(-16) x (2-8-)3-6(-9) mm, oblong, broadly elliptic or ovate, apex rounded to subacute, mucronate, base cuneate or subtruncate, undersurface fawn to greyish with the scales contiguous in groups or more scattered. Inflorescence l-3(-4)-flowered, pedicels lepidote, 0.5-3 mm. Calyx 2.5-5-5 mm, lobes oblong or bluntly triangular, apex rounded or acute, scaling variable, margin usually ciliate. Corolla bright lavender-blue to pinkish or rich purple, funnel-shaped (9-5-) 10-15.5(-18) mm, tube 3-6-5(-8) mm, pubescent inside and rarely also outside, usually elepidote outside. Stamens (6-)10, filaments pubescent towards the base. Ovary lepidote, occasionally with an apical tuft of hairs, style exceeding the stamens, glabrous or rarely pubescent and/or lepidote at the base. Capsule ovoid, 5-6 mm, lepidote.
Habitat: Open stony pastures, screes, cliffs and in forest
Distribution: China (N & C Yunnan)
Altitude: 3400-4400m
The Philipsons (1975, p. 38) record a natural hybrid with R. rupicola var. rupicola.
Type: China, Yunnan, in monte Tsang-chan supra Tali, vi 1883, Delavay 360 (holo. P; iso. A, E p.p., K)
Synonymy: R. nanum Leveille, Feddes Rep. 12:285 (1913). Type: China, Yunnan, 1911, Maire (holo. E). R. capitatum sensu Franchet, Bull. Soc. Bot. Fr. 32:7 (1885) non Maximowicz (see p. 107)
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: lavender, pink, purple
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):100
Shrub or small tree, 1.5-5(-6.5)m; bark smooth; young shoots ± glabrous. Leaves oblanceolate, 7—12 x 2.5-3.5cm, usually widest in the upper third, 2.8-3.5 x as long as broad, apex rounded, base cuneate, upper surfaceglabrous, lower surface greenish, epidermis epapillate, with a few scattered hairs near the midrib towards the base, also with persistent red punctate hair-bases overlying the veins; petioles 0.7-1.5cm, stipitate-glandular, often winged for part of their length. Inflorescence compact, 5-10-flowered; rhachis (8-)10-20mm; pedicels 5-10mm, glabrous or stipitate-glandular, sometimes also with dendroid or crisped hairs. Calyx 3-5mm, chartaceous, glandular-ciliate, otherwise glabrous. Corolla campanulate, pink to white tinged pink or rarely sulphur yellow, with purple flecks, 37-40mm. Ovary densely stipitate-glandular, style glabrous. Capsule not known.
Habitat: Forest margins, rock faces
Distribution: China (SE Xizang)
Altitude: 2600-3350m
R. faucium is closely allied to R. hylaeum but differs in the smaller leaves that taper below, the shorter petioles, and the glandular ovary. The punctate hair-bases on the lower surface of the leaves confirm the affinity with R. hylaeum.
Ludlow, Sherriff & Elliot 13594 & 13620, which differ in their darker pink flowers and more acute leaves, show some of the characters of R. ramsdenianum (subsection Irrorata) but are otherwise closer to the present species.
Type: China, SE Xizang, Pome Province, Layoting, Tongyuk Chu, 9000ft, 12 iii 1947, Ludlow, Sherriff & Elliot 12289 (holo. E; iso. BM)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: pink, purple, white, yellow
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):421
Shrub 4 m high, young branches glabrous. Leaves glabrous except for scattered stiff bristles on the mid-rib below and on the petiole; blade oblanceolate, c.130 x 32 mm, tapered to the base, apex slightly acuminate, coriaceous, veins forming a close network; petiole c. 10-12 mm long. Inflorescence buds lateral, at the ends of leafy shoots, c.5-flowered; bud scales not seen; pedicel glabrous, 25-30 mm long. Calyx an undulate rim, glabrous. Corolla not seen, Stamens not seen. Ovary glabrous. Capsule narrowly cylindric, c.25 x 3 mm, glabrous.
Distribution: China (Guizhou)
The stiff bristles on the underside of the mid-rib and the close network of veins make the leaves of this species readily recognizable. The species is evidently rare. Besides three collections by Cavalerie we have seen only one other (Tsiang 8456).
Type: China, Guizhou, Pin Fa, 18 vi 1903, Cavalerie 1074 (holo. E).
Occurs in Countries: CN Subgenus: Azaleastrum Habit: Non-Tree
Philipson, W.R. & Philipson, M.N. (1986) A Revision of Rhododendron III. Subgenera Azaleastrum, Mumeazalea, Candidastrum and Therorhodion. Notes from the Royal Botanic Garden Edinburgh 44(1):9
Small shrub with erect or ascending branches, to 1.5 m. Young growth densely lepidote, sometimes with a few loriform hairs. Leaves narrowly elliptic to elliptic, acute or mucronate at the apex, 28-40 x 8—16 mm, slightly revolute, dark shining green above, ferrugineous beneath with dense overlapping scales. Inflorescence many-flowered, the rachis 10-20 mm, filiform-acicular pubescent, pedicels rather strict, densely lepidote. Calyx small, 5-lobed, lobes up to 1-5 mm, lepidote and loriform-ciliate. Corolla 12-15(-17) mm, tube 6-9(-10) mm, deep pink, rarely pale pink or white, lepidote and usually filiform-acicular pubescent outside. Stamens 10, filaments pubescent towards the base. Ovary 5-locular, lepidote, style glabrous, up to 2 x longer than the ovary. Capsule sparsely lepidote, ± oblong, 5-7 mm.
Habitat: Mountain slopes, open woodland and scrub.
Distribution: Austria, France, Germany, Italy, Spain, Switzerland (Alps and Pyrenees)
Illustrations:
The type species of the genus
Type: Habitat in Alpibus Helveticis, Allobrogicis, Pyrenaeis'
Occurs in Countries: AT, CH, DE, ES, FR, IT Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: pink, white
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):110
Shrub or small tree to 2.5m tall, usually non-rhizomatous; young twigs red-brown, densely covered with unicellular and multicellular eglandular hairs. Vegetative bud scales glabrous, to densely covered with unicellular hairs abaxially; margin unicellular-ciliate. Leaf blade membranaceous, ovate or obovate to elliptic, (2.9-)3.9-6.3(-8.2) x (1.3-)1.5-2.4(-2.7)cm; base acute to oblique; apex acute to obtuse, often mucronate; adaxial surface glabrous or sparsely covered with multicellular eglandular hairs or with unicellular hairs, the midvein densely covered with unicellular hairs; abaxial surface densely covered with unicellular or multicellular eglandular hairs, or with both, or glabrous, the midveie sparsely to densely covered with unicellular hairs and multicellular eglandular hairs; margin entire, ciliate with multicellular eglandular hairs; petiole Q.2-0.6cm long, sparsely to densely covered with unicellular and multicellular eglandular hairs. Flower bud scales chestnut brown; abaxial surface sparsely to densely covered with unicellular hairs, rarely completely glabrous; margin unicellular-ciliate. Flowers appearing before or with the leaves', inflorescence a shortened raceme of 6 to 11 flowers. Pedicels (0.3-)0.5-0.9(-1.0)cm long, sparsely to densely covered with unicellular and multicellular eglandular hairs. Sepals less than 0.1-0.3(-0.5)cm long, often varying in length on the same flower; margins setose with multicellular eglandular hairs; abaxial surface sparsely covered with unicellular and multicellular eglandular hairs. Corolla scarlet, reddish orange to orange, fragrance acrid, the tube longer than the limb and abruptly expanding into it; upper corolla lobe 0.8-1.7(-2.2) x(0.7-)0.8-1.6(-1.9)cm wide; lateral lobes (1.0-)1.1-1.8(-2.1) x (0.5-)0.6-1.0(-U)cm; corolla tube (1.7-)1.8-2.3 (-2.5)cm long, 0.2-0.3(-0.4)cm wide at base; outer surface of corolla sparsely covered with unicellular and multicellular eglandular hairs, the multicellular hairs continuing up the corolla lobes, rarely with unicellular and multicellular gland-tipped hairs (glands of hairs minute, poorly developed); inner surface of corolla densely covered with unicellular hairs. Stamens (4.0-)4.3-6.3(-7.3)cm long, with dense terete or flattened unicellular hairs on proximal (2.0-)2.1-2.8 (-3.3)cm of filament, exserted (2.4-)2.5-3.9(-5.0)cm beyond throat of corolla. Style (4.5-)4.9-6.8(-7.4)cm long, exserted (3. l-)3.3-5.0(-5.4)cm beyond throat of corolla, with dense unicellular hairs on proximal (0.0-)0.1-1.4(-2.2)cm; stigma 0.1-0.2(-0.4)cm wide. Ovary 0.3-0.4(-0.5)cm long, 0.1-0.2(-0.3)cm wide at the base, densely covered with multicellular eglandular hairs over unicellular hairs. Capsules L5-2.3(-2.6) x 0.5-0.7(-0.8)cm, ovate, sparsely covered with unicellular hairs and moderately to densely covered with multicellular eglandular hairs. Seeds pale to dark chestnut brown, ovate or elliptic to fusiform, (1.8-)2.0-2.7(-2.8) x 0.7-1.l(-1.2)mm, body 0.9-1.3 x 0.4-0.7(-0.8)mm; testa expanded and dorsiventrally flattened, surrounding the body, the cells elongate over the body of the seed, short in the expanded portion of the testa, with transverse end-walls (Fig. 5). Chromosome number: In = 26 (Li, 1957). Figure 31; see additional illustrations in Prince, 1978 (photo) and Galle, 1985 (photo).
Habitat: Upland woods, dry slopes and ridges, bluffs of rivers or stream banks, sandhills
Distribution: USA: Georgia and South Carolina
Altitude: 0-500m
Hybrids between R. flammeum and R. canescens have been studied by the present author at Stone Mountain, Georgia (Kron et al., 1993). This population is most likely the same as T. G. Harbison's #900 collection noted by Rehder (1921). The hybrids at Stone Mountain are intermediate in flower colour (pink with a yellow blotch on the upper corolla lobe), in floral bud-scale pubescence (the population of the probable R. flammeum parent possesses glabrate bud scales, and those of the probable R. canescens parent possess densely unicellular pubescent bud scales), and in plant height (see Appendix under hybrids of R. canescens).
Although the name Rhododendron speciosum (Willd.) Sweet is often used for the Oconee azalea, it is not the correct one. Willdenow (1811) cites Michaux's (1803) Azalea calendulaceo in his description of Azalea speciosa. In doing this Willdenow thus included the type of a previously validly published name (Azalea calendulacea Michaux) making Azalea speciosa Willd. superfluous (International Code of Botanical Nomenclature, 1981, Art. 63.2). The correct name for the Oconee azalea is Rhododendron flammeum (Michaux) Sargent since Sargent (1917) raised Michaux's A. calendulacea vax.flammea to specific rank.
Flowering in April
Rhododendron flammeum, a species that is rather variable in corolla colour and in the pubescence of the floral bud scales, is related to R. prunifolium and R. cumberiandense (see Phylogenetic Analysis). These three red to orange-flowered species are isolated geographically. Rhododendron flammeum can be distinguished from both by its flowering before or with the expansion of the leaves. While it is marginally sympatric with R. calendulaceum, R. flammeum is reproductively isolated from it by the tetraploid condition of R. calendulaceum and the discontinuous distribution of R. flammeum. Although the flower colour is similar between R. calendulaceum and R. flammeum, they can be distinguished from one another by the eglandular corolla tube and the unicellular-ciMate floral bud-scale margins in R. flammeum vs. the densely glandular corolla tube and the glandular floral bud-scale margins in R. calendulaceum.
Synonymy: Azalea calendulacea Michx. Nm.flammea Michx., Fl. Bor.-Amer. 1: 151 (1803). Type: Georgia: Savannah River, Two Sisters Ferry. 26-27 iv 1787, A Michaux s.n. (lecto. P-MICHX; photo of holo. A). Azalea nudiflora var. coccinea Aiton, Hort. Kew. 1: 202 (1787). A. periclymenoides var. coccinea (Aiton) Pursh, Fl. Am. Septentr. 1: 152 (1814). Rhododendron nudiflorum var. coccineum (Aiton) Sweet, Hort. Brit. ed. 2, 343 (1830). Type: n.v.
Occurs in Countries: US Altitude Ranges: 0 - 1,000m Subgenus: Pentanthera Habit: Tree Fl. Colour: orange, red
Kron, K.A. (1993) A Revision of Rhododendron Section Pentanthera. Edinburgh Journal of Botany 50(3):311
Very similar to R. monanthum, differing as follows: leaves less clearly papillose beneath, the scales more distant, pale; calyx 5-lobed, the lobes broadly triangular, ± obtuse, c. 2.5 mm
Habitat: North-facing cliffs
Distribution: China. (SE Xizang)
Altitude: 2450-2750m
Known only from the type collection; doubtfully distinct from R. monanthum.
Type: China, Tibet, Tsangpo gorge near Churung confluence, 8-9000 ft, 25 ii 1924, Kingdon Ward 6313 (iso. E)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m Subgenus: Rhododendron Habit: Non-Tree
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):60
Erect shrub to 2.5 m. Leaves 7-15 x 3-7 mm, broadly elliptic to oblong, apex rounded, shortly mucronate, base broadly to narrowly cuneate, undersurface pale grey-green with well-spaced scales. Inflorescence 1-3-flowered, pedicels pubescent, sometimes with a few scales as well, 1-4 mm. Calyx 2-4(-7) mm, minutely pubescent at the base, lobes strap-shaped or deltoid, acute, sometimes unequal, sparsely lepidote or elepidote, ciliate. Corolla yellow, broadly funnel-shaped, pubescent outside and inside, 12-18 mm, tube 4-7 mm, elepidote or sparsely lepidote. Stamens (8-)9-10, ± equal to the corolla, filaments pubescent towards the base. Ovary densely lepidote, style exceeding stamens, pubescent at base. Capsule ovoicl, lepidote, c. 6 mm.
Two varieties can be distinguished
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):101
Scales on leaf undersurface uniform in colour; calyx lobes 2-4(-7) mm
Habitat: Alpine regions
Distribution: China (NW Sichuan)
Altitude: 3000-4000m
Type: China, 'E Tibet'(sic!), Tatsienlou, 1893, Soulie 625 (iso. E)
Synonymy: R. primulinum Hemsley, Gard. Chron. 47:4 (1910). Type: a cultivated specimen (holo. K)
Scales on leaf undersurface dimorphic, some dark, the rest golden; calyx lobes c. 2 mm
Distribution: China (NW Sichuan)
Known only from one collection
Type: China, Szechuan, west of Kuan hsien, summit of Niu-tou-shan, 3300 m, 20 vi 1908, Wilson 3452 (holo. A; iso. BM, E, K)
Synonymy: R. psilostylum (Rehder & Wilson) Balfour f., Notes R.B.G. Edinb. 11:104(1919)
Erect shrub or tree to 10m. Twigs 2–4mm in diameter, rounded, green, densely pale brown or translucently scaly, becoming glabrescent; internodes 2.5–8cm. Leaves 3–6 together in tight pseudowhorls at the upper 1–3 nodes. Blade 30–70 x 20–33mm, broadly-elliptic or ovate-elliptic sometimes obovate-elliptic; apex obtuse or rounded; margin narrowly to broadly revolute; base rounded, or broadly tapering; initially scaly on both sides, glabrescent above, the scales leaving dense, minute, black pits, more persistently and sub-densely scaly beneath. Scales flat, or concave, marginal zone wide, transparent, shortly sub-stellately-lobed; centre minute, impressed becoming dark. Mid-vein narrow and slightly impressed above, grooved proximally for a few millimetres, beneath strongly raised to within c.1cm of the apex; lateral veins 4–8 per side, spreading at a wide angle, irregular, anastomosing, slightly depressed above and raised beneath in dried leaves, reticulation dense, slightly impressed above, faintly to markedly raised beneath. Petiole 3–11 x 2–3mm, grooved above, densely scaly. Flower buds to 30 x 16mm, narrowly ovoid, acutely to broadly and bluntly pointed, smooth, green, but with just the basal bracts with the tips becoming revolute. Bracts broadly spathulate, glabrous except for a fringe of brown scales along the edges, hooded and emarginate at the apex, green along a broad median stripe, translucent towards the edges. A few of the shortest bracts with brown scales outside. Bracteoles to 20mm, linear to linear-spathulate, glabrous or with a few scales on the margins apically. Inflorescence a 3–6-flowered open umbel. Pedicels 10–30 x c.1.5mm, densely covered with pale brown appressed, sub-stellate scales, without hairs. Calyx 4–5mm in diameter, obliquely disc-shaped, shortly and obtusely 5-lobed. Corolla 45–50 x 33–42mm, on opening almost horizontal, becoming vertically hanging, pale-green, fragrant or without scent; tube 35–38 x 6–8 x 12–15mm, sub-cylindrical, distinctly curved, laxly but obscurely, sub-stellate-scaly outside, shortly hairy inside; lobes 16 x 18mm, sub-circular, spreading horizontally or sometimes a little reflexed, overlapping to about ½ their length, with a few very small scales near the base outside. Stamens exserted to 9mm, clustered around the style on the lower side of the mouth; filaments green, filiform, sub-densely to laxly patently hairy in the proximal ½; anthers 2.5–3 x 1mm, cream to pale brown, oblongoid curved, the base obtuse. Disc glabrous or hairy at the upper margin. Ovary c.5 x 2mm, sub-cylindrical-conical, base and apex tapering, yellowish or silvery, densely sub-patently hairy, the hairs covering small scales; style at first with the stigma just below the anthers in the mouth of the flower, later exserted to 15mm, hairy and scaly in the proximal ¼–1⁄3, scaly and sometimes very laxly hairy up to the middle, glabrous above; stigma globose.
Habitat: In open, swampy localities, or on the edge of sub-montane forest.
Distribution: Indonesia, New Guinea (W), Oranje Mts, Kajan Mts and near Lake Habbema.
Altitude: Around 3200m
Latin – flavus – pale yellow; viridi – green. Alluding to the flower colour.
Type: Pulle (Versteeg) 2455, 9 Feb. 1913. New Guinea (W), Kajan Mts, 3200m (BO, K, L, U).
Occurs in Countries: ID Altitude Ranges: 3,000 - 4,000m Subgenus: Vireya Habit: Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:216
Very similar to R. valentinianum, differing as follows: leaves with distant scales beneath, the surface conspicuous, green; leaf margin distinctly crenate in the upper half; midrib usually not setose above; ovary conspicuously setose towards the apex, the setae persisting on the capsule.
Habitat: Forests at 4000-4300 m
Distribution: China (SE Xizang)
Illustrations:
Known only from two collections; vicariating with the very similar R. valentinianum
Type: SE Tibet, province of Tsarung, forests and alpine regions of the Solo-la, 14000 ft, vi-vii 1922, Rock 22302 (holo. E)
Occurs in Countries: CN Subgenus: Rhododendron Habit: Non-Tree
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):42
Shrub, 3-5 m. Leaves oblong-lanceolate, tapering to base and apex, 50-80 x 20-40 mm, margins somewhat loriform-ciliate, dark green above, brownish beneath with dense almost contiguous scales; petioles loriform-ciliate. Inflorescence 5-6-flowered, pedicels sparingly lepidote, markedly recurved in fruit. Calyx disc-like, glabrous. Corolla white with 5 yellow lines on the tube, c. 40 mm, glabrous. Stamens 10, filaments pubescent towards the base. Ovary lepidote, tapering into the style which is sparsely lepidote.near the base.
Habitat: Hillsides
Distribution: Laos
Altitude: 2000-2500m
Illustrations:
Type: Laos, prov. Darlac, massif du Langbian, au sommet du piton du Langbian, 2000-2500 m, Chevalier 30896 (holo. P)
Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):54
Shrub, 0.6-3m; young shoots densely floccose-tomentose, setulose-glandular or eglandular. Leaves narrowly elliptic to oblong or elliptic, (3.5—)6—11 x(l-)1.5-2.7cm, 3.3-4.5(-6) x as long as broad, apex ± acute, apiculate, base cuneate to ± rounded, upper surface glabrous, lower surface with a floccose, rufous, usually patchy (rarely ± continuous) ramiform tomentum, lower epidermis glaucous-papillate; petioles 0.7-1.5cm,.floccose-tomentose, usually eglandular (rarely setulose-glandular). Inflorescence 4-7-flowered; rhachis 2-3mm; pedicels c.lOmm, tomentose, eglandular. Calyx l-4mm, lobes rounded, sparsely tomentose to glabrous, margins ciliate. Corolla tubular-campanulate, usually crimson to scarlet, occasionally yellowish to pink, 30-40mm. Ovary densely stellate-tomentose, eglandular, tapering into the glabrous style. Capsule 10-25 x 4-5mm, straight to curved.
Habitat: Cliffs, Rhododendron scrub
Distribution: China (SE Xizang & adjacent NW Yunnan)
Altitude: 2750-3950m
Illustrations:
Plants apparently intermediate between R. floccigerum and R. sperabile var. sperabile occur in SE Xizang (outside the range of var. sperabile) and around Wei-hsi in NW Yunnan. These are characterised by their glandular shoots and narrow leaves, usually with a thick rufous indumentum. Over most of their respective ranges the two taxa remain distinct so the status of these intermediates remains uncertain.
Several fruiting specimens have been tentatively assigned to R. floccigerum but differ in their setulose-glandular petioles and young shoots and in their shorter leaves, 4-6cm long, that are usually glabrous by maturity and sometimes epapillate. In the absence of flowering material their status remains doubtful though they may have affinities with R. neriiflorum rather than with R. floccigerum. They are as follows: Forrest 20305, 20321, 20877, 20855, 22808, 25640,25800,25831.
R. floccigerum is closely allied to R. neriiflorum and R. sperabile but may be recognized from both by its discontinuous floccose leaf indumentum.
Type: China, NW Yunnan, Tsekou, dans la Vallee du Mekong, a Thra nu, Soulie 1014 (iso. E,K)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: crimson, pink, scarlet, yellow
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):410
Shrub or small tree, 2-5m. Leaves coriaceous, oblanceolate to elliptic, 10-18 x 3.2—5.5cm, 3—3.3 x as long as broad, apiculate, upper surface glabrous when mature, veins deeply impressed, lower surface with a bistrate indumentum more or less covering the veins, the lower layer adpressed and whitish, the upper loose and lanate, hairs ramiform, yellowish at first, becoming white or greyish, persistent; petioles l-2cm, tomentose. Inflorescence 7—12-flowered; rhachis 3-5mm; pedicels c.lOmm, densely tomentose. Calyx c.lmm, lobes minute. Corolla broadly campanulate, magenta-rose fading pale pink, with crimson flecks and a basal blotch, c.40mm. Ovary densely tomentose; style glabrous. Capsule 20-30 x c.lOmm, cylindrical, sometimes slightly curved.
Habitat: Woodlands
Distribution: China (Sichuan)
Altitude: 1300-2600m
Illustrations:
Closely allied to R. denudatum and R. farinosum (q.v.).
Type: China, Sichuan, circa Moupine, v-vi 1869, Abbe David (iso. E, K).
Occurs in Countries: CN Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: crimson, magenta, pink
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):320
Shrub, c.2m; young shoots densely spreading-setulose and glandular-hairy. Leaves persistent, dimorphic, elliptic; spring leaves 3.5-8.5 x I.2-4.5cm, 2.2-3 x as long as broad, apex acute to acuminate, base cuneate, margin entire, upper surface becoming greyish-setulose, lower surface with a ± dense reddish-brown setulose indumentum; summer leaves smaller, 22-30mm, otherwise as for spring leaves; petioles 5-IOmm, densely brownish-setulose. Inflorescence 7-14-flowered; pedicels 10-20 mm, densely brownish-strigose. Calyx minute, indumentum as for pedicels, lobes narrowly triangular to ± absent. Corolla tubular-campanulate, reddish purple to rose, c.25mm; tube 14-16 x 2-3mm, glabrous; lobes 8-10mm. Stamens 5, filaments glabrous or puberulent below. Ovary densely brownish-strigose; style glabrous. Capsule 5-8mm, ovoid, densely brownish-strigose.
Habitat: Open woodland
Distribution: China (E Guangdong, S Hunan, W Fujian).
Altitude: Around 1100m
R. hepaticum differs from R. florulentum only in the somewhat larger leaves and is thus treated here as a synonym.
The discoloured leaves that are used to separate R. piceum from the other two species may well be due to different drying techniques and are not of any taxonomic value.
Type: China Fujian, Longyan Xian, Yen-Chung, 10 v 1974, L. G. Li (L. K. Lee) 740501 (holo. Inst. Mat. Med. Fujian).
Synonymy: R. hepaticum P.X.Tan, Survey Gen. Rhododendron S. China 98, f.3 (1983). Type: China, Guangdong, Jiaoling Xian, Shek- 104 EDINB. J. BOT. 47(2) wu Chuen, Tafong Chang, 1100m, 9 v 1957, L. Teng 4669 (holo. IBSC). R. piceum P.X.Tan, Bull. Bot. Res. N.E. Forest. Inst. 2(4): 83 (1983). Type: China, Fujian, Sanming Xian, Shiao-Hu, 20 iv 1964, Fujian Forestry Coll. (Silvicul Fok.) 86 (holo. IBSC).
Occurs in Countries: CN Altitude Ranges: 1,000 - 2,000m Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: purple, red, rose
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):103
Shrub, 2-3m; young shoots densely adpressed-strigose. Leaves persistent, chartaceous, dimorphic; spring leaves elliptic, 5.7-9 x 2.3-3cm, 2.3-2.5(-3) x as long as broad, apex acute to cuspidate, both surfaces with scattered adpressed hairs on lamina, hairs more dense on midrib; summer leaves (12-)25-30 x (8-)14-15mm; petioles 6-8mm, adpressed-strigose. Inflorescence 3-7-flowered; pedicels 4-8mm, densely golden-brown-strigose. Calyx c.lmm, strigose. Corolla funnel-campanulate, pinkish white to red, with darker flecks, c. I8mm; tube c.9mm, 3mm broad at base, 6mm broad below lobes, glabrous on outer surface. Stamens 5, filaments glabrous. Ovary densely strigose; style strigose towards base. Capsule c,7 x 2.5mm, ovoid, strigose.
Habitat: Mixed forest
Distribution: China (S Yunnan)
Altitude: 1400-1750m
Closely allied to R. rufohirtum but differing in the greater number of flowers per inflorescence and in the adpressed-hairy indumentum on the shoots.
Type: China, Yunnan, Jinping Xian, 1800m, 30 iii 1958, Q. Huang 291 (holo. PE)
Occurs in Countries: CN Altitude Ranges: 1,000 - 2,000m Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: pink, red, white
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):101
Shrub or small tree, 2-5.5m. Leaves narrowly elliptic to oblanceolate, 7-13 x 1.5-2.5cm, 4.5-5.5 x as long as broad, apex acute, glabrous above, with a compacted fawn indumentum beneath intermixed with a few glands; petioles l-2cm, floccose at first, soon glabrescent. Inflorescence 10-20-flowered; rhachis 15-20mm; pedicels 10-30mm, densely rufous-tomentose. Calyx c.lmm, tomentose, lobes minute. Corolla widely funnel-shaped, white to pink, with purplish flecks, 30-40mm. Ovary densely rufous-tomentose; style glabrous. Capsule not known.
Habitat: Broad-leaved forests
Distribution: Taiwan
Altitude: 800-2000m
Illustrations:
Type: Taiwan, South Cape, Henry 1976 (iso. BM, K).
Occurs in Countries: TW Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: pink, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):324
Erect shrub to 2 m. Young growth loriform-setose. Leaves narrowly elliptic to linear-elliptic or linear-obovate, long-tapering to the base, acute or acuminate at the apex, (26-)42-72 x 10-21 mm, not more than 21 mm broad, the blade narrowly decurrent on the petiole, upper surface dark green, elepidote, margin loriform-setose when young, some, at least, of the setae persisting, lower surface lepidote with unequal scales about their own diameter apart; petioles loriform-setose. Inflorescence 2-3-flowered, pedicels lepidote. Calyx disc-like, lepidote, weakly loriform-ciliate. Corolla white or white flushed pink, often with a yellow blotch and pink markings along the tube, openly funnel-campanulate, 40-55 mm, the tube 24-30 mm, pilose at the base and variably lepidote outside. Stamens 10, filaments pubescent towards the base. Ovary lepidote, style impressed, lepidote to well above the base. Capsule c. 16 mm, lepidote.
A rather variable and geographically scattered species, divisible into two varieties
Occurs in Countries: IN Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: pink, white, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):46
Leaves 10-16 mm broad
Habitat: Hillsides
Distribution: India (Meghalaya)
Altitude: 1450-2300m
Illustrations:
Type: Described from 'Assam, Khasia Hills, 3-5000 ft'
Synonymy: R. gibsoni Paxton, Mag. of Bot. 8: t. 217 (1841). Type: a cultivated specimen (n.v.). R. formosum var. salicifolium C. B. Clarke, Fl. Brit. India 3:473 (1882). Described from the Khasia Hills. R. iteaphyllum Hutchinson, Notes R.B.G. Edinb. 12:83 (1919). Syntypes: Assam, Khasia Hills, rocks of Bor-Panee, 2000 ft, 24 vii 1850, Hooker & Thomson (K); along the stream at the same place, Simons (K); without locality, Lobb 3 and G. Mann (both K)
Leaves 15-21 mm broad
Habitat: Hillsides
Distribution: India (Meghalaya, Manipur, Arunachal Pradesh)
Altitude: 1450-2230m
Illustrations:
Synonymy: R. inaequale Hutchinson, Notes R.B.G. Edinb. 12:75 (1919). Type: India, Kollong, 6000 ft, 23 viii 1885, Clarke 40025 (holo. K)
Dwarf creeping shrub; stems up to 0.6m long though rarely more than 0.1m high; perulae persistent. Leaves obovate to orbicular, 1-2.8 x 0.9-1.8cm, 1.1—2.5(—3.2) x as long as broad, apex rounded to retuse, sometimes mucronate, base broadly cuneate, often narrowly decurrent, upper surface glabrous, lower surface glabrous or with a few stipitate glands and branched hairs towards the base, green to purple or glaucous-papillate below when mature; petioles 0.5-0.8cm, stipitate-glandular and sparsely floccose-tomentose. Flowers solitary; pedicels 10-20mm, stipitate-glandular. Calyx c.lmm, lobes fleshy. Corolla fleshy, tubular-campanulate, crimson, 30-35mm. Ovary densely stipitate-glandular and rufous-tomentose. Capsule 15-20 x 6-7mm.
Habitat: Moist stony pasture, on boulders
Altitude: 3050-4500m
20*. ? R. forrestii x haematodes. Syn: R. chaetomallum Balfour f. & Forrest var. chamaephytum Cowan, Notes R.B.G. Edinb. 21: 146 (1936). Type: China, Xizang, Singo Samba, Lo La Chu, 16 v 1936, Ludlow, Sherriff & Taylor 3786 (holo. BM; iso. E, fragm.). Prostrate shrub, 0.3-0.6m. Leaves obovate, c.4.5 x 2.2cm, apex rounded, base cuneate, lower surface with traces of a red-brown floccose indumentum; petioles very short. Inflorescence few-flowered. Calyx c.7mm, cupular, irregular, red, glabrous. Corolla tubular-campanulate, fleshy, deep crimson, c.35mm. Ovary densely rufous-tomentose. CHINA (S Xizang). Scrambling over rocks in Abies/Rhododendron forest, 3950m. Apparently a hybrid between R. forrestii (or possibly R. chamaethomsonii) and R. haematodes. Field studies are however required to confirm the status of this plant.
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: crimson
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):407
Plants in which the juvenile state, with leaves purple below, persists to maturity, have been referred to R. forrestii sensu stricto. These may be no more than local ecotypes and are not worthy of formal taxonomic recognition. The more usual form with leaves green below at maturity has been referred to R. forrestii var. repens.
Kingdon-Ward 9816, from the Adung Valley in NE Burma, has sulphur-yellow flowers but otherwise matches subsp. forrestii.
Three plants from S Xizang, Ludlow & Sherriff 1883, 3942, 4751, have the growth form, small leaves, scarlet to crimson flowers and densely tomentose ovaries of subsp. forrestii but differ in their 3-4-flowered inflorescence. The status of these plants is uncertain, particularly as they come from an area outside the range of the species (see Map 121).
Type: China, NW Yunnan, ascent of the Tsedjiong Pass, Mekong/Salween divide, 10-11000ft, vii 1905, Forrest 699 (holo. E).
Synonymy: R. repens Balfour f. & Forrest, Notes R.B.G. Edinb. 11:115 (1919). Type: China, W NW Yunnan, Mekong/Salween divide, 28°20'N, 12-14000ft, vi 1917, Forrest 14011 (holo. E). R. forrestii Diels var. repens (Balfour f. & Forrest) Cowan & Davidian, Rhododendron Yearbook 6: 69 (1951). Ic: Bot. Mag. 153: t.9186 (1929).
Distribution: China (S Xizang)
Subsp. papillatum apparently intergrades with R. chamaethomsonii, especially on Doshong La and Deyang La. Intermediates include: Ludlow, Sherriff & Elliot 13278, 13783, 15070, 15098, 15170, 15285, 15292, 15400 and Kingdon- Ward 5846 (E), the type of R. forrestii Diels var. tumescens Cowan & Davidian (NotesR.B.G. Edinb. 26: 69, 1951). One specimen, L.} S. &E. 15013, is apparently a hybrid between subsp. papillatum and R. campylocarpum.
Type: China, S Xizang, Doshong La, 11-13000ft, 24 vi 1924, Kingdon-Ward 5845 (holo. E; iso. K).
Shrub to 2m. Twigs c.1.5mm in diameter, densely and persistently brown-scaly; internodes 2–7cm. Leaves 3–5 together in a loose pseudowhorl, or, especially the smaller ones, spirally and evenly arranged along the stems. Blade 25–130 x 6–40mm, narrowly elliptic to elliptic; apex acute or acuminate, the extreme tip rounded; margin revolute especially in the smaller leaves; base acutely tapering, scaly on both sides initially, silvery-scaly but glabrescent above with age although leaving dark pits from scale attachments; beneath completely covered with overlapping brown scales. Scales very variable in size, the largest c.0.2mm in diameter, with pale brown, broad flanges and large, dark brown, centres. Mid-vein very broad beneath, gradually decreasing distally; lateral veins 5–10 per side, wide-spreading almost to a right angle or in small leaves not visible, clearly anastomosing; distinctly impressed above, prominent beneath, with lax reticulation; lamina markedly rugose. Petiole 5–12 x 2–3mm, grooved above, somewhat flattened, densely scaly. Flower buds ovoid, large. Bracts to 24 x 12mm, ovate to obovate-spathulate, the outer ones all over finely hairy, scaly in the upper outer part, the inner ones scaly only externally, all fringed with simple white hairs. Bracteoles to 16mm, linear below, spathulate distally, ciliate. Inflorescence of 10–13 flowers in a complete or open umbel. Pedicels 15–20mm, thick, densely scaly. Calyx oblique, small, cup-shaped, shortly obtusely 5-lobed, densely scaly. Corolla 15 x 20mm, widely funnel-shaped, white, without scent; tube 3–6 x 3 x 6mm, shortly funnel-shaped, very densely brown-scaly, densely hairy inside except where the filaments are inserted; lobes 9–12 x 9–12mm, glabrous inside, brown-scaly in the lower ½ outside. Stamens c.9mm; filaments white, linear, glabrous at the very base then hairy to the apex; anthers c.3mm, purple-brown, the cells divergent below, each bearing a basal conical obtuse lobe. Disc glabrous. Ovary 2.5 x 1.7mm, conical, densely scaly, gradually tapering distally; style 2.5mm, thick, glabrous; stigma thick, rounded. Fruit brown, shortly cylindrical, 18–23 x 3mm.
Distribution: Indonesia, C Borneo, top of Bukit Raya in the Schwaner Mts
Altitude: 1500-2300m
Latin – fortunatus – prosperous, lucky or happy; presumably the collector was happy to find such an attractive plant.
This is an interesting species repeatedly collected on Bukit Raya but not yet introduced into cultivation. The flowers are, as far as can be compared from dry specimens, identical with those of R. himantodes but the leaves are markedly different. They are not linear in shape, but elliptic and markedly rugose, with very prominent lateral veins which give R. fortunans a very different appearance to that of R. himantodes. The very wide range of leaf sizes in different specimens of this species is curious and field observations are needed to explain these differences.
Type: Molengraaf 3436 B, 6 Oct. 1984. Indonesia, (Borneo), Central Kalimantan, Schwaner Mts, B. Raja (BO, L).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: brown, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:116
Shrub or tree, 3-10 m. Leaves broadly oblanceolate to obovate, 8-18 x 2.5-6cm, 1.7-4 x as long as broad, apex ± acute to rounded and mucronate, base rounded, lower surface glabrous except for persistent punctulate hair bases; petioles 1.2-3 cm, glabrous. Inflorescence 5-12-flowered; rhachis 15-40 mm; pedicels 25-40 mm, stipitate-glandular or glabrous. Calyx 1-3 mm, lobes minute, rounded, stipitate-glandular or glabrous. Corolla 7-lobed, open- to funnel-campanulate, glandular or glabrous outside, glabrous within, pale rose, sometimes becoming almost white, 55-70 mm. Stamens 14-16, filaments glabrous. Ovary and entire style stipitate-glandular. Capsule 25-40 x c. 12 mm, straight or curved.
Habitat: Open woods, etc
Altitude: 600-2300m
Occurs in Countries: CN Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: rose, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):234
Leaves oblanceolate, 2.8-4 x as long as broad
Distribution: China (Sichuan, Hubei, Guizhou, Guangxi, Hunan, Anhui, Zhejiang)
Illustrations:
R. fortunei in the strict sense refers to plants with broad leaves, not tapering below. The narrower-leaved forms include both R, discolor and R. houlstonil the former supposedly differing from the latter in the length of its calyx, a character difference not even borne out by the type specimens. There is apparently some overlap, even in the leaf shape and, contrary to published accounts of these taxa, there is only partial geographical separation between them. For these reasons the two taxa are treated as subspecies under R. fortunei. R. kwangfuense was originally described as having glabrous styles and was thus allied to R, oreodoxa; the styles of the type are however clearly glandular confirming that R. kwangfuense is better treated as a synonym of subsp. discolor.
Synonymy: R. discolor Franchet, J. Bot. (Morot) 9: 391 (1895). Type: China, aux environs de Tchen-keou-tin, Farges 705 (iso. E,K). R. mandarinorum Diels, Bot. Jahrb. 29: 510 (1900). Syntypes: China, Sichuan, Nan ch'uan, Bock von Rosthorn 2150, 2156, 2160 (n.v.). R. houlstonii Hemsley & Wilson, Kew Bull. 1910: 110 (1910). Syntypes: China, W Hubei, 1900, Wilson 312 (A); 2154 p.p. (K). R. kirkii Millais, Rhododendrons, ed. 1: 169 (1917)- nom. illegit. R. kwangfuense Chun & Fang, Acta Phytotax. Sin. 6: 170, t. 41 (1957). Type: China, Guangxi, Lungsheng Hsien, Tati Hsiang, Hungyai Shan, 2-8 v 1955, Kwangfu Exped. 146 (holo. SZ; iso. Herb. Inst. Bot. Guangzhou).
Leaves obovate, 1.8-2.5 x as long as broad
Distribution: China (E Sichuan, Guangxi, Hunan, Guangdong, Jiangxi, Fujian, Anhui, Zhejiang)
Illustrations:
Cavalerie 4387 & 7826, from Yunnan-sen and the type of R. albicaule are too poor to be certain whether they belong to R. vernicosum or to R. fortunei but the locality suggests that they are probably referable to the latter species.
Type: A cultivated specimen grown by Mr Glendinning, collected in China, Zhejiang Prov., W of Ningpo, by Mr Fortune -(n.v.)
Synonymy: R. albicaule Leveille in Feddes Repert. 18: 148 (1914), Type: China, Guizhou, montagnes de Sin Tchen, pres Hin-y-Hien, vi 1912, Cavalerie 3923 (holo. E; iso. K)
Tussock-forming shrublet up to 40 cm. Young growth lepidote and puberulent. Leaves oblong-elliptic, 10-17 X 5-9 mm, ± rounded at the base, obtuse or rounded at the apex, upper surface dark green, rugose, glossy with persistent scales, puberulent along the midrib, lower surface pale green with reticulate venation and distant, golden or brown, vesicular scales, margin crenulate, and, at least when young, loriform-ciliate. Inflorescence 2-3-flowered, pedicels lepidote with stalked scales and densely pubescent, 7-10 mm. Calyx lobes reddish, oblong, rounded at the apex, 5-7 mm, sparsely lepidote and sometimes puberulent, fringed with scales and filiform-acicular hairs. Corolla strawberry-red to purple, 13-18 mm, tube 5-7 mm, usually elepidote and glabrous outside, rarely with a few hairs or scales on the lobes near the margins, pubescent within the tube. Stamens 10, filaments pubescent towards the base. Ovary lepidote, style glabrous, elepidote. Capsule lepidote, c. 7 mm.
Habitat: Open hillsides and in swampy pasture
Distribution: Bhutan, China (SE Xizang)
Altitude: 3650-4500m
Type: China, S Tibet, Temo La, 15000 ft, 5 vi 1924, Kingdon Ward 5734 (holo. K)
Occurs in Countries: BT, CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: purple
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):119
Small shrub to 0.5 m. Leaf-bud scales deciduous. Leaves oblong-elliptic to oblong-ovate, 10-20 x 5-10 mm, somewhat revolute, tapered to rounded at the base, tapered to the obtuse apex, above dark glossy green, elepidote, somewhat rugose, beneath pale yellowish with dense, overlapping, ± plastered scales. Inflorescence 7-15-flowered, pedicels lepidote. Calyx lobes 1-3 mm, ovate, obtuse, fringed with dense loriform cilia. Corolla pale pink to pink, lobes usually with prominent darker veins, tube 6.5-8.5 mm, glabrous and elepidote outside, villous-pilose within, the lobes 4-5-6 mm, pilose within for some distance from the throat of the tube. Stamens 5(-6). Ovary lepidote. Capsule lepidote, 3-6 mm. USSR (Siberia: Angara-Sayan, Dauria, River Lena area, Okhotsk), MONGOLIA. Forming thickets in the alpine zone. (Cf. Busch, Fl. Sib. et Or. Ext. fasc. 2:21 for a distribution map of this species under the name R. anthopogon)
Illustrations:
A well-marked species, similar to, but quite distinct from, R. primuliflorum, with which it has been confused in most of the horticultural literature.
Type: described from USSR, NE Siberia, non Paxton in Paxton's Bot. Mag. 10:147 (1843), which is an elepidote hybrid, thought to beR. viscosum x ? catawbiense.
Synonymy: Azalea fragrans Adams, Mem. Soc. Mosc. 5:92 (1808). Osmothamnus fragrans (Adams) De Candolle, Prodr. 7:715 (1839). O. pallidus [Turczaninow ex] De Candolle, loc. cit. Type: USSR, in rupibus Alpium Baicalensium, Turczaninow. R. adamsii Rehder, Publ. Arn. Arb. 9:190 (1921). Type: as for R. fragrans.
Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: pink
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):167
Small, much-branched shrub, to 75cm. Twigs rounded, sparsely to sub-densely covered with sub-stellate low scales, older glabrescent parts at first a little rough with scale bases later becoming smooth; internodes 0.3–3.5cm. Leaves 5–8 together in dense pseudowhorls, obovate-elliptic or spathulate. Blade 18–35 x 4–8mm; apex obtuse or rounded; margin slightly revolute; base tapering; glabrescent above, persistently scaly or slowly glabrescent beneath also. Scales small, flat, with a narrow marginal zone, sub-entire or irregularly shallowly lobed; centre relatively large and somewhat impressed. Mid-vein impressed above, obtusely raised beneath in the proximal ½, disappearing distally; lateral veins not visible. Petiole 1–2mm, scaly, flat. Bracts to 6 x 2mm, narrowly ovate-acuminate, long subulate, membranous, sparsely scaly and papillose at the apex, glabrous proximally, the margins fringed with scales. Flowers solitary, half-hanging to hanging. Pedicels 10–13mm, thick, densely covered with stellate scales and with a few short hairs. Calyx c.3mm in diameter, small, disc-shaped, thin, shortly 5-lobed, scaly and often shortly hairy outside. Corolla 14–16 x 7–9mm, broadly tubular-campanulate, thin, red; tube 10–12 x 4–5 x 5–7mm, broadly cylindrical, densely covered with sub-entire, thick scales outside, laxly long-hairy in the proximal ½ inside; lobes c.3.5 x 3.5mm, ovate, obtusely pointed, scaly outside, erect to partly spreading. Stamens exserted to c.2mm, sub-equal; filaments linear, dilated at the base, densely patently hairy nearly to the top; anthers c.1.4mm, sub-quadrangular, truncate. Disc glabrous. Ovary c.4 x 2mm, ovoid-conical, densely scaly and long white-hairy, the hairs covering the scales, abruptly contracted distally; style 7–8mm, covered in the proximal 2⁄5 with white hairs; stigma globose. Fruit 13–15 x 4–5mm, sub-cylindrical, laxly hairy and scaly. Seeds 4mm, including the long tails.
Habitat: Terrestrial on slopes.
Distribution: Indonesia, N Sumatra, Gajo Lands: Bur ni Tèlong and Redelong Volcano.
Altitude: 1800-2000m
Named after the Swiss botanist Albert Friedrich Frey-Wyssling, who collected this species.
Resembling R. pubigermen in the foliage but differing in the much more parallel-sided corolla tube with shorter corolla lobes which are held much more erect. Not known in cultivation.
Type: Frey-Wyssling 25, 16 June 1930. Indonesia, Sumatra, Atjeh, Boer-ni-Telong (AA, L).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:193
Upright shrub; young shoots covered with flattened adpressed brown hairs. Leaves apparently monomorphic, elliptic to ovate, 1-4 x 0.5-1.4cm, 2-2.5 x as long as broad, apex acute or acuminate, base cuneate, margin entire, upper surface strigose, lower surface with flattened strigose hairs on midrib, otherwise glabrous; petioles 3-5mm, densely covered with brown strigose hairs. Inflorescence 3-5-flowered; pedicels 3-5mm, covered with shiny long brown strigose hairs, with an understorey of glandular hairs. Calyx densely covered with brown flattened strigose hairs, lobes 2-4mm, linear-lanccolaate. Corolla funnel-shaped, pale rose, 5-10mm; tube 3-5mm, with five rows of glandular hairs on outer surface. Stamens 5, c. as long as corolla, glandular below middle. Ovary covered with shining red-brown hairs; style glandular and pilose below middle, shorter than stamens. Capsule not known.
Distribution: China (Guizhou, Guangxi)
The recently described R. tenue lacks flowers but in all other respects resembles R. fuchsiifolium.
Type: China, Guizhou, Pin-fa, 20 v 1907, Cavalerie 3221 (holo. E)
Synonymy: R. tenue [Ching ex] Fang & MY. He, Bull. Bot. Res. N.E. Forest. Inst. 2(2): 87, t.5 (1982). Type: China, Guangxi, Xingan Xian, Jiu Qu, Leigontien, ad Tangton, vi 1953, Guangxi PL Exp. 677 (holo. PE, iso. IBSC).
Occurs in Countries: CN Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: rose
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):128
Shrub, 1.5-4.5m; young shoots glabrous. Leaves broadly ovate to obovate, (7—)9—11 x (4-)5-7cm, 1.5-1.8 x as long as broad, apex rounded, apiculate, base cordate to rounded, upper surface glabrous, lower surface covered with a dense fulvous lanate tomentum composed of fasciculate hairs; petioles 1 -2cm, glabrous when mature. Inflorescence dense, 8-14-flowered; rhachis 10-25mm, pedicels 7—10mm, glabrous. Calyx 1 -2mm, glabrous. Corolla tubular-campanulate, scarlet to blood-red, with darker nectar pouches, 20-35mm. Ovary glabrous. Capsule 13-30 x c.5mm, curved.
Habitat: Mixed forests
Distribution: E Nepal, Bhutan, NE India (Sikkim, Bengal, Arunachal Pradesh) China (S Xizang).
Altitude: 3200-4300m
Illustrations:
R. fulgens superficially resembles R. succothii (subsection Barbata) but clearly differs in its lanate leaf indumentum.
Type: Sikkim, 12-14000ft, Hooker (holo. K; iso. E)
Occurs in Countries: BT, CN, IN, NP Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: scarlet
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):415
Shrub or small tree, 2-8m; young shoots rufous-tomentose. Leaves oblanceolate to elliptic, 8-22 X 3.6-8cm, 2.2-3.5 x as long as broad, apex ± rounded, apiculate, base cuneate, upper surface glabrous when mature, lower surface with a dense bistrate indumentum, the upper layer fulvous, largely composed of capitellate hairs, giving the surface a granular appearance, the lower stellate-velutinous, whitish; petioles l-2cm, with a compacted tomentum intermixed with some stipitate glands. Inflorescence 10-20-flowered; rhachis 10-15mm; pedicels 20-30mm, slender, glabrous. Calyx c.0.5mm, glabrous. Corolla campanulate, white to pink, usually with a basal blotch, with or without purple or crimson flecks, 25-45mm. Ovary glabrous. Capsule 25-40 x 4—5mm, strongly curved.
Habitat: Rhododendron thickets, etc.
Distribution: China (W Yunnan, SE Xizang), and adjacent ne Upper Burma.
Altitude: 3000-4700m
There is variation in leaf shape and in the colour of the indumentum which is only partly correlated with geographical distribution. Plants with relatively broad leaves on which the indumentum is pinkish-brown to rust-coloured (matching the type) occur in the southern part of the species range, though apparently alongside narrower-leaved forms, with a darker, often yellowish-brown indumentum (matching R. fulvoides) that become more common in the northern part of the range. There is however considerable overlap between the two extremes so that R. fulvoides has not been maintained, even at varietal rank.
Type: China, W Yunnan, western flank of the Shweli/Salween divide, 10- 11000ft, viii 1912, Forrest 8929 (holo. E)
Synonymy: R. fulvoides Balfour f. & Forrest, Notes R.B.G. Edinb. 12: 112 (1920). Type: China, NW Yunnan, Mekong/Salween divide, 11000ft, x 1914 Forrest 13400 (holo. E)
Occurs in Countries: CN, MM Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: crimson, pink, purple, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):366
Tree, 5-8m (in the wild). Leaves ovate-lanceolate, 14-20 x 5-6.2cm, 2.6—3.3 X as long as broad, apex ± obtuse, apiculate, base rounded, upper surface glabrous, smooth, lower surface with a bistrate indumentum, the lower layer whitish and compacted, the upper dense, cinnamon, composed of strongly fimbriate, narrowly cup-shaped hairs; petioles 2—3.5mm, terete, tomentose. Inflorescence 9—15-flowered; rhachis c.5mm; pedicels 50—55mm, sparsely tomentose. Calyx c.lmm, tomentose, teeth triangular. Corolla 7-lobed, campanulate, pale rose with a crimson basal blotch, (30—)40—50mm. Stamens 14. Ovary glabrous or with a few rufous hairs. Capsule not known.
Distribution: China (C Sichuan)
The wild-collected specimen of Wilson 4254 is in fruit and, although close to R. rex subsp. rex, it differs in the more strongly fimbriate hairs. The ovary is apparently consistently much less hairy than that of subsp. rex.
Type: A plant cultivated at Caerhays by J. C. Williams; raised from seed as Wilson 4254 from Pan-lan-shan, W of Kuan hsien in C Sichuan (?E)
Occurs in Countries: CN Subgenus: Hymenanthes Habit: Tree Fl. Colour: crimson, rose
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):257
Shrub to 2.5m. Twigs 6–8mm in diameter, thick, rounded, brown scaly when young quickly becoming glabrescent and often glaucous white in the older parts; internodes 15–20cm. Leaves 3–5 together in well-marked pseudowhorls at the upper nodes, very stiff and leathery. Blade 80–150 x 55–90mm, patent, elliptic or broadly elliptic, rarely sub-obovate-elliptic; apex obtuse, or rounded to a little retuse; margin cartilaginous, flat or narrowly but distinctly revolute; base broadly tapering to rounded; densely brown scaly initially on both sides, soon becoming glabrescent and rough to the touch due to the persistent tubercles on both sides but especially beneath. Scales minute, deeply stellately divided and distinctly dendroid, each on top of a paler minute epidermal tubercle. Mid-vein robust in the lower ½ of the blade, impressed above, very prominent beneath, flat and wrinkled in dry specimens; lateral veins 8–10 per side, straight below, curved and indistinctly anastomosing before the margin, very slightly prominent on both sides or somewhat impressed above, often becoming inconspicuous towards the edge, no distinct reticulation visible. Petiole 20–40 x 2.5–4mm, brown scaly initially, often glaucous. Flower buds to 50 x 30mm, green or purple, ovoid with a broadly acute apex, the bracts all appressed. Bracts broadly elliptic, to obovate to spathulate, often splitting at the apex to become emarginate, scabrid with short erect hairs outside and short appressed hairs inside. Bracteoles to 60 x 4mm, linear, slightly broadened upwards, laxly hairy. Inflorescence an open 3–4-flowered umbel, the flowers semi-erect to half-hanging. Pedicels 10–35 x 3–5mm, thick, densely covered with brown sessile scales and laxly hairy, more densely near the calyx. Calyx 8–10mm in diameter, oblique, scaly and hairy outside, glabrous inside and irregularly obtusely 5–8-lobed; the lobes triangular, 2–3mm, white-ciliate along the margins. Corolla 90–110 x 110–140mm, tubular-funnel-shaped, white or suffused with pink, cream, or even (when very young) green on the tube, sometimes with pink ‘dimpled’ spots at the base of each lobe, fleshy, (the tube up to 3mm thick just below the lobes), strongly fragrant; tube 50–70 x 10–12 x 15–25mm, straight, glabrous outside, densely covered with retrorse white hairs in its lower ½–¾ inside; lobes 50–60 x 30–50mm, 5–8, spreading perpendicularly, overlapping to ¾, or with reflexed lateral margins in which case they hardly overlap, broadly obovate, glabrous. Stamens 10–16, slightly unequal, clustered on the lower side of the mouth, drooping downwards with age, exserted to c.20mm; filaments linear and densely patently hairy below, glabrous and filiform distally; anthers 10–12 x 1.5mm, curved upwards, pale brown, linear-oblong, base obtuse. Disc prominent, very densely hairy. Ovary oblong-cylindrical, densely covered with sub-appressed, yellowish, stiff hairs which completely cover the numerous scales, c.13 x 5mm, abruptly tapering distally; style 60–110 x 3–5mm, strong, glabrous except for some hairs at the very base; stigma 4–6mm in diameter, sub-globose, obtusely 5–8-lobed, becoming exserted to 50mm. Fruit 75–85 x 14–15mm, ellipsoid. Seeds 6.5–8mm, without tails c.1mm, the longest tail 3.8mm, crimped.
Habitat: High epiphyte in forest, but also a terrestrial shrub in sandy openings in mossy forest on the crest of mountain ridges, said to be locally abundant and conspicuous around Telefomin.
Distribution: Indonesia, New Guinea (W), Bele R. Valley, 25km NE of Lake Habbema; E of Baliem R. Valley, Angguruk. Papua New Guinea, Sepik R. region, Schrader Mts, W Sepik region: above airfield at Telefomin; Along Eliptamin track, Telefomin; Oksapmin near Telefomin; Star Mts between Busilmin airstrip and Bielga R.
Altitude: 1400-2300m
Named after the genus Gardenia in the Rubiaceae as the white, strongly scented flowers are reminiscent of this genus.
Type: Ledermann 12024. New Guinea (E), Northeastern part, Sepik R. region, Schrader Mts (B†). Lectotype: Brass 10832, Oct. 1938. New Guinea (W), Bele R. Valley, 25km NE of Lake Habbema (A, L).
Occurs in Countries: ID, PG Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: cream, green, pink, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:81
Latin – Gaultheria – a genus in the Ericaceae; folium – leaved. With leaves like a Gaultheria.
Type: Lam 1661. New Guinea (W), Doormantop, 3520m (BO, lectotype, L).
Occurs in Countries: ID, PG Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Vireya Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:56
Shrub of erect ascending or prostrate habit, 0.05–1m. Leaves 2–5 x 3–4mm, elliptic, very leathery and shining. Flowers dark-red or orange-red. Fruit 6–7 x 2.5–3mm.
Distribution: Indonesia, New Guinea (W), Mt Jaya (Carstensz), Mt Antares and the Burgers Mts. Growing in open alpine grassland, on exposed limestone or sandstone slopes. Locally abundant
Altitude: 3000-3800m
Latin – expositus – exposed, alluding to the extreme habitat of this variety.
An alpine form with smaller leaves and capsules.
Type: Brass & Meijer Drees 10122. New Guinea (W), 2km east of the top of Mt Wilhelmina, 3000–3800m (L, A).
Slender erect shrub to 5m. Twigs slender, tips covered with stalked scales, lower parts densely rough with the persistent scale stalks. Leaves spirally arranged, crowded towards the ends of the twigs. Blade 5–10 x 4–7mm, ovate, rarely elliptic-ovate; apex shortly obtusely acuminate; margin thickened and revolute, irregularly crenulate with impressed scales; base rounded to sub-truncate, dark to yellowish green, paler below, sparsely scaly and early glabrescent above, sub-densely and persistently brown scaly below. Scales round, sessile, entire, with a broad dark centre, thick and impressed. Mid-vein slightly impressed above, slightly raised beneath, lateral veins indistinct. Petiole 1.5–2mm, grooved above, scaly and minutely hairy. Flower buds to 8 x 4mm, ovate, acutely pointed, brown, with both scales and short appressed hairs outside. Outer bracts subulate, densely scaly, inner ones to 7 x 4mm, ovate-acuminate, apiculate, shortly hairy and scaly outside in the upper part, shortly hairy or glabrous inside, all bracts densely white ciliate on the margins. Bracteoles to 7mm, linear, glabrous, or hairy and scaly distally. Inflorescence of solitary or paired flowers, rarely 3–4 together, hanging vertically. Pedicels 6–9 x c.1mm, densely scaly and laxly minutely hairy. Calyx oblique, disc-shaped, densely scaly outside, obtusely 5-lobed, occasionally one or a few lobes elongate-triangular, acute, to 1mm. Corolla 12–17 x c.9mm, deep red to brownish red, sometimes greenish yellow or orange, tubular, somewhat zygomorphic; tube 8–12 x 3–8 x 5–7mm, straight, densely scaly outside, glabrous inside; lobes 3–5 x 3–5mm, sub-circular, erect or a little spreading, scaly outside except along the margins and laxly hairy outside in the distal ½, and distinctly ciliate crenulate-denticulate on the distal margin. Stamens clustered on the lower side at the corolla mouth, or exserted to 2mm, slightly unequal; filaments 9–10mm, red, linear at the base, filiform upwards, glabrous; anthers c.1mm. Disc glabrous. Ovary c.3 x 2.5mm, conical, densely scaly, gradually tapering distally; style c.7mm, lying on the lower side of the tube, thick, scaly at the base, otherwise glabrous; stigma shortly club-shaped, irregularly lobed. Fruit 8–9 x 3.5–4mm, erect, narrowly conical, longitudinally 5-ribbed, densely scaly.
Habitat: In shrubberies bordering the sub-alpine forest, occupying patches of wet sandy or peaty soil, or on the more sterile peaty ridges; also in grassland above the timber line, between summit rocks. Locally common, occasionally dominant
Distribution: Indonesia, New Guinea (W), Oranje Mts, Mt Doorman. Papua New Guinea, Star Mts, Eastern and Western Highlands.
Altitude: 2900-4150m
Small shrub to 0-6 m. Young growth densely lepidote. Leaves 16-22 x 8-11 mm, ± elliptic, obtuse at the apex, rounded-cuneate at the base, glabrous but lepidote above with ± dried-out scales, densely lepidote beneath with flat, broadly rimmed, pale to dark brown scales about their own diameter apart. Inflorescences 2-3-flowered, pedicels lepidote, 6-10 mm. Calyx rim-like, lepidote, occasionally somewhat ciliate with loriform setae. Corolla pale lavender, not very strongly zygomorphic, c. 12 mm, lube c. 5 mm, glabrous and elepidote outside, pubescent within the tube. Stamens 10, filaments pubescent towards the base. Ovary lepidote, style glabrous, elepidote. Capsule unknown.
Habitat: Open pasture and margins of thickets
Distribution: China (N & NW Yunnan)
Altitude: 3350-4250m
A rather obscure species, which, as pointed out by the Philipsons, is in many ways intermediate between subsections Triflora and Lapponica. For this reason it is included here at the end of subsection Triflora, which it resembles particularly in the characters of its inflorescence. It is possible that it may be of hybrid origin between R. siderophyllum or R. tatsienense (both small-flowered species of subsection Triflora) and some unknown species of subsection Lapponica.
Type: China, Yunnan, on the Li-ti-ping, 11-12000 ft, vi 1917, Forrest 13902 (holo. E)
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: lavender
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):80
Shrub to 5 m; bark of older branches smooth, purplish, young shoots glabrous. Leaves narrowly elliptic to narrowly elliptic-oblanceolate, abruptly acuminate at the apex, tapered to the base, 65-120 x 25-40 mm, upper surface dark green, lower surface conspicuously white-papillose with distant, small, equal, golden yellow to brown scales. Inflorescence many-flowered, racemose, pedicels thin, rather strict in flower, lepidote, pruinose, 20-30 mm. Calyx a rim or sometimes slightly lobed, 1-2 mm, glabrous, elepidote or sparsely lepidote, pruinose. Corolla fleshy, 12—17 mm, tube 6-8 mm, reddish purple, pruinose, glabrous and elepidote. Capsule lepidote, cylindric, 6-9 mm.
Habitat: Scrub, thickets and on forest margins
Distribution: N Burma, China (W Yunnan, SE Xizang)
Altitude: 2450-4250m
Illustrations:
Type: NE Burma, N'Maikha/Salween Divide, Salween flank, iv 1919, Forrest 17824 (holo. E)
Synonymy: R. mirabile Kingdon Ward, Gard. Chron. 92:465 (1932) nomen nudum.
Occurs in Countries: CN, MM Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: purple, red
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):148
Shrub to 1.5m. Twigs rounded, sub-densely scaly when young, glabrescent and whitish later; internodes 5–9cm. Leaves 2–4 together in tight pseudowhorls. Blade 35–60 x 14–25mm, elliptic or very slightly obovate- elliptic; apex broadly acute to obtuse; margin narrowly revolute; base broadly to narrowly tapering; sub-densely scaly when young, though quickly glabrescent above, persistently impressed-scaly beneath. Scales rounded, brown, dome-shaped with a narrow marginal zone, impressed and surrounded by transparent depressions. Mid-vein slightly grooved above, strong and prominent beneath; lateral veins 1–4 per side, obscure, slightly curved, parallel to each other, smooth, reticulation obscure. Petiole 2–5 x 1–3mm, semi-circular in section, grooved above, scaly. Bracts broadly ovate, fringed with scales and with a few scales on the outer surface near the tip, especially along the median line, otherwise glabrous. Bracteoles to 10mm, narrowly linear. Inflorescence a 5–8-flowered umbel. Pedicels to 7 x 0.5mm, slender, sparsely scaly. Calyx very small, disc-shaped, sub-entire, moderately scaly. Corolla 30–35 x 11mm, trumpet-shaped, white; tube 28 x 3.5 x 4mm, straight or very slightly curved, almost parallel sided, densely scaly outside, hairy and with a few scales inside near the base; lobes 5 x 4mm, spreading, circular to elliptic, with a few scales outside, glabrous inside. Stamens exserted to c.5mm; filaments slender, sparsely and patently hairy in the proximal 1⁄3 only, glabrous distally; anthers c.1.5 x 0.7mm, oblong. Disc hairy on the upper side, otherwise glabrous. Ovary 2.8 x 1.2mm, narrowly cylindrical, moderately hairy with semi-appressed white hairs and very densely scaly, abruptly tapering distally; style exserted from the mouth, laxly hairy and with scattered scales to within 2mm of the stigma, this distal part glabrous; stigma shortly-obconical.
Habitat: Epiphytic shrub growing in montane rain forest on ridge tops dominated by Dacrycarpus, Decussocarpus (Retrophyllum) and Serianthes and in steep limestone country dominated by Weinmannia.
Distribution: Papua New Guinea, Province of New Ireland, subprovince Namatanai, Northern Hans Meyer Range, 70km SE of Namatanai (the type) and also from subprovince Konos, E of Letet Farm.
Altitude: 850-1020m
Named in honour of Osia Gideon, botanist with the Lae herbarium and collector of this species.
At present known only from two herbarium collections.
This species is in some respects like R. protandrum Sleumer and would be a surprising distributional pattern if it were this species as R. protandrum at present is known only from the Sibil River Valley in West New Guinea a great distance away. It does in fact differ from R. protandrum in several respects. The stamens and stigma are not as dramatically exserted from the mouth of the flower (up to c.5mm whereas in R. protandrum they are exserted to 10mm or more). The style is both scaly and hairy almost to the stigma, whereas in R. protandrum the style is hairy only in the basal 10mm, although scaly almost to the summit. Other small differences are that there are scales on the bracts and bracteoles and there are no backwardly pointing hairs on the inside of the corolla tube in this species.
It would make a more likely distribution pattern if it were a form of R. herzogii which is widespread on the mainland of New Guinea, but the ovary and style of that species totally lack simple hairs, the flowers are much larger and the anthers longer. Shrinkage of the corollas has undoubtedly taken place in the herbarium specimens studied so that the real dimensions of the flower might be larger, but the anthers usually remain constant and the indumentum certainly does not change with poor pressing. Overall the impression of this species is of a smaller and more delicate plant than R. herzogii.
Type: Gideon & Obedi LAE 77179, 1 Nov. 1984. Papua New Guinea, New Ireland, Northern Hans Meyer Range, 70km SE of Namatanai (LAE, L).
Occurs in Countries: IE, PG Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:68
Shrub to 3m. Twigs c.1.5mm in diameter, slender, densely covered with shortly stalked scales in the younger parts, rough with the stalks after the scales have gone and with conspicuous rounded lateral buds. Leaves spreading, spiral, mostly at the upper 1⁄3 of the internodes which are 2–8cm apart. Blade 15–20 x 7–12mm, glossy dark green above, brown beneath, elliptic to ovate-elliptic, sometimes nearly rounded; apex broadly tapering, obtuse to rounded, not apiculate; margin slightly revolute; base rounded, abruptly contracted, densely scaly on both sides initially, early glabrescent above, the flat scales leaving small, shallow pits on the upper surface, very densely overlapping, brown-scaly beneath. Scales translucent or pale brown, with broad lobed flanges and small impressed centres; scattered at fairly regular intervals are much larger, darker brown scales, with large swollen centres which gives the underside of the leaf a spotted appearance. Mid-vein narrowly impressed above, moderately to strongly raised beneath; lateral veins 2–3 per side, spreading, irregular, indistinctly anastomosing, slightly depressed above, obscure below. Petiole 2–3 x c.1mm, flattened, and somewhat winged by the decurrent blade in the distal ½, grooved above, scaly. Flower buds to 10 x 7mm, deep red, broadly ovoid, the tips and margins appressed. Bracts to 10 x 7mm, ovate, obtuse, outer ones scaly outside, inner ones larger, glabrous, not hairy. Bracteoles to 10mm, filiform, glabrous. Inflorescence 1–4-flowered, the flowers held horizontally. Pedicels 10–14mm, thick, densely brown-scaly. Calyx 3–4mm in diameter, obliquely disc-shaped, the margin wavy, densely scaly outside. Corolla 28–35 x 15–18mm, red, completely glabrous both outside and inside; tube 20–25 x 4–5 x 7–10mm, cylindrical, straight, flaring slightly at the mouth; lobes c.10 x 10mm, nearly circular, spreading, often retuse. Stamens 25–30mm, unequal; filaments linear, but dilated below, glabrous; anthers 2.6–3 x c.1mm. Disc glabrous. Ovary 5 x 2.5mm, conical, densely shortly patently hairy and scaly, gradually tapering distally; style c.24mm, thick, glabrous except for scales at the base; stigma broad-conical, the lobes inconspicuous.
Distribution: Papua New Guinea, Owen Stanley Range: Mt Scratchley, English Peaks near Lake Omha, Mt Victoria
Altitude: 3050-3960m
Named after the collector, who was one time travelling government agent for the collecting of natural history objects and was shot at Mekeo, New Guinea in 1901.
This species has been confused with R. comptum but differs in the spreading leaves, the more rounded leaf shape, the usually visible lateral veins and the completely glabrous corollas outside. It would also appear to have larger flowers with a different disposition but this needs to be confirmed with more observations.
Type: Giulianetti s.n., 1896. E New Guinea, Owen Stanley Range, Mt Scratchley (B†, K, MEL).
Synonymy: R. papuanum (non Becc.) C.H.Wright, Kew Bull. 1899. 104.
Occurs in Countries: PG Altitude Ranges: 3,000 - 4,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:136
Shrub. Twigs slender, sparsely scaly; internodes 3.5–13cm. Leaves 3–5 together in tight pseudowhorls. Blade 40–160 x 12–50mm, elliptic to narrowly ovate-elliptic; apex acuminate, acute, margin entire, flat, base broadly tapering, sometimes slightly decurrent; glabrescent above, sub-densely and more persistently scaly beneath. Scales sub-stellately lobed, margin broad; centre small and slightly impressed. Mid-vein narrowly impressed above, strongly prominent beneath; lateral veins 5–13 per side, spreading at a wide angle, anastomosing before the margin, reticulation lax to obscure. Petiole 2–5 x c.2mm, grooved above, scaly. Inflorescence 3–15 flowers in an open to complete umbel, flowers erect to semi-erect. Pedicels 30–50 x c.1mm, sparsely scaly. Calyx a low disc, scaly. Corolla c.27 x 33mm, red or yellow; tube 11–13 x c.8.5 x c.10mm, scaly outside, glabrous inside, or with a few sparse hairs, 5-angled, lobed at the base; lobes 11–13 x 8–10mm, wide-spreading to reflexed, not or only shortly overlapping, scaly outside. Stamens 21–23mm, arranged all round the flower, exserted to c.10mm; filaments filiform, glabrous or occasionally very sparsely hairy near the base; anthers c.2.5mm, oblong. Disc 10-lobed, glabrous. Ovary c.5 x 2.5mm, shortly cylindrical, longitudinally grooved, densely covered with distally pointing hairs which hide small scales; style hairy and scaly in the proximal ½, glabrous distally; stigma rounded.
Habitat: According to Sleumer (1966) it is predominantly or possibly exclusively epiphytic.
Distribution: Indonesia, New Guinea (W), Legarei R., near Manokwari, Arfak Mts; Mt Ditschi (as R. mayrii), Doormantop; Idenberg R.; Japen Is. Papua New Guinea, Torricelli Mts, Jimmy Valley
Altitude: 420-1675m
Latin – glaber – glabrous; filum – filament. Alluding to the glabrous filaments.
This species has been reinstated after having been reduced to a variety of R. macgregoriae by Sleumer as it is readily identifiable and appears to have a mostly coherent northerly distribution. The flowers are usually red although the type specimen is recorded with a degree of uncertainty as having yellow flowers. The leaves are generally much larger than those of R. macgregoriae and with much shorter petioles relative to the blade length.
Type: Janowski 65, June 1912. New Guinea (NW), Legarei R., near Manokwari (BO).
Synonymy: R. torricellense Schltr., Bot. Jahr. 1917. 55: 142. R. mayrii J.J.Sm., Nova Guinea 1936. 18: 97, t.20, f.2. R. macgregoriae F.Muell. var. glabrifilum Sleumer, Reinwardtia 1960. 5: 206.
Occurs in Countries: ID, PG Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:314
Shrub to 3m. Twigs 4–7mm in diameter, rounded, at first sub-densely scaly, often white, minutely warty; internodes 4–5cm. Leaves 6–7 together in lax pseudowhorls. Blade 60–90 x 20–40mm, elliptic; apex broadly acute to obtuse; margin narrowly cartilaginous, narrowly revolute; base tapering or broadly tapering; glabrescent and rugulose above; laxly to sub-densely scaly beneath. Scales flat, thin, marginal zone relatively large, irregularly sub-stellately lobed; centre minute, dark, hardly impressed. Mid-vein narrow and deeply impressed above, strong and prominent proximally beneath, gradually narrowing distally; lateral veins 8–10 per side; lowest from the base, steeply ascending, anastomosing, slightly impressed above, raised beneath, reticulation dense, not or faintly impressed above, distinct and prominent beneath. Petiole 8–12 x 20–25mm, grooved above, a little flattened, densely scaly. Flower buds to 35 x 32mm, sub-spherical, smooth, pale translucent whitish-green. Bracts to 28 x 25mm, broadly ovate, the apices rounded, densely scaly along a broad middle line outside, with fragile scales on the margins, without hairs, glabrous inside. Inflorescence 9–22-flowered, at first tightly clustered, later a lax open one-sided umbel. Pedicels 11–18mm, thick, very densely scaly, without hairs. Calyx c.3.5mm in diameter, disc-shaped, but slightly oblique, obscurely and very obtusely 5-lobed, scaly outside. Corolla 45–52mm, tubular-campanulate, fleshy, yellow (possibly sometimes red); tube c.35 x 6–7 x c.15mm, straight, glabrous inside and out; lobes 14–20 x 14–20mm, spreading, sub-circular. Stamens c.35mm, regularly arranged around the mouth of the corolla, not exserted; filaments linear, glabrous; anthers 4–4.5 x 2–2.2mm, obovoid, narrowed towards the base, each cell ending in a narrow apiculus. Disc glabrous. Ovary 6–7 x c.3mm, sub-ovoid-conical, densely scaly, abruptly narrowed distally; style c.20mm, scaly up to the proximal 1⁄3, glabrous distally; stigma rounded, yellow, deflexed to the side of the mouth, not exserted. Seeds 4.3–4.5mm, without tails 0.9–1.2mm, the longest tail 2.1mm.
Distribution: Indonesia, New Guinea (W), Wichmann Mts; Lake Habbema near Wamena.
Altitude: 3000-3200m
Latin – glaber – glabrous; florum – flower. The flowers being without hairs or scales.
Type: Pulle 1030. New Guinea, SW, top of the Wichmann Mts, 3100m (L).
Occurs in Countries: ID Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: red, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:294
Shrub. Leaves oblong-lanceolate, ± glabrous below; petioles c. 2.5 cm, glabrous. Inflorescence 5-6-flowered; rhachis elongate; pedicels densely covered with long-stipitate glands. Calyx c. 3 mm, lobes rounded, stipitate-glandular. Corolla 7-8-lobed, funnel-campanulate, densely long-stipitate-glandular on outer surface, white, c. 50 mm. Stamens 14-16, filaments glabrous. Ovary and style stipitate-glandular.
Distribution: China (NE Yunnan)
Only known for certain from the type specimen which is very incomplete. The long-stipitate glands on the corollas are unlike those found on any of the remaining species in the subsection. A specimen, Feng, K. M. 73436 from NE Yunnan, with setose-glandular capsules, 45-50 x c. 18 mm, probably belongs to this species but, without flowers, a definite determination cannot be made.
Type: China, NE Yunnan, ad Ta'kuan, Delavay 295 (iso.E)
Occurs in Countries: CN Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):229
Shrub to 1.5 m. Leaves narrowly elliptic to elliptic, rarely somewhat obovate, usually acute at the apex (very rarely obtuse), cuneate at the base, (35-)40-60 x (13—) 15—25 mm, upper surface dark brownish green. Inflorescence (2-)4-6-flowered, pedicels lepidote, 13-20 mm, rachis very short, lepidote. Calyx lobes ovate, acuminate, 6—9(—11) mm, often somewhat glaucous, lepidote at the base and around the margins, usually slightly loriform-ciliate, and with a tuft of hairs inside the apex. Corolla campanulate to tubular campanulate, (18-)20-27(-32) mm, tube (10-)13-17(-19) mm, pink or white flushed pink, rarely entirely white, sometimes spotted inside, rather densely lepidote outside, occasionally with a few hairs as well. Style impressed, sharply deflexed and shorter than the corolla, or declinate and exceeding the corolla. Capsule lepidote, ovoid, c. 10 mm.
Two varieties may be recognised
Occurs in Countries: BT, CN, IN, NP Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: pink, white
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):140
Distribution: Nepal, India (Sikkim), Bhutan. Rocky slopes, 3050-3350 m
Illustrations:
Type: Sikkim Himalaya, ridges of Cholen, Lachen and Lachoong, 10-12000 ft, Hooker (holo. K, iso. E)
Synonymy: R. glaucum Hooker, Rhodo. Sikkim Himalaya t. 17 (1849) non Sweet, Hort. Brit. ed. 2, 344 (1830). Type: as for var. glaucophyllum
Habitat: Forests and rocks
Distribution: India (Arunachal Pradesh), Bhutan, China (S Xizang)
Altitude: 2750-3650m
Type: India, Assam, Manda La, Balipara frontier tract, 10-11000 ft, 19 v 1935, Kingdon Ward 11463 (holo. E)
Shrub or small tree, 2-8m; shoots densely glandular-setose. Leaves herbaceous, obovate to elliptic, 11.5-30 x 3.3-8cm,2-4.2 x as long as broad, apex ± cuspidate, base rounded, margin herbaceous, ciliate, upper surface smooth to moderately rugose, with glandular setae above the midrib at base, otherwise glabrous, occasionally with bristles scattered over the whole surface, lower surface with a dense covering of setae, especially overlying the veins, sometimes also with a thin brown or whitish tomentum, especially towards the base; petioles l-2cm, stout, covered with stout glandular setae. Inflorescence 10-14-flowered, lax; rhachis very short; pedicels (15-)25-35 (-45)mm, densely stipitate-glandular. Calyx 5-10mm, lobes Ungulate, ciliate. Corolla campanulate, rose-pink to scarlet, occasionally white flushed rose, with purple flecks and usually also a basal blotch, 30-50mm. Ovary densely stipitate-glandular; style glabrous or glandular at base. Capsule 15—20 x 5—6mm.
Habitat: Mixed forests, etc.
Altitude: 3000-4000m
R. glischrum is a variable species with at least partial segregation into geographically distinct taxa. Subsp. glischroides is apparently intermediate between R. vesiculiferum and subsp. glischrum, but lacks the characteristic vesiculate hairs of R. vesiculiferum. R. glishcrum is also closely allied to R. habrotrichum.
Occurs in Countries: CN, MM Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: purple, rose, scarlet, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):284
Leaves glabrous above when mature or with setae confined to base above midrib. Upper surface of leaves rugose, veins with a thin covering of indumentum on lower surface.
Distribution: NE Upper Burma
R. glischroides Tagg & Forrest var. arachnoides Tagg & Forrest (loc. cit., 1931), based on Forrest 26425 & 27600, is probably a hybrid of subsp. glischroides. The leaves are smaller, 6-8cm long, with a denser, white indumentum over the whole of the lower surface.
Synonymy: R. glischroides Tagg & Forrest in Stevenson (ed.), The Species of Rhododendron 137 (1930) & Notes R.B.G. Edinb. 16: 194 (1931). Type: NE Upper Burma, western flank of the N'Maikha/Salween divide, nr Pan-ti-ho, 10-11000ft, iv 1925, Forrest 26426 (holo. E).
Leaves glabrous above when mature or with setae confined to base above midrib. Upper surface of leaves smooth, lower surface lacking tomentum.
Distribution: China (S Xizang, NW Yunnan), ne Upper Burma
Illustrations:
Forrest 25626, with the lower surface of the leaves tomentose and stipitate-glandular, is probably a hybrid of subsp. glischrum.
Type: China, NW Yunnan, Kari Pass, Yangtze/Mekong divide, vii 1914, Forrest 12901 (holo. E)
Distribution: China (NW Yunnan)
A specimen from the Tsangpo Gorge, Ludlow, Sherriff& Elliot 13606, is close to subsp. rude but differs in its smaller leaves, 7-10cm long, which are apparently glabrous above when mature.
Synonymy: R. rude Tagg & Forrest in Stevenson (ed.), The Species of Rhododendron 141 (1930) & Notes R.B.G. Edinb. 16: 207 (1931). Type: China, NW Yunnan, Salween/Kiu-chiang divide, 12000ft, vi 1924, Forrest 25645 (holo. E).
Shrub to 2m. Twigs 4–6mm in diameter, rounded, densely, smoothly, brown-scaly; internodes 4–15cm. Leaves 4–6 together in tight pseudowhorls. Blade 50–100 x 30–60mm, broadly elliptic to obovate; apex very shortly acuminate, broadly obtuse to almost rounded; margin entire, narrowly recurved or flat; base broadly tapering, glabrescent above, sub-densely scaly beneath. Scales small, circular to weakly lobed, with a broad margin and small darker brown centre, distinctly impressed. Mid-vein broadly raised and grooved for the proximal c.10mm, distally narrowly impressed, beneath broadly raised for most of its length and tapering gradually; lateral veins 7–9 per side, diverging at c.45°, straight proximally but curving in the distal 1⁄3, reticulation obscure. Petiole 10–15 x 3–4mm, a little flattened, not grooved above or very faintly in the distal part, scaly initially. Flower buds to 35 x 20mm, elongate-ellipsoid, distinctly imbricate, yellowish-green, smooth with all tips appressed. Bracts to 25 x 18mm, ovate, obtuse, outer ones densely scaly and very shortly hairy outside, appressed-hairy and scaly near the apex only inside. Bracteoles to 15 x 0.5mm, narrowly linear, hairy throughout. Inflorescence of 8–22 flowers, at first held semi-erect in a tight cluster by the collarette of bracts, these later spreading and falling, so the umbel becomes open with the flowers horizontally displayed. Pedicels 5–10 x 2–3mm, sub-densely scaly, sometimes with a few hairs just under the calyx. Calyx c.2.5mm in diameter, oblique, indistinctly lobed, brown-scaly and hairy. Corolla 65–75 x 30–35mm, trumpet-shaped, white, sweetly scented; tube 55–65 x 4–5 x 7–9mm, cylindrical, slightly curved, weakly grooved or angled and sub-glabrous outside but hairy inside, in the proximal ½, tubular and distinctly scaly distally outside; lobes 15–17 x 12–15mm, spreading obliquely, the lower two becoming reflexed, the upper three staying semi-erect, obovate, laxly scaly outside at the base, otherwise glabrous. Stamens at first exserted to 18mm, in a tight group on the upper side of the mouth, in later stages spreading more irregularly; filaments linear, white, sub-densely hairy in the lower 2/3, nearly filiform and glabrous distally; anthers 4–6 x 1mm, brown, each cell with a short basal apiculus. Disc sub-glabrous or hairy on the upper side. Ovary 8–10 x 2–3mm, elongate-cylindrical, densely covered with appressed, white hairs which cover small silvery scales, gradually narrowed distally; style c.50mm, on the upper side of the corolla, green, densely covered with scales and forwardly directed hairs in the lower 2/3, glabrous distally; stigma green, at first deep within the corolla tube, later exserted to c.15mm, thick-obconical.
Distribution: Papua New Guinea, Goodenough Island, Mt Goodenough.
Named after the island from which it was collected, which in turn was named after Commodore Goodenough, a British naval sea captain.
Type: W.E. Armit s.n., 1895. New Guinea (SE), Mt Goodenough (MEL, L).
Occurs in Countries: PG Subgenus: Vireya Habit: Non-Tree Fl. Colour: green, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:181
Erect or prostrate shrub with spreading branches, to 60cm. Twigs 1–1.5mm in diameter, sub-densely covered with brown, stellate, shortly stalked scales at first, later glabrescent and warty; internodes 0.5–3cm. Leaves 2–7 in tight pseudowhorls, often somewhat recurved. Blade 6–18 x 3–6mm, narrowly ovate or narrowly elliptic; apex shortly acuminate, or acute to rounded, occasionally mucronate; margin entire, slightly wavy and weakly revolute; base acutely tapering, dark green and glossy above, distinctly paler beneath, laxly scaly on both sides initially, glabrescent above, persistently scaly beneath. Scales irregularly and obtusely stellately divided at the margin; centre not impressed. Mid-vein smooth and inconspicuous above, more distinct and slightly raised beneath; lateral veins obscure. Petiole 1.5–3 x 0.6–1mm, grooved above, brown-scaly and often with a few white hairs which are scale stalks. Flower buds to 10 x 4mm, ovoid, smooth, acutely pointed, green or flushed with red. Bracts to 8 x 4mm, ovate, acutely pointed or mucronate, glabrous except for the marginal brown scales. Bracteoles 7 x 1.2mm, spathulate with an irregular margin and hooded apex, glabrous except for a few marginal scales. Flowers solitary, or rarely in pairs, hanging. Pedicels 8–16 x c.1mm, pink, densely covered with shortly stalked sub-stellate scales and sometimes with a few very short hairs. Calyx membranous, rounded to deeply 5-lobed, stellate-scaly outside, the lobes triangular, sub-acute, to c.1mm. Corolla 26–33 x 20–25mm, cylindrical, red, or pink, without scent, laxly covered with pale brown scales outside, glabrous inside; tube 18–22 x 6–8 x 9–11mm; lobes 8–11 x 8–10mm, semi-erect to spreading or slightly revolute, obovate to sub-circular. Stamens unequal, clustered on the lower side of the mouth, exserted to c.3mm; filaments linear, glabrous, pink; anthers c.1.5 x 1mm, dark purplish-brown. Disc prominent, glabrous, green. Ovary 4–7 x 1.5–2mm, oblong-cylindrical, densely and exclusively scaly, gradually tapering distally; style on the lower side of the mouth, becoming exserted to 4mm, covered with fine patent, white hairs for the proximal ½–¾ of the length; stigma club-shaped, c.1mm. Fruit 15–22 x 3–4mm, erect, oblique, oblong, a little curved, glabrescent.
Habitat: Terrestrial in open low vegetation, on dry slopes or clayey ground of old gold mine workings, also epiphytic in Nothofagus forest or in summit vegetation
Distribution: Papua New Guinea, Central District: Mt Musgrave; Morobe District: Mt Kaindi and Edie Creek above Wau.
Altitude: 2000-2745m
Latin – gracilis – slender, alluding to the delicate habit of the plant.
Type: MacGregor s.n. New Guinea (E), Central District, Mt Musgrave, Upper Vanapa Valley, 2240–2745m (MEL).
Occurs in Countries: PG Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: brown, pink, red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:151
Tree, 8-12m. Leaves elliptic to oblanceolate, 15-27 x 5-9.5cm, 2.4-3.3 x as long as broad, glabrous above, with a thin compacted silvery indumentum beneath; petioles 2—3.5cm, sparsely floccose to glabrous when mature. Inflorescence 15-25-flowered; rhachis 40-50mm; pedicels 15-30mm, densely covered with sessile glands, sometimes also floccose. Calyx c.lmm, glandular. Corolla 8-lobed, ventricose-campanulate, pale yellow (rarely with a purplish tinge), with purple nectar pouches, 50-/70mm. Stamens 15-16. Ovary densely stipitate-glandular, sometimes also with a dense pale brown tomentum. Capsule 30-45 x 8- 12mm.
Habitat: Open stony slopes, mixed woodland
Distribution: E Nepal, NE India (Bengal, Sikkim, Arunachal Pradesh), Bhutan, China (S Xizang)
Altitude: 2500-3000m
Illustrations:
Closely allied to R. sinogrande. Four plants: Ludlow & SherriffMSd, 1208, 1235 & 1258, from SE Bhutan and adjacent parts of S Xizang, differ from R. grande in their narrower leaves, 3.5-3.8 x as long as broad, their pink, 7-lobed corollas that are probably funnel-campanulate, and in the few (10) stamens. These may represent a new taxon allied to or within R. grande, or they may be hybrids. A precise indication of the corolla shape is lacking and this is essential for an assessment of the status of these plants.
Type: Bhutan, Griffith (holo. K)
Synonymy: R. argenteum Hooker f., Rhododendrons Sikkim Himalaya t. 9 (1849). Type: Sikkim, summit of Sinchal, Suradah and Tonglu, 8000-10000ft, Hooker (holo. K). R. longiflorum Nuttall, Hooker's J. Bot. Kew Gard. Misc. 5: 366 (1853). Type: India, Arunachal Pradesh, on the slopes of the Oola Mountain, 6500-7500ft, Booth (?holo. K).
Occurs in Countries: BT, CN, IN, NP Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: purple, yellow
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):244
Shrub, 3m; young shoots covered with adpressed grey-brown hairs, becoming glabrous. Leaves dimorphic, coriaceous, elliptic; spring leaves 2-2.8 x c.lcm, 2-2.8 x as long as broad, apex mucronate, base acuminate to acute, upper surface with a few strigose hairs, especially on midrib, lower surface more densely strigose; summer leaves smaller, 16-19 x 8-9mm; petioles 3-6mm, strigose. Inflorescence 5-6-flowered; pedicels 4~6mm, covered with brown strigose hairs. Calyx indumentum as for pedicels. Corolla funnel-campanulate, pale purple or red, c. 16mm; tube 9 x 2.5-3mm, glabrous. Stamens 5, filaments glabrous. Ovary densely strigose; style glabrous. Capsule not known.
Distribution: China (Guangxi, Guangdong)
Type: China, Guangxi, Beilun, 590m, 22 iv 1956, Hopu PI. Exp. 2463 (holo. IBSC)
Occurs in Countries: CN Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: purple, red
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):137
Shrub, 1.5-3m; young shoots densely setulose-glandular and lanate-tomentose. Leaves elliptic, 10-20 x (2-)3-5cm, 3-4(-7) x as long as broad, apex acute to ± acuminate, base broadly cuneate to rounded, upper surface glabrous at maturity, lower surface densely whitish to pale brown lanate-tomentose; petioles 1-2.5cm, densely setulose-glandular and floccose, at least when young. Inflorescence 5-12-flowered; rhachis 12-20mm; pedicels 20-30mm, densely long-stipitate-glandular. Corolla tubular- to funnel-campanulate, densely hairy on outer surface of tube, deep rose to crimson or scarlet, 55-80mm. Ovary densely dendroid-hairy, with scattered stipitate glands. Capsule c.20 x 8mm.
Habitat: Mixed forests
Distribution: China (W Yunnan), ne Upper Burma
Altitude: 2150-2700m
Illustrations:
A distinctive species with no close allies.
Type: China, W Yunnan, Shweli/Salween divide, Shweli valley, 9000ft, vi 1917, Forrest 15815 (holo. E; iso. K).
Occurs in Countries: CN, MM Altitude Ranges: 2,000 - 3,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: crimson, rose, scarlet
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):374
Shrub or tree, 1.3-10 m. Leaves oblong, 10—19(—30) x 4-7.5(-10) cm, 2.6-3.8 x as long as broad, apex acute to rounded and mucronate, base rounded, lower surface glabrous; petioles 2-3.5 cm, glabrous. Inflorescence 4-5-flowered; rhachis 50-70 mm; pedicels 35-40 mm, usually sparsely glandular. Calyx cupular, 7—20 mm, lobes rounded, glabrous. Corolla 5-lobed, open-campanulate, entirely glabrous, pale pink at first, soon fading white, 55-80 mm. Stamens 12-18, filaments glabrous. Ovary and entire style glandular. Capsule 22-40 x 13-18 mm, stout.
Habitat: Open mixed woodland
Distribution: E Nepal, NE India (Bengal, Sikkim, Arunachal Pradesh), Bhutan
Altitude: 2100-2850m
Illustrations:
A distinctive species on account of its well-developed calyx, etc.; without close allies
Type: Bhutan, Griffith 1045 (iso. E?)
Synonymy: R. aucklandii Hooker f., RhododendronsSikkimHimalayat.il (1851) Type: N India, Sikkim, 7-9000 ft, Hooker (iso. E). R. oblongum Griffith, Ic. PL Asiat. t. 523 (1854) & Not. PL Asiat. 303 (1854). Type: Bhutan, ascent to Chupcha, 8000-8500 ft, Griffith 1045 (n.v.). R- griffithianum Wight var. aucklandii (Hooker f.) Hooker f., Bot. Mag. 84: t. 5055(1858)
Occurs in Countries: BT, IN, NP Altitude Ranges: 2,000 - 3,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: pink, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):237
Shrub. Twigs smooth, the tips laxly scaly; internodes 4–9cm. Leaves 3–5 together in tight pseudowhorls. Blade 35–60 x 15–30mm, obovate or obovate-elliptic; apex obtuse to rounded, often apiculate by a small protruding gland; margin entire, recurved when dry; base broadly tapering to truncate-rounded or sub-cordate, shining and brownish-green above, dull and paler beneath. Scales lax to sub-dense, small, rounded, and slightly immersed on both sides in fully mature leaves. Mid-vein strongly impressed above, distinctly raised beneath; lateral veins 6–10 per side, straight, arching inwards near the margin, very slightly impressed above, prominent beneath, reticulation inconspicuous or very slightly impressed above, dense and clearly raised beneath. Petiole 4–7 x c.1.5mm, grooved above, densely scaly. Bracts to 15mm, ovate to obovate, outer ones acuminate, inner ones obtuse, scaly outside, glabrous inside. Bracteoles 10–15mm, filiform to linear-spathulate, glabrous. Inflorescence a 5–8-flowered umbel. Pedicels 6–15mm, slender, densely scaly. Calyx small, shortly and irregularly 5-toothed. Corolla trumpet-shaped, white; tube 33–55 x 5–6 x 6–7mm, narrowly-cylindrical, straight or slightly curved, pouched at the base, densely covered with small rounded scales outside, glabrous inside; lobes 10–14 x 6–10mm, obovate, obtuse, scaly outside. Stamens unequal; filaments 35–40mm, linear, laxly to very laxly hairy; anthers 3 x 1mm, oblong. Disc glabrous or almost so. Ovary 6–7 x 1.5mm, sub-cylindrical, 5-ribbed, very densely scaly; style 27–35mm, slender, becoming exserted from the mouth, with spreading hairs and scales proximally, then exclusively hairy, the distal part glabrous; stigma obconical.
Habitat: Both in forest on wet mossy ground and on humus- and moss-covered exposed rocks
Distribution: Indonesia, New Guinea (W), Main Range from Mt Carstensz to the Hellwig Mts and Mt Goliath.
Altitude: 2000-3450m
Named either after the locality from which it was originally collected, Lake Habbema, or after D. Habbema, after whom the lake was named. D. Habbema commanded the military detachment covering the 2nd Lorentz expedition to Dutch Southern New Guinea and helped collect plants on the ascent of Mt Wilhelmina (G. Trichora).
Type: von Römer 1208. Hellwig Mts, 2000–2600m (BO, L, lectotype).
Synonymy: R. bodenii Wernham, Trans. Linn. Soc. London, II, Bot. 1916. 9: 94.
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:66
Shrub, 1 -4m; young shoots densely glandular-setose. Leaves subcoriaceous, ovate to obovate, 7-16 x 3-7.5cm, 1.8-2.4 x as long as broad, apex acute, base rounded, margins ciliate-setulose, upper surface smooth, glabrous, lower surface with lamina glabrous, midrib and main veins glandular-setose; petioles 1 -2cm, densely glandular-setose. Inflorescence c. 10-flowered; rhachis c. 10mm; pedicels 20—25mm, densely glandular-setulose. Calyx red, 10-15mm, densely stipitate-glandular, lobes rounded. Corolla campanulate, white flushed rose to pink, with or without purple flecks and a basal blotch, 40-50mm. Ovary densely glandular-setulose. Capsule c.20 x 6mm.
Habitat: Thickets, rocky slopes, etc.
Distribution: China (W Yunnan ), ne Upper Burma
Altitude: 2700-3350m
Illustrations:
Closely allied to R. glischrum subsp. glischrum but distinguished by the broader leaves, etc.
4*. R. diphrocalyx Balfour f., Notes R.B.G. Edinb. 11: 55 (1919). Type: a cultivated specimen of unknown origin, grown by Major Magor; flowered v 1919 (holo. E). R. burrifolium Balfour f. & Forrest, Notes R.B.G. Edinb. 13: 34 (1920). Type: China, W Yunnan, Shweli/Salween divide, vi 1918, Forrest 17598 (holo. E). Ic: Millais, Rhododendrons ed.2, 152 t. (1924). Shrub, l-5m; bristles present on the young shoots. Leaves elliptic to obovate, 9-14 x 3.5~5cm, 2.4-2.8 x as long as broad, apex apicuiate, base cuneate, upper surface glabrous, lower surface with a few bristles at base of midrib at maturity, otherwise glabrous, cuticle glaucous-papillate; petioles 1 -2cm, with scattered floccose hairs, at least when young, and a few deciduous bristles. Inflorescence c.lO-flowered; rhachis c.5mm; pedicels 10-15mm, with a ± persistent tomentum. Calyx fleshy, red, 8-20mm, lobes unequal, rounded, ciliate. Corolla funnel-campanulate, with poorly defined nectar pouches, light to deep crimson, without markings, 30-40mm. Ovary and style-base densely rufous-tomentose, with a few stipitate glands. Capsule c.25 x 4mm, curved. china (W Yunnan). Open thickets, 3O00-3350m. Map 85, p. 282. The type of R. diphrocalyx did not originate from any of the known wild-collected specimens but matches well with several of them. R. diphrocalyx may be a hybrid of R. habrotrichum, with a member of subsection Neriiflora, possibly R. neriiflorum. The bristly indumentum suggests the former alliance and the well-developed calyx and papillate leaf epidermis the latter. Without proper field studies the status of this taxon remains in doubt.
Type: China, W Yunnan, western flank of the Shweli/Salween divide, vii 1912, Forrest 9048 (holo. E; iso. K)
Occurs in Countries: CN, MM Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: pink, purple, rose, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):287
Small shrub, 0.6-1.8m; young shoots densely tomentose to setose. Leaves obovate to oblong, 4.5-8.5(-10) X 1.8-4.5(-5.5)cm, (1.5-)1.8-2.6 X as long as broad, apex rounded, apiculate, base rounded to ± cuneate, upper surface glabrous when mature or with a few scattered hairs, lower surface with a ± densely matted bistrate tomentum, the upper layer fawn to red-brown, dendroid, the lower whitish, compacted; petioles 0.5-lcm, densely tomentose or setose and tomentose. Inflorescence 4—6(—8)~flowered; rhachis c.5mm; pedicels 10-23mm, tomentose to setose. Calyx minute to ± cupular, if well developed then usually irregular, lobes 3- 15mm, rounded, ± glabrous. Corolla fleshy, tubular-campanulate, scarlet to deep crimson, 35-45(-50)mm. Ovary densely rufous-tomentose. Capsule 10-15 x 5-7mm.
Habitat: Alpine thickets, open rocky slopes
Altitude: 3350-4450m
Subsp. haematodes tends to have smaller leaves with a red-brown indumentum and subsp. chaetomallum larger leaves with a mid-brown to fawn indumentum. The latter is always more setose than the former; the degree of overlap is however considerable so there is little justification in maintaining them at specific rank.
Occurs in Countries: CN, MM Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: crimson, scarlet
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):390
Petioles and young shoots predominantly setose, setae ± stout
Distribution: NE Upper Burma, China (SE Xizang, NW Yunnan)
Illustrations:
Synonymy: R. chaetomallum Balfour f. & Forrest, Notes R.B.G. Edinb. 12: 95 (1920). Type: China, Yunnan, Dokar La, Mekong/Salween divide, 12-13000ft, vi 1918, Forrest 16691 (holo. E). R. chaetomallum Balfour f. & Forrest var. glaucescens Tagg & Forrest, Notes R.B.G. Edinb. 16: 189 (1931). Type: NE Upper Burma, western flank of the Salween/Kiu-chiang divide, 27°28'N, 98°40'E, 13000ft, vii 1924, Forrest 25607 (holo. E).
Petioles and young shoots predominantly tomentose, setae few and slender or lacking.
Distribution: China (W Yunnan)
Illustrations:
Type: China, Yunnan, ad montem Tsang-chan, Delavay 298 (iso. E)
Synonymy: R. haematodes Forrest var. calycinum Franchet, Bull. Soc. Bot. France 33: 232 (1886). Type: China, Yunnan, in monte Tsang-chan, 4000m, Delavay (iso. K). R. haematodes Franchet var. hypoleucum Franchet, ibid. 33: 232 (1886). Type: China, Yunnan, in silvis ad montem Tsang-chan, 3500m, 26 vii 1886, Delavay 2425, n.v.
Erect rigid shrub to 2.5m. Twigs 2–3mm in diameter, rounded, stellate-scaly but very early glabrescent, and rough due to the numerous minute tubercles; internodes 2–8cm. Leaves often spirally arranged, more rarely 3–5 together in loose pseudowhorls, stiffly spreading. Blade 50–90 x 20–35mm, broadly elliptic; apex shortly acuminate, apiculate or obtuse; margin entire, revolute; base truncate to rounded, sometimes slightly cordate; when young densely scaly, early glabrescent and very rough with the persistent tubercles on both sides. Scales minute, stellate and shortly dendroid, each of which is on top of a pale epidermal tubercle. Mid-vein as thick as the petiole proximally, raised (and grooved when dry) in the proximal 1⁄3 above otherwise level or slightly impressed, distinctly raised throughout its length below; lateral veins 7–10 per side, irregular, spreading, straight, indistinctly anastomosing, inconspicuous above, slightly raised beneath; very rigid, yellowish or bluish green above, often brown from the colour of the scales below. Petiole 6–17 x 2–3mm, semi-rounded, rugose. Bracts to 20 x 10mm, ovate to obovate or spathulate, obtuse, membranous, glabrous. Bracteoles to c.20 x 1mm, linear, apex sub-spathulate, glabrous. Inflorescence a 4–10-flowered open umbel. Pedicels 15–40 x c.2mm, very densely brown stellate-scaly, without hairs. Calyx c.4mm in diameter, oblique, disc-shaped, irregularly 5-lobed, or sometimes with 1 or 2 elongate, acute lobes up to 3mm, densely scaly outside, without hairs. Corolla distinctly zygomorphic, tubular below, dilated towards the mouth, red; tube 30–55 x 5–7 x 10–15mm, densely brown stellate-scaly outside, very shortly hairy inside, distinctly curved; lobes 15–20 x 9–15mm, irregularly broadly obovate or sub-circular, densely scaly outside except near the margins. Stamens unequal, exserted to c.10mm, arranged in a distinct group on the upper side of the flower; filaments linear, laxly patently hairy below, glabrous distally; anthers 3.5–4 x 1.3–1.5mm, purple, broadly oblong to obovate-oblong. Disc glabrous. Ovary 5–6 x c.3mm, cylindrical, abruptly tapering distally; style thick, as long as the stamens, densely shortly patent-hairy and scaly in the proximal ½ with the scales clearly visible amongst the hairs, glabrous distally; stigma thick-globose, distinctly 5-lobed.
Habitat: Common at the edges of mossy thickets, frequent in shrubberies on peaty ridges or peaty treeless areas in forest or in mossy thickets, observed to have regenerated strongly on one burnt over slope
Distribution: Indonesia, New Guinea (W), near Wamena, Lake Habbema.
Altitude: 3000-3225m
Greek – haemat – blood red; opthalmum – eye. Referring to the colour of the flowers.
A spectacular plant in the wild with its stiffly rigid habit and beautiful flowers.
Type: Brass 9571, Aug.–Oct. 1938. New Guinea (W), Northern Part: Lake Habbema, 3225m (A, L).
Occurs in Countries: ID Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: brown, red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:83
Shrub, l-2m, with many erect twiggy branches; young shoots covered with flattened brown adpressed hairs. Leaves monomorphic, subpersistent, subcoriaceous, lanceolate, 2-5 x 0.7-1.4cm, 3-6 x as long as broad, apex acute, base cuneate, margin entire, upper surface with scattered red-brown hairs and with midrib impressed, lower surface glaucous, with scattered red-brown hairs, midrib covered with long shining adpressed red-brown hairs; petioles 2-4mm, covered with adpressed red-brown hairs. Inflorescence 1-3-flowered; pedicels 2-3mm, covered with adpressed hairs. Calyx densely pilose and ciliate, lobes lanceolate, 2-4mm. Corolla funnel-shaped, bright red, 20-30mm; tube c.l2mm, outer surface glandular, inner surface hairy. Stamens 10, pubescent below. Ovary densely setose-pilose, style glabrous. Capsule ovoid, c.8mm long.
Habitat: Mountain tops, thickets amongst rocks, rocks by rivers
Distribution: China (Hainan Island, Guangxi)
Altitude: 500-1000m
Closely allied to R.meridionale, which may be conspecific.
Type: China, Hainan, eastern part of the Island, i 1921, K.L. Schaeffer (holo. K)
Occurs in Countries: CN Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: red
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):109
Very low, probably creeping shrublet. Twigs slender, tips densely covered with stalked scales or rough in the lower parts where the scales have gone. Leaves spiral or sub-opposite. Blade 7–10 x 5–8mm, broadly obovate to sub-circular; apex rounded or minutely retuse; margin entire, not or very slightly recurved; base broadly tapering or mostly rounded, laxly scaly initially, early glabrescent above, persistently scaly beneath. Scales circular, entire, flat, the large, dark, centre slightly impressed. Mid-vein impressed above, prominent beneath; lateral veins obscure. Petiole 1.5–2mm. Bracts elliptic-obovate, sparsely hairy outside, densely white-ciliate on the margins. Inflorescence of solitary or rarely paired flowers. Pedicels 5–6mm, slender, densely scaly. Calyx small, obscurely 5-lobed. Corolla 17–20 x 3–4mm, tubular, sub-densely scaly all over outside, glabrous inside; lobes c.4 x 3mm, obovate to sub-circular, with an entire margin. Stamens nearly equalling the corolla in length; filaments linear, glabrous; anthers 1mm. Disc glabrous. Ovary c.3mm, sub-conical, densely scaly, tapering distally; style laxly scaly in the proximal ¼, glabrous distally, equalling or slightly exceeding the corolla in length; stigma club-shaped.
Distribution: Indonesia, New Guinea (W), Mt Jaya (Carstensz)
Altitude: 2350-3350m
Named after Hamelia (Rubiaceae), tropical American ornamental shrubs, alluding to a similarity of the flowers.
Very imperfectly known species which has not been recollected from the type locality despite considerable recent botanical activity there.
Type: Kloss s.n. New Guinea (W), Mt Carstensz (BM, L, fragment).
Occurs in Countries: ID Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:58
Shrub to 2 m. Young growth lepidote. Leaves narrowly ovate or ± oblong-elliptic, acuminate at the apex with a conspicuous drip tip, tapered to the abruptly or more smoothly rounded base, 70-115 x 34-57 mm, lower surface pale green with rather distant, flat or slightly sunken golden-brown scales, upper surface elepidote, slightly puberulent along the main vein near the base. Inflorescence 5-15-flowered with a conspicuous rachis up to 12 mm, pedicels sparsely lepidote, c. 10 mm. Calyx lobes c. 5 mm, narrowly triangular, sparsely fringed with scales. Corolla white, narrowly funnel-campanulate, c. 20 mm, tube c. 12 mm, glabrous and elepidote outside, sparsely pilose inside at the base of the tube. Stamens 10, filaments pilose towards the base, long-exserted from the corolla. Ovary lepidote, style impressed, glabrous, exceeding stamens. Capsule ovoid-cylindric, lepidote, c. 8 mm
Habitat: Cliffs
Distribution: China (C Sichuan)
Altitude: 1200-1500m
Illustrations:
A very distinctive species, most closely allied to R. longistyium. Its resemblance to R. afghanicum (p. 156), with which it was formerly associated in the Triflorum series is limited to the inflorescence, and is superficial.
Type: China, Szechuan, Mt Omei, 4000 ft, Faber (holo. K)
Occurs in Countries: CN Altitude Ranges: 1,000 - 2,000m Subgenus: Rhododendron Habit: Non-Tree
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):128
Shrub to 2 m high, young branches glabrous. Leaves glabrous; blade broadly elliptic to narrowly obovate 95-150 x 30-60 mm, base cuneate to narrowly cuneate, apex acute or acuminate, coriaceous; petiole 8-12 mm long. Inflorescence buds lateral, clustered at the ends of leafy shoots, 1-flowered; bud scales numerous, outer short, inner elongate (to 40mm), margins sometimes minutely ciliate (and sometimes glandular) and with an apical rim of minute white hairs, surface not shining, persistent until anthesis; pedicels 15-20 mm long, with scattered pubescence. Calyx lobes 5, small, rounded or slightly longer, ovate, glabrous, or pubescent on the outer surface and margin. Corolla white, upper lobe with intense yellow blotch, glabrous, tube c.25-30mm long, lobes c.30-40 x 25-30 mm, spreading. Stamens 10, filaments hairy on lower half. Ovary cylindric c.8-9 mm high, covered with silky hairs, 5-6-locular; style glabrous or a few basal hairs. Capsule narrowly cylindric, falcate, c.60mm long.
Distribution: China (Yunnan, Guangxi)
Illustrations:
The inflorescences with solitary large flowers are striking, and combined with the densely hairy ovary serve to distinguish this species.
Type: China, Yunnan, Mongtse (Mengzi), Hancock 156 (holo. K).
Occurs in Countries: CN Subgenus: Azaleastrum Habit: Non-Tree Fl. Colour: yellow
Philipson, W.R. & Philipson, M.N. (1986) A Revision of Rhododendron III. Subgenera Azaleastrum, Mumeazalea, Candidastrum and Therorhodion. Notes from the Royal Botanic Garden Edinburgh 44(1):10
Shrub, 4—6m. Leaves coriaceous, lanceolate to obianceolate, 7—10 x 3-4cm, c.2.5 x as long as broad, apex acuminate, base broadly cuneate, upper surface glabrous, lower surface with a fulvous floccose-pannose tomentum; petioles 1.5—2.2cm, glabrous. Inflorescence 5—9-flowered; rhachis small; pedicels 25-35mm. Calyx c. 1mm, villous. Corolla broadly campanulate, white, sometimes flushed with rose, 40-45mm. Stamens 18-20, villous below. Ovary with a dense whitish to pale brown lanate tomentum; style glabrous. Capsule to c.20 x 10mm.
Distribution: China (Guizhou, Guangxi, Hunan)
Altitude: Around 1500m
A distintive species on account of the large number of stamens and the densely lanate-tomentose ovary.
Type: China, Guangxi, Lungsheng Hsien, Tati Hsiang, 1430m, 13 v 1955, Kwangfu Exped. 165 (holo. SZ; iso. Hb. Inst. Bot. Guangzhou, Hb. Inst. Bot. Kunming).
Occurs in Countries: CN Altitude Ranges: 1,000 - 2,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: rose, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):320
Shrub to c.5m. Twigs c.2mm in diameter, slender, laxly sub-stellately scaly; internodes 2–3cm. Leaves 4–5 together in pseudowhorls. Blade 45–75 x 15–30mm, narrowly ovate to narrowly elliptic, rarely narrowly sub-obovate; apex gradually tapering, sub-acute; margin entire, slightly revolute; base tapering; obscurely scaly above, distinctly laxly scaly below. Scales flat, sub-stellate; centre small, somewhat impressed, finally blackish. Mid-vein slightly impressed above, raised below; lateral veins moderately irregular, 7–8 per side, with a moderately dense, raised reticulation on both sides. Petiole 18–25 x c.1mm. Bracteoles filiform to elongate spathulate, 10–15mm, the apex up to 2mm broad. Inflorescence 6–8-flowered. Pedicels c.15 x 1mm, slender, red, densely, shortly white, patent hairy. Calyx c.2.5mm in diameter, oblique, saucer-shaped, obscurely 5-lobed. Corolla tubular, slightly curved, slightly dilated towards the mouth, slender, white, laxly sub-stellately scaly outside, laxly hairy in the proximal 1⁄3 inside; tube 60–65 x 3–4 x 5–6mm; lobes c.13 x 10mm, obovate, spreading or more or less reflexed, glabrous on both sides. Stamens with the filaments hairy for the proximal 20mm, glabrous distally, slightly exserted from the tube; anthers c.2.5mm, oblong, the base obtuse. Disc slightly hairy. Ovary 5–6 x c.1.5mm, cylindrical, slightly greyish-white hairy, tapering distally; style 60–65mm, laxly patently hairy proximally for 10–15mm, laxly patently hairy distally, not scaly; stigma 5-lobed.
Habitat: Epiphytic in moss forest
Distribution: Papua New Guinea (E), Morobe District, above Bakaia, 15 miles SE of Garaina.
Named after the collector, G. Hartley.
Known only from the type locality.
Said to be ‘close to R. cruttwellii but sufficiently distinct by more slender and much longer petioles, smaller leaves, and a hairy disk’ (Sleumer 1973).
Type: Hartley 12788, 24 Jan. 1964. New Guinea (E), Morobe District, above Bakaia, 15 miles SE of Garaina (L, LAE).
Occurs in Countries: PG Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:180
Low shrub, to 50cm, branches spreading. Twigs slender, laxly scaly; internodes 0.8–6cm. Leaves 3–6 together in pseudowhorls. Blade 20–60 x 9–30mm, ovate-elliptic to elliptic; apex shortly acuminate or broadly tapering, obtuse, sometimes rounded, or apiculate; margin cartilaginous, distinctly revolute; base broadly tapering; glabrescent above with age, persistently sub-densely scaly beneath. Scales small, flat, sub-stellate, faintly impressed, eventually glabrescent beneath with only blackish pits remaining. Mid-vein impressed above, prominent beneath; lateral veins 4–6 per side, straight below, looping near the margin, impressed above, distinctly raised beneath, or sub-obscure. Petiole 2–4mm, flat. Bracts to 10 x 5mm, ovate-acuminate, shortly subulate, membranous, glabrous, except for the marginal scales. Bracteoles to 10mm, filiform. Inflorescence 2–6-flowered. Pedicels 10–24mm, slender, densely scaly and patently hairy. Calyx c.3mm in diameter, disc-shaped, often reflexed, obscurely 5-lobed, scaly and hairy outside. Corolla c.25mm, tubular-funnel-shaped, sub-oblique, bright to dark red, waxy and glossy; tube 15 x 4–5 x 5–6mm, sub-cylindrical, laxly hairy, mainly in the proximal ½ outside, or sometimes glabrous, always without scales, laxly patently hairy in the proximal ½ inside; lobes 8 x 12mm, spreading, broadly obovate-spathulate. Stamens exserted to c.5mm; filaments linear, laxly patently hairy above the base to the proximal ¼, glabrous distally; anthers c.2mm, dark purple to almost black, oblong-obovate. Disc glabrous. Ovary c.5 x 3mm, sub-ovoid, densely, shortly covered with spreading hairs, the hairs covering the scales, tapering distally; style equalling the stamens, hairy nearly to the top; stigma sub-globose.
Distribution: Indonesia, New Guinea (W), Vogelkop Peninsula, Arfak, Tamrau and Nettoti Mts. Epiphytic in mossy Nothofagus forest. Apparently very scattered or rare.
Altitude: 1550-1900m
Named after the place from which it was first collected.
Sleumer (1960) noted a Clemens collection (12327), from Papua New Guinea, Morobe District, A-mieng, on Yaneng R. (a tributary of the R. Buso), was similar but with smaller flowers and less hairy pedicels. This material has not been examined but would be a very surprising extension to the range of this species.
Type: Beccari 5811. New Guinea (W), Arfak, Hatam, 1525–2135m (FI).
Synonymy: R. coenenii J.J.Sm., Nova Guinea 1914. 12(2): 132, t.30a. R. gibbsiae J.J.Sm. in Gibbs, Phyto. Fl. Arfak Mts 1917. 169.
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:218
Shrub to 3 m. Young growth lepidote, purplish. Leaves oblong-ovate to oblong-elliptic, (50-)57-105 x (18-)20-40mm, acute at the apex, rounded, truncate or cuneate at the base, lepidote above with whitish, scurfy deciduous scales, the undersurface with close but not contiguous golden or brownish scales. Inflorescence (4-)6-10-flowered, pedicels lepidote. Calyx rim-like or variably lobed, sometimes with one lobe rather longer than the rest, at most 3 mm, sparsely lepidote, filiform-acicular-ciliate. Corolla funnel-shaped, white to pink, more rarely purplish, usually with reddish, greenish or brownish spots on the upper lobes, puberulous outside towards the base and at the sinuses and densely lepidote, pilose inside the tube, (22-)24-34 mm, tube (13-)16-21 mm. Stamens 10, filaments densely pilose towards the base. Ovary densely lepidote, usually puberulous in the impressed part at the base of the style. Style shorter than the longest stamens, straight, variably pubescent towards the base, rarely entirely glabrous. Capsule lepidote, cylindric, 10-14 mm.
A complex and variable species; variation in many characters (leaf shape and size, scale density, pedicel length, corolla size and style indumentum) is continuous and it is difficult to find correlated characters that will serve to divide the species. Two varieties are recognised here, but they intergrade considerably and show no geographical separation. Characters previously used for the distinction of species within R. heliolepis are entirely unsatisfactory
Occurs in Countries: CN, MM Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: brown, green, pink, red, white
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):89
Leaves cuneate at the base, length/breadth ratio (2-2-)2.7-3.3 (-3.6); inflorescence (5-)6-10-flowered
Habitat: Thickets
Distribution: China (N, NW & W Yunnan, SE Xizang, SW Sichuan)
Altitude: 3000-3700m
Illustrations:
Synonymy: R. brevistylum Franchet, Journ. de Bot. 8:261 (1898). Type: China, Setchuen oriental, vallee de haut Mekong a Sela, 15 vii 1875, Soulie (holo. P—n.v., iso. E). R. pholidotum Balfour f. & W. W. Smith, Notes R.B.G. Edinb. 10:132 (1917). Type: China, Yunnan, Tali range, eastern flank, 10000 ft, viii 1906, Forrest 4162 (holo. E). R. porrosquameum Balfour f. & Forrest, Notes R.B.G. Edinb. 13:57 (1920). Type: China, Yunnan, Likiang range, western flank, vi 1917, Forrest 15071 (holo. E)
Leaves truncate or rounded at the base, length/breadth ratio 2-2-2-8(-3.3); inflorescence (4-)5-8-flowered
Habitat: Thickets and woodland
Distribution: China (N, NW, W & SW Yunnan, SW Xizang), NE Burma
Altitude: 2500-3700m
Illustrations:
Type: China, Yunnan, circa Hokin, in sylvis alt. 2500 m, usque ad cacumina supra collum Koua-la-po, 3500 m, Delavay 2089 (holo. P—n.v., iso. E)
Synonymy: R. fumidum Balfour f. & W. W. Smith, Notes R.B.G. Edinb. 10:112 (1917). Type: China, W Yunnan, plateau of Te-ma-tchouen, vii 1912, Maire 224 (holo. E). R. oporinum Balfour f. & Kingdon Ward, Notes R.B.G. Edinb. 10:129 (1917). Type: E Upper Burma, Wulaw pass, valley of Naung chaung, 11-12000 ft, 27 viii 1914, Kingdon Ward 1906 (holo. E). R. plebeium Balfour f. & W. W. Smith, op. cit.: 136. Type: China, W Yunnan, Shweli/Salween Divide, western flank, 10000 ft, Forrest 8938 (holo. E)
Shrub or small tree. Twigs 4–6mm in diameter, at first densely brown, stellate-scaly, quickly glabrescent, rounded, or slightly angular; internodes 2–12cm. Leaves 3–5 together in pseudowhorls, or sometimes with 2 or 3 more loosely arranged. Blade 80–160 x 50–100mm, ovate to ovate-elliptic, sometimes sub-circular; apex obtuse to rounded; margin entire and flat; base rounded to cordate; brown with stellate scales on both sides initially quickly glabrescent both above and below. Scales small, irregularly lobed, sessile or very shortly stalked, each on top of a minute epidermal tubercle which remains visible for a long time beneath. Mid-vein grooved above in the proximal ½ and somewhat impressed distally, below strongly raised throughout its length; lateral veins 8–10 per side, irregular, the lowest 2 from near the base of the blade, all straight below, curved-anastomosing to the margin, smooth to slightly prominent on both sides, veins coarse, much less visible, reticulation obscure. Petiole 10–20 x 3–4mm, robust, a little flattened, not or only faintly grooved above, densely brown-scaly. Flower buds to 60 x 35mm, ovoid, dark purple, the bracts all tightly appressed, rough with short white hairs outside. Outer bracts ovate to sub-circular, inner ones broadly spathulate, obtuse or very shortly apiculate, densely covered with short, thick hairs on both sides, glabrescent but remaining rough, fringed with scales. Bracteoles c.20–35 x 1–4mm, linear to sub-spathulate, hairy below, glabrous distally. Inflorescence an open umbel of 2–6 flowers, held horizontally or slightly hanging. Pedicels 6–15 x 3–5mm, densely dark-brown scaly. Calyx c.6mm in diameter, rim-like, very shortly obtusely 5–6-lobed. Corolla 65–90 x 50–60mm, broadly funnel-shaped, dark blood-red, fleshy; tube 40–55 x 10–15 x 17–23mm, slightly dilated upwards, curved upwards and longitudinally channelled, glabrous outside, densely covered with short retrorse hairs inside in the proximal ½, lobes c.31 x 30–35mm, 6–7, spreading to the perpendicular, broadly spathulate or obovate, overlapping to ¾. Stamens 12–14, clustered on the lower side of the mouth of the flower, exserted to 12mm; filaments pink, linear, (1mm wide), with retrorse or patent hairs in their proximal 2⁄3, glabrous and filiform distally; anthers 7–8 x c.1.5mm, dark purple, linear-oblong, the base of each cell shortly obtusely bilobed. Disc glabrous, purple. Ovary c.10 x 4–5mm, sub-ovoid-cylindrical, densely covered with small flattened scales, abruptly tapering distally; style 30–40 x c.2mm, upwardly curved, presenting the stigma on the upper side of the mouth, thick, glabrous, sometimes shining; stigma shortly thick-globose, obscurely 5–6-lobed. Fruit c.30 x 18mm. Seeds 5–5.6mm, without tails c.1mm, longest tail to 2.5mm, one or both tails quite broad and often deeply crimped.
Habitat: Mostly epiphytic, high in large trees in montane Nothofagus forest, occasionally terrestrial on steep slopes among grasses
Distribution: Papua New Guinea, restricted to the Huon Peninsula on the Finisterre and Saruwaged Mts, locally common.
Altitude: 1065-3050m
Named after Franz Carl Hellwig, collector of this species.
Commonly forming hybrids at the western end of its range with R. superbum which has white to pink, strongly scented flowers. The hybrids are intermediate in colour and scent, with deep pink flowers.
Type: Hellwig 315. New Guinea (E), Finisterre Mts; Clemens 7184a, (7139a), Mt Saruwaged, Sambanga, Lectotype (L, A, B†).
Occurs in Countries: PG Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Epiphyte, Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:84
Shrub, with strong, spreading branches, to 50cm. Twigs c.3mm in diameter, rounded, densely covered with appressed sub-stellate scales becoming glabrescent; internodes 3.5–8cm. Leaves 4–6 together in pseudowhorls at the upper 2–3 nodes. Blade 20–40 x 8–15mm, elliptic, broadly elliptic or rarely sub-obovate; apex shortly broadly acuminate, sub-acute or blunt, apiculate with a protruding gland; margin narrowly cartilaginous, irregularly crenulate with impressed scales or sub-entire; base broadly tapering and decurrent; laxly impressed-scaly or glabrescent above, more distinctly and persistently scaly beneath, but eventually glabrescent, leaving impressed, dark points, laxly scaly distally, dense and touching proximally, and on the petiole. Scales with a fragile, marginal transparent zone, large and variously lobed; centre more persistent, small and impressed. Mid-vein impressed in the proximal 2⁄3 above, dilated and obtusely prominent beneath, gradually disappearing distally; lateral veins 2 per side just above the base, high-ascending and with 2–3 other less conspicuous veins arising further from the base. Petiole 3–5 x 2–3mm, flat. Outer bracts few, short, ovate-subulate, inner ones to 18 x 7mm, more numerous, broadly obovate-spathulate, shortly acuminate, sub-acute, at first densely reddish-scaly, early glabrescent. Inflorescence 1–4-flowered. Pedicels 20–30 x c.1mm, very densely covered with red or orange, stellate scales, but without hairs. Calyx c.5mm in diameter, disc-shaped, scaly outside, the membranous margin reflexed and irregularly lobed, lobes up to 1mm and appressed to the corolla. Corolla 30–35mm, tubular, red or yellowish red; tube 20–25 x 6–7 x 10–12mm, slightly narrowed distally before becoming gradually dilated again to the mouth, sub-densely stellately scaly outside, glabrous inside; lobes 9–11 x 7–9mm, erect or spreading, broadly spathulate or sub-circular, very slightly emarginate, sub-densely scaly except near the margins. Stamens unequal, the longest as long as the corolla tube; filaments linear, glabrous; anthers c.2mm, obovate. Disc prominent, glabrous. Ovary c.8 x 3mm, sub-cylindrical, abruptly contracted distally, densely covered with white or yellowish hairs, which are directed forwards and cover numerous scales; style c.20mm, slender, exceeding the stamens in length, shortly hairy for 2mm proximally, glabrous distally; stigma globose.
Habitat: Terrestrial in low shrubberies, grassy marshes and open boggy slopes, locally frequent.
Distribution: Indonesia, New Guinea (W), Lake Habbema region.
Altitude: Around 3225m
Greek – helodes – growing in marshy places.
A poorly known species which has not been recollected recently.
Type: Brass 9316, Aug. 1938. W New Guinea, Lake Habema camp (A, L).
Occurs in Countries: ID Altitude Ranges: 3,000 - 4,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: red, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:222
Shrub 0.6-2 m. Young shoots lepidote and with an indumentum of filiform-acicular hairs. Leaves narrowly elliptic, 25-40 x 7-13 mm, the indumentum on the upper surface of filiform-acicular hairs only, the lower surface shining white-papillose, glabrous except for a few hairs along the midrib, lepidote with ± rimless scales. Inflorescences 2-3-flowered, pedicels lepidote and puberulent with filiform-acicular hairs. Calyx rim-like, lepidote, ciliate with filiform-acicular and loriform hairs. Corolla openly funnel-shaped, 9.5-14.5 mm, the tube 4-8 mm, pink, or white edged with pink, glabrous and elepidote outside, puberulent inside the tube. Filaments pubescent towards the base. Ovary densely lepidote and sparsely pilose, style often slightly pilose at the base. Capsule lepidote and sparsely pilose, 5-7 mm.
Habitat: Forests, open slopes
Distribution: China (N Yunnan, SW Sichuan)
Altitude: 2900-4300m
Type: China, SW Szechuan, Mu-li, valley of the Litang, 12000 ft, vi 1918, Forrest 16250 (holo. E)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):83
Shrub or tree, 2-8 m. Leaves ovate to ovate-elliptic, 10-20 x 4-10 cm, 1.7-2.5 x as long as broad, apex rounded, mucronate, base cordate, margin often undulate when dry, lower surface with scattered minute punctulate hair-bases and with a few stipitate glands towards the base, otherwise glabrous; petioles 2.5-5.5 cm, glabrous. Inflorescence 5-8-flowered; rhachis stout, 40-50 mm; pedicels 25-30 mm, stipitate-glandular or glabrous. Calyx c. 1 mm, lobes ± stipitate-glandular or glabrous. Corolla 6—7-lobed, cam-panulate, glabrous or ± glandular outside, sometimes puberulent within at base, white, without flecks, 45-60 mm. Stamens c. 14, filaments glabrous. Ovary and entire style glandular. Capsule c. 30 x 12 mm.
Habitat: Woods, etc.
Distribution: China (Sichuan-Mt. Omei)
Altitude: 1100-2000m
Illustrations:
R. chengianum is supposed to differ from R. hemsleyanum in its glabrous pedicels. The type of R. hemsleyanum, however, also has glabrous pedicels. Both have a ± undulate leaf margin when dry, a feature unique in subsection Fortunea.
Type: China, Sichuan, Mt Omei, vi 1904, Wilson 5738 (holo. A; iso. K)
Synonymy: R. chengianum Fang, PI. Omeiens. 1: t.31 (1942). Syntypes: China, Sichuan, Mt Omei, Hung-chun-ping, 1200 m, 1933, Tu 130, 950; 7x1940, Lee 3702 (n.v.)
Occurs in Countries: CN Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):235
Shrub to 5 m high, young branches glabrous. Leaves glabrous; blade elliptic to slightly obovate, 50-100 x 15-35 mm, base cuneate, apex acuminate, coriaceous, veins impressed on upper surface; petiole 8-12 mm long. Inflorescence buds lateral, at the ends of leafy shoots, 3-5-flowered; bud-scales with a tuft of brown, wavy hairs below the tip, caducous; pedicels 20-25 mm long, densely covered with spreading glandular hairs. Calyx lobes 5, variable in size, often in the same flower, short and rounded to linear (5 mm long) glabrous or with glandular hairs. Corolla pink, glabrous, tube c.Bmm long, lobes c.35 x 17-20mm. Stamens 10, shortly exserted, filaments hairy on lower part. Ovary cylindric c.7mm high, glabrous or densely covered with coarse appressed brim, 5-locular hairs; style glabrous. Capsule narrowly cylindric, falcate, 50-60 x 4-5 mm.
Distribution: China (Guangxi, Guangdong, Fujian, Zhejiang)
Illustrations:
The inflorescences of this species are distinctive, having several flowers borne on pedicels with dense patent glandular hairs. The glabrous or hairy ovary has been used as the basis for separating R. dunnii from R. henryi. According to Fang (1939) specimens from the two western Provinces have densely hairy ovaries while those from the two eastern Provinces have glabrous ovaries, but evidently there is some intermingling. There has been confusion in the literature regarding this character. Hutchinson (1930) and Sleumer (1958) describe the ovary as glabrous, while we find the type material to have a densely hairy ovary. Wilson in describing R. dunnii confirms our finding.
Type: China, Guangdong, Fi-loi-tsz, ad angustias Tsing-in, North River, Henry (Hb Hance 21638) (holo. BM).
Synonymy: R. dunnii Wilson, J. Arnold Arb. 6:170 (1925). Type: China, Guangdong, Swatow, Phoenix Mt, Dunn 5802 (holo. K). R. ciliato-pedunculatum Hayata, Icon. PI. Formosan. 3:131 (1913). Type: China, Fujian, Mt Isan, 1910, Nagasawa, n.v.
Occurs in Countries: CN Subgenus: Azaleastrum Habit: Non-Tree
Philipson, W.R. & Philipson, M.N. (1986) A Revision of Rhododendron III. Subgenera Azaleastrum, Mumeazalea, Candidastrum and Therorhodion. Notes from the Royal Botanic Garden Edinburgh 44(1):12
Erect shrub to 2m. Twigs rounded, sub-densely scaly when young, glabrescent and whitish later; internodes 3–13cm. Leaves 4–6 together in tight pseudowhorls; aromatic with a pleasantly resinous smell when crushed. Blade 40–60 x 20–40mm, elliptic or obovate-elliptic; apex broadly obtusely acuminate, sometimes rounded; margin slightly revolute towards the base; base broadly tapering to almost rounded, sub-densely scaly when young, though early glabrescent above persistently impressed-scaly beneath. Scales rounded, pale yellow, their marginal zones narrow and shallowly irregularly crenate. Mid-vein slightly grooved above, robust and prominent beneath; lateral veins 6–10 (rarely up to 12) per side, slightly curved, parallel to each other, obscurely anastomosing, faintly impressed above, raised beneath, reticulation obscure. Petiole 4–10 x 1.5–2mm, semi-circular, grooved above, scaly, pink or green. Flower buds c.20 x 10mm, obovoid, pale green when fresh. Bracts to 15 x 10mm, ovate, thin, densely scaly outside except for a glabrous marginal area, with scales along the edges and some sparse short hairs on the outer side, the scales transparent-silvery in fresh specimens. Bracteoles to 30mm, narrowly linear. Inflorescence a 5–10-flowered umbel of stiffly semi-erect flowers. Pedicels 4–8 x c.1.5mm, thick, densely scaly. Calyx very small, oblique, disc-shaped, sub-entire. Corolla 40–90mm, pure white, or slightly pinkish at the tube externally, fragrant, semi-erect, trumpet-shaped; tube 35–85 x 3–4 x 5–6mm, straight or slightly curved, densely scaly outside, densely hairy and sparingly or not scaly in the proximal part inside; lobes 8–9 x 5–6mm, spreading to somewhat reflexed, circular to elliptic-obovate, scaly outside, glabrous inside. Stamens exserted in a tight cluster beyond the recurved corolla lobes at first, later deflexed to lie against the lower lobes; filaments white, very slender, densely and patently hairy in the proximal 2⁄3 only; anthers orange, oblong. Disc very sparsely hairy or glabrous. Ovary 6–7 x 1.5mm, narrowly cylindrical, very densely scaly, abruptly tapering distally; style exserted from the mouth, densely scaly below, less so or glabrous distally; stigma green, shortly obconical. Fruit 30–50 x 4–5mm, reddish, cylindrical, straight, scaly.
Habitat: Terrestrial or epiphytic, on cliff faces, landslides, steep eroded banks or slopes, also in montane forest or heath-like scrub on infertile sandy or clayey soil, occasionally found in fern re-growth, as a coloniser in sluiced areas or in gullies of old garden land
Distribution: Indonesia and Papua New Guinea. New Guinea, the Main Range from the Wissel Lakes to the Owen Stanley Range, Mt Garatun in the Milne Bay District, the Cromwell Mts and on Mt Saruwaged.
Altitude: 1530-2500m
Named after Th. Herzog, a missionary in the Finisterre Mountains in New Guinea.
Type: Hellwig 306, 14 Oct. 1888. Finnisterre Mts, New Guinea (B†, BO, K, L, fragment).
Occurs in Countries: ID, PG Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: orange, pink, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:67
Shrub, to 3m; young shoots greyish, ± glandular, later glabrescent. Leaves broadly rhombic-ovate, 2.5-6 x 1.5-5cm, apex shortly cuspidate, base broadly cuneate, upper surface sparsely glandular ar first, covered with long white hairs, later glabrescent, with persistent hair bases, lower surface pale, with adpressed hairs, or glabrous though with minute papillate glands and long hairs on the nerves; petioles 5-12mm, glandular. Inflorescence l-3-flowered; pedicels 10-15mm, glandular, pilose below. Calyx c.3mm. glandular, sometimes ciliate. Corolla funnel-campanulate, 25-30mm, magenta, lobes C.17mm, oblong-obovate. Stamens 10, unequal, filaments glabrous. Ovary shortly stipitate-glandular, with scattered pilose hairs; style glabrous. Capsule 9-11 x c.3mm.
Habitat: Wooded mountain slopes
Distribution: Japan (S Hokkaido)
Illustrations:
Apparently allied to R. decandrum on account of its glandular ovary but with a more northerly distribution. The most significant differences appear to be in the larger calyx and less hairy leaves of R. hidakanum.
Type: Japan Hokkaido, Maruyama, Shoya, 80m, 11 ix 1974, Hara et al. (holo. TI, n.v.)
Synonymy: R. dilatatum Miquel var. boreale Sugimoto, New Keys Woody PI. Japan 509 (1972). Type as above.
Occurs in Countries: JP Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: magenta
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):146
Greek – himas – a strap, alluding to the narrow strap-shaped leaves.
Type: Clemens 31818, 3 March 1993. East Malaysia, Sabah, (Borneo), Mt Kinabalu, Kina Taki River (BM, A, BO, E, K, L, NY).
Occurs in Countries: ID, MY Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Fl. Colour: brown, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:117
Shrub to 2m. Twigs slender, rounded, smooth or somewhat rough with the dense covering of brown scales; internodes 1–5.5cm. Older branches with raised leaf scars at intervals. Leaves in pseudowhorls of 12–25 or regularly spirally arranged. Blade 15–120 x 2–6mm, linear; apex acute or sometimes rounded at the extremity; margin somewhat irregular but otherwise entire, slightly reflexed, becoming strongly so when dry; base tapering, densely scaly, becoming glabrescent above or with silvery patches of scale remains; below persistently brown scaly with overlapping scales. Scales variable in size with broad striate, lobed flanges; large darker brown centres. Mid-vein deeply impressed above, prominently raised beneath; lateral veins obscure. Petiole 2–6 x 1mm, densely brown-scaly, slightly grooved in the distal part. Flower buds (see p.327) to 14 x 10mm, ovoid-conical, broadly pointed. Bracts ovate to obovate-spathulate, spotted brown with scales but with broad, green, scale-free, lateral areas, the margins finely white ciliate. Bracteoles to 8mm, narrowly linear, glabrous or laxly scaly. Inflorescence of 8–15 horizontal or semi-erect flowers in a complete umbel. Pedicels 20–30 x c.1.25mm, pale green but densely scaly. Calyx a low disc or minutely 5-lobed, densely scaly. Corolla 7–12 x 20–25mm, white with prominent brown scales, without scent; tube 3–4 x 3.5 x 5mm, deeply longitudinally grooved and weakly funnel-shaped, white but covered in brown scales outside and densely but very shortly hairy within; lobes 8–10 x 7–10mm, wide-spreading, white, conspicuously brown-speckled outside with scales that sometimes form distinctive but irregular radial lines inside. Stamens wide-spreading, irregularly arranged around the corolla but mostly towards the lower side; filaments 5mm, white, hairy especially towards the base; anthers 2.5–3 x c.0.3mm, dark brown. Disc glabrous. Ovary 3.5–5 x 1.5–2mm, conical, entirely covered by scales, gradually tapering distally; style green, passing to yellow, glabrous, on opening almost straight, 2mm, growing to 7mm and curving downwards through 90° from just above the ovary; stigma hardly broadened from the style, green, 1mm in diameter. Fruit 15–20 x 4mm, narrowly fusiform or slightly curved, scaly. Seeds 6–8mm, without tails 1mm, the longest tail 2.5–3.5mm.
Habitat: Epiphyte in large trees in mossy montane forest on Mt Kinabalu where it can be very difficult to spot even when in flower as the small plants are often obscured by other leaves and branches. Terrestrial on mountain ridges of the correct altitude where the vegetation is sufficiently open; abundant on the summit ridge of Mt Api in the Mulu National Park, Sarawak where it occurs on the deep peat overlying limestone in an open sub-montane shrubbery.
Distribution: Malaysia (Borneo), Sabah, Mt Kinabalu, Mt Trus Madi, Mt Alab and in the Long Pa Sia area. Sarawak, G. Mulu National Park (Mt Mulu and Mt Api), Mt Murud. Indonesia (Kalimantan), Mt Kongkemul (Kangkemul).
Altitude: 1300-2000m
This dainty species is very distinct with its narrow strap-shaped leaves and short, white, but brown-scaly flowers with highly contrasting chocolate brown anthers. It is unlikely to be confused with any other rhododendron. Rhododendron stenophyllum has similarly narrow leaves but it is a much less scaly plant with glossy green leaves and orange or red flowers. Rhododendron vinicolor with similar strap-shaped leaves has purple flowers and does not occur in Borneo. It could possibly be confused with R. lineare but this species, apart from having bright yellow flowers, usually has much shorter leaves, is much greener in appearance and has the scales well spaced on the underside of the leaf, not dense and overlapping as in R. himantodes. The flowers would appear to be very similar to R. fortunans but that species has broad, deeply wrinkled leaves with distinct lateral veins.
Leaves 30–45 x 2mm. Flowers only seen in bud, reported to be very light yellow.
Known only from the type locality in mountain forest
It is doubtful if the flowers on this variety really are yellow and would not have opened the normal white. Sleumer (1973) doubted the significance of the variety as forms with small leaves have been collected elsewhere, notably on Mt Api in Sarawak, and are almost certainly due to greater exposure. It would be interesting to get further collections from Mt Kongkemul which might rule out the colour difference.
Type: Endert 4257. Indonesia, East Borneo, W Kutei, Mt Kemul (L, A, BO, SING).
Erect shrub to 1 *25 m. Leaves (8-)12-25(-30) X (4-)5-10(-ll) mm, elliptic to oblong, apex rounded to obtuse, base cuneate, undersurface yellowish buff, scales overlapping. Inflorescence 4-7-flowered, pedicels lepidote, 2.5-7 mm. Calyx up to 1 -8 mm, the lobes often unequal, rounded to broadly deltoid, variably lepidote and ciliate. Corolla bright rose or lavender blue to bluish purple, rarely white, broadly funnel-shaped, 10.5-15 mm, tube 4-6.5 mm, elepidote, pubescent inside. Stamens 10, shorter than corolla, filaments pubescent towards the base. Ovary lepidote, style slightly shorter than to slightly longer than the stamens, glabrous or occasionally pubescent at the base. Capsule narrowly ovoid, 5-6 mm, lepidote.
Two varieties may be distinguished
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: blue, lavender, purple, rose, white
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):96
Style 4-10.5 mm
Habitat: Open slopes, often marshy
Distribution: China (NW, W, SW, N & C Yunnan, SW Sichuan)
Altitude: 2400-4800m
Type: Yunnan, mountains west of Tengku valley, 3650 m, Forrest 12562 (holo. E, iso. K)
Synonymy: R. fimbriatum Hutchinson, Gard. Chron. 91:438 (1932). Type: a cultivated specimen (holo. K)
Style 13-16 mm
Habitat: Open stony slopes
Distribution: China (N & C Yunnan)
Altitude: 3500-4250m
The Philipsons (1975, p. 20) record various natural hybrids of R. hippophaeoides.
Type: China, mid-west Yunnan, Chienchuan/Mekong Divide, vi 1923, Forrest 23341 (holo. E, iso. BM)
Small shrub to 1 m. Young growth sparsely lepidote, filiform-acicular pubescent and sparsely loriform-setose. Leaves narrowly obovate to obovate-orbicular, 13-30 x 7-14 mm, ± flat, glabrous above, sparsely lepidote beneath with well-separated, golden scales, the margins ciliate with long straight loriform hairs. Inflorescence many-flowered, the rachis short or reaching 10 mm. Pedicels sparsely lepidote and filiform-acicular puberulent. Calyx with narrowly triangular lobes, 2-4 mm, lepidote and fringed with loriform setae. Corolla pink, sparsely lepidote and pubescent outside, 12-18 mm, tube 6-10 mm. Stamens 10, filaments pubescent towards the base. Ovary lepidote, style as long as the ovary or a little longer, sparsely pubescent at the base. Capsule sparsely lepidote, oblong-globose, 5-6 mm.
Habitat: Open woodland, screes, slopes and scrub
Distribution: Austria, France, Germany, Italy, Yugoslavia, Switzerland (Alps)
Illustrations:
A calcicole species, ecologically vicariant with R. ferrugineum in the Alps. Hybrids between the two species (R. x intermedium Tausch) are found in suitable habitats.
Type: Habitat in Alpibus Helveticis Austriacis, Styriacis'
Occurs in Countries: AT, CH, DE, FR, IT Subgenus: Rhododendron Habit: Non-Tree
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):111
Low shrub to tree, 0.5-8m; young shoots covered with glandular bristles. Leaves broadly obovate, 5-11 x 3.5-6cm, 1.6-2(-2.2) x as long as broad, apex rounded, blunt, base rounded, margin cartilaginous, sometimes ciliate towards the base, upper surface glabrous, lower surface with scattered stipitate glands and a sparse floccose indumentum, midrib with glandular bristles near the base; petioles 1.5-2.5cm, densely covered with persistent glandular bristles. Inflorescence lax, 3-5-flowered; rhachis less than 5mm; pedicels 15-20mm, with a dense covering of glandular bristles. Calyx 4-10mm, stipitate-glandular, lobes rounded. Corolla campanulate, white to pink, usually darker in bud, usually with a few purple flecks, c.40mm. Ovary and style base densely stipitate-glandular. Capsule c. 17 x 6mm, straight or curved.
Habitat: Ravines, wet conifer forest
Distribution: China (SE Xizang)
Altitude: 3000-4000m
A distinctive species, more closely allied to R. selense than it is to R. glischrum, with which it has been traditionally associated (for a further discussion of the affinities of this species see p. 459).
Type: China, SE Xizang, Tsela Dzong, Tsangpo Valley, 13000ft, v 1934, Kingdon-Ward 5659 (holo. E;iso. BM, K)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: pink, purple, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):283
Shrub to 2.5m. Twigs 2–5mm in diameter, rounded, sub-densely covered when young with fragile, sub-stellate, reddish-brown scales, later glabrous and smooth; internodes 2–18cm. Leaves 4–8 together in pseudowhorls. Blade 40–105 x 20–42mm, elliptic, or obovate-elliptic; apex broadly tapering or shortly sub-acuminate, obtuse to nearly rounded; margin slightly revolute; base broadly tapering, sub-truncate to rounded, rarely sub-cordate; glabrescent above when mature, densely and more persistently scaly beneath. Scales small, variously sub-stellate-lobed in the marginal zone; centres dark, slightly impressed, scale pits black and shallow. Mid-vein slightly impressed above, thick and prominent in the proximal part beneath; lateral veins 6–10 per side, spreading, straight below, curved and indistinctly anastomosing before the margin, slightly raised on both sides, or a little impressed above, reticulation obscure. Petiole 4–16 x 1.5–2.5mm, semi-rounded, grooved above, scaly and rugulose. Bracts to 15 x 8mm, ovate to obovate, obtuse, firm-membranous, with some sparse scales at the top outside or quite glabrous. Bracteoles to 22 x 1.5mm, linear below, sub-spathulate apically, glabrous. Inflorescence 5–9-flowered. Pedicels 30–40 x 0.6–0.8mm, sparsely stellate-scaly proximally, more densely so distally. Calyx c.4mm in diameter, oblique, disc-shaped, 5-angular, outside densely scaly. Corolla 44–50mm, tubular below, sub-oblique, red, membranous; tube 20–30 x 6–7 x 7–8mm, laxly to sub-densely scaly outside, lobed at the base, shortly hairy in the proximal ½ inside; lobes 9–17 x 10–12mm, obliquely obovate-spathulate. Stamens slightly shorter than the corolla; filaments linear, densely hairy proximally, less so distally; anthers 3.5–4 x 1mm, oblong, obtuse at the base. Disc shortly hairy on the upper margin, glabrous below. Ovary c.8 x 2.5mm, sub-cylindrical, densely stellate-scaly, with some spreading hairs at the top between the scales, gradually tapering distally; style as long as the corolla tube, laxly scaly and sub-densely patently hairy in the proximal 10–15mm, glabrous distally; stigma deeply 5-lobed. Fruit 35–40 x 4–5mm, sub-cylindrical, sub-densely covered with red-brown scales.
Habitat: Terrestrial or occasionally epiphytic in light mossy forest in poor humus or sandy soil, or in swampy places with Sphagnum.
Distribution: Indonesia, New Guinea (W), Vogelkop Peninsula, Arfak Mts, Nettoti Range, Mt Watjetoni.
Altitude: 1200-2000m
Latin – hirti – hairy; Greek – lepido – scaly. With both hairs and scales, possibly alluding to the ovary.
Type: Gjellerup 1133, 28 April 1912. New Guinea (NW), Arfak Mts, Angi Lake, 1900m (L, BO).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:311
Shrub or small tree, 3-1 lm. Leaves obovate to oblanceolate or elliptic, 17-24 x 6.4—10cm, 2.4-3.2 x as long as broad, apex rounded to retuse, base ± rounded, upper surface glabrescent, not strongly reticulated, lower surface with a dense silvery to cinnamon indumentum of two layers, the lower compacted, the upper composed of slightly fimbriate, broadly cup-shaped hairs; petioles 2.5-5cm, terete, with a thin, ± floccose greyish indumentum. Inflorescence dense, 15-25-flowered; rhachis 25-50mm; pedicels 20-40mm, with a sparse greyish floccose indumentum. Calyx 2-3mm, sparsely tomentose. Corolla fleshy, 7-8(-10)-lobed, tubular-campanulate, pink to magenta or purple, with a darker basal blotch, 30-40(-50)mm. Stamens 15-18. Ovary tomentose. Capsule 30-40 x c.6mm, curved.
Habitat: Open hillsides, Abies forests, etc.
Distribution: E Nepal, n India (Sikkim, Bengal, Arunachal Pradesh), Bhutan, China (S Xizang)
Altitude: 3000-4000m
Illustrations:
R. hodgsonii usually occurs at higher altitudes than does R. falconed, though where the two grow together hybrids occur (e.g. Ludlow & Sherriff29Sly 3047; Grierson & Long, s.n.; Cooper 2088). R. decipiens Lacaita (/. Linn. Soc, Bot. 43, 473, 1916), described from specimens from N Bengal & Sikkim (Lacaita 15375 (K); Ribu 18445 (K), 18446 (K)), almost certainly has the same hybrid origin.
Type: Sikkim Himalaya, 10-12000ft, Hooker (holo. K)
Occurs in Countries: BT, CN, IN, NP Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: magenta, pink, purple
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):259
Shrub to 5 m, minutely puberulous on the young branches, petioles and upper mid-ribs. Leaves elliptic to narrowly elliptic, 30-65 x 13-33 mm, base cuneate, tapering to a blunt or emarginate apex, mucronate; petiole 6-13 mm long. Inflorescence buds lateral, 1-flowered, clustered near the ends of the leafy shoots; outer bud scales short, inner elongate (c.l2mm long); pedicel only slightly longer than the inner bud scales, densely covered with long glandular hairs. Calyx lobes rounded, 2-75-3-25 x 1 -5-3-Omm, copiously to sparsely fringed with delicate hairs and stalked glandular hairs. Corolla white with a variable number of violet to red-purple spots on the upper lobes, occasionally with a yellow centre, puberulous on the outside of the tube; rotate, with a short tube and spreading lobes about 50mm across. Stamens 5, protruding, filaments hairy for half or more of their length. Ovary subglobose, c.2-5mm high, with glandular hairs, 5-locular; style exserted, up-curved, glabrous or with very few basal hairs. Capsule broadly ovoid, c.8mm high, verrucose.
Habitat: Rocky slopes
Distribution: Hong Kong, China (Guangdong)
Altitude: 300-1200m
Herklots (Rhododendron Year Book 184, 1949) describes this species (as R. ovatum) as free flowering and fragrant.
Synonymy: Azalea myrtifolia Champion, Bot. Mag. 77: sub t. 4609 (1851), non Loddiges (1824). Type: Hongkong, Black Mountain, iii 1849, Eyre (holo. K).
Occurs in Countries: CN, HK Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Azaleastrum Habit: Non-Tree Fl. Colour: red, yellow
Philipson, W.R. & Philipson, M.N. (1986) A Revision of Rhododendron III. Subgenera Azaleastrum, Mumeazalea, Candidastrum and Therorhodion. Notes from the Royal Botanic Garden Edinburgh 44(1):5
Straggling, much-branched shrub to 2.5m. Twigs densely covered with stalked scales, warty and rough to the touch in the youngest parts; internodes 2–8cm. Leaves 4–6 together in pseudowhorls. Blade 20–55 x 2–6mm, linear; apex sub-obtuse; margin entire, strongly revolute to near the midrib; base tapering; densely covered on both sides with yellowish stalked, deeply stellately divided scales which fall early, leaving the stalks, thus making the surface of the lamina rough. Mid-vein faintly impressed above, as thick as the petiole and somewhat prominent beneath; lateral veins not visible. Petiole 3–8mm, thick, densely scaly with stalked scales. Flower buds c.10–12 x 5–6mm. Bracts to 3–7 x 1–4mm; outer bracts ovate, appressed, inner ones ovate-sub-acuminate, almost blunt, glabrous or with just a few scales along the outer middle line and on the margins. Bracteoles filiform, minute. Inflorescence 1–2-flowered, the flower half-hanging to hanging. Pedicels 10–12 x c.1.5mm, densely covered with yellowish, stalked scales. Calyx c.3mm in diameter, obliquely circular, very obtusely and shortly 5-lobed, densely set with nearly sessile scales. Corolla 30–35 x 17–22mm, pinkish-red or cream, without scent; tube 20–25 x 5–6 x 7–8mm, slightly broadened upwards and somewhat curved, densely scaly outside, glabrous inside; lobes c.10 x 8mm, scaly outside except for the margins. Stamens exserted to 10mm, clustered on the upper side of the flower; filaments linear, glabrous; anthers 1.5 x 1mm. Disc glabrous. Ovary c.5 x 2mm, conical, gradually tapering to the style, very densely scaly, without simple hairs; style c.20mm, red or cream, slender, with some scales at the base, glabrous distally; stigma sub-globose, greenish yellow, 5-lobed. Fruit 15–20 x 3–5mm, fusiform.
Distribution: Papua New Guinea, Eastern Highlands, Goroka subdistrict, Kerigomna; Western Highlands, Upper Minj Valley on the Minj–Nona Divide; Mt Ormogadzin. Growing near the margins of forest grassland or alpine shrubberies
Altitude: 3000-3400m
Named after Ruurd Dirk Hoogland of CSIRO Land Research, and later of Research School of Biological Sciences, Canberra, Australia. One of the collectors of the type and very active in research and plant collecting in New Guinea.
There is still some confusion between this species and R. caliginis. Kores (1984) distinguished R. caliginis from R. hooglandii ‘on the basis of its patent, slightly or non-revolute leaves; golden-brown more or less stellate scales; conspicuously verrucose [warty] older branchlets; ovate perulae [bracts] which are either entirely glabrous or with a few scattered scales and tubular pink or red flowers’. There is also a distributional and altitude difference cited: R. hooglandii is said to be from ‘the north central portion of Papua New Guinea’, 3050–3400m, while R. caliginis is restricted to the extreme north western portion of Papua New Guinea from 2400 to 2850m. A collection by T.M. Reeve (444) from Mt Miap combines the narrow revolute leaves with very scaly, subulate bracts coming from the classic area of R. caliginis. The collection of J.M. Mangen (2021) from West New Guinea also has extremely narrow revolute leaves, is from the lowest elevation recorded (1650m) and should therefore be referred to R. caliginis; unfortunately this specimen lacks flower buds. Both species are likely to have both white- and pink-flowered forms, and the colour of the scales is difficult as a character. The most reliable difference would appear to be the difference in flower bud morphology which at present correlates with altitude and is used here to discriminate between these two species.
Type: Hoogland & Pullen 5576, 9 July 1956. Papua New Guinea, E Highlands district, Goroka subdistrict, near Kerigomna Camp, c.3000m (L, CANB).
Occurs in Countries: PG Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: cream, pink
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:85
Shrub or small tree, c.4m; bark smooth; young shoots glabrous. Leaves broadly oblanceolate, c.12.5 x 5cm, 2.5 x as long as broad, apex rounded, apiculate, base rounded, upper surface glabrous, lower surface glabrous except for large well-developed fasciculate hairs overlying the veins, epidermis epapillate; petioles 1.5-3cm, slightly winged, glabrous. Inflorescence 8-15-flowered, dense; rhachis c.2mm; pedicels 8-15mm, glabrous. Calyx (5-)10-20mm, cupular, greenish to yellowish, glabrous, lobes rounded, erose. Corolla tubular-campanulate, deep rose to crimson, with darker nectar pouches and a few flecks, 35-45mm. Ovary and style glabrous. Capsule 20-25mm.
Habitat: Mixed forests
Distribution: NE India (Arunachal Pradesh)
Altitude: 2500-3700m
Illustrations:
Allied to R. hylaeum and its immediate relatives but with distinctive and well-developed fasciculate hairs on the lower surface of the leaves.
Occurs in Countries: IN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: crimson, rose
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):422
Epiphytic or free-growing shrub up to 3 m. Young growth loriform-setose. Leaves narrowly elliptic, tapered to the base and the long-acuminate apex, 85-100 x 28-31 mm, upper surface brownish green, margins variably loriform-ciliate, lower surface brownish with rather lax, dark scales. Inflorescence 2-3-flowered, pedicels lepidote. Calyx disc-like or obscurely undulately lobed, fringed with rather sparse loriform setae and also with filiform-acicular hairs, surface lepidote. Corolla white, flushed pink, with a yellow blotch inside, funnel-campanulate, 60-70 mm, tube 35-36 mm, pubescent all over the tube and bases and middles of the lobes outside, sparsely lepidote on the tube, more densely so on the lobes. Stamens 10, filaments pubescent towards the base. Ovary densely lepidote, tapering into the lepidote style. Capsule lepidote, oblong, 20-25 mm.
Habitat: Rocks, or epiphytic on trees
Distribution: N Burma (Adung valley)
Altitude: 1200-2150m
A recently described but rather distinct species, known only from the Adung valley, easily recognised by its very acuminate leaves, pubescent corolla and the occurrence of filiform-acicular hairs on the margins of the calyx lobes.
Type: N Burma, Adung valley, 16 iv 1931, Kingdon Ward 9403 (holo. A)
Occurs in Countries: MM Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Rhododendron Habit: Epiphyte, Non-Tree Fl. Colour: pink, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):54
Shrub or small tree, 2-9 m. Leaves oblanceolate, 10-12.5 x 2-3cm,3.3-5 x as long as broad, apex long-cuspidate, base cuneate, lower surface glabrous; petioles 2-2.5 cm, glabrescent. Inflorescence 6-10-flowered; rhachis (10-) 30-60 mm; pedicels 25-40 mm, glabrous. Calyx 5-10mm, lobes rounded, glabrous or gland-fringed. Corolla 7-lobed, open-campanulate, glabrous, pale red to purplish or lilac, 35-50 mm. Stamens 12-14, filaments glabrous. Ovary glandular; style glandular to tip, stigma capitate. Mature capsule not known
Distribution: China (NE Yunnan, Sichuan)
Altitude: 1000-2700m
Allied to R. davidii but differing in the larger calyx. Fang (loc. cit.) remarks on the similarity in leaf shape with R. calophytum var. openshawianum but notes the obvious floral difference between the two species.
Type: China, Sichuan, Ma-pien hsien, Shiao Liang-shan, 2500 m, 20 vi 1930, Fang 4546 (fr.-SZ); Nof Ma-pien-hsien, 2400-2700 m, 11 v 1931, Wang 22900 (fl.~A, E)
Occurs in Countries: CN Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: lilac, red
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):228
Erect shrub; young shoots sparsely stellate-tomentose. Leaves oblanceolate, c.5.5 x 2cm, 2.7 x as long as broad, apex acuminate to apiculate, base rounded; both surfaces ± glabrous at maturity; petioles c.lcm, sparsely tomentose. Inflorescence c.6-flowered; rhachis c.5mm; pedicels c.lOmm, stellate-tomentose. Calyx c. 1.5mm, lobes rounded, glandular-ciliate. Corolla campanulate with a broad base and ? nectar pouches, red, 40-45mm. Ovary densely light brown-tomentose; style stellate-tomentose almost to tip. Capsule not known.
Habitat: Slopes in forest
Distribution: China (S Sichuan)
Altitude: Around 3200m
Probably most closely allied to R. facetum though differing in the smaller leaves and calyces, and in the tomentose styles.
Type: China, S Sichuan, Huidong Xian, 3200m, 25 iv 1959, Wu, S. K. 1558 (holo. Herb. Inst. Bot Kunming).
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: red
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):377
Shrub, to 1.5m; shoots slender, covered with dense, adpressed strigose hairs, twigs with grey-brown hairs, becoming glabrous. Leaves ? dimorphic, thick, coriaceous, obovate-elliptic, 1-3.5 x 0.6-2cm, 1.7-1.8 x aslongasbroad, apex blunt mucronate, base obtuse to cuneate, margin entire, upper surface of leaf almost glabrous, with a few scattered chestnut hairs on midrib, lower surface with scattered chestnut adpressed hairs, especially on midrib; petiole 4-7mm, densely covered with brown strigose hairs. Inflorescence 8-10-flowered; pedicels 2-4mm, densely covered with dark brown bristlelike hairs. Calyx cup-shaped, indumentum as for pedicels. Corolla funnel-shaped, glabrous, red, 15mm, lobes oblong; tube c.7mm. Stamens 5, unequal, filaments flattened, papillate. Ovary ovoid, densely covered with dark brown bristle-like hairs; style glabrous. Capsule not known.
Distribution: China (Guangdong)
Allied to R. tsoi and R. chunii but differing in the larger leaves, etc.
Type: China, Guangdong, Huiyang Xian, Bai-yun-zhang, 850m, iii 1932, T.M. Tsui 129 (holo. PE, iso. K)
Occurs in Countries: CN Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: red
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):138
Shrub, c.2m; young shoots densely covered with spreading hairs and villose glands. Leaves dimorphic, chartaceous; spring leaves elliptic to ovate-lanceolate, 3-7 x 1.5-2.8cm, 2-2.2 x as long as broad, apex acute to acuminate, base cuneate, margin entire, ciliate, upper surface strigose, soon glabrescent, lower surface pale, densely brownish-villose-strigose; summer leaves obovate, 15-20 x 8-10mm, otherwise as for spring leaves; petioles 5-8 mm, densely strigose. Inflorescence c.lO-flowered; pedicels 5-7mm, densely brownish-strigose. Calyx minute, densely strigose, lobes oblong. Corolla rotate-campanulate, pale lilac, with darker flecks, c.lOmm; tube c.5 x 3mm. Stamens 5, densely puberulent below. Ovary densely strigose; style strigose at base. Capsule ovoid, 5-6 x c.5mm.
Habitat: Wooded valleys
Distribution: China (Hunan)
Altitude: 700-1700m
R. flosculum Fang & G.Z. Li, Bull. Bot. Res. N.E. Forest. Inst. 4(1): 4 (1984). Type: China, Guangxi, Ziyuan Xian, Maoer Shan, 1700m, 26 v 1982, G.Z. Li 10720 (holo. IBK, n.v.). Differs from R. hunanense in its 2-3-flowered inflorescence, its glabrous stamens and in its less dense stem and leaf indumentum. The authors compare this species with R.jinxiuense but the description leads us to believe that it is closer to and possibly conspecific with R. hunanense, the specimens of which were probably not available to the authors. The type locality of R. flosculum is in E Guangxi, close to the western edge of the range of R. hunanense.
The type of var. hunanense is represented by two dissimilar specimens. One, which is labelled as the type, has relatively small spring leaves and the other, with larger leaves, resembles the type of var. mangshanicum.
Type: China, Hunan, Mang Shan, 1700m, 2 v 1934, X.P. Gao, (S.P. Ko) 54218 (holo. IBSC, photo. E; iso. PE)
Synonymy: R. hunanense [Chun ex] P.X.Tan var. mangshanicum Tan, loc. cit., t.4 (1982). Type: China, Hunan, Yizhang Xian, Mang Shan, 500m, 26 x 1942, S.Q. Chen (S.H. Chun) 2937 (holo. IBSC, photo. E.)
Occurs in Countries: CN Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: lilac
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):100
Shrub or small tree, 2—6m. Leaves coriaceous, narrowly oblanceolate, 7—15 x 1.6-2.8cm, 4-4.5 x as long as broad, apex acuminate, upper surface glabrous, lower surface with a bistrate indumentum, the lower layer compacted, whitish, the upper loose, white to yellow, detersile or persistent, tomentose, hairs ramiform, intermixed with scattered glands that are more evident on the midrib; petioles l-2cm, puberulous when young, later glabrescent. Inflorescence lax, 6-10-flowered; rhachis 10-15mm; pedicels c.20mm, sparsely tomentose and shortly stipitate-glandular. Calyx c.lmm, glandular-ciliate, lobes minute. Corolla widely campanulate, white to pale rose or purple, with purple flecks, 40-50mm. Ovary densely and coarsely yellowish-tomentose. Capsule 20-25 x 8-10mm, cylindrical.
The only certain distinction between the two subspecies is in the leaf indumentum that turns yellow with age in subsp. rockii and does not do so in subsp. hunnewellianum. Subsp. rockii usually has relatively small leaves though still within the range of cultivated plants of subsp. hunnewellianum.
Occurs in Countries: CN Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: purple, rose, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):322
Habitat: Thickets
Distribution: China (C Sichuan)
Altitude: 2000-3000m
Type: China, W Sichuan, west and nr Wen Chuan Hsien, 2000-2600m, 7 x 1908, Wilson 1198 (iso. E,K)
Synonymy: R. leucolasium Diels, Feddes Repert. 17: 196 (1921). Type: China, Sichuan, Wen tschuan-hsien, Pe mu shan, supra Schu lin kou, pr. Hou schao pu, 3000m, 20 iv 1914, Limpricht 1462 (iso. E, fragm.)
Habitat: Mountain slopes, thickets
Distribution: China (S Gansu & adjacent parts of Sichuan)
Altitude: 2000-2400m
Synonymy: R. rockii Wilson, J. Arnold Arbor. 9: 103 (1928). Type: China, S Gansu, slopes beyond Sichuan border, 2000m, iv 1925, Rock 12064 (iso. K).
Shrub to 3m. Twigs c.4mm in diameter, rounded, stellate scaly; internodes 3–6cm. Leaves 3 together in pseudowhorls and spirally along the internodes. Blade 60–90 x 35–50mm, elliptic, broadly elliptic or ovate elliptic; apex rounded or obtuse; margin revolute; base rounded to weakly cordate; when young golden stellate-scaly on both sides, becoming glabrescent above but rough with epidermal tubercles; below more persistently scaly. Scales stellately divided, tapering to a short foot with distinct, whitish epidermal tubercles when mature and dry, rough to the touch. Mid-vein only slightly impressed above, grooved for 5–8mm proximally; strongly raised beneath; lateral veins 6–7 per side, irregular, visibly raised on both sides, reticulation obscure below. Petiole 7–12 x 2–3.5mm, only faintly grooved, densely scaly, the scales leaving a papillose surface when they have gone. Flower buds to 35 x 17mm, ovoid, smooth, green. Bracts to 45 x 20mm, ovate to sub-spathulate, appressed hairy on both sides and with a few small brown scales outside and prominent brown marginal scales. Bracteoles 18–30mm, linear, channelled, somewhat broadened upwards to 2mm wide, densely hairy and with scales along the margins. Inflorescence 2–5-flowered in an open umbel, the flowers horizontal to half-hanging. Pedicels 8–10 x 2mm, densely scaly and with hairs protruding above the scales. Calyx c.7mm in diameter, 5-lobed, densely scaly and white hairy outside, glabrous inside, the lobes c.2mm long. Corolla 70–100 x 70–75mm, 5-lobed, tubular below, expanded above, white with a waxy appearance but spotted with pink at the base of the lobes, strongly scented; tube 60–70 x 7–8 x 15–20mm, glabrous outside, hairy for 40–50mm proximally inside; lobes 30–40 x 26–30mm, rounded to spathulate, glabrous. Stamens c.60mm long, exserted to c.15mm, at first in a tight cluster in the centre of the flower, later spreading irregularly around the mouth; filaments densely to laxly hairy, white; anthers 7–8 x c.1.5mm, creamy to pale yellow, obtuse at the base, the pollen pale yellow. Disc, white hairy. Ovary cylindrical, c.10 x 4mm, white hairy, gradually contracted distally; style c.50mm, the proximal 40mm densely covered in distally pointing white hairs, the ultimate 10mm glabrous, lying on the lower side of the flower, curving upwards later; stigma green, c.2mm in diameter. Fruit (sub-mature) 30–40 x c.10mm, oblong, grooved, hairy.
Habitat: Epiphytic or terrestrial shrub in mossy forest.
Distribution: Papua New Guinea, Milne Bay District, Daga country, Mt Wayat, on the very top of the pass; Mt Mon, Maneau Range; Mt Suckling area, Mt Gauru.
Altitude: 1800-2070m
The collector making a comparison between the scent of this species and that of hyacinth plants (Liliaceae), noted for their powerfully scented flowers.
Type: Cruttwell 1529, 6 June 1969. New Guinea (E), Milne Bay District, Mt Wayaat on the Gamatawa side, 1900m (K, L).
Occurs in Countries: PG Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: pink, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:86
Shrub or small tree, 2.5-12m; bark smooth, peeling; young shoots ± glabrous. Leaves oblong to oblanceolate, 8.5—14.5 x 3.4-5.7cm, 2.5—3.2 x as long as broad, apex rounded, minutely apiculate, base rounded, upper surface glabrous, lower surface greenish with an epapillate epidermis, with scattered fasciculate hairs arising from red persistent bases on the veins, otherwise glabrous; petioles 1.5-2cm, usually narrowly winged, stipitate-glandular when young, soon giabrescent. Inflorescence 10—12-flowered; rhachis 13—40mm; pedicels 8-12mm, glabrous or glandular. Calyx 2-8mm, cupular when well-developed, lobes broad and rounded, remotely glandular-ciliate, otherwise glabrous. Corolla tubular-campanulate, fleshy, rose-pink, with dark flecks, 35—50mm. Ovary and style glabrous. Capsule 15—22 x 6-10mm.
Habitat: Open mixed forests
Distribution: NE Upper Burma & adjacent parts of China (SE Xizang)
Altitude: 2700-3700m
As Cowan & Davidian, Rhododendron Yearbook 6: 179 (1952) point out, R. hylaeum has affinities with subsection Irrorata, particularly R. anthosphaerum. The fasciculate hairs on the leaves do, however, link this species with R. subansiriense and R. faucium and suggest a closer affinity with R. hookeri.
Type: NE Upper Burma, Chawchi Pass, 10500ft, 15 v 1920, Farrer 1551 (holo. E; iso. K).
Occurs in Countries: CN, MM Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: rose
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):421
Shrub; young shoots glabrous. Leaves elliptic, 8-12 x 2.5-3.5cm, 3.2-3.4 x as long as broad, apex ± cuspidate, base cuneate, upper surface glabrous when mature, lower surface with persistent punctate hair-bases, sometimes also with persistent dendroid hairs, especially towards the base and on the midrib; petioles 1.5-2cm, with a floccose indumentum at first, soon becoming ± glabrous. Inflorescence c.lO-flowered; rhachis 15-25mm; pedicels c.35mm, with a sparse dendroid indumentum. Calyx c.3mm, sparsely hairy. Corolla funnel-campanulate, white with reddish flecks, 35-45mm. Ovary densely glandular; style sparsely glandular below. Capsule not known.
Distribution: Taiwan
Illustrations:
R. hyperythrum is a distinctive species, only distantly allied to the remaining members of this subsection. Itdoes, however, clearly belong to this subsection on account of the form of the inflorescence and the shape of the corolla. The punctate hair-bases are a distinctive feature in subsection Pontica.
Type: Formosa, regionibus meridionaiibus, Konishi & Vani, n.v*
Synonymy: R. rubropunctatum Hayata, ibid. 3: 141 (1913), non Leveille (1911). Type: Taiwan, Mt Shichiseitonzan, iv 1910, Sasaki (iso. A,E).
Occurs in Countries: TW Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: red, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):306
Shrub or small tree, 1.5 -9m. Leaves coriaceous, oblanceolate to elliptic, 7-14 x 2—3.7cm, 3—4 x as long as broad, apex acuminate, base cuneate to rounded, margin slightly undulate, both surfaces glabrous when mature though with red punctate hair-bases overlying the veins beneath; petioles l-2cm, stipitate-glandular. Inflorescence 12-17-flowered; rhachis up to 20mm; pedicels 10-25mm, stipitate-glandular, sometimes also with scattered dendroid hairs. Calyx c.2mm, densely glandular, sometimes also dendroid-hairy. Corolla campanulate to tubular-campanulate, with nectar pouches, pubescent within near the base, white or cream to violet-rose, with at least a few greenish or more commonly purple flecks, 35-50mm. Ovary stipitate-glandular, sometimes also sparsely to densely dendroid-tomentose, at least near the base; style glandular to tip. Capsule 10-25 x 6-10mm, curved.
R. irroratum has an extremely wide geographical distribution. In the north of its range the flowers tend to be white or cream with strong flecks and the ovaries are exclusively glandular (subsp. irroratum). In the southern part of its range the flowers are mauve with few flecks and the ovaries have eglandular as well as glandular hairs (subsp. kontumense). Subsp. pogonostylum is morphologically intermediate and occupies an intermediate geographical range. Furthermore, there are mixed populations (as in S Yunnan) where subsp. irroratum and subsp. pogonostylum occur together along with a complete range of intermediates.
9*. R. lapidosum T. L. Ming, Acta Bot. Yunnanica 3: 113, t.l (1981). Type: China, NE Yunnan, Zhenxiong Xian, 1900m, 26 iv 1974, Giu, X. Z. 74-1 (holo. Herb. Inst. Bot.Kunming). Shrub; young shoots puberulous though soon glabrescent. Leaves lanceolate, 5.5-7.5 x 1.3-1.7cm, apex acuminate, margin slightly undulate, both surfaces glabrous, though with red sessile punctate glands below; petioles 0.8-1.3cm, glabrous. Inflorescence c.9-flowered; rhachis c.l5mm; pedicels c.llmm, sparsely glandular. Calyx c. 1.5mm, lobes ciliolate, otherwise glabrous. Corolla tubular-campanulate, 35-40mm, white. Ovary densely tomentose, eglandular; style glabrous. Capsule not known. CHINA (NE Yunnan). Only known from the type. This species was originally allied to R. araiophyttum on account of the glabrous style though the apparently tubular-campanulate corolla suggests a closer affinity with R. irroratum, a species that occurs in NE Yunnan. R. lapidosum is indeed only doubtfully distinct from R. irroratum subsp. pogonostylum, differing for certain only in the glabrous style. The ovary in subsp. pogonostylum is usually glandular as well as tomentose though at least one specimen has a tomentose, eglandular ovary (as in R. lapidosum) but with a glandular style.
Occurs in Countries: CN Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: cream, green, pink, purple, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):296
Ovary and usually calyx stipitate-glandular, not tomentose
Habitat: Thickets, pine forests
Distribution: China (W & C Yunnan, SW Sichuan)
Altitude: 2500-3500m
Illustrations:
The type of R. ninguenense is technically referable to R. irroratum in that it has a glandular ovary. Material from S Sichuan and adjacent NE Yunnan does, however, appear to have a more open corolla than is usual in subsp. irroratum and tends to have slightly more hairy pedicels (this material includes the type of R. ninguenense). This material may represent a minor geographical variant at the eastern end of the range of the subspecies but the differences are relatively minor.
Type: China, Yunnan, in silvis ad Pee-tsao-lo, supra Mo-so-yu, 2500m, 9 iv 1886, Delavay 2952 (iso. E, K)
Synonymy: ?R. ninguenense Handel-Mazzetti, Akad. Wiss. Wien Math.-Naturwiss. Kl. Anz. 57: 288 (1920). Type: China, Sichuan, reg. temperatis montis Lose-shan, supra vicum Luschui, ad austro-or. urbis Ningyen, 2200-3200m, 16 iv 1914, Handel-Mazzetti 1445 (holo. WU, iso. E).
Ovary and calyx tomentose and glandular. Corolla violet-rose, occasionally paler towards base; filaments with slender hairs at base; capsule 10- 15mm.
Habitat: Montane meadows, moss forests
Distribution: Vietnam, Sumatra.
Altitude: 1800-3000m
Illustrations:
Subsp. kontumense is only doubtfully distinct from subsp. pogonostylum. R. atjehense does have a more persistent indumentum on the petioles and young shoots than do the remaining specimens seen but, as I cannot confirm the other supposed differences between R. kontumense and the other taxa cited as synonyms (see Sleumer, Blumea, suppl. 4: 52-54, 1958), I am treating them all as belonging to a single subspecies.
Synonymy: R. kontumense Sleumer, Blumea, suppl. 3: 54 (1946). Type: Vietnam, sommet de Ngoe Pang, prov. de Kontum, 2187m, Poilane 32176 (holo. P; iso. L). R. langbianense [Chevalier ex] Dop, Fl. Gen. Indo-Chine 3: 745 (1930). Syntypes: Vietnam, massif de Langbian, sommet du Pic Grand Piton, 2500m, 15 ii 1914, Chevalier 30896 (P), 30896 bis (P). R. ninguenense sensu Sleumer, Blumea, suppl. 3: 55 (1946), non Handel-Mazzetti (1920). R. atjehense Sleumer, Reinwardtia 5: 226 (1960). Type: Sumatra, Atjeh, Gajo Landa, Putjuk Anasan, 1800-3000m, 28 i 1937, Van Steenis 8394 (holo. L; iso. K).
Ovary and calyx tomentose and glandular. Corolla white or cream to deep pink; stamens with broad papillae at base; capsule 15-25mm long.
Habitat: Forests, rocky slopes
Distribution: China (Yunnan, SW Sichuan)
Altitude: 2100-3000m
Synonymy: R. pogonostylum Balfour f. & W. W. Smith, Trans. Bot. Soc. Edinb. 27: 210 (1917). Type: China, Yunnan, Mengtsz, 7000ft, Henry 11066 (holo. K; iso. E). R. adenostemonum Balfour f. & W. W. Smith, ibid. 27:174 (1917). Type: China, Yunnan, Mengtsz, Henry 11067 (holo. K; iso. E).
Habitat: Forests, open slopes, alpine meadows, cliffs, etc.
Distribution: China (N Yunnan, SW Sichuan)
Altitude: 3300-4600m
The Philipsons (1975, p. 42) record hybrids between R. impeditum and various other species.
Type: China, Yunnan, western flank of the Lichiang range, 3650-3960 m, vi 1910, Forrest 5876 (holo. E)
Synonymy: R. litangense [Balfour f. ex] Hutchinson in Stevenson (ed.), The Species of Rhododendron 411 (1930). Type: none cited. R. semanteum Balfour f., loc. cit., nom. nud. Compact, much branched shrub to 0.9(—I -2) m. Leaves (4—)5—14(—15) x (2-5-)3-6(-7) mm, elliptic or ovate to broadly elliptic or oblong, apex obtuse or acute, mucronulate, base broadly cuneate, undersurface pale grey-green speckled brown or more uniformly rusty, the scales markedly to slightly discontiguous. Inflorescence up to 4-flowered, pedicels lepidote and rarely pubescent, 0.8-3 mm. Calyx usually 2-5-4 mm, occasionally shorter, lobes strap-shaped with a rounded or deltoid apex, usually with a few scales forming a central band, margin ciliate. Corolla violet or purple to rose-lavender, rarely white, broadly funnel-shaped, (7—)8—15 mm, tube (2-)3-6 mm, pubescent inside, rarely also outside, elepidote or with a few scales on the outside of the lobes. Stamens usually 10, often rather variable in number, filaments pubescent towards the base. Ovary lepidote, style very variable in length, from shorter than to longer than the stamens, glabrous or pubescent towards the base. Capsule ovoid, 4-6 mm, lepidote.
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):102
Shrub or small tree to 4m. Twigs rounded, c.5mm in diameter, young parts with pale brown scales, quickly glabrescent; internodes 4–5cm, shorter than the leafy area. Lateral buds conspicuous, spherical. Leaves loosely spirally arranged. Blade 40–100 x 25–55mm, broadly elliptic to obovate or ovate; apex shortly and abruptly acutely acuminate, rarely obtuse; margin entire although finely crenulate by impressed scales if viewed with a lens, narrowly cartilaginous, often broadly revolute; base broadly tapering to rounded, sometimes sub-cordate. Initially densely scaly on both sides, the scales often touching each other on the upper side, glabrescent and remaining minutely pitted above, densely to sparsely scaly beneath. Scales mostly transparent or pale brown with small darker centres, sub-stellate, slightly impressed. Mid-vein broad, but quickly tapering, raised above in the proximal ½ and more weakly raised below for c.¾ of its length; lateral veins 4–9 per side spreading at an angle of c.45°, high-ascending, curved-anastomosing before the margin, slightly raised and often minutely grooved above, smooth beneath, reticulation obscure above, moderately visible beneath. Petiole 5–10 x 4–5mm, robust, silvery scaly initially, without a groove, becoming rugulose when dry. Flower buds to 50 x 23mm, ovate or narrowly ovate, with an acute apex, smooth with all the bracts appressed, green flushed with red. Bracts ovate, obovate to spathulate, appressed hairy outside and with small pale brown scales in a central band, glabrous inside, fringed with brown often dendroid scales. Bracteoles 17–22mm, filamentous but slightly broadened upwards, laxly sub-appressed hairy throughout. Inflorescence an open umbel of 6–15 flowers, these horizontally displayed or half-hanging, not or only very faintly scented. Pedicels 25–50 x c.2.5mm, densely to sparsely stellate-scaly, strongly flushed pink. Calyx c.4mm in diameter, obliquely disc-shaped, normally shortly lobed or occasionally with one or two elongate deflexed teeth up to 5 x 1mm, scaly outside, glabrous inside. Corolla 35–45 x 35–55mm, funnel-shaped, white, pink or red; tube c.24 x 5 x 10mm, white, straight, glabrous or sparsely scaly outside, hairy in the basal ½ inside; lobes 23–26 x 17–22mm, reflexed to the horizontal, overlapping ½–2⁄3, rounded or slightly retuse. Stamens at first clustered together in the mouth of the flower, becoming a little exserted (to c.3mm), strongly incurved; filaments linear and laxly hairy below, narrower to filiform and glabrous upwards, white; anthers cream, oblong, 3–3.5 x c.1mm, the base obtuse or minutely apiculate. Disc glabrous, or hairy at the upper margin. Ovary 5–7 x 2.5–3mm, ovoid-conical or somewhat cylindric-obovoid, densely covered with appressed, long white, (brown on drying), hairs which cover the scales, abruptly contracted distally; style slender, white, lying on the lower side of the tube but curving upwards, with some sparse hairs at the very base or glabrous, remaining distinctly shorter than the stamens; stigma globose, deeply lobed, white. Fruit 25–30 x 7–8mm, cylindrical, densely and persistently short brown hairy, the outer layer peeling irregularly and then the valves reflexing and the placentae weakly splayed and breaking away at the base. Seeds 3–3.5mm, without tails c.0.9mm, the longest tail 1.2–1.5mm.
Habitat: In low forest
Distribution: Indonesia, Sulawesi (SW Central), Latimodjong Range.
Altitude: 2400-3000m
Latin – impositus – placed upon, alluding to the abrupt junction between ovary and style in this species.
Type: Kjellberg 4149. Indonesia, Sulawesi, Enrekang, Bukit Pokapindjang (S, E).
Occurs in Countries: ID Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Tree Fl. Colour: pink, red, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:291
Shrub to 1.2m. Twigs semi-rounded, densely covered with stellate scales, becoming glabrescent; internodes 2–10cm. Leaves 4–5 together in pseudowhorls. Blade 62–83 x 24–32mm, elliptic; apex shortly acuminate, sub-acute or rarely obtuse; margin slightly recurved; base broadly tapering to nearly rounded; above sub-densely covered with small, flat, non-impressed scales which become silvery and persist for a long time, especially on the mid-vein, eventually glabrescent; more densely and more persistently scaly beneath. Scales dense, but mostly not touching, orange-brown, small, marginal zone irregularly lobed; centre dark, distinctly impressed. Mid-vein grooved above, strongly and obtusely prominent beneath; lateral veins 8–10 per side, spreading, obscurely anastomosing, very slightly impressed above, hardly raised beneath, reticulation inconspicuous. Petiole 8–10 x 1.5–2mm, densely scaly, the scales touching initially as they do on the proximal area of the mid-vein beneath, semi-rounded, grooved above. Inflorescence 5–7-flowered. Pedicels 10–19 x 0.7mm, sparsely scaly. Calyx c.4mm in diameter, obliquely disc-shaped, unequally 5-angular. Corolla 30–35mm, tubular-funnel-shaped, red, glabrous inside and out; tube 20–23 x c.5 x c.7mm, straight, lobed at the base; lobes 10–13 x 7–12mm, spreading, obovate to sub-circular. Stamens somewhat exserted from the mouth; filaments linear, densely patently hairy in the proximal 5–7mm; anthers c.3.5 x 1mm, oblong, the base obtuse. Disc prominent, glabrous. Ovary 5–6 x 2–2.5mm, conical-sub-cylindrical, densely stellate-scaly, without hairs, abruptly contracted distally; style as long as the stamens, glabrous; stigma rounded.
Habitat: Terrestrial on a peat moor at Kunturun
Distribution: Indonesia, Maluku, Buru, known only from the type collection.
Altitude: Around 1075m
Latin – impressi – sunken or impressed; punctatus – marked with dots or spots. Alluding to the impressed scales on the leaves.
Sleumer (1966) noted that ‘Size and colour of the scales suggest that R. impressopunctatum is a hybrid of R. malayanum with another species of the Javanicum group, presumably R. seranicum; these three species grow together at Kunturun’. There are no recent observations to confirm or refute this.
Type: Toxopeus Ac. Moluccas, Buru, Kenturun, 1075m (BO, L).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:266
Shrub to 1m. Twigs slender, rounded, scaly when young; internodes 0.5–6cm. Leaves 3–4 together in pseudowhorls at the upper nodes. Blade 50–75 x 25–40mm, elliptic; apex broadly and obtusely acuminate; margin slightly revolute proximally; base tapering, sub-densely and persistently scaly beneath; laxly scaly initially, finally glabrescent above. Scales small, round, entire or nearly so, yellowish, somewhat impressed. Mid-vein a little impressed above; beneath strong and very prominent in the proximal part, gradually less so distally; lateral veins 4–6 per side at an acute angle with the mid-vein, obscurely anastomosing, slightly impressed above, raised beneath, reticulation obscure. Petiole 4–20 x c.1.5mm, semi-circular, rugose. Bracteoles filiform, very sparsely scaly. Inflorescence a c.8-flowered open umbel. Pedicels c.10 x 0.5mm, slender, sub-densely covered with pale yellow scales. Calyx c.2.5mm in diameter, sub-obliquely disc-shaped, wavy, very shortly 5-lobed. Corolla tubular, 50–55mm, red; tube 35–40 x 3 x 10mm, straight or slightly curved, laxly to sub-densely covered with small yellowish scales outside, very laxly hairy and sparingly scaly inside; lobes 10–15 x 5–7mm, obovate or elliptic-obovate, spreading, very sparsely scaly outside, glabrous inside. Stamens well exserted from the mouth; filaments filiform, sparsely hairy especially proximally, glabrous distally or completely glabrous; anthers 2–3 x 1mm, obovate-oblong, base obtuse. Disc glabrous. Ovary c.5 x 1.7mm, elongate-conical, very densely scaly, gradually tapering distally; style to 50mm, sparsely scaly to the top; stigma shortly obconical, small.
Habitat: Locally common, a high epiphyte in mixed rain forest
Distribution: Papua New Guinea, Ogeramnang in the Sattelberg–Saruwaged area, and Purosa in the Okapa area, Eastern Highlands.
Altitude: 1830-2070m
Latin – incommodē – unsuitable or troublesome, probably due to the ambiguous position of this species in the section (see below).
A puzzling species which has not been recollected recently. It is the only really red-flowered species in Siphonovireya and has a much broader flower tube in relation to its length than any of the other species (the lobe to tube length is rather more than the ¼ allowed for this section). It would be tempting to regard it as a hybrid between a Siphonovireya and a red-flowered species from another section if it was not reported as locally common.
Type: Clemens 4733, 23 Dec. 1936. Papua New Guinea, Morobe District, Sattelberg region, Ogerammang, 1830m (A, B, L).
Occurs in Countries: PG Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: red, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:63
Erect shrub or tree to 5m, or occasionally up to 10m. Twigs 1.5–2mm in diameter, rounded, at first densely covered with sub-stellate, stalked scales, becoming glabrescent, warty and rough to the touch; internodes 1.5–4cm. Leaves in loose pseudowhorls at the upper ends of the internodes or spirally arranged in the upper ½ of the internode. Blade 10–35 x 6–20mm, elliptic, ovate-elliptic or ovate; apex broadly tapering, obtuse or rounded; margin not or slightly cartilaginous, distinctly crenulate, slightly or not revolute; base tapering to rounded, rarely sub-cordate, dark green above, much paler and often yellowish green or brownish beneath, densely scaly initially on both sides, early glabrescent but densely marked with blackish minute pits above, more persistently and densely scaly beneath. Scales round to angular, distant, or only partly touching each other, the thin, marginal zone irregularly crenate or shortly sub-stellately lobed; centre relatively large, dark yellow, thick and a little impressed. Mid-vein narrowly impressed above, prominent beneath proximally, less so distally; lateral veins 4–7 per side, spreading, faintly impressed above and raised beneath in fully mature leaves, often inconspicuous. Petiole 1–3 x 1.5–5mm, grooved above, densely scaly. Flower buds to 11 x 6mm, pale greenish-brown, ovoid, acutely pointed, smooth, densely scaly outside, often with lateral flower buds around the terminal bud. Bracts to 10 x 4mm, ovate; outer acute or apiculate; inner obtuse, thin and membranous, with scales along a broad outside middle line, or quite glabrous and shining; margin irregular with a few brown scales. Bracteoles to 10mm, linear proximally, sub-spathulate distally, sparsely scaly. Inflorescence 3–7-flowered in an open umbel, half-hanging to hanging. Pedicels 8–14mm, slender, densely covered with shortly stalked scales. Calyx 2.5–3.5mm in diameter, disc-shaped, irregularly, very shortly and obtusely 5-lobed, densely scaly outside. Corolla 11–16mm, shortly tubular, pink to red, densely covered with thick, sub-stellate, yellow scales outside, glabrous inside; tube 7–12 x 4 x 6mm, straight; lobes 3–4.5 x 3–4.5mm, erect or only slightly spreading, sub-circular. Stamens exserted to c.3mm, unequal; filaments filiform, glabrous; anthers c.1mm, obovoid. Disc low, glabrous. Ovary 3–4 x 1.5–2mm, ovoid-conical, very densely covered with thick sub-circular scales, abruptly tapering distally; style thick, quite glabrous, as long as the ovary; stigma rounded to deeply 5-lobed. Fruit 12–17 x 4–5mm, fusiform-cylindrical, longitudinally 5-ribbed, somewhat curved, densely scaly, with a sub-persistent style. Seeds c.3mm including the tails.
Habitat: In mossy forest or forest openings, Vaccinium-shrubbery, commonly on old landslides, the edges of deep gullies or steep mountainsides with grassy slopes in full sun, often on infertile sandy soil, sometimes on limestone ridges, locally common
Distribution: Indonesia and Papua New Guinea. Widespread in New Guinea, from the Vogelkop Peninsula, Arfak Mts, in the west along the Main Range to Mt Dayman in the Milne Bay District in the east.
Altitude: 1800-3400m
Latin – inconspicuus – inconspicuous. Named from a herbarium specimen that had been prepared with formaldehyde and was totally brown. Not inappropriate as the flowers of this species are in any case very small.
This species is easily confused with R. yelliotii (section Albovireya) and superficially looks very similar. The main differences between the two species are as follows. In R. inconspicuum the scales on the undersurface of the mature leaves are dense, but usually with gaps between them, only occasionally touching; the bracts are sometimes scaly along the middle line outside, and not hairy at all, often shining. In R. yelliotii the scales are much denser, generally all of them touching each other; the bracts are scaly and shortly hairy outside, the margins distinctly ciliate. These two species are however reported to hybridise (van Royen & Kores 1982) which then blurs the distinctions. Sleumer (1973) reduced R. invasiorum to synonymy with R. inconspicuum and van Royen & Kores (1982) confirmed this collecting intermediate specimens from the Murray Pass and Mt Suckling areas. Sleumer (1966) also commented that ‘R. luteosquamatum, [which] is perhaps only a variety of R. inconspicuum’. The differences are insignificant: R. inconspicuum often has the distinctive yellow scales of R. luteosquamatum and the longer petiole length is insufficient to warrant even varietal distinction.
Type: Pulle 1000, 2 Feb. 1913. New Guinea (W), Wichmann Mts, 1000m (BO, K, L, U).
Synonymy: R. invasiorum Sleumer, Reinwardtia 1960. 5: 60. R. luteosquamatum Sleumer, Reinwardtia 1960. 5: 166.
Occurs in Countries: ID, PG Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Tree Fl. Colour: pink, red, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:228
Much-branched shrub, usually low and prostrate, though sometimes up to 2m; young shoots covered with adpressed flattened chestnut-brown setose hairs. Leaves dimorphic, chartaceous; spring leaves narrowly lanceolate to oblanceolate, 2-3 x 0.8-1 cm, 2.3-3 x as long as broad, apex acute, base cuneate, margin remotely crenate-serrulate, ciliate, upper surface with scattered bristles, lower surface paler, with setose bristles restricted to midrib; summer leaves 10-18 x 3-5mm, otherwise as for spring leaves; petioles 2-4mm, clothed with adpressed chestnut-brown setose hairs. Inflorescence 1-2-flowered; pedicels 5-10mm, clothed with brown strigose hairs. Calyx with brown strigose hairs, especially on lobe margins, lobes ovate to orbicular, c.lmm long. Corolla broadly funnel-shaped, bright red to scarlet, occasionally rose-red, 30-50mm; tube half the length of corolla, glabrous. Stamens 5, as long as or slightly exceeding the corolla, filaments scabrid below. Ovary densely covered with adpressed shining brown hairs; style glabrous. Capsule oblong-ovoid, c.lOmm long, densely strigose.
Habitat: Wooded river banks, etc.; also widely cultivated and sometimes escaping.
Distribution: Japan (S & W Honshu, Kyushyu)
Illustrations:
Many forms of this species are known in cultivation. All are presumed to have been derived from Japanese stock though many 18th and 19th century introductions into Europe arrived via China. The extensive synonymy, of which only a part is cited above, reflects the popularity of this species in cultivation.
Synonymy: Azalea indica L., Sp. PI. 150 (1753)óbased on 'Chamae- rhododendron exoticum, amplissimis floribus lilaceis' of Brey- nius(Prodr. 1:23,1680). A. macraniha Bunge, Mem. Soc. Etr. Acad. Sci. St. Petersb. 2: 115 (1833). Described from China, Beijing. A. indica L. var. lateritia Lindley, Edward's Bot. Reg. 20: t.1700 (1834). Type: a plant originating in China, cultivated by Mr Knight (or the plate drawn from it). Rhododendron decumbens [D. Don ex] G. Don, Gen Syst. 3: 846 (1834). Described from a plant grown by Knight & Tate, originally from China. Azalea danielsiana Paxton, Mag. Bot. 1: t.129 (1834). Type: the plate cited, of a plant grown by Mr Tate, originally introduced by Capt Daniels in 1830. Rhododendron crispiflorum Hooker, Bot. Mag. 79: t.4726 (1853). Type: a plant grown by Standish & Noble, originating as a garden plant in China (or the plate drawn from it). R. breynii Planchon, Fl. des Serres 9:77 (1855), nom. superfluum. R. sieboldii Miquel var. serrulatum Miquel, Ann. Mus. Bot. Lugduno-Batavum 1: 33 (1863). Described from a specimen collected by Keiske on Mt Kirisima, Satsuma Prov, Japan. R. balsaminiflorum Carriere, Rev. Hort. 432, t. (1882). Type: a double-flowered form from Japan, brought by Viesener to France in 1872 (or the plate cited). R. hannoense Nakai, Bot. Mag. (Tokyo) 29: 261 (1915)ó Japanese text. Type not known.
Occurs in Countries: JP Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: red, rose, scarlet
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):119
Shrub to 2m. Twigs 1–2mm in diameter, with stalked scales, conspicuously rough with persistent protruding scale bases after the scales have fallen; internodes 2–10cm. Leaves 4–7 together in tight pseudowhorls. Blade 20–30 x 8–16mm, obovate to spathulate; apex emarginate or rounded, with a small protruding mucronate gland; margin entire, revolute especially in the basal ½; base narrowly tapering; upper surface green, glabrescent, lower surface sparsely covered with scales, paler green. Scales sub-circular, brown or translucent, mostly pale, variable in size and slightly impressed. Mid-vein impressed above and raised beneath; lateral veins 1–4 per side, impressed above and strongly and conspicuously raised beneath. Petiole 2–4 x 1–1.5mm, grooved above, rounded below, brown scaly and very shortly hairy above. Flower buds to 8 x 3mm, green becoming pale brown, the bracts with a few scales mainly outside and fringed with white hairs, glabrous inside. Bracteoles to 5mm, slender, glabrous except for a few hairs near the apex. Pedicels 15–25 x c.1mm, green, moderately to densely scaly. Inflorescence of solitary, or paired, flowers, these held semi-erect, horizontal to half-hanging. Calyx green, densely scaly; lobes c.1 x 1.5mm, rounded or triangular. Corolla c.12 x 12mm (dry!), orange, or yellow, moderately densely scaly outside, and with long patent white hairs just below the mouth inside; lobes probably reflexed but semi-erect in dry specimens, overlapping up to 2⁄3. Stamens arranged all round the mouth, dimorphic, the long filaments hairy towards the base only, the short ones along their entire length and protruding up to 5mm. Disc green, mainly glabrous, but with just a few hairs on the upper side. Ovary green, densely covered in scales and moderately densely hairy; style c.5 x 1mm, deflexed, glabrous. Fruit c.20 x 5mm, green passing to brown, cylindrical with longitudinal grooves and a persistent deflexed style; valves splitting to the base and curving backwards, straight, not twisting, placentae becoming detached from the base of the central column. Seeds reported to be tailed (not seen).
Habitat: An epiphyte in temperate rain forest
Distribution: Myanmar, (Upper), Seinghku Wang and Adung Valley. China, Yunnan, Gongshan Qiqi.
Altitude: 1800-2100m
Latin – insculptus – engraved or with sunken markings due to the deeply impressed veins on the leaf.
Said to grow with R. vaccinioides but to flower earlier than that species, the flowers being reported for April and as almost over in May.
Rarely collected and not yet known to be cultivated. This species is very similar to R. emarginatum but differs in that the flowers were originally described as orange in colour and it lacks hairs on the outside of the bracts; it has more distinct venation on the leaves than most of the specimens attributed to R. emarginatum although the type specimen of that species at Kew has equally distinct venation to R. insculptum.
Type: Ward 6735, 20 May 1926. Upper Burma, Seinghku Wang (K, E, L).
Occurs in Countries: CN, MM Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:30
Shrub, 1.3-3.5m. Leaves elliptic, 7-13 x 2-4.5cm, 3-3.5 x as long as broad, apex acuminate, glabrous above, lower surface with a compacted fawn indumentum embedded in a surface film, so appearing shiny; petioles 1.5-2cm, lanate at first, soon glabrescent. Inflorescence lax, c.8-flowered; rhachis c.5mm; pedicels 20-40mm, with a sparse white to rufous tomentum. Calyx 1—2mm, floccose, lobes minute. Corolla widely campanulate, pink with a darker median line down each lobe, c.40mm. Ovary densely white lanate-pilose; style glabrous. Capsule c.25 x 10mm, broadly cylindrical.
Habitat: Woodlands
Distribution: China (Sichuan, Wa Shan)
Altitude: 2300-3000m
Illustrations:
The species is remarkable for the shining compacted indumentum of the lower surface of the leaves.
Type: China, Sichuan, Mt Wa, 2300-3000m, vii 1903, Wilson 3965 (holo. A; iso. E, K)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: pink
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):327
Shrub to 40cm. Twigs c.4mm in diameter, brown scaly; internodes 1.5–3cm. Leaves loosely to densely spiral. Blade 110–180 x 80–110mm, broadly elliptic to elliptic-obovate, deeply sulcate between the lateral veins; apex rounded-obtuse, or sometimes very shortly apiculate; margin narrowly revolute, often red; base broadly tapering, rounded, truncate, or cordate, glabrescent above when mature, sub-persistently scaly beneath. Scales minute, flat, marginal zone variously sub-stellately lobed; centre small, slightly impressed. Mid-vein as wide as the petiole and slightly raised proximally on the upper surface, strongly prominent beneath; lateral veins 12–16 per side, at right angles, straight and parallel, with numerous similar less distinct veins between, prominent above, broadly impressed beneath, anastomosing and united into an inner intramarginal vein, which is connected by numerous transverse veinlets with an outer, less distinct one; reticulation dense, slightly prominent on both sides, especially beneath. Petiole c.6–12 x 7–10mm, without a groove, flattened above and inconspicuously winged, rounded beneath, densely and finely brown scaly. Flower buds to 50 x 26mm, narrowly ovoid, acute, pale green sometimes with a pink flush, bracts erect, slightly gaping, not tightly appressed. Bracts to 35 x 9mm, narrowly elliptic, acutely pointed, strongly keeled, with a few scales outside and minutely scaly at first along the margins, otherwise glabrous. Bracteoles to 26 x 4mm, narrowly spathulate, channelled, glabrous. Flowers 2–10 in a loose umbel. Pedicels 40–65 x 1.5–2mm, very densely patently short-hairy, scaly. Calyx disc-shaped, wavy, obtusely 5-lobed, c.4mm in diameter, glabrous, lobes sometimes narrowly elongate, appressed. Corolla 35–50 x 50–100mm, funnel-shaped, lobed to halfway, light yellow, without scent, commonly with 4- and 5-lobed flowers; tube c.21 x 12 x 32mm, densely hairy at the base inside, glabrous outside, base slightly 5-lobed; lobes 25–40 x 35–40, obovate-spathulate, spreading, overlapping to c.¼. Stamens c.30mm, arranged all round the mouth, exserted 6–8mm; filaments linear and densely hairy in the lower ½, filiform and glabrous above; anthers 7–8 x 1.5mm, cream, narrowly oblong, curved, each cell with a basal obtuse swelling. Disc prominent, thickly 10-lobed, glabrous below, laxly hairy above. Ovary c.6 x 2mm, sub-cylindrical, densely white-hairy and apparently scaly, tapering distally; style slender, glabrous, 10–15mm; stigma green, thick-conical with 5 distinct lobes. Fruit 35–40 x 9–10mm. Seeds 5–7mm, with irregularly crimped tails, without tails c.0.8mm, the longest tail 3mm.
Habitat: Epiphytic in Agathis forest on waterlogged, white, acid sands or on granite rock faces
Distribution: Indonesia (Borneo), Mt Palimasan, near Tabang on Belajan R. in W Kutei. Malaysia (Borneo), Sarawak, Mt Penrissen and Mt Berumput.
Altitude: 600-1050m
Latin – intra – inwardly; nervus – vein. Alluding to the prominent veins on the leaves.
Type: Kostermans 12886, 10 Sept. 1956. Borneo (E), W Kutei, Mt Palimasan, near Tabang on Belajan R., 600m (L, BO).
Occurs in Countries: ID, MY Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:272
Shrub to 1-5 m, compact and intricately branched. Leaves (4-8-)6-12(-14) X (2.7-)3-5-7(-8) mm, oblong to elliptic or rotund, apex rounded, usually shortly mucronate, base cuneate to rounded, the margin often bearing branched hairs, undersurface uniformly buff to straw-coloured, scales ± contiguous to overlapping. Inflorescence (1—) 2—6(—8)-flowered, pedicels lepidote, to 5 mm. Calyx 0.5-2 mm, lobes deltoid to oblong, margin lepidote with pale golden scales and/or marginal cilia. Corolla almost hypocrateriform, pale lavender to dark blue, rarely yellowish, elepidote outside, 8—12(—14) mm, tube 4—6(—7) mm. Stamens 10, not exserted from corolla tube, filaments pubescent towards the base. Ovary lepidote, style shorter than the stamens. Capsule ovoid, lepidote, c. 5 mm.
Habitat: Open moist meadows, hillsides, forest margins
Distribution: China (N Yunnan, SW & C Sichuan)
Altitude: 2800-4900m
Type: China, Szechuan occidental, aux environs de Tongolo, Soutie 765 (holo. P; iso. K, US)
Synonymy: R. blepharocalyx Franchet, op. cit.: 396. Type: China, Sutchuen occidental, au voisinage de Tongolo, dans la vallee de Mouma et dans les montagnes de Tche-to, Soulie 398 (holo. P). R. peramabile Hutchinson, Gard. Chron. 91:366 (1932). Type: a cultivated specimen (holo. K)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: blue, lavender, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):96
Shrub to 1m. Twigs striate, slightly whitish when dry, variously obtusely compressed, c.3–4mm in diameter, sparsely scaly, but the scales quickly falling; internodes 6–12cm. Leaves spreading, 4–5 in tight pseudowhorls, pleasantly resinously aromatic when crushed. Blade 40–70 x 20–50mm, broadly elliptic to elliptic-obovate; apex obtuse to rounded, sometimes apiculate; margin slightly revolute in dry specimens; base broadly tapering, quickly glabrescent above, persistently sub-densely scaly beneath. Scales small, rounded, distant from each other by about their own diameter; marginal zone thin, narrow; centre small and impressed. Mid-vein narrowly impressed above, as thick as the petiole at the base; moderately raised beneath; lateral veins 6–7 per side, with some additional less conspicuous ones in between, straight, obscurely anastomosing before the margin, slightly impressed above, a little prominent or indistinct below, with no obvious reticulation. Petiole 6–9 x 1–1.5mm, densely scaly, grooved above. Flower buds to 11 x 9mm, pink, ovoid, quite smooth with all the bracts appressed. Bracts to 10 x 6mm; outer bracts ovate-acuminate, often mucronate by a small protracted apex, densely covered with thick scales and very short hairs at the base and the middle outside; inner ones spathulate, thinner, the margin minutely divided with scale stalks. Bracteoles c.12mm, linear, sparsely scaly, not hairy. Inflorescence of 4–8 flowers, the flowers with an upward curving tube so that the lobes are displayed vertically. Pedicels 10–12 x c.0.5mm, green or pink, densely scaly but without hairs. Calyx c.2.5mm in diameter, a little oblique, obscurely lobed. Corolla 40 x 25mm, white, trumpet-shaped; tube 32 x 4 x 7mm, densely white-scaly outside and distinctly fluted longitudinally to the base of the lobes, expanded mostly in the distal ½, inside densely patently white-hairy; lobes to 12 x 9mm, spreading perpendicularly, overlapping to c.1⁄3, the lateral margins often at least partially reflexed, inconspicuously scaly outside except for the margins. Stamens exserted to c.6mm, irregularly clustered in the mouth; filaments white, narrowly linear and densely, patently, white-hairy in the proximal ¾, filiform and glabrous distally; anthers c.2mm, cream, oblong, the base obtuse. Disc hardly prominent, glabrous. Ovary 4–5 x c.1.5mm, sub-cylindrical, densely scaly and sparsely patently white-hairy, tapering gradually distally; style slender, as long as the corolla tube or very slightly protruding when receptive, densely scaly and sometimes laxly patently hairy in the proximal ½, exclusively densely scaly in the distal ½; stigma sub-globose. Fruit to 20 x 6mm, pale green when immature. Seeds 3–4.2mm, without tails c.2mm, the longest tail 2mm.
Distribution: Indonesia, New Guinea (W), mountain valleys above Wamena. First recorded from a temporarily flooded grass-plain on peaty soil, at 1650m, where it was reported to be locally common. It was also a common terrestrial constituent of the poor open heath-forest vegetation on white sand in the area around Wamena where it has been reported in flower in June and Oct.–Nov.
Altitude: Around 1650m
Named after the seasonally flooded area in which the original plants collected were growing.
Type: Versteegh BW 10454, 24 June 1961. Wiligimaan, 1650m, Balim River Valley, New Guinea (L).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:64
Shrub to 2 m with thin, lepidote branches. Leaves 40-50 x 22-25 mm, ovate or elliptic, ± acute, somewhat cuneate at the base, elepidote but puberulous along the main veins above, glabrous beneath but with dense golden scales. Inflorescence unknown. Calyx very small, rim-like, sparsely lepidote, the margin ciliate with small, fine hairs. Corolla funnel-shaped, c. 28 mm, tube c. 12 mm, purple (?), very sparsely puberulous and lepidote along the adaxial suture outside, sparsely pilose within. Stamens 10, filaments pilose towards the base. Ovary densely lepidote with a few hairs in the impressed part near the style base. Style shorter than the longest stamens at anthesis. Capsule sparsely lepidote, c. 9 mm.
Distribution: China (Gansu)
An obscure species, known only from the type collection which appears to have suffered some damage since Balfour and Farrer wrote their type description. The plant is similar in most respects to R. heliolepis, but is widely separated from it geographically.
Type: China, Kansu, Siku-Satanee ranges 8-9000 ft, iv-v, Farrer 79 (holo. E)
Occurs in Countries: CN Subgenus: Rhododendron Habit: Non-Tree
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):88
Shrub, l-2.5m; young shoots sparsely tomentose, eglandular, perulae deciduous. Leaves elliptic to oblanceolate, 8-14 x 2.5-3.5cm, 3-4 x as long as broad, apex acute to ± rounded, apiculate, base cuneate to rounded, upper surface glabrous, lower surface with a dense compacted grey to fawn tomentum or indumentum thin and agglutinated or occasionally giabrescent; petioles 2-2.5cm, usually densely floccose-tomentose. Inflorescence lax, 9-12-flowered; rhachis 10-20mm; pedicels 20-30mm, with a sparse dendroid indumentum. Calyx 2-3mm, lobes rounded-triangular, glabrous. Corolla widely funnel-campanulate, pink to soft rose, with conspicuous flecks, 30-45mm. Ovary white-tomentose. Capsule to at least 22 x 10mm.
Habitat: Hill tops, mountain ridges
Distribution: Japan (Honshu, Kyishu)
Altitude: 200-1200m
See also Doleshy (1968)—ref. p. 305
The name R. japonicum (A. Gray) Suringar, the current name for Azalea japonica A. Gray, is rejected as the combination was only proposed provisionally to replace R. molle Siebold & Zuccarini, should that name prove to be nomenclaturally inapplicable for Gray's plant. By the time that it was realised that R. molle G. Don was an earlier homonym of R. molle Siebold & Zuccarini, the combination R. japonicum (Blume) Schneider had been effectively published, precluding the use of the name for Gray's plant.
Doleshy (op. cit., 1968) maintains var. kyomaruense as distinct on the basis of its agglutinated leaf indumentum (analogous to var. hondoense), though it is probable that it is no more than a local geographical variant of var. pentamerum. He proposed the combination R. metternichii var. metternianum (Wada) Doleshy for this plant, a superfluous name as var. kyomuraense is the first name at varietal rank for this taxon if it is retained. In his paper he discusses in detail the distribution of the taxa and points out that var. pentamerum has a more northerly distribution than does var. japonicum. This perhaps justifies subspecific rank though the respective combinations have never been made under R. japonicum.
R. japonicum is closely allied to and possibly conspecific with R. yakushimanum.
Occurs in Countries: JP Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: pink, rose
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):308
Doleshy (1968) distinguishes var. hondoense from the type ofVar. japonicum on account of its agglutinated rather than velutinous leaf indumentum and suggests that it replaces var. japonicum (var. metternichii) in the west of Honshu, though both occur in Kyishu. Intermediates between the two forms undoubtedly occur, though, if the geographical separation of the two forms is confirmed, then there is some justification in maintaining var. hondoense, perhaps as a subspecies.
Synonymy: Hymenanthes japonica Blume, Bijdr. 862 (1826). Type not designated. R. metternichii Siebold & Zuccarini, FL Japon. 1: 23, t.9 (1835). Type: in alpibus Japoniae borealis, Siebold (LE, n.v.), nomen illegit. R. metternichii Siebold & Zuccarini var. heptamerum Maximovicz, Rhododendrons As. Or. 21 (1870)-type as above. R. hymenanthes Makino, Bot. Mag. (Tokyo) 16:33 (1902). nomen illegit. R. metternichii Siebold & Zuccarini var. hondoense Nakai, Bot. Mag. (Tokyo) 38: 26 (1924). Described from Japan, 'the mountains of Hondo and Shikaku'& var. micranthum Nakai, ibid. 38: 27 (1924). Described from Japan, Prov. Yamato.
Illustrations:
Synonymy: R. degronianum Carriere, Rev. Hort. 40: 186, t.77 (1869). Type not designated. R. metternichii Siebold & Zuccarini var. pentamerum Maximovicz, Rhododendrons As. Or. 22 (1870). Type: a cultivated specimen originating from Yedo in Japan. R. pentamerum (Maximovicz) Matsumura, Cat. Sem. Hort. Bot. Univ. Tokyo 1916: 24 (1916). R. nakaii Komatzu in Matsumura, Icon. PL Koisikav. 1:145, t.73 (1913). Described from Nikko in Japan. R. metternichii Siebold & Zuccarini subsp. pentamerum (Maximovicz) Sugimoto, New Key Jap. Trees 470 (1961). R. metternichii Siebold & Zuccarini var. kyomaruense Yamazaki, J. Jap. Bot. 39: 17 (1964). Type: Japan, Prov. Tutomi, Iwala-yun, Jokojisan, 900m, 16 v 1961, Yamazaki (holo. TI, n.v.).
With flowers like that of a Jasminum (Oleaceae), noted for their sweetly scented flowers.
Type: Peninsula Malaya, Johore, Mt Ophir, Lobb s.n. cultivated from seed (K).
Synonymy: R. elongatum Blume, Fl. Jav. Pl. inéd. 1863–83. t.7 B, f.1. Azalea jasminiflora (Hook.) Kuntze, Rev. Gen. Pl. 1891. 2: 387.
Occurs in Countries: ID, MY, PH Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:157
Shrub to 1m. Leaves 7–10 together in tight pseudowhorls, linear to narrowly elliptic. Blade 30–50 x 5–6mm. Flowers white or tinged with pink, scented. Disc glabrous.
Distribution: Malaysia (Borneo), Sarawak, Mt Lambir.
Altitude: 300-450m
Greek – chamae – on the ground or low growing; pitus – a pine tree (Pinus). Alluding to the narrow leaves and being like a small pine tree.
Known only from the summit area of this isolated peak
Type: Haviland & Hose 2015, 21 May 1895. Borneo, Sarawak, Mt Lambia, 305m (BM).
Synonymy: R. chamaepitys Sleumer, Bot. Jahr. 1940. 71: 144.
Shrub to 2.5m. Twigs 1.5–3mm in diameter, scaly and sometimes very shortly hairy. Leaves in tight pseudowhorls 3–8 together. Blade elliptic to obovate-elliptic. Petiole 3–8 x 1–2mm. Corolla hairy in the proximal ½ only inside, otherwise like ssp. jasminiflorum.
Distribution: Philippines, Mindanao, summit area of Mt Apo, sub-alpine shrubbery
Altitude: 1900-3100m
Named after the collector, H.F. Copeland, who published a landmark account of Philippine rhododendrons in 1929.
Type: Copeland 1439, Oct. 1904. Philippines, Mindanao, Davao Province, Mt Apo 2350–3100m (PNH†, A, K, P, US).
Synonymy: R. jasminiflorum var. copelandii (Merr.) Sleumer, Reinwardtia 1960. 5: 130.
Shrub with densely hairy and scaly twigs. Leaves in dense pseudowhorls 3–6 together. Blade 35–40 x 20–25mm, ovate, cordate at the base, sub-sessile. Petiole 1–2 x 1–2mm. Inflorescence mostly 2–5-flowered, the flowers horizontal to half-hanging. Corolla white (see below), sparsely scaly and densely patently short-hairy outside.
Habitat: Terrestrial in open rocky places often near volcanic vents, and a high epiphyte in sub-montane rain forest.
Distribution: Indonesia, Sumatra, Atjeh, Mt Kemiri, Gajolands; East Coast: Sibolangit and near Pematang Siantar; around Lake Toba, especially the Samosir Peninsula.
Altitude: 750-1500m
Named after Dr Carl Heusser, the collector, who worked for some years in Medan, Sumatra.
Type: Heusser 9a, 10 Aug. 1916. Indonesia, Sumatra, Tapanuli, Lake Toba, Samosir Peninsula, solfataras (BO, BM, BRI, L, PNH).
Synonymy: R. jasminiflorum var. heusseri (J.J.Sm.) Sleumer, Reinwardtia 1960. 5: 129. R. retusum [non (Blume) Benn.] Steenis, Arch. Hydrobiol. Suppl. 1932. 11: 18, f.21, 22. R. longiflorum Lindl. var. heusseri J.J.Sm., Bull. Jard. Bot. Buit. III, 1935. 13: 447.
Shrub to 2.5m. Twigs rounded, covered in stellate scales, quickly becoming glabrescent; internodes 2–9cm. Leaves 3–5 together in tight pseudowhorls, appearing sub-sessile. Blade 25–60 x 10–36mm, broadly obovate-elliptic or elliptic, sometimes sub-circular, usually widest in the middle; apex broadly obtuse, acuminate or rounded; margin entire, revolute especially when dry; base sub-truncate, rounded or weakly cordate; dark green and glossy above, paler and dull beneath, laxly sub-stellately scaly but quickly glabrescent above, laxly and more persistently scaly below. Scales stellate to sub-dendroid with a deeply divided margin, each on top of a minute, blunt epidermal tubercle. Mid-vein slightly impressed above, strongly raised beneath; lateral veins c.5 per side, straight, often obscure, reticulation not visible. Petiole 2–4 x 1.5–2mm, scaly. Flower buds to 14 x 6mm, ovoid, smooth, green or flushed with purple. Bracts to 10 x 6mm, ovate to obovate-spathulate, obtuse, glabrous or with a few scales outside near the apices and along the margins, glabrous inside. Bracteoles to 10 x 0.6mm, linear, glabrous. Inflorescence 5–15-flowered, an open umbel, the flowers half-hanging to semi-erect, white, or flushed with pink, especially when young, scented. Pedicels 8–11 x c.2mm, patently shortly hairy and scaly. Calyx c.2mm in diameter, obscurely 5-lobed. Corolla 40–50 x 10–14mm, trumpet-shaped; tube 35–43 x 3–4 x 3–4mm, straight, laxly scaly but not hairy outside, laxly hairy almost to the mouth inside; lobes 8–15 x 6–11mm, spreading horizontally, broadly obovate, glabrous or laxly scaly outside. Stamens exserted to 4mm, in an irregular group in the centre at first, reflexing back against the corolla lobes in old flowers; filaments linear, laxly hairy for almost the whole length; anthers c.1.8 x 1mm. Disc densely shortly hairy. Ovary 5 x 2mm, shortly cylindrical, densely hairy and scaly, abruptly contracted distally; style laxly scaly in the proximal 1⁄3 and laxly hairy almost to the top; stigma shortly obconical, at first below the mouth, later becoming exserted to c.10mm. Fruit 18–28 x 4–5mm, narrowly ellipsoid.
Habitat: Epiphytic or terrestrial in ridge forest and shrubberies and in open places on rocks
Distribution: Malaysia (Peninsula), Johore, Mt Ophir, Mt Ledang.
Altitude: 1100-1500m
The material figured for Curtis’s Botanical Magazine (t.4524) in the Kew Herbarium is hairy to above halfway up the outside of the tube so the distinctness of var. punctatum is not valid and this variety is included within the type subspecies which probably always has at least a few hairs on the outside of the corolla tube.
Synonymy: R. jasminiflorum var. punctatum Ridl. [punctata], J. Fed. Mal. St. Mus. 1909. 4: 42. R. jasminiflorum var. maculatum Ridl. [maculata], Fl. Mal. Pen. 1923. 2: 218.
Leaves in tight pseudowhorls of 3–6 larger and almost as many smaller. Blade 40–75 x 10–28mm, narrowly elliptic; apex obtuse to rounded; base obtuse or truncate-rounded. Petiole 4–7mm, grooved above, often red. Bracts glabrous or laxly scaly, shiny. Corolla white, laxly scaly but without hairs outside, laxly hairy inside the entire length of the tube.
Distribution: Malaysia (Peninsula), Pahang; P. Tioman, Mt Rokam, Johore; Mt Blumut. Sarawak (Borneo), Mt Santubong, Mt Bongo, delta of the Sarawak River.
Altitude: 0-1000m
Latin – oblongus – oblong; folium – leaf. Alluding to the leaf shape.
Type: Sinclair SF 38353, 23 Feb. 1949. Borneo, Sarawak, Summit Mt Santubong, 760m (SING, BO, K).
Synonymy: R. jasminiflorum var. oblongifolium Sleumer, Reinwardtia 1960. 5: 130. R. verticillatum (non Low ex Lindl.) Becc., Malesia 1878. I: 204.
Named after Java, the island on which it was first collected.
This species is presently treated in a broad sense including R. brookeanum and R. moultonii. This complex of mainly low altitude forest epiphytes is characterised by large, elliptic, acutely pointed leaves and large, funnel-shaped flowers in a range of colours. As conceived here, it is widespread, occurring through Sumatra, Peninsular Malaysia, the Philippines, Borneo, Java and Bali to Sulawesi. It is highly variable in its leaf arrangement and ovary indumentum, even within some populations, and is difficult to deal with satisfactorily although various populations are distinct.
Type: Blume s.n. (coll. Zippel?). Java, G. Salak, 800–2215m (L, U).
Synonymy: Vireya javanica Blume, Bijdr. 1826. 854. Azalea javanica (Blume) Kuntze, Rev. Gen. 1891. 2: 386.
Occurs in Countries: ID, MY, PH Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Tree Fl. Colour: cream, lemon, orange, pink, red, white, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:244
Twigs scaly. Leaves spirally arranged. Blade 80–110 x 25–60mm, apex acute, margin flat, base tapering. Lateral veins 6–12 per side. Petiole 15–20 x 3–4mm. Pedicels 20–30mm, glabrous or scaly. Calyx c.5mm in diameter. Corolla 20–45mm, red or pink. Stamens with the filaments hairy at the base; anthers 5–7mm. Ovary glabrous or with a few scattered scales.
Distribution: Philippines, Luzon; Camiguin de Misamis; Jolo; Mindanao. Indonesia, Sulawesi (NE), Menado. The records from Palawan in the Philippines are all likely to be ssp. palawanense. The record from Menado is doubtful and has not been checked; it is more likely to be R. seranicum.
schadenbergii
Named after Dr Alexander Schadenberg, German ethnologist who also collected plants in the Philippines.
The status of R. clementis is not clear. I have followed Sleumer (1966) in treating it as a synonym of this subspecies but the variations in the Philippines are still far from well understood.
Type: Schadenberg s.n. Philippines, Luzon, Abra Province, 1300m (B†).
Synonymy: R. schadenbergii Warb. in Perkins, Frag. Fl. Philip. 1905. 172. R. sarasinorum Warb. in Sarasin, Reisen in Celebes 1905. 2: 386. R. clementis Merr., Phil. J. Sc. Bot. 1908. 3: 160, 381. R. spectabile Merr., Publ. Gov. Lab. Philip. 1929. 29: 42. R. javanicum var. schadenbergii (Warb.) Sleumer, Reinwardtia 1960. 5: 195.
Shrub to 4m. Roots large and fleshy. Twigs obtusely angular to rounded, laxly covered with appressed sub-stellate scales at first, quickly glabrescent; internodes 2–15cm. Leaves 3–5 together in distinct pseudowhorls. Blade 120–250 x 35–80mm, elliptic to narrowly ovate-elliptic, sometimes sub-sessile; apex gradually and shortly acuminate, acute; margin entire, flat; base tapering, or sometimes sub-truncate, or even rounded at the very base; glabrescent above, the scales leaving dense, minute, dark pits after they have fallen, laxly to very laxly scaly for some time beneath, eventually completely glabrescent. Scales small, marginal zone variously sub-stellately lobed; centre minute, shallowly impressed. Mid-vein broad, slightly raised above in the proximal ½ then smooth, strongly raised below; lateral veins 14–24 per side, spreading, arching inwards to the margin, slightly raised on both sides, reticulation coarse and inconspicuous, sometimes dense and more visible raised especially beneath. Petiole 7–15 x 4–6mm, without a groove, laxly scaly. Flower buds to 50 x 30mm, smooth, green. Bracts to 40 x 20mm, thin, outer ones ovate-sub-acuminate, inner ones elliptic to spathulate, glabrous. Pedicels 20–50 x 1–2mm, sparsely scaly or glabrous. Inflorescence a complete umbel of 5–14 flowers. Calyx 4–5mm in diameter, shortly disc-shaped or rim-like, obscurely angled or lobed, glabrous. Corolla 50–80 x 50–80mm, funnel-shaped, orange-pink with white or cream centre, or yellow, throat then mostly yellow, often with a delicate lemon-like fragrance; tube 30–35 x 6–8 x 20–25mm, straight, angular, pouched at the base, glabrous outside, laxly hairy proximally inside; lobes 25–45 x 25–35mm, sub-circular, slightly retuse or delicately wavy at the margin. Stamens exserted to c.20mm, sub-equal, arranged all round the mouth or in two irregular groups on either side; filaments linear, densely sub-patently hairy in the proximal 1⁄3, glabrous distally; anthers 4–6 x 1–1.3mm, oblong, curved, base obtuse. Disc prominent, shortly hairy on the upper margin. Ovary sub-cylindrical, densely long hairy and scaly, abruptly contracted distally; style 8–10 x 2–3mm, at first shorter than, later equalling the stamens, glabrous; stigma deeply lobed. Fruit 35–50 x 7–8mm, fusiform-cylindric, scaly and shortly hairy with some elliptic minute warts.
Habitat: Epiphytic on mangrove or rocks at sea level, ascending to 1525m in the mossy forest, with preference for trees along rivers at the lower altitudes.
Distribution: Widespread in Borneo. Brunei. Malaysia, Sarawak and Sabah. Indonesia, Kalimantan.
Named after Sir James Brooke (Rajah Brooke), an Englishman who became governor of Sarawak in 1841 after helping the Sultan of Brunei to suppress a revolt.
Type: Low s.n. Borneo, Sarawak, Upper Limbang R. (CGE, BM, K).
Synonymy: R. brookeanum Low ex Lindl., J. Hort. Soc. Lond. 1848. 3: 82, 83.
Shrub to c.1.5m, twigs minutely hairy, leaves in pseudowhorls, smooth, not rugose, minutely hairy along the mid-vein. Flowers orange with a pink throat.
Distribution: Indonesia (Borneo), Kalimantan, Central East, W Kutei. Malaysia (Borneo), Sabah, Mt Silam near Lahad Datu.
Altitude: 300-500m
Greek – clad or clados – branch or shoot; trichome – hair. Referring to the hairs on the stem.
Distinctive in the finely very shortly hairy stems but otherwise similar to Javan forms of R. javanicum with smooth leaves and orange flowers.
Type: Endert 4000, 2 Sept. 1925. Borneo, W Kutei, Long Suh, 300m (L, A, BO).
Synonymy: R. brookeanum var. cladotrichum Sleumer, Reinwardtia 1960. 5: 224. R. javanicum ssp. javanicum [non (Blume) Benn.], Rhododendrons of Sabah, Sabah Parks Publ. 1988. 8: 20.
Shrub with scaly stems, leaves in loose pseudowhorls. Blade 100–180 x 30–55mm, narrowly elliptic, apex acute, margin flat, base tapering, strongly rugose with 9–18 lateral veins per side spreading at almost 90°. Petiole 12–20 x c.3mm. Inflorescence of 2–5 flowers, semi-erect to half-hanging. Corolla bright red; tube constricted at the proximal 1⁄3, expanded both towards the base and distally.
Distribution: Malaysia (Borneo), Sabah, Mt Lotung and Long Pa Sia area
Altitude: Around 1000m
Named after P.F. Cockburn, former forest botanist at Sandakan who collected this plant on G. Lotung.
Most similar to ssp. schadenbergii but that subspecies has many fewer lateral veins and smoother leaves and lacks the distinctive corolla shape. It approaches R. triumphans Yersin & A.Chev. from Vietnam in respect of flower size and colour and the long slender petioles but that species has simple hairs on the ovary and smoother leaves.
Type: Cockburn SAN 83123, 15 May 1976. Sabah, Lamag Dist., SE of Inarat, ridge to Mt Lotung (SAN).
Twigs with scales only. Leaves in tight to loose pseudowhorls, smooth, not puckered, up to 30mm wide. Petiole 3–10mm, grooved above or smooth, scaly. Flowers mostly yellow, sometimes orange. Anthers c.4mm. The ovary covered in simple hairs.
Distribution: Widespread in Borneo. Brunei. Malaysia, Sabah and Sarawak. Indonesia, Kalimantan.
Altitude: 0-1500m
Latin – gracilis – thin or slender, the leaves being more slender than the type.
This subspecies includes all the slender-leafed forms of R. javanicum, some of which may merely be impoverished forms of ssp. brookeanum but they usually have grooved petioles and retain their narrow leaves in cultivation. It is recorded on Mt Kinabalu in the vicinity of the Park Headquarters and surrounding hills. On the southern slopes of Mt Lotung this subspecies grows terrestrially in low pole forest at about 1000m altitude where it is quite strikingly distinct in appearance. This population shows strong similarities to R. salicifolium Becc. from southern Sarawak, although it is larger than that species without the tendency to curvature of the leaves. A pink-flowered form of this subspecies from Sarawak was cultivated for some years in the Royal Botanic Garden Edinburgh and maintained its distinctive appearance. It is possible that this plant and many similar forms from Sarawak are the result of hybridisation with R. longiflorum.
Type: Low s.n. Borneo, Sarawak, ‘Sirul’ rocks, mouth of Sarawak R. (CGE).
Synonymy: R. gracile Lindl., J. Hort. Soc. Lond. 1848. 3: 84.
Shrub or tree to 5m, trunk up to 8cm in diameter. Twigs 3–6mm in diameter, young shoots rounded and laxly sub-stellately scaly, becoming glabrescent and smooth; internodes 3–15cm. Leaves 4–8 together in tight, or occasionally loose, pseudowhorls. Blade 80–150 x 25–50mm, narrowly-elliptic, elliptic to elliptic-ovate; apex shortly acuminate, acute; margin entire, flat; base acutely tapering; initially laxly scaly on both sides, early glabrescent above, laxly and more persistently scaly beneath, eventually spotted with brown after the scales have gone. Scales small, flat, with a variously lobed marginal zone; centre dark, not impressed. Mid-vein strong, broad and obtusely prominent proximally on both sides, narrowly impressed distally above, prominent throughout beneath; lateral veins 7–10 per side, at c.45°, minutely channelled above and smooth below when fresh, slightly prominent on both sides when dry, indistinctly anastomosing before the margin, reticulation a lax network, faintly raised or often obscure on both sides. Petiole 6–23 x 2–4mm, without a groove, flattened, often brown or red, scaly. Flower buds 30–40 x 15–20mm, ovoid, with an acute point, the bract tips standing out at c.45°. Bracts to 35 x 22mm; outer bracts broadly ovate, shortly subulate-mucronate, inner ones ovate-elliptic to elliptic, obtuse, all membranous, glabrous except for fragile marginal scales. Bracteoles to 30 x 1.5mm, linear, glabrous. Inflorescence of 4–12 flowers in a complete umbel. Pedicels 20–40 x 2.5mm, laxly stellately scaly especially distally, without hairs. Calyx c.4mm in diameter, oblique, disc-shaped, obtusely 5-angular, glabrous or laxly scaly. Corolla 30–50 x 70–80mm, funnel-shaped, orange with red or violet markings at the mouth, or occasionally yellow; tube often red inside, without scent, lobed to c.halfway; tube 17–28 x 8–10 x 20–25mm, lobed at the base and obtusely 5-angled, glabrous or nearly so, with just the occasional scale outside, shortly hairy or occasionally glabrous inside; lobes 30–35 x 25–30mm, slightly unequal, spreading, slightly reflexing, overlapping up to 1⁄3, obovate to sub-spathulate. Stamens slightly dimorphic, exserted to c.15mm, loosely arranged mostly on the lower 2⁄3 of the mouth, often with one or two stamens on the upper side; filaments purple, linear, densely hairy in the proximal 1⁄3, filiform and glabrous distally; anthers 2.5–4 x c.1.3mm, oblong, purple, strongly turned inwards. Disc prominent, shortly hairy on the upper margin. Ovary 7–9 x c.3mm, obliquely conical-cylindrical, 5-angled, glabrous or very sparsely scaly, tapering distally; style glabrous, as long as the shorter stamens, lying on the lower side of the tube, the tip curving upwards; stigma 3–5mm in diameter, dark purple, rounded. Fruit 30–50 x 7–9mm, fusiform, 5-angled, glabrous. Seeds 6–7mm including the tails.
Habitat: Mostly epiphytic and in primary and secondary forest, but also terrestrial near craters, on narrow ridges, between rocks and on steep slopes, locally common.
Distribution: Indonesia, Sumatra, Natuna I., Lingga Arch., Java, Bali.
Altitude: 800-2550m
Shrub to 2.5m. Twigs 8–12mm in diameter, round, scaly only. Leaves spirally arranged. Blade 100–200 x 35–70mm, narrowly elliptic; apex acute; margin flat and entire; base tapering; the surface deeply and regularly grooved. Petiole 10–18 x 4–7mm, scaly, not grooved. Inflorescence a complete umbel of 12–25 erect to horizontal flowers. Flowers bicoloured with orange lobes and a yellow tube. Stamens hairy in the proximal ½. Ovary hairy all over.
Habitat: Distinctly sub-montane in its ecology, growing as an epiphyte in forest or on the ground in openings such as road cuttings and landslips.
Distribution: Malaysia (Borneo), Sabah, Mt Kinabalu and the Crocker Range.
Altitude: 1000-1800m
Latin – coming from Kinabalu.
Type: Collenette 39/79, Sept. 1979. Sabah, Sinsuron Road, W of G. Alab, 1400m (E).
Synonymy: R. javanicum ssp. brookeanum var. kinabaluense Argent, A.Lamb & Phillipps, Notes RBG Edinb. 1984. 42(1): 113.
Similar to ssp. brookeanum but with the ovary completely glabrous. Flowers yellow or orange.
Habitat: Intermediates with ssp. brookeanum with only very sparsely hairy ovaries do occur.
Distribution: Malaysia (Borneo), Sarawak, Upper Limbang R., Mt Derian; Mt Dulit; Upper Baram R., Mt Muler. Sabah, Long Pa Sia area; Sugut/Paitan area and around G. Alab on the Crocker Range.
Named after J.C. Moulton, Englishman, naturalist, curator of the Sarawak Museum and founder of the Sarawak Museum Journal, who first collected this rhododendron from the Upper Limbang River, Sarawak.
Type: Moulton 3. Borneo, Sarawak, Upper Limbang R., B. Labeng Barian (Mt Derian), 1220–1525m (SAR).
Synonymy: R. moultonii Ridl., J. Str. Br. R. As. Soc. 1912. 63: 61.
Shrub to 1.5m. Leaves spirally arranged, smooth. Flower buds green, narrowly ovoid with an acute apex and appressed bracts. Pedicels glabrous or sparsely scaly. Flowers c.100 x 90mm, bicoloured, with a yellow tube, hairy inside near the base and forming a yellow ‘star’ in the mouth, lobes c.50 x 25mm, orange. Stamens with hairs in the basal ¼ of the filaments; anthers c.5mm with grey pollen. Ovary glabrous or variably hairy and scaly.
Distribution: Philippines, Palawan, Mt Mantalingajan; Cleopatra Needle; Thumb Peak. A vegetative specimen from Victoria Peak is probably the same subspecies.
Named from the island of Palawan from which it was collected.
This subspecies is very similar to ssp. kinabaluense from Mt Kinabalu. These two subspecies are both high altitude forms (for this species). They both have large, conspicuously bicoloured flowers, flower buds with appressed bracts and leaves arranged in regular spirals. Subspecies palawanense differs from ssp. kinabaluense in having smooth leaves, more slender flower buds with acutely pointed bracts which are never emarginate and longer flowers, with longer and narrower lobes to the corolla.
Type: Argent & Romero Acc. 19922770. Cultivated specimen collected 16 Jan. 1998. Philippines, Palawan, Mt Mantalingajan (PNH, E).
Distribution: Malaysia (W). Indonesia, Sumatra, Java, Bali. Montane forests
Altitude: 800-2000m
Differing from ssp. javanicum by the ± densely hairy ovary and from ssp. brookeanum by the hairy pedicels.
Sleumer (1966) noted specimens collected in North Sumatra that had capsules 5.8–8cm long, thus distinctly longer than stated above for R. javanicum s.lat. In these long capsules they agree with R. beccarii, also from Sumatra (East Coast), which, however, has a practically glabrous (or certainly not hairy) ovary. Sleumer stated: ‘It is possible that these North Sumatran specimens correspond with R. basirotundatum described from Atjeh (Bur ni Telong) without fruits and might represent a fourth variety. Material at hand is not sufficient to decide this question’.
Type: Teysmann H.B. 777. Sumatra W coast, Mt Singalang (U, BO, CAL, K).
Synonymy: R. teysmannii Miq., Fl. Ind. Bat. Suppl. 1860. 1: 251, 585. Azalea teysmannii (Miq.) Kuntze, Rev. Gen. Pl. 1891. 2: 387. R. javanicum var. teysmannii (Miq.) King & Gamble, J. As. Soc. Beng. 1905. 74(2): 75. R. basirotundatum J.J.Sm., pro parte in Merr., Contr. Arn. Arb. 1934. 8: 124.
Shrub to c.50cm. Twigs 4–5mm in diameter, rounded, sparsely scaly and quickly glabrescent. Leaves arranged in a loose spiral. Blade 95–150 x 22–40mm, elliptic to sub-spathulate; apex rounded; margin entire, revolute when dry; base narrowly tapering; glabrescent above, sub-densely and more persistently scaly below. Scales lobed, with a thin, broad marginal flange, and small slightly impressed centre. Mid-vein raised above in the proximal ¼–½; strongly raised below to within 10mm of the apex; lateral veins 6–10 per side, emerging at a wide angle, slender, often somewhat obscure. Petiole 14–18 x c.3mm, not grooved above, laxly scaly initially. Inflorescence of c.20 flowers in a slightly open umbel, the flowers half-hanging. Pedicels 22–30 x c.0.8mm, glabrous, orange. Calyx c.3.5mm in diameter, a low glabrous disc. Corolla c.25 x 20mm, funnel-shaped, dull red outside, pale orange inside, without scent; tube 10 x 3 x 6mm, glabrous outside, densely hairy in the proximal ½ inside; lobes c.11 x 6mm, broadly elliptic to oblong, erect, not overlapping. Stamens to 14mm, exserted to c.4mm, arranged regularly all round the flower, dimorphic; filaments hairy in the proximal 1⁄3, glabrous distally; anthers c.2mm. Disc 10-lobed, glabrous. Ovary 28 x 13mm, glabrous; style c.30mm, glabrous; stigma c.1.6mm in diameter, rounded, only weakly lobed.
Habitat: Lower montane forest.
Distribution: Malaysia (Borneo), Sabah, Tawau Hills Park, Summit area of Mt Magdalene
Altitude: Around 1310m
Named in honour of Tan Jiew Hoe, plant enthusiast, explorer and collector who has supported many natural history projects.
R. crassifolio affinis sed floribus multo minoribus et costa inferne valde elevata haud plana differt.
This interesting species looks in many respects like a miniature version of R. crassifolium but the flowers are less than ½ the size and the mid-vein is strongly raised underneath, not smooth as in that species. It is tempting to think that the ultramafic environment is causing the miniaturisation of the flowers but the difference in leaf structure is significant and the environment would be doubtful to account for this difference. Cultivation alongside R. crassifolium would demonstrate how much of the difference between these species is genetic and how much environmental.
Type: Dauni, Soinin & Patrick SAN 146491, 5 July 2005. Sabah, Mt Magdalena, Tawau Hills Park, 1310m (SAN).
Occurs in Countries: MY Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:259
Shrub; young shoots slender, densely covered with brownish strigose hairs intermixed with glandular setae. Leaves dimorphic, thickly chartaceous, elliptic to elliptic-oblong; spring leaves 3.5-4.5(-5) x 1.5-2cm, apex shortly acuminate, base broadly cuneate to obtuse, margin entire, lower surface pale, main and lateral veins strigose; summer leaves smaller; petioles 2-3mm, densely brownish-setose strigose. Inflorescence 3-5-flowered; pedicels 2-10mm, densely brownish-setose-strigose. Calyx to 3mm, lobes oblong-ovate, sparsely glandular. Corolla funnel-shaped, reddish, with darker flecks, c.lOmm; tube cylindrical, c.5 x 2mm, lobes sparsely glandular on outer surface. Stamens 5, filaments puberulent below; style sparsely glandular in lower half. Capsule not known.
Distribution: China (Yunnan)
Allied by the author to R. microphyton but differing in smaller and glandular flowers; also allied to R. subenerve but differing in its larger thicker leaves. The apparently narrowly tubular flower may also be a reliable character to separate this species from R. microphyton. Since we have not seen any material of this species we cannot be certain of its affinities.
Type: China, Yunnan, Jinping Xian, 1850m, 13 iv 1964, S.C. Tung 494 (holo. SZ, n.v.)
Occurs in Countries: CN Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: red
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):126
Shrub. c.3m; young shoots densely spreading-glandular-setose. Leaves persistent, coriaceous, dimorphic; spring leaves ovate to oblong-ovate, 7-10 x 2-2.5cm, 2-3 x as long as broad, apex acuminate, base rounded, upper surface soon glabrescent, lower surface with greyish brown indumentum, especially on veins and midrib; summer leaves 25-30 x 15-20mm, otherwise as for spring leaves; petioles 5-7mm, densely hirsute and glandular. Inflorescence 5-6-flowered; pedicels densely brownish-spreading- hairy. Calyx c.2mm, hirsute, lobes triangular-ovate, ciliate. Corolla funnel-shaped, 18-20mm, purple; tube c.7 x 4mm, glabrous. Stamens 5, filaments puberulent. Ovary densely hirsute; style hirsute below. Capsule not known.
Distribution: China (Guangxi)
Altitude: Around 1000m
Closely allied to R. yaoshanicum (q.v.)
Known only from the type
Type: China, Guangxi, Jinxiu Yaozu Zizhi Xian (Dayaoshan Xian), 1000m, 20 v 1964, F.N. Wei 894 (holo. IBK, n.v., iso. IBSC)
Occurs in Countries: CN Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: purple
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):100
Variably sized shrub. Young growth loriform-setose. Leaves elliptic to broadly elliptic, tapering to the base, obtuse or subacute at the apex, 55-75 x 24-30 mm, margins variably loriform-ciliate, undersurface brownish with dense, contiguous or overlapping scales. Calyx disc-like, loriform-ciliate. Corolla white, often with a yellowish blotch and pink or purplish flush, 48-55 mm, tube 25-30 mm, pilose at the base only, laxly lepidote over most of the surface. Capsule lepidote, 16-22 mm.
Habitat: Forest margins, slopes
Distribution: India (Manipur, Mizoram)
Altitude: 1850-3100m
Illustrations:
A specimen from western central Burma (Mindat ridge, Kingdon Ward 22200) is very similar to R. johnstoneanum and may well be a minor variant of it; it lacks the ciliation of the leaves.
Type: Manipur, Sirhorifurar, 6000-7500 ft, 11 iv 1882, Watt 6401 (holo. K, iso. E)
Synonymy: R. formosum var. johnstoneanum [Watt ex] Brandis, Indian Trees 411 (1906)
Occurs in Countries: IN Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: pink, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):47
Shrub, 1-3 m; young shoots densely covered with adpressed flattened red-brown strigose hairs. Leaves dimorphic, persistent, chartaceous; spring leaves lanceolate to elliptic, 2-4(-5) x 1-2.5cm, 1.7-2.3 x as long as broad, apex acute or obtuse, base cuneate, margin entire, strigose on both surfaces, especially on midrib; summer leaves 10-20 x 5-1 Omm, otherwise as for spring leaves; petioles 3~-5mm, indumentum as for young shoots. Inflorescence 2-3-flowered; pedicels 3-5mm, densely covered with adpressed brown strigose hairs. Calyx 3-5mm, strigose, lobes divided to base, ovate-orbicular. Corolla funnel-shaped, 20-30mm, red (in cultivated forms from pink to salmon-red); tube 10-15mm, glabrous. Stamens 5(-6), longer than corolla, filaments papillate in lower half. Ovary densely red-brown strigose; style glabrous. Capsule c.5mm long, setose.
Habitat: Mixed deciduous forest
Distribution: Japan (C Hokkaido to Yakushima)
Altitude: 600-1000m
Illustrations:
35*. R. x komatsui Yamazaki, J. Jap. Bot. 51: 31 (1976).ó-(R. kaempferi x R. mueronatum var. ripense). Syn.: R.purpureum Komatzu, Bot. Mag. (Tokyo) 32: (16) (1918), non G.Don (1834); R. tectum Koidz. var. purpureum (Komatzu) r Hara, Enum. Sperm. Jap. 1: 54 (1948). Type: C Japan, Umato Prov., n.v. R, kaempferi Planchon var. purpureum Nakai, Tress Shrubs Japan ed. 1:103 (1922). Type: Japan, Prov, Yamaguchi, Miya-gun, T. Nakai, s.n. (holo. TI, n.v.). We have not seen any material of this hybrid and are not therefore able to comment on Yamazaki's synonymy quoted above.
35*. R. x transiens Nakai, Trees Shrubs Japan ed 1,1: 103 (1922)ó(R. kaempferi x R. macrosepalum). Syn.: R. tectum Koidzumi, Bot. Mag.(Tokyo) 37: 38(1923)ó-Japanese text. Type: Japan, Yamashiro, Kyoto, Daimonji-yama, 16-18 v 1920, Koidzumi, n.v. R. poukhanense Levi. f. obtusifolium Komatzu and f. acutifolium Komatzu, Bot. Mag, (Tokyo) 32:37,38 (1918)óJapanese text. R. indicum Sweet var. mikawanum Makino, Bot. Mag. (Tokyo) 23:251 (1909). Type: Japan, Takashi-mura, 25 x 1893, Makino, n.v. The specimens seen labelled R. transiens and R. tectum are compatible with the proposed parentage of this natural hybrid that occurs within the area of overlap between the ranges of the two putative parents. The specimens tend lo have the larger leaves and flowers of R. macrosepalum but the adpressed shoot indumentum of R. kaempferi. The sepal lobes are intermediate in size and shape between those of the two species.
Closely allied to R. indicum and possibly conspecific, but differing in its broader leaves and greater stature. R. kaempferi hybridises with R. kiusianum where the ranges of the two overlap. R. kaempferi is widely cultivated and consequently there are a number of cultivars available. Forms with stamens and pistil petaloid (var. plenum Nakai) and with petaloid calyx (var. komatsui Nakai) have been found in the wild.
Synonymy: Tsutsusi'Kaempfer, Amoen. Exot. Fasc. 845, t.846 (1712)ó basionym, (Sloane Hb 211:8, 62, BM). Azalea kaempferi (Pianchon) Andre, Belgique Hort. 15: 184 (1865); Rhododendron indicum (L.) Sweet var. kaempferi (Planchon) Maxim., Rhododendr. As. Orient. 38 (1870); R. scabrum G. Don var. kaempferi (Planchon) Nakai, Bot. Mag. (Tokyo) 33:208(1919). Rhododendron sieboldii Miquel, Ann. Bot. Mus. Lugduno-Batavum 1: 33 (1863). Described from Japan. R. kaempferi Planchon var. macrogemma Nakai, Trees, Shrubs Japan ed. 1: 103 (1922); R. macrogemma (Nakai) Nakai, Bot. Mag. (Tokyo) 45: 128 (1931). Type: Japan, Idzu Prov, Oshima, nearSenzu, Okubo, n.v.
Occurs in Countries: JP Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: pink, red
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):120
Much-branched shrub, 1-2.5m; young shoots densely clothed with adpressed broad flattened stiff, persistent chestnut-brown hairs. Leaves dimorphic, persistent; spring leaves oblanceolate to narrowly obovate, 2-5 x 0.5-1.5cm, apex acute, gland-tipped, base cuneate, margin entire, both surfaces sparsely strigose, especially on midrib; summer leaves 15-30 x 2-6mm, otherwise as for spring leaves; petioles 2-5mm, densely strigose. Inflorescence 1 (-2)~flowered; pedicels 5-8mm, densely chestnut-stri-gose. Calyx c.lmm, indumentum as for pedicels. Corolla funnel-campanulate, 25-40mm, pink (or carmine to scarlet); tube 15-25mm, glabrous. Stamens 10, as long as corolla, unequal, filaments papillose below middle. Ovary densely clothed with grey or chestnut-brown strigose hairs; style glabrous or with a few adpressed hairs at base. Capsule cylindric-oblong, c. 10mm long.
Distribution: China (N Taiwan)
Altitude: Around 400m
Illustrations:
Apparently closely allied to R. tashiroi from the southern islands of Japan and possibly conspecific. Wilson originally described the flower colour as being scarlet or carmine; later authors have suggested that it is pink. Also allied to R. indicum but differing in the number of stamens, etc.
Type: Taiwan, prov. Taihoku, Urai, in a garden at the police station, 1 iv 1918, Wilson 10276, n.v.
Occurs in Countries: CN, TW Altitude Ranges: 0 - 1,000m Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: carmine, pink, scarlet
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):112
Very similar to R. monanthum, differing as follows: leaves less clearly papillose beneath, the scales more distant, pale; inflorescences 3-flowered; capsule perhaps more slender.
Distribution: India (Arunachal Pradesh), China (SE Xizang). Forests, 2450-2750 m
Known only from a few collections, and scarcely different from R. monanthum except in the characters noted above, of which the inflorescence is the most important.
Type: Assam, Delei valley, Kaso peak, 7000-8000 ft, Kingdon Ward 8522 (iso. E)
Occurs in Countries: CN, IN Subgenus: Rhododendron Habit: Non-Tree
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):60
Shrub to 1.5m. Twigs green, c.2mm in diameter, laxly covered with brown scales each slightly raised on a short stalk; internodes 1–4cm. Leaves arranged in loose pseudowhorls. Blade 30–45 x 12–22mm, obovate, or elliptic; apex broadly obtuse often mucronate with a small protruding pale gland; margin entire, slightly to strongly revolute; base broadly to narrowly tapering, often a little decurrent; upper surface green, glabrescent; lower surface covered with blackish-brown scales each about 3–5 times their own diameter apart. Scales circular with narrow marginal flanges and large centres. Mid-vein narrowly impressed above throughout its length, more broadly raised below, strongly so in the proximal ½, becoming smooth distally; lateral veins 3–5 per side, spreading at 45° to almost 90°, minutely impressed above, very slightly raised below or obscure. Petiole 4–8 x c.1.5mm, grooved above, sparsely scaly. Flower buds to 16 x 8mm, pale green, ellipsoid, smooth with an acute apex. Bracts fully appressed, ovate, broadly acute but often splitting to appear emarginate, brown scaly outside especially in a broad strip along the midline, also minutely sub-papillose hairy or long appressed hairy, glabrous inside, fringed with short white hairs along the margins. Bracteoles to 10 x 1mm, narrowly spathulate, glabrous except for marginal hairs at the apex. Inflorescence of 3–7 flowers in an open umbel. Flowers semi-erect to half-hanging. Pedicels 15–25mm, sparsely scaly and minutely shortly hairy, sometimes becoming vertically striate. Calyx small, distinctly 5-lobed; lobes broadly rounded, scaly outside and fringed with scales. Corolla 8–10mm, light yellow, campanulate; tube c.5 x 4 x 3.5mm, densely scaly outside and hairy in the distal part inside; lobes c.7–9 x 4–7mm, elliptic, scaly outside, without markings. Stamens exserted to c.6mm in an irregular cluster, later spreading back against the corolla lobes, dimorphic; filaments glabrous for c.1mm proximally, then densely long hairy, the hairs gradually decreasing in length and density distally, becoming glabrous for c.2mm apically; anthers c.2 x 0.8mm, brown. Ovary scaly and shortly hairy; style very short, patently hairy at the base or completely glabrous. Fruit c.6 x 3mm, hairy, turning to become erect; valves spreading to a wide angle; placentae remaining fixed to the central column. Seeds to 2.6mm, without tails 1.1mm, the longest tail 1.1mm.
Habitat: Growing in sub-montane, humid forest, epiphytic on the trunks of Chamaecyparis formosensis Matsum. or terrestrial in open areas
Distribution: Taiwan, Ilan Co., Ta-yuen-shan, Yuan-yang Lake. Chiayi Co., Yu-shan (Mt Morrison). Co.: Kuei-hu: Taipei Co., below summit of Mt Chilanshan
Altitude: 1400-2400m
Named after Takiya Kawakami, 1871–1915, a Japanese collector in Taiwan.
Flowers June–July
Type: Kawakami & Mori 2005, 12 Oct. 1906. Mt Morrison, Taiwan (TI, L, fragment).
Synonymy: R. kawakamii Hayata var. flaviflorum Liu & Chuang, Quart. J. Taiwan Mus. 1960. 13: 64. R. taiwanianum Ying, Quart. J. Chinese Forest. 1976. 9(4): 116.
Occurs in Countries: TW Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:36
Erect shrub to 4m. Twigs cylindrical, 3.5–5mm in diameter, scaly when young, rough with scale bases after the scales have fallen, whitish-green. Leaves in tight pseudowhorls of 6–8 together. Blade 60–100 x 30–55mm, mostly elliptic, occasionally ovate to obovate; apex obtuse but cuspidate or apiculate; margin entire, weakly revolute; base obtuse or rounded, occasionally acute and a little decurrent on the petiole; upper side sparsely scaly, dark green and slightly rough; underside moderately scaly, yellowish-green, scabrous with epidermal tubercles when the scales have gone. Scales reddish-brown, sub-circular to sub-stellate; centre relatively small, sessile or prolonged into a stalk which is fixed to the top of a small epidermal tubercle which remains after the scales have fallen. Mid-vein depressed above, raised below; lateral veins 10–15 per side, a little depressed above and a little raised below, reticulation obscure. Petiole 7–23mm, rigid, sub-cylindrical with a groove on the upper side, scaly, whitish-green. External bracts triangular to ovate, cuspidate to rounded at the apex, scaly and hairy outside, scaly at the margin and hairy inside; internal bracts to 45 x 6mm, elliptic to linear-spathulate, truncated to rounded at the apex, sparsely and shortly hairy on both sides, the margin scaly at the apex. Bracteoles c.38mm, linear, broader at the apex, sub-glabrous. Inflorescence of 4–10 semi-erect, scented flowers in an open umbel. Pedicels 7–10 x 1.5–2mm, densely scaly, rough. Calyx c.5mm in diameter, obliquely disc-shaped, sub-entire to obscurely 5-lobed, sparsely scaly outside, fringed with scales on the margin. Corolla 70–77 x c.45mm, the tube pink, the lobes white, trumpet-shaped; tube 46–55 x 4–6 x 7–11mm, slightly curved, sparsely scaly-papillose outside and hairy inside; lobes 23–25 x 16–17mm, obovate to elliptic, rounded or retuse at the apex, reflexed to the horizontal or a little beyond, overlapping c.halfway. Stamens unequal, exserted to 20mm from the mouth; filaments white, densely hairy at the base becoming less so upwards and glabrous for a few millimetres distally; anthers c.5 x 1.5mm, yellow, narrowly oblong, the cells rounded at the base. Disc 10-lobed, densely hairy. Ovary c.8 x 3mm, narrowly oblong, tapering to the style, densely hairy and densely scaly; style pink, exserted from the mouth, scaly in the basal ½; stigma 5-lobed.
Habitat: Growing at 2280m altitude at the edge of secondary forest with other ericaceous pioneers.
Distribution: Indonesia, New Guinea (W).
Altitude: Around 2280m
Derived from the local name attributed to this species by the inhabitants of Dimba.
Known only from the type collection made in the valley at Nambulaga near Dimba village, near Mt Jayawijaya.
Said to be similar to R. rappardii and R. opulentum. Rhododendron rappardii differs in having shorter flowers up to 55mm long, anthers which are pointed at the base not rounded and a style which is both hairy and scaly in the basal ½. Rhododendron opulentum differs with its prominent reticulation which can be seen on both sides of the leaves; it also has hairy pedicels and a calyx and a corolla which is glabrous outside and a style with hairs not scales in the basal part.
Type: Danet 4247. Indonesia, Papua, Mt Jayawijaya at Nambulaga near Dimba village (LYJB, L, MAN, P).
Occurs in Countries: ID Altitude Ranges: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:107
Small shrub, 0.3-3 m. Leaves lanceolate or oblong-lanceolate or narrowly elliptic, acute or acuminate at the apex, cuneate and abruptly rounded at the base, (25-)35-75 x (8—)11—28 mm, upper surface dark green, variably lepidote, puberulent along most of the length of the midrib and on the surface towards the base, lower surface greenish, lepidote with distant, large scales, rarely loriform-ciliate on margins and petiole. Inflorescence 2-3 (-4)-flowered, pedicels lepidote, 5-10(-14) mm. Calyx variably developed, undulate, less than 1 mm, to clearly 5-lobed with lobes up to 2-5 mm, lepidote, frequently loriform-ciliate. Corolla pale yellow, unspotted, 18-24 mm, tube 8-11 mm, variably lepidote outside and sometimes sparsely puberulent with short, straight hairs. Stamens 10, filaments pubescent towards the base. Ovary lepidote, style glabrous. Capsule very narrowly cylindric, 6-13 mm
Habitat: Hills and rocky places, rarely epiphytic
Distribution: Japan
Altitude: 600-1850m
Illustrations:
A variable species, which, in recent years, has been split up into a number of taxa at different levels, often on the basis of material in cultivation.
Synonymy: R. laticostum Ingram, R.H.S. Rhodo. Yearbook 25:31 (1971). Type: a cultivated plant (holo. K). R. trichocalyx Ingram, op. cit.: 33. Type: a cultivated plant (holo K)
Occurs in Countries: JP Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Rhododendron Habit: Epiphyte, Non-Tree Fl. Colour: yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):78
Tree, trunk c.35cm in diameter. Twigs 3–4mm in diameter, rounded, red brown, with lax, small sub-stellate, flat scales, early glabrescent; internodes 2–8.5cm. Leaves 5–7 together in pseudowhorls. Blade 70–120 x 20–45mm, elliptic to narrowly ovate-elliptic; apex gradually tapering or shortly acuminate, sub-acute or obtuse; margin weakly recurved; base acutely narrowed; densely minutely scaly on both sides when very young, glabrescent and shining above when mature, more persistently scaly beneath. Scales minute, marginal zone irregularly lobed, fragile and disappearing early; centre dark, shallowly impressed, finally glabrescent beneath too, but remaining conspicuously punctate. Mid-vein narrow and impressed above, as broad as the petiole and obtusely prominent proximally beneath; lateral veins 7–10 per side, irregular, ascending, obscurely anastomosing, very slightly impressed above, slightly prominent or inconspicuous beneath, reticulation obscure. Petiole 4–15 x 2–2.5mm, semi-rounded, rugose, grooved above, minutely scaly. Bracteoles 20–30 x 0.5–1mm, linear, laxly hairy. Inflorescence a 7–12-flowered umbel. Pedicels 20–25 x c.1mm, laxly scaly at both ends, laxly shortly hairy, often glabrescent. Calyx 4–5mm in diameter, sub-oblique, disc-shaped, obscurely 5-angular, minutely scaly. Corolla 50–70 x 30–40mm, narrowly funnel-shaped, orange-pink; tube 30–40 x 3–5 x c.10mm, straight, sparsely minutely scaly outside, shortly hairy in the proximal ½ inside; lobes 20–30 x 15–25mm, broadly elliptic-obovate. Stamens 40–50mm, sub-equal; filaments linear and densely patently short-hairy in the proximal 1⁄3, narrower, filiform and glabrous distally; anthers 3–4 x c.1mm, oblong, base obtuse. Disc shortly hairy on the upper margin, otherwise glabrous. Ovary c.6 x 2.5mm, sub-cylindrical, scaly especially at the base and apex, early glabrescent, tapering distally; style nearly as long as the stamens, sub-densely scaly proximally, more laxly so to the middle, glabrous distally; stigma knob-like.
Habitat: In primary forest, said to be common locally.
Distribution: Indonesia (Borneo), Kalimantan, Mt Kemul. Malaysia (Borneo), Sarawak, Mt Mulu.
Altitude: 1800-1850m
Named after the mountain on which it was collected.
This species is somewhat intermediate between R. polyanthemum and R. verticillatum.
Type: Endert 4255, 17 Oct. 1925. Borneo (C, E), W Kutei, Mt Kemul, 1800m (BO, BM, L, SING).
Occurs in Countries: ID, MY Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Tree Fl. Colour: orange
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:259
Shrub or small tree, 3-8m. Leaves sub-coriaceous, narrowly elliptic to oblanceolate, 10-13.5 x 2-3.5cm, 4-6 x as long as broad, apex acuminate, base cuneate to rounded, margin usually strongly undulate, upper surface glabrous when mature, lower surface hairy on the midrib, otherwise glabrous, punctate hair-bases lacking; petioles 1 — 1.5cm, glabrescent. Inflorescence dense, 10-20-flowered; rhachis up to 15mm; pedicels c.8mm, sparsely stellate-tomentose. Calyx 2-3mm, with conspicuous rounded lobes, glabrous or sparsely glandular-ciliate. Corolla fleshy, tubular-campanulate, with nectar pouches, glabrous within, deep rose to scarlet, with darker flecks, 30-40mm. Ovary with a few rufous dendroid hairs, eglandular; style glabrous. Capsule 15—25 x c.4mm, curved.
Habitat: Mixed forests
Distribution: NE India (Arunachal Pradesh), Bhutan & adjacent parts of China (S Xizang)
Altitude: 2300-2800m
The status of R. shepherdii is problematical. The type description is inadequate in that the flowers were not known. A specimen raised from seed, supposedly from the type, flowered in cultivation and was illustrated (Bot. Mag. 85: t.5125,1859). This plant differed from R. kendrickii in its glabrous ovary and larger calyx, but neither the cultivated nor the herbarium specimens are now extant. The available evidence suggests that R. shepherdiiis synonymous withR. kendrickii.
Type: Mountains of Bhutan', c.7000ft, Booth (holo. K).
Synonymy: ?R. shepherdii Nuttall, ibid. 5: 360 (1853). Type: NE India, Arunachal Pradesh, Oola Mts, Booth, n.v. R. pankimense Cowan & Kingdon-Ward, Notes R.B.G. Edinb. 19: 180 (1936). Type: NE India, Arunachal Pradesh, Pankim La, 8000-9000ft, 3 v 1936, Kingdon-Ward inn (holo. E). Ic.: Bot. Mag. 85: t.5129 (1859).
Occurs in Countries: BT, CN, IN Altitude Ranges: 2,000 - 3,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: rose, scarlet
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):302
Shrub to 2m. Twigs 1–2mm in diameter, at first minutely rough with stellate scales which leave hair-like stalks but quickly the stems become smooth; internodes 1.5–4cm. Leaves clustered into loose pseudowhorls of 7–12 variably sized leaves. Blade 7–15 x 3–5mm, ovate or sometimes broadly elliptic, mostly widest in the lower 1⁄3, occasionally about the middle; apex acute, occasionally obtuse to rounded and sometimes apiculate; margin strongly revolute; base narrowly to broadly tapering; glabrescent above, densely brown scaly below. Scales dendroid, deeply stellately divided, each on top of a minute epidermal tubercle. Mid-vein weakly impressed above, very prominent beneath; lateral veins obscure. Petiole 1–2 x 1mm, densely scaly. Flower buds ovoid, acute, often lateral. Bracts to 8 x 5mm; outer appressed, with short subulate points, inner, ovate, abruptly subulate-acuminate, fringed along the margins with large scales and densely but fragilely scaly outside, revealing short, white semi-appressed simple hairs in the upper ½ outside when the scales have fallen, glabrous inside. Flowers solitary or up to 4 in an open umbel. Pedicels c.10 x 1mm, slender, densely stellate-scaly. Calyx c.2mm in diameter, disc-like, not or very shortly obtusely lobed, scaly outside. Corolla 15–20mm, dark red, tubular, slightly expanded distally; tube c.12 x 4 x 5mm, slightly curved, densely stellate-scaly but without hairs outside, very laxly patent hairy inside; lobes c.7 x 5mm, broadly obovate to sub-circular. Stamens unequal, well exserted from the mouth, about as long as the corolla; filaments narrowly linear, glabrous; anthers c.2 x 1mm, oblong. Disc glabrous or very minutely hairy on the upper margin. Ovary c.6 x 2–2.5mm, sub-cylindrical, densely stellate-scaly, and with a few simple white hairs, which are completely obscured by the scales, gradually tapering distally; style thick, scaly and with simple hairs in the proximal 1⁄3, then laxly patently hairy for another 1⁄3, glabrous distally; stigma broadly rounded, obscurely 5-lobed. Fruit (immature) 20 x 4mm, fusiform.
Habitat: Terrestrial in open montane shrubbery
Distribution: Papua New Guinea, Simbu Province, Kerowagi Subprovince, Mt Wilhelm.
Altitude: Around 3600m
Named after the subprovince from which this plant was collected.
Distinctive with its very small ovate leaves. It is undoubtedly closely related to R. rarum, with which it shares many characters. Rhododendron rarum does not have hairs on the ovary although they are hidden and difficult to see in this species. Where hairs occur on the style of R. rarum, they are much longer, and clearly overtop the scales. In R. kerowagiense the hairs and scales are about the same length on the style. The material examined is slightly mouldy which makes it difficult to be absolutely certain that the filaments are glabrous.
Type: Umba for Katik, LAE 74842, 20 Aug. 1980. Papua New Guinea, Simbu Province, Kerowagi Subprovince, Mt Wilhelm, c.3600m (LAE, E, K).
Occurs in Countries: PG Altitude Ranges: 3,000 - 4,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:87
Straggling shrub, 1 *2-6 m, rarely epiphytic. Leaves elliptic, apex acute, base cuneate or rounded, 60-100(-150) X 19-30(-36) mm, upper surface persistently lepidote, undersurface densely so with close to distant, unequal, flat, broadly rimmed scales. Inflorescences axillary, each 2-5-flowered, but individual inflorescences often coalescing; flowers pendulous. Calyx inconspicuous, undulate, lepidote, rarely ciliate. Corolla tubular, lobes slightly flaring, deep red to salmon pink, lobes usually yellow, (14-)20-25 mm, tube (11 —) 15 —20 mm. Stamens 10, filaments pubescent for about Vi their length. Ovary lepidote, slightly pubescent at the top. Style pubescent towards the base. Capsule cylindric, lepidote, c. 10 mm
Habitat: Forests
Distribution: India (Sikkim, Arunachal Pradesh), Bhutan, China (S Xizang)
Altitude: 2440-3650m
Illustrations:
Type: Mountains of 'Bhutan'(i.e. India, Arunachal Pradesh, cf. Ludlow, Trans. Bot. Soc. Edinb. 41:351-363, 1972) at an elevation of 9-10000 ft, on the summit and nothern slopes of Loblung, Booth (holo. K)
Synonymy: R. keysii var. unicolor Hutchinson, Journ. Roy. Hort. Soc. 59: xxxix (1934). Type: a cultivated specimen (holo. K). R. igneum Cowan, Notes R.B.G. Edinb. 19:235 (1937). Type: S Tibet, 4 miles below Lung, Chayul Chu, 8500 ft, 10 vii 1936, Ludlow & Sherriff 2334 (holo. E)
Occurs in Countries: BT, CN, IN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: pink, red, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):126
Shrub of 1 m. Leaves oblong-elliptic, 40-50 x 20-25 mm, tapered to the base, apex rounded, undersurface greyish with scales 1-2 x their own diameter apart. Inflorescence 2-fIowered, pedicels 10-14 mm, densely lepidote. Calyx 5-lobed, the lobes ovate, 7-8 mm, margins sinuous, lepidote outside. Corolla white, c. 40 mm, tube 20-22 mm, lepidote outside. Stamens 8, filaments pubescent in the lower part. Ovary lepidote, tapering into the style which is lepidote in the lower part. Capsule unknown.
Distribution: China (Jiangxi)
Known only from the type material. I have seen no specimens, but its origin and Fang's brief description leave no doubt that it is a distinct species allied to R. liliiflorum and R. levinei.
Type: China, Kiangsi, south of Ping-huang hsien, Wu-king-shan, Tze-chi-kung, on slopes, 1100 m, 30 iv 1954, Institute of Botany Kiangsi Exped. 100 (holo. PE, n.v.)
Occurs in Countries: CN Subgenus: Rhododendron Habit: Non-Tree
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):40
Dwarf much-branched shrub, 0.6-lm; young shoots covered with adpressed flattened red-brown hairs. Leaves monomorphic, deciduous, oval-obovate, 0.5-2 x 0.2-1.5cm, c.2 x as long as broad, apex acute, base cuneate, margin entire, both surfaces covered with red-brown strigose hairs; petioles l-3mm, densely covered with red-brown strigose hairs. Inflorescence 2-3-flowered; pedicels 5-10mm, covered with red-brown hairs. Calyx 2-3mm, indumentum as for pedicels, lobes ovate c.2mm. Corolla funnel-shaped, 5-20mm, usually rose-pink though occasionally with a wide range of colours from rose to deep purple, lobes 7-10mm; tube glabrous. Stamens 5, longer than or as long as the corolla, pubescent below the middle. Ovary densely covered with red-brown strigose hairs; style glabrous. Capsule 5-6 x c.4mm, strigose.
Habitat: In open woodland on hillsides
Distribution: Japan (Kyushyu)
Altitude: 600-800m
36*. R. saisiuense Nakai, Bot. Mag. (Tokyo) 49: 587 (1935). Type: a cultivated plant exhibited in Tokyo in 1935 by Suzuki; originally from Mt Hallasan, Quelpaert Island, Korea. We are uncertain of the status of R. saisiuense as we have not seen any herbarium specimens. Plants in cultivation at Edinburgh under this name appear to be small forms of R. kiusianum. There is however no independent evidence that R. kiusianum occurs anywhere within the boundaries of Korea.
The nomenclature of this species has been confused by the cultivated forms and hybrids that include R. obtusum and R. amoenum, as well as at least some of the Kurume cultivars.
Type: as for R. indicum var. amoenum forma japomcum Maxim
Occurs in Countries: JP Altitude Ranges: 0 - 1,000m Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: purple, rose
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):122
Leaves oval to obovate, 0.5-2 x 0.2-1cm
Illustrations:
Synonymy: R. indicum (L.) Sweet var. amoenum (Lindley) Maxim, forma japonicum Maxim., Rhododendr. As. Orient. 41 (1870)ó basionym; R. kaempferi Planchon var. japomcum (Maxim.) Rehder in Sargent, Trees and Shrubs 2: 30 (1907); R. indicum (L.) Sweet var. japonicum (Maxim.) Makino, Bot. Mag. (Tokyo) 22: 56 (1908); R. obtusum var. japonicum (Maxim.) Kitamura, Acta Phytotax. Geobot. 25 (2-3): 37 (1972). Type: Japan, in Kiusiu prov. Simabara vulcano Wuzen, medio, Maijo florens (iso. BM).
Illustrations:
Var. sataense is intermediate between var. kiusianum and R. kaempferi and may have arisen as a hybrid of these two taxa. According to Doleshy (J. Amer. Rhodod. Soc. 37:88, 1983) var. sataense occurs in stabilized populations in which the type variety does not occur, and is less variable than plants from those populations where hybrids between R. kiusianum and R. kaempferi are known to occur. The flower colour of var. sataense is variable, as it is in some though not all populations of var. kiusianum.
Synonymy: R. sataense Nakai, Bull. Nat. Sci. Mus. Tokyo 27: 33 (1949). Type: Japan, Kyushyu, Prov. Osuma, in montibus Sata, cum R. obtusum et eius varietate latifolio mixte, 16 iv 1948, Nakai & Maruyama, n.v.
Shrub or small tree; shoots glabrous. Leaves rhombic, 3-5 x 2.5-3cm, apex acuminate, upper and lower surfaces sparsely covered with brown hairs when young, midrib glabrous or shortly pilose beneath, margins ciliate; petioles 4-8mm, mostly glabrous, with scattered brown hairs near leaf base. Inflorescence 1-2-flowered; pedicels 3-5mm, with scattered brown hairs. Calyx minute, ciliate. Corolla open funnel-campanulate, 20-30mm, purple, lobes 10-20mm, oblong. Stamens 10, filaments glabrous. Ovary densely strigose; style glabrous. Capsule 4-10 x 4-5mm, curved.
Habitat: Forests
Distribution: Japan (E Honshu)
Altitude: Around 650m
Illustrations:
Synonymy: Azalea kiyosumensis Makino, J. Jap. Bot. 6: 18 (1929); R. dilatation Miq. var. kiyosumense (Makino) Hatusima, Sci. Rep. Yokosuka City Mus. 15: 22(1969). Syntypes: Japan, Prov. Awa, Mt Kiyosumi,1929, Suszuki, n.v.; 1929, Makino, n.v. Rhododendron shimidzuanum [Honda ex] Makino , Fl. Jap. ed. 2:890(1931)
Occurs in Countries: JP Altitude Ranges: 0 - 1,000m Subgenus: Tsutsusi Habit: Tree Fl. Colour: purple
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):149
Shrub, or small tree, to 10m. Twigs 3–5mm in diameter, rounded, scaly; internodes 5–9cm. Leaves 4–8 together in tight pseudowhorls. Blade 70–160 x 25–50mm, elliptic, broadly elliptic to obovate; apex shortly and abruptly acuminate, the tip acute, often shortly deflexed; margin entire or slightly wavy, very slightly, or not revolute; base broadly tapering, rarely sub-rounded, densely scaly on both sides initially, becoming glabrescent above, laxly sub-persistently scaly beneath. Scales flat, small, with a relatively wide marginal zone sub-stellately lobed; centre small and shallowly impressed. Mid-vein dilated at the base, suddenly narrowed and a little impressed above, as thick as the petiole and obtusely prominent in the proximal part beneath; lateral veins 8–10 per side, spreading and ascending, arching inwards near the margin, slightly impressed or raised above, distinctly prominent beneath, reticulation dense, smooth when living, raised slightly on both sides, when dry or at least underneath. Petiole 15–20 x 2–3mm, almost rounded, not grooved, flushed with red. Flower buds (see p.327) 25–40 x 18mm, sub-spherical to obovoid; apex rounded, or broadly acute to obtuse, glossy white with pale green or red margins to the bracts and a light pink flush along the centre line, smooth in outline, the bracts tightly appressed except for a collarette of small broad dead bracts spreading at a wide angle around the base. Bracts to 20 x 12mm; outer ovate, obtuse, inner ones obovate to spathulate, sometimes retuse, with a small gland-like apiculus, often splitting apically to become emarginate, laxly scaly apically outside or glabrous, often rugose by minute tubercles; margins with a few fragile scales. Bracteoles to 20mm, filiform to linear-spathulate. Inflorescence 10–20-flowered, an open umbel, the flowers mostly horizontal but also semi-erect, to half-hanging. Pedicels 20–30 x c.2mm, densely covered with pale sub-stellate scales, without hairs. Calyx 3–4mm in diameter, obliquely disc-shaped, shortly obtusely 5-lobed, lobes occasionally up to 8mm, densely scaly outside. Corolla 35–47 x 45–47mm, narrowly funnel-shaped, white, not or sweetly scented; tube 30–33 x 9 x 14–17mm, laxly covered with sub-stellate scales outside, sub-densely short-hairy inside; lobes 19–20 x 22–23mm, spreading nearly to the perpendicular, overlapping to c.¾, obovate-sub-circular, often emarginate. Stamens arranged all round the mouth of the flower, at first thrust forward in a group, exserted 6–8mm, later wide-spreading, reflexed back against the corolla lobes; filaments linear, white and sub-densely patently hairy in the proximal ½–¾, glabrous and filiform distally; anthers 3–3.5 x 1mm, white, obovate-oblong; base shortly though distinctly possessing 2 appendages. Disc glabrous. Ovary 5–6 x 2.5mm, sub-cylindrical, white-hairy, the hairs patent or slightly distally directed, covering small, silvery scales, gradually narrowed distally; style deep within the tube, lying on the lower side when the flower first opens, later elongating, becoming exserted to 15mm, the distal part curving upwards to present the stigma on the upper side of the flower, green at the base, white distally and sub-densely to sparsely hairy to the lower ½–¾, glabrous distally and totally without scales; stigma 2.5–3mm in diameter, green. Fruit 25–40 x 6–10mm, sub-cylindrical, laxly scaly but densely grey-hairy, green strongly flushed with purplish red; valves splitting and opening to the perpendicular or a little beyond, not or only slightly twisting; placentae opening slightly. Seeds 3–4.5mm, without tails c.1mm, the longest tail to 2mm, the tails both crimped and with one sometimes broader than the other.
Habitat: On ridges in mossy forest.
Distribution: Philippines, Luzon, Mindoro, Negros, Mindanao.
Altitude: 1000-2300m
Named after Otto Koch, collector of plants and animals in the Philippines and nephew of the collector of the type.
This species is widespread in the Philippines and somewhat variable but has a distinctive habit with shorter, more acuminate leaves on longer petioles than most of the other large-leafed Philippine species. All the material examined has distinctive, glossy white, sub-spherical flower buds with the bracts all closely appressed which is like no other species. Sleumer states the flowers are without scent but there is at least one accession in cultivation which is sweetly scented and P. Wilkie noted scented flowers in this species on Negros. This was one of the species illustrated by Stein (1885) in the Gartenflora but there is no evidence that it was cultivated then. It was probably first introduced into cultivation in America but there appears to be no record of this early introduction. It has been cultivated in Edinburgh since 1990 from an unknown source. It flowers irregularly throughout the year, but mostly in the winter months. The plant is large and leggy but the flowers are very attractive and freely produced.
Type: Schadenberg s.n., Aug. 1909. Philippines, Mindanao, Mt Apo, Seriban Creek (B†, MA). Neotype: Elmer 11435, Aug. 1909. Mt Apo (L, A, BM, BO, E, FI, GH, K, NY, U).
Occurs in Countries: PH Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Tree Fl. Colour: white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:278
Spindly, thin, branched shrub to 1 m. Leaf-bud scales deciduous. Leaves oblong or elliptic-oblong, 13-28 x 6-12 mm, rounded to the base and the subacute apex, upper surface usually persistently lepidote, lower surface fawn to pale brown with dense, ± overlapping, plastered scales, all similar and pale brown, most with well-developed domed centres. Inflorescence many-flowered, pedicels short, lepidote. Calyx lobes 3-4 mm, ± oblong or somewhat obovate, lepidote or elepidote, glabrous outside, margins loriform-ciliate, sometimes with scales as well, inner surface glabrous. Corolla pink to red, rarely pinkish white, tube 6-8 mm, lobes 2-5-4 mm, tube variably pilose outside, densely pilose at the mouth inside and sometimes also well down into the tube. Stamens 5. Ovary lepidote. Capsule lepidote, scarcely exceeding the calyx.
Habitat: Cliffs, moraines, rocky slopes and moorland, occasionally in marshy places, 3200-4700 m
Distribution: China (S Xizang)
Very similar to some variants of R. primuliflorum, with which it has been confused in the past. It differs, however, in scale type, leaf shape, habit and flower colour
Type: China, Tibet, Doshong La, Kingdon Ward 5850 (holo. K, iso. E)
Occurs in Countries: CN Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: pink, red, white
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):163
Named after a god or semi-mythical leader of the Hattam people in New Guinea.
Type: Beccari 5809. New Guinea (W), Mt Arfak (FI, A, B, L, fragment).
Occurs in Countries: ID, IE, PG Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Tree Fl. Colour: pink, white, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:88
Shrub or small tree to 6m. Twigs 3–9mm in diameter, robust, rounded, at first stellately-scaly, quickly glabrescent, at first rough, finally smooth, often whitish in dry specimens; internodes 6–20cm, sometimes with several, much reduced scattered and quickly deciduous cataphylls. Leaves scattered in loose pseudowhorls or sometimes more tightly crowded 3–5 together. Blade 70–200 x 50–100mm, elliptic or broadly-elliptic, more rarely ovate; apex obtuse or rounded; margin entire, flat or slightly revolute; base broadly tapering to rounded, more rarely sub-cordate, densely covered with brown fragile scales on both sides when young, glabrescent on both sides at maturity except along the mid-vein. Scales deeply stellately divided, dendroid, each on top of a paler permanent epidermal tubercle. Mid-vein as broad as the petiole at the base, weakly raised above in the proximal ½, becoming slightly impressed distally, strongly prominent in the proximal ½ beneath; lateral veins 7–11 per side, straight, curved and less visible towards the edge, anastomosing, slightly impressed above in fully mature leaves, somewhat raised beneath, often obscure on both sides, reticulation inconspicuous. Petiole 10–35 x 2–5mm, rounded, without a groove, densely scaly, rough in later stages. Flower buds (see p.327) to 50–110 x 40–50mm, ovoid, the bracts tightly appressed, dark purple. Bracts to 75 x 30mm; outer bracts ovate, the inner ones obovate-spathulate, rough outside with minute stiff hairs or their remaining warty bases. Bracteoles to 50 x 1–4mm, linear-spathulate, often divided into teeth distally, sub-densely hairy, white. Inflorescence of 4–10 flowers in an open umbel, the flowers horizontal to half-hanging. Pedicels 4–15 x 2–4mm, densely brown stellately scaly, sometimes hairy below the calyx. Calyx 6–10mm in diameter, distinctly oblique, shortly (1–2mm) irregularly and obtusely 6–7-lobed, sometimes with one or more lobes up to 15mm, stellate-scaly outside and often with some stiff hairs, whitish ciliate or fringed on the margin. Corolla 80–190 x 70–150mm, tubular below, expanded, funnel-shaped, towards the lobes, fleshy, pure white, or pink, often with pink spots at the bases of the lobes, sweetly and powerfully scented; tube 60–110 x 6–15 x 10–20mm, cylindrical, or sometimes slightly 7-angled, laxly scaly or glabrous outside, densely retrorse hairy inside; lobes 40–80 x 30–60mm, 6 or 7, spreading, obovate-spathulate to sub-circular, often sinuous distally. Stamens 12 or 14, unequal, lying on the lower side of the flower, mostly exserted for 10–20mm; filaments white, densely hairy and linear proximally, glabrous and almost filiform in the distal 1⁄3; anthers 8–15 x c.1.5mm, orange or yellowish, linear-oblong. Disc densely white-hairy. Ovary 10–15 x 4–7mm, sub-cylindrical, somewhat tapering towards the base, densely covered with yellowish, stiff, forwardly directed hairs which cover the numerous scales, abruptly tapering distally; style 40–85mm, white to reddish, rapidly elongating during and after flowering, attaining the length of the corolla in later stages, densely hairy and laxly stellate-scaly in the proximal ½, gradually more scaly and less hairy in the following ¼, then exclusively scaly, finally glabrous in the distal 1⁄5–¼; stigma 5–7mm in diameter, yellow, globose, shortly 6–7-lobed. Fruit 40–120 x 12–18mm, fusiform, widest a little below the middle, gradually tapering to the apex, rough with persistent hairs and numerous minute tubercles and surmounted by the persistent style; stigma lobes to 2 x 1mm. Capsule irregularly splitting from the top, the valves twisting after the outer coat has been shed. Seeds narrowly fusiform, flattened, 6–10mm, without tails 1.75mm, the longest tail 5mm.
Habitat: Epiphytic in montane forest, or terrestrial at forest margins and other open areas on burned open summits, also on peat bogs, swamps or marsh. A common and widespread species
Distribution: Indonesia, New Guinea (W), from the Vogelkop Peninsula in the west throughout the main ranges to Papua New Guinea where it reaches the easternmost tip of the island; also recorded from Fergusson Is., New Britain and New Ireland.
Altitude: 750-2500m
Differing from the type in being small in all its parts. Leaves up to 100 x 50mm, with a petiole up to 15 x 3mm. Inflorescence up to 6-flowered. Corolla up to 90mm long; tube up to 45mm long, anthers 6–7mm.
Habitat: Heathland and open, fern-covered ridge within the Nothofagus–Castanopsis forest
Distribution: Indonesia, New Guinea (W), Wissel Lakes region and Arfak Mts, above the Wajori R.
Altitude: Around 1300m
Greek – phaos – dusky; peplos – cover. Alluding to the dark-coloured covering of scales.
Rhododendron konori var. phaeopeplum is a small form of R. konori, and possibly in the Wissel Lakes region a hybrid of R. konori with a related species of the same subsection with smaller flowers, possibly R. rappardii. A number of natural, intermediate hybrids have been observed with the 5-lobed, orange-red-flowered R. zoelleri, which is abundant in the same place. These exhibited pale pink, 5- and 6-lobed corollas on the same plant, longer, more acuminate, thinner, glossy leaves, on which the epidermal tubercles are much less distinct than in species of section Phaeovireya in general, and longer, more slender pedicels. A few specimens of R. zoelleri, typical except for the white corollas with a yellowish colour, at least at the tube, were found in the same place; these are probably due to a slight introgression with R. phaeopeplum (Sleumer 1966).
Type: Eyma 4818, 29 March 1939. New Guinea (W), Wissel Lake region, Enarotali-Kugapa-Egogitoagapa-Enarotali (L, A, BO, K).
Synonymy: R. phaeopeplum Sleumer, Reinwardtia 1960. 5: 92.
Probably a shrub. Leaves oblanceolate to elliptic, 7-8 x 1.8-2.4cm, 3.3-4 x as long as broad, apex bluntly acuminate, base cuneate, margins slightly undulate, upper and lower surfaces glabrous when mature; petioles 1 — 1.5cm,±glabrous when mature. Inflorescence c.6-flowered; rhachis c.7mm; pedicels c.l5mm, densely stipitate-glandular. Calyx 4-5mm, lobes ovate, rounded, glandular-ciliate. Corolla open-campanulate, c.25mm, with a pubescent spot within near the base. Ovary sparsely rufous-tomentose, eglandular; style glabrous. Capsule not known.
Distribution: Sumatra. Only known from the type specimen
Probably distantly allied to R. wrayi.
Type: Central Sumatra, Korthals (holo. L)
Subgenus: Hymenanthes Habit: Non-Tree
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):296
Shrub, to 2.5m; young shoots densely clothed with spreading strigose hairs and stipitate glands. Leaves dimorphic, subcoriaceous; spring leaves lanceolate to oblong-lanceolate, up to 8 x 2.5cm, c.3 x as long as broad, apex acuminate, base cuneate, upper surface sparsely setose when young, soon glabrescent, lower surface pale, sparsely setose, especially on midrib and veins; summer leaves 20-30 x 8-14mm, otherwise as for spring leaves; petioles 2.5-4mm, setose. Inflorescence c.l2-flowered; pedicels covered with strigose hairs and stipitate glands. Calyx c.l.5mm with broad lobes, long-ciliate. Corolla tubular-campanulate, white to pale purple, 20-22mm; tube c.lOmm, cylindrical, glabrous. Stamens 5, glabrous. Ovary densely long-setose; style glabrous. Capsule c.9mm long, setose.
Habitat: In thickets
Distribution: China (Guangxi, Guangdong, Hunan)
Type: China, Guangdong, Lokchang, 18 v 1929, Zo, Jing Lie (Tso, C.L.) 20627, n.v.
Synonymy: R. fongkaiense C.N. Wu & P.X.Tan, Mat. Med. Guangdong 4: 34, f.2 (1978). Type: China, Guangdong, Fongkai Xian, L. Teng 11072 (holo. IBSC).
Occurs in Countries: CN Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: purple, white
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):104
Shrub, 3-9m; young shoots densely stellate-tomentose and glandular-setose. Leaves elliptic to oblong, 9-22(-30) x 4-9(-10)cm, 2.2-2.5(-3) x as long as broad, apex rounded, sometimes ± acuminate, base rounded, upper surface glabrous above, lower surface with a cinnamon stellate tomentum intermixed with a few glands, to ± glabrescent; petioles (1—)2.5—4cm, stellate-tomentose and glandular-setose, at least at first. Inflorescence 10-15-flowered; rhachis up to 40mm; pedicels 20-30mm, predominantly glandular-setose, usually also sparsely floccose. Calyx 1—2mm, glandular-setose, lobes broad and rounded. Corolla tubular-campanulate, bright crimson to scarlet, without flecks, 45—60mm. Ovary densely stellate-tomentose with an admixture of setose glands; style stipitate-glandular and floccose, at least in the lower half. Capsule 25-40 x 5-8mm, slightly curved.
Habitat: Thickets
Distribution: NE Upper Burma, China (W Yunnan)
Altitude: 1800-3650m
Illustrations:
At one extreme there are forms with short petioles and styles glandular only below. These have been referred to R. agapetum. However, these forms completely intergrade with R. kyawi so that there is no justification for maintaining the former as distinct at any rank.
Type: Burma, Kachin Hills, 1 mile beyond Paypat Bungalow, 6000ft, Kyaw 36 (holo. K; iso. E).
Synonymy: R. agapetum Balfour f. & Kingdon-Ward, Notes R.B.G. Edinb. 13: 58 (1920). Type: E Upper Burma, Hpimaw, 6000-7000ft, 31 vii 1914, Kingdon-Ward 1851 (holo. E). R. prophantum Balfour f. & Forrest, Notes R.B.G. Edinb. 13: 58 (1920). Type: NE Upper Burma, N'Maikha/Salween divide, v 1918 Forrest 17928 (holo. E)
Occurs in Countries: CN, MM Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: crimson, scarlet
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):376
Shrub or small tree, 2—7.5m. Leaves elliptic to obovate, 8—17 x 4.5—7cm, 2-2.5 X as long as broad, apex rounded, apiculate, base rounded, lower surface covered with a thin unistrate compacted indumentum composed of grey-brown radiate hairs; petioles 2-2.5cm, glabrescent. Inflorescence 15-30-flowered; rhachis 25-30mm; pedicels 25-30mm, floccose at first, soon glabrescent. Calyx c.lmm, glabrescent. Calyx c.lmm, glabrous, lobes rounded. Corolla widely campanulate, pure yellow, without flecks, sometimes with a purple basal blotch, 40-50mm. Ovary densely tomentose; style glabrous. Capsule c.20 x 5mm, curved.
Habitat: Rocky slopes, forest margins
Distribution: China (W Yunnan)
Altitude: 3700-4000m
Illustrations:
Two plants, Forrest 25583 & 25776, with pink flowers but otherwise resembling R. lacteum, may be hybrids.
Type: China, Yunnan, ad collem Yen-tze-hay, 3200m, 31 v 1887, Delavay 164 (iso. E)
Synonymy: R. mairei Leveille, Feddes Repert. 12: 285 (1913). Type: China, Yunnan, Lei Tsou mountains, 3000m, v 1912, Maire (holo. E).
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: purple, yellow
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):362
Shrub to 3m. Twigs 3–6mm in diameter, sub-angular to rounded, laxly scaly; internodes 2.5–16cm. Leaves 4–6 together in tight pseudowhorls. Blade 40–95 x 25–53mm, broadly elliptic or sub-ovate-elliptic; apex very shortly acuminate or sub-cuspidate, more rarely broadly tapering, sub-acute or obtuse to rounded; margin entire, flat; base rounded, rarely broadly tapering or sub-cordate, dark green and glossy above, paler beneath, sub-densely scaly on both sides at first becoming glabrescent above, more persistently and laxly scaly beneath but eventually glabrescent there also but spotted from the persistent bases. Scales small, marginal zone irregularly sub-stellately lobed; centre minute, shallowly impressed. Mid-vein narrow and grooved above, as wide as the petiole and obtusely prominent proximally beneath; lateral veins 6–8 per side, spreading, obscurely anastomosing before the margin, faintly impressed, or inconspicuous above, slightly to distinctly raised beneath, reticulation lax, a little prominent beneath, or invisible. Petiole 2–7 x 2–3mm, grooved above, laxly scaly. Flower buds c.45 x 25mm, ovoid, smooth, green. Outer bracts 35–50 x 15–20mm, rounded to ovate, apiculate or obtuse, with short appressed hairs initially outside, glabrescent and smooth finally; inner ones ovate-oblong to sub-spathulate, glabrous or nearly so. Bracteoles filiform, sub-spathulate at apex, very laxly hairy or glabrous, c.40 x 0.5–1mm. Inflorescence an open to full umbel of 5–12 horizontal or semi-erect flowers. Pedicels 25–55 x c.1mm, sub-densely stellately scaly and minutely hairy. Calyx obliquely disc-shaped, shortly obtusely 5-lobed, scaly and minutely hairy outside, c.4mm in diameter. Corolla 50–70 x 50–60mm, broadly funnel-shaped, fleshy, sometimes fragrant, pure deep yellow first, becoming suffused with red or orange with age; tube 28–35 x 8–12 x 15–20mm, straight, distinctly 5-angular and often pouched at the base, laxly stellately scaly and sometimes with some hairs at the base outside, shortly hairy inside; lobes broadly obovate, 20–30 x 15–22mm. Stamens dimorphic, exserted 5–10mm, irregularly arranged but with a tendency to be spread around the lower ½; filaments linear, sub-densely short-hairy in the proximal ½, narrower and glabrous distally; anthers 4–5 x c.1.5mm, broad-oblong, base obtuse. Disc prominent, hairy on the upper margin otherwise glabrous. Ovary 6–8 x 2.5–3mm, sub-cylindrical, sub-abruptly contracted distally, white-hairy, the hairs covering minute scales; style thick, hairy at the base, laxly hairy above to the lower ½–2⁄3, usually without scales, glabrous distally, mostly lying close to the lower side of the flower; stigma thick-globose, green, becoming exserted to 10mm. Fruit sub-fusiform or cylindrical, curved, densely hairy and scaly, 35–55 x c.0.8mm. Seeds 4–6mm including the tails.
Habitat: Terrestrial on the edge of primary and secondary forest, in open marsh and in swamps at the edge of lakes.
Distribution: Indonesia, New Guinea (W), Anggi Lakes area in Arfak Mts.
Altitude: 1800-2300m
Latin – laetus – cheerful or bright, an allusion to the bright flowers.
Sleumer comments that this species is ‘Much related to R. zoelleri’. It differs mainly in the pure yellow colour of the flowers, at least when they first open, and the shorter pedicels. The anther length difference breaks down when one considers the forms of R. zoelleri found at the eastern end of New Guinea.
Type: Gjellerup 1136, 20 April 1912. New Guinea, NW, Arfak Mts, Angi Lakes, 1800–2135m (BO, A, L).
Synonymy: R. uliginosum J.J.Sm., Nova Guinea 1914. 12: 136, t.33.
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: orange, red, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:300
Much-branched shrub or tree, to 2m. Twigs 1–2.5mm in diameter, erect or erecto-patent, the tips densely covered with scales, the lower parts rough to the touch with scale stalks; internodes 4–11cm. Leaves in loose pseudowhorls, with 7–12 leaves, in the upper 1⁄3 or ½ of the internode. Blade 10–25 x 6–16mm, sub-circular to elliptic, rarely sub-ovate-elliptic; apex obtuse to rounded, with a small glandular point; margin flat or slightly revolute, crenulate with impressed scales; base broadly tapering to rounded; glabrescent above, but often densely pitted, not rough to the touch, undersurface densely scaly, the scales mostly touching and overlapping. Scales of two sizes: small silvery scales with small impressed centres which leave pits after they have fallen and regularly scattered amongst them, larger, brown, scales, with large swollen centres. Mid-vein impressed in a narrow groove above, somewhat raised beneath, sometimes becoming indistinct distally; lateral veins 4–6 per side, irregularly spreading and curved-ascending, anastomosing, slightly depressed above, faintly raised beneath. Petiole 2–4 x 1–1.5mm, grooved above, scaly. Flower buds to 12 x 8mm, ovoid, smooth or with the tips of the bracts slightly spreading. Outer bracts ovate to sub-circular-ovate, sub-acuminate, with a narrow raised keel, inner ones ovate to spathulate, obtuse, thin, scaly outside towards the apex, all fringed with scales. Bracteoles linear-spathulate, glabrous, up to 8mm. Inflorescence an open umbel of 4–6 flowers, the flowers horizontal or half-hanging. Pedicels 10–13mm, densely covered with sessile, or very shortly stalked scales. Calyx 3–4mm in diameter, oblique, disc-shaped, scaly outside, wavy and irregularly minutely lobed, sometimes with one lobe longer than the others. Corolla 17–20 x 10–12mm, yellow or orange, elongate-campanulate; tube 10–13 x 4–5 x 7–8mm, straight, densely scaly outside, glabrous inside; lobes 4–5 x 4–5mm, not or hardly reflexed, overlapping to c.¾, scaly except near the margins, irregularly crenate and often retuse. Stamens arranged all round the mouth, exserted to c.2mm; filaments linear but expanded near the base, glabrous, 10–12mm; anthers sub-orbicular, c.1mm. Disc glabrous. Ovary 3–4 x 2.5–3mm, broadly ovoid-conical, densely silvery scaly, abruptly contracted distally; style 3–4mm, glabrous, stigma shortly 5-lobed, centrally placed. Fruit 13–15 x 6–7mm, ellipsoid to obovoid-fusiform, conspicuously 5-ribbed, densely brown-scaly, becoming erect on the pedicels which elongate to 22mm, the style not elongating. Seeds 3–3.5mm, without tails 0.9mm, the longest tail c.1.5mm.
Habitat: Locally common in short sub-alpine forest and mountain heath vegetation
Distribution: Indonesia, Sulawesi, Latimodjong Range: Mt Pokapindjang and its spurs; Mt Rantemario.
Altitude: 2800-3000m
Latin – lagunuli – a small bottle; Greek – carpo – relating to the fruit. Alluding to its bottle-shaped fruit but not especially apt.
Introduced into cultivation by David Binney in 1998, it is a straggly plant which flowers irregularly with its smallish orange or yellow flowers. Cultivated plants are less scaly than they are in the wild, with quite substantial spaces between the scales; they also tend to have longer petioles which might cause confusion with R. zollingeri but R. lagunculicarpum retains the broadly tapering to rounded leaf bases which distinguishes them from the narrowly tapering bases of R. zollingeri. Rhododendron lagunculicarpum is very similar to R. correoides from New Guinea, having a similar arrangement of scales on the leaves and similar colour variants. Rhododendron correoides is distinguished from this species by its style which is longer than the ovary (reflecting a longer flower), and the flower bud morphology appears from the limited material examined to be different, with R. correoides having much longer, subulate pointed bracts.
Type: Kjellberg 3922, June 1929. Celebes, Enrekang, B. Pokapindjang (S, L, fragment).
Occurs in Countries: ID Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Tree Fl. Colour: orange, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:134
Shrub or small tree to 3m. Twigs 3–4mm in diameter, bright red passing to green, finely but fairly densely scaly; internodes 3–12cm. Leaves 3–5 together in loose pseudowhorls. Blade 60–120 x 20–45mm, narrowly obovate to narrowly elliptic; apex broadly acute and sometimes tipped with a very small, pale gland; margin entire, slightly irregular, flat or minutely revolute and with a very narrow cartilaginous edge; base rounded from a tapering lower ½; minutely brown scaly above and below, quickly glabrescent above. Scales small, sub-circular to irregularly lobed, marginal zone pale brown or silvery; with a small slightly impressed centre. Mid-vein raised above proximally, tapering rapidly from the petiole, faintly grooved when fresh and deep pink for c.10mm, becoming impressed in the distal ½; below prominently raised for almost the whole length and tapering gradually; lateral veins 8–12 per side, slender, spreading at c.45°, hardly visible below. Petiole 2–7 x 3–6mm, not grooved, deep pink, finely scaly. Flower buds to c.4 x 2cm, narrowly ovate, green or reddish-brown, especially the basal bracts, acutely pointed with the bract tips narrow and erect or slightly spreading. Bracts ovate, concave, acuminate, the apical portion inrolled to a subulate point, the margins fringed with scales, otherwise glabrous. Bracteoles to 23mm, linear, glabrous, silvery. Inflorescence of 14–18 flowers in a complete umbel or slightly flat-topped. Pedicels c.35 x 1.75mm, bright red, sparsely silvery scaly and minutely patently white-hairy. Flowers mostly disposed horizontally, some half-hanging to semi-erect, pink, fading to almost white with age, sweetly scented. Calyx a low almost circular disc with a red margin, scaly. Corolla 40–50 x 40–50mm, pale pink; tube 36–42 x 7–10 x 6–7mm, straight, narrowest at about 2/3 of the distance from the base, completely glabrous outside, densely hairy proximally inside, becoming glabrous distally; lobes 17–23 x 16–20mm, spreading horizontally, flat and overlapping to c.halfway. Stamens arranged regularly all round the mouth of the flower, distinctly dimorphic (about 3mm difference between the longer and shorter); filaments white, shortly patently hairy in the proximal 1⁄3, glabrous distally; anthers c.3mm, pale brown, each cell with a small apiculus at the base. Disc prominent, green, deeply lobed, shortly hairy on the upper surface only. Ovary c.10 x 3mm, green, sparsely silvery scaly and shortly, white, patently hairy, tapering gradually distally; style white, with just a few scales at the very base, shortly patently hairy in the proximal 1⁄3 and glabrous distally; stigma c.3mm in diameter, pink, disc-like with 5 lobes. Fruit c.36 x 5mm, green or flushed red, tapering gradually to the style. Seeds c.5.5mm, without tails 1.3mm, the longest tail c.2.6mm.
Habitat: Terrestrial or epiphytic in upper montane forest
Distribution: Malaysia (Borneo), Sabah, Mt Alab. Sarawak, Mt Mulu, E ridge.
Altitude: 1400-1600m
Named in honour of Tony Lamb who first found this species, and who has made a major contribution to the knowledge of the Sabah flora during his many years of residence there.
This species when first collected on Mt Alab was thought to be a hybrid between R. suaveolens and R. orbiculatum and was recorded as such (Argent et al. 1988). It is florally intermediate between these two species but its foliage was always anomalous in being longer and narrower in proportion than in either of the supposed parents, an unusual attribute for a hybrid. The second collection from the Mulu National Park in northern Sarawak was a long way from the first record and well outside the range of one of the supposed parents (R. suaveolens). This second collection has been growing alongside the original now for more than ten years and is identical. This species is still only known from two localities, although two simultaneous collections originally made on Mt Alab show small differences in leaf shape. Rhododendron lambianum, although apparently closely related to R. suaveolens, is quite distinct: it has broader flowers, fewer in number in the inflorescence, and narrower leaves with a length/breadth ratio of 3:1 or more for the largest leaves (in R. suaveolens 2:1 or less). It also has much more distinct petioles which are longer than broad, rounded to broadly tapering leaf bases and a distinctly if broadly acute apex, compared with the rounded apices and cordate to rounded bases from petioles which are broader than long in R. suaveolens. It also differs from R. suaveolens in flower bud morphology, lacking the broad, green, spreading to reflexed, leafy apices of that species, instead having red, narrow subulate points. From R. orbiculatum, a species with a very widespread distribution in Borneo, it differs in having more, smaller flowers in each umbel and distinctly long petiolate narrow leaves. It has been in cultivation since its discovery in 1980 and grows vigorously, flowering profusely usually several times a year.
Type: Argent & Lamb 19801308, 15 Feb. 1980. Sabah, Gunong Alab, Tuaran District, 1400–1600m (SAN, A, CANB, E, L).
Occurs in Countries: MY Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Epiphyte, Tree Fl. Colour: pink
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:165
Shrub to 2m. Twigs 5–6mm in diameter, rounded, laxly scaly at first; internodes 0.8–1.7cm. Leaves 6–7 together in tight to loose pseudowhorls with persistent large cataphylls between the foliage leaves. Blade 18–33 x 8–18mm, broadly elliptic-obovate; apex broadly sub-acuminate or obtuse to rounded, with a thick and somewhat protruding gland; margin distinctly crenulate, flat or a little recurved; base broadly tapering and decurrent, sub-sessile, initially sub-densely scaly on both sides, early glabrescent above, less so beneath. Scales small, marginal zone narrow, irregularly sub-stellately lobed or crenate; centre slightly or not impressed. Mid-vein faintly impressed above, flat beneath; lateral veins 4–6 per side, erecto-patent, obscure on both sides, reticulation inconspicuous. Petiole 1–2 x 3–4mm, flattened. Outer bracts to 10 x 8mm, membranous, glabrous outside, ovate, apiculate; middle bracts to 20–35 x c.15mm, ovate-elliptic, innermost bracts to 50 x 20mm, elliptic-obovate to spathulate, not fringed. Bracteoles to 20 x 1mm, linear, glabrous. Inflorescence 3–4-flowered. Pedicels c.10 x 1mm, densely scaly, without hairs. Calyx c.4mm in diameter, oblique, disc-shaped, shortly sub-acutely 5-lobed. Corolla 30 x 45mm, funnel-shaped, dark red, fleshy, glabrous both in and outside, 5-lobed to nearly halfway; tube c.15 x 4 x 10mm; lobes 12–15 x 12–15mm, obovate to sub-circular. Stamens unequal, slightly exserted; filaments linear, dilated above the base, glabrous; anthers c.3.5 x 1.8mm, obovate, base sub-acutely tapering into 2 appendages which are very close together. Disc prominent, glabrous. Ovary 6 x 2.5–3mm, sub-cylindrical, densely scaly, tapering distally; style thick, glabrous, exceeding the stamens in length; stigma obconical, distinctly lobed. Fruit c.25 x 7mm, thick-fusiform, on pedicels to 30 x 2mm. Seeds 3mm, without tails c.1mm, the longest tail 1mm, with a very broad tail at one end.
Distribution: Indonesia, New Guinea (W), Mt Doorman, on an open slope with rocks
Altitude: Around 3280m
Named after the collector, H.J. Lam, former director of the Rijksherbarium and professor at Leiden University, previously posted in Indonesia and collecting extensively between 1919 and 1933.
Not recently recollected and never cultivated.
Type: Lam 1620, 17 Oct. 1920. New Guinea (N), Doormantop, 3280m (BO, L).
Occurs in Countries: ID Altitude Ranges: 3,000 - 4,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:229
Shrub. Twigs robust, rounded, tips densely brown-scaly, glabrescent below; internodes 3–11cm. Leaves 5–6 together in pseudowhorls. Blade 40–95 x 20–45mm, narrowly ovate to elliptic; apex shortly to sub-caudately acuminate, broadly acute; margin revolute in dry specimens; base tapering, dark green above, brownish green underneath, practically glabrous above at maturity, dark brown or reddish-scaly beneath. Scales very dense, touching and overlapping with broad lobed flanges and small centres, leaving small pits when they disappear. Mid-vein strongly impressed above, very prominent beneath; lateral veins c.8 per side, irregular, spreading, straight below, anastomosing towards the edge, slightly impressed above in mature leaves, minutely or not raised beneath, visible above only. Petiole 10–25 x 1.5–3mm, semi-rounded, grooved above, densely scaly. Flower buds ovate-apiculate as in R. album. Bracts to 16 x 6mm; outer bracts ovate, abruptly and longish apiculate or subulate, inner ones elliptic-spathulate, obtuse, all scaly outside. Bracteoles to 15mm, linear, laxly scaly. Pedicels 10–15mm, thick, densely brown-scaly and laxly short-hairy. Calyx c.4mm in diameter, obtusely shortly 5-lobed, densely scaly. Corolla 18–20mm, campanulate, yellow; tube c.15 x 3–4 x 6–7mm, laxly scaly outside; lobes broadly obovate-spathulate, spreading, 7–9 x 6–8mm. Stamens 14–16mm; filaments linear, patently long-hairy in the proximal 1⁄3, glabrous distally; anthers 2 x 1mm, broadly oblong. Disc glabrous at the base, densely hairy upwards. Ovary c.4 x 2mm, obovoid-cylindrical, tapering at the base, densely scaly and patently hairy, gradually narrowed distally; style nearly as long as the corolla, slender, scaly and patently hairy in the proximal 1⁄3, conspicuously hairy in the middle, glabrous in the distal 1⁄3 stigma indistinctly lobed. Fruit (sub-mature) c.18 x 3mm, obovoid-fusiform, long-tapering to the base, broadest in the upper 1⁄3, sub-densely scaly and patently hairy.
Habitat: Low forest
Distribution: Indonesia, Sumatra, Padang Highlands: Mt Gombak; Lampongs: Mt Radja Bassa
Altitude: 1370-2330m
Named after the province of Lampung at the southern tip of Sumatra.
Not apparently recently recollected or cultivated.
Type: Teysmann 4479, Sumatra, west coast, Lampong, G. Radja Bas(s)a (U, BO, L, fragment).
Synonymy: Azalea lamponga (Miq.) O.Kuntze, Rev. Gen. Pl. 1891. 2: 387.
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:129
Named in honour of Datuk Lamri Ali, Director of Sabah Parks, who supported field work on rhododendrons in Sabah.
Type: Argent 84/12 (19841164), March 1984. E Malaysia, Sabah, G. Trus Madi, east ridge (SAN, E).
Synonymy: R. variolosum auct. non Becc.; Sleumer, Reinwardtia 1960. 5: 105, pro parte; Blumea 1963. 12: 101; Flora Malesiana 1966. 6(4): 536 var. andersonii, pro parte. Argent et al., Sabah Parks Publ. 1988. 8: 88.
Occurs in Countries: MY Altitude Ranges: 2,000 - 3,000m Subgenus: Vireya Fl. Colour: orange, white, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:118
Differing from the type subspecies in the taller laxer habit, up to 1.5m. Corolla tube glabrous or only sparsely scaly outside and densely white hairy in the proximal ½ within.
Habitat: Occurring from 2150 to 2700m as an epiphyte in moderately shady situations in the tall montane valley forest, often occurring high up in trees but apparently not competing successfully on open ridges where many of the other Rhododendron species such as the closely related R. acuminatum do so well. It is characteristic of the zone usually dominated by the climbing bamboo Racemobambos gibbsiae (Stapf) Holttum and becomes much more conspicuous after one of the mass flowerings and death of most of these bamboos. At this time the forest takes on a much more open aspect for a year or two before the bamboo again begins to dominate the sub-canopy.
Distribution: Malaysia (Borneo), Sabah, Mt Kinabalu
Altitude: 2150-2700m
Named in honour of Ansow Gunsalam who has accompanied many scientists on field visits in Sabah; a lively companion, an acute observer and free thinker.
This species is easily known from all other rhododendrons in section Malayovireya by its bicoloured, red and yellow flowers, and in having only a small area of the bract margins near the apex with simple hairs, otherwise the bracts are fringed with scales. Rhododendron variolosum Becc. (now considered a hybrid) included, in the past, materials now separated as R. lamrialianum and is only reliably reported from southern Sarawak. It is highly likely that R. lamrialianum is the product of a hybridisation event in the past which would account for the anomalous marginal indumentum of both scales and hairs, but it behaves as a good species on Kinabalu and Trus Madi and on both mountains it is common in its own distinctive ecological niche. Rhododendron acuminatum could easily be supposed to have been one parent but the other is not obvious. Professor Sleumer (1966) attributed the Kinabalu forms of this species to R. variolosum Becc. var. andersonii (Ridl.) Sleumer, saying: ‘almost certainly a natural hybrid of R. malayanum with a yellow-flowered species of series Javanica’. The type of R. andersonii comes from Mt Rumput in southern Sarawak and appears very similar to Beccari’s R. variolosum, differing only in the hairy filaments and the slightly hairy corolla tube inside. Ridley’s species appears to be very similar to Beccari’s and it is highly likely that they are both hybrids between R. jasminiflorum and R. malayanum. Rhododendron lamrialianum is very different from the southern Sarawak plants, having considerably shorter leaf blades and the distinctive bicoloured flowers. The pattern of distribution from southern Sarawak to Sabah is also an unlikely one with no other parallel in the family.
Rhododendron lamrialianum is closely related to R. acuminatum from which it differs in its smaller, smoother leaves, the bicoloured flowers, and having fewer flowers in the umbel. It also had different ecology, being essentially an epiphyte of lightly shaded situations whereas R. acuminatum is a terrestrial plant of open ridges. In its small leaves R. lamrialianum is similar to R. micromalayanum Sleumer but differs from that species in the scales on the leaves being less dense and in flower colour, R. micromalayanum being pale-purple or green, never bicoloured or with orange pigmentation. Rhododendron micromalayanum also has a different distribution pattern.
The only hybrids recorded are with R. fallacinum on Mt Trus Madi. These hybrid plants are locally common, usually have intermediate-sized leaves, long petioles, pure orange flower colour and totally ciliate bract margins. It would be surprising however if hybrids between this species and R. acuminatum did not occur from time to time, but the different flowering times and very different habitats does no doubt effect good isolation of these two species.
Type: Mitchell & Smith 312 (19952748), 12 Oct. 1995. East Malaysia, Sabah, Mt Kinabalu (SAN, E).
Compact shrub to 1m. Twigs rounded, brown, slightly rough with a dense covering of scales. Vegetative buds obscure, rounded, to 2mm. Leaves in pseudowhorls of 4–5 together with small, scale leaves on the stems between, these quickly falling off. Blade 45–80 x 12–30mm, elliptic; slightly acuminate, with an acute apex which is often rounded at the extreme point; margin flat and entire; base broadly tapering; densely scaly above initially with pale scales but quickly glabrescent; underside with persistent scales which are less dense than is typical for the section, only occasionally touching and with areas of the lower leaf surface showing. Scales large, dark brown, with a large centre in relation to the paler marginal zone, very dissimilar in size. Mid-vein impressed above and strongly raised beneath throughout its length; lateral veins 3–5 per side, wide-spreading, slightly impressed above, raised below for about 1⁄3 the distance from the mid-vein to the edge in the fresh state (further when dried); dark-green above and dark-brown beneath. Petiole 15–25 x 2–2.5mm, grooved above, very densely covered in brown scales. Flower buds (see p.327) to 20 x 12mm, ovoid, smooth, but somewhat irregularly imbricate, brown, with scales outside. Bracts fringed with brown scales for most of the perimeter but with white hairs near the apex. Outer bracts externally with brown scales, these extending to the margin in the upper part but leaving a narrow to broad green margin in the proximal ½, also minutely hairy; internally glabrous or minutely hairy in the distal 1⁄3. Inflorescence of 2–5 flowers in open umbels, (up to 10-flowered in cultivation). Flowers tubular-funnel-shaped, half-hanging to hanging. Pedicels 5–10 x 1mm, densely brown-scaly. Calyx a low scaly ring or with short triangular lobes. Corolla 25–28 x 18–21mm, bicoloured with orange lobes and a yellow tube, without scent; tube 15–18 x 5–6 x 7–8mm, mostly glabrous in the proximal ¼, prominently scaly distally, with a few scales often following longitudinal lines, glabrous within; lobes 8–9 x 8–9mm, half-spreading, not or only slightly overlapping, with the smallest lobes on the lower side of the flower, all lobes with occasional scales on the outer sides, sometimes forming a distinct triangle with the apex near the tip of the lobe. Stamens slightly dimorphic, arranged irregularly all round the mouth of the flower; filaments 18mm, somewhat swollen and hairy in the proximal 1⁄3; anthers 2.5mm, brown. Ovary 5 x 2mm, densely brown-scaly; style 15mm, densely scaly in the proximal ½, glabrous distally; stigma only slightly broader than the style, 1mm in diameter. Fruit to 32 x 4mm, becoming erect as it develops, densely brown-scaly, splitting to the base, with the valves strongly curving back, without first shedding the outer layer. Seeds 6.5mm, without tails 1.2mm, the longest tail 2.6mm.
Distribution: Malaysia (Borneo), Sabah, known only from Mt Trus Madi, E ridge and above Kidukaruke.
Shrub, 2-4m. Leaves lanceolate, 9-11 x 2.1-2.7(-3.2)cm, (3-)4-4.7 X as long as broad, apex acuminate, upper surface glabrous except for a persistent tomentum overlying the midrib towards the base, lower surface covered with a dense lanate, dark fawn to light brown indumentum composed of dendroid hairs with long ± straight (not crisped) branches; petioles 1-1.5cm, densely light brown to whitish tomentose. Inflorescence dense, 10—15-flowered; rhachis 7-10mm; pedicels 7- 15mm, densely brownish lanate-tomentose. Calyx c.lmm, lobes triangular, sparsely tomentose. Corolla campanulate, white flushed pink, with a few faint flecks, 35-40mm. Ovary densely brown-tomentose; style glabrous. Capsule not known.
Habitat: Among rocks
Distribution: China (SE Xizang)
Altitude: 3200-3650m
Allied to R. lanatum but leaves narrow and acuminate, with a non-crisped lanate indumentum and flowers white flushed pink.
Type: China, SE Xizang, Pome, Tongyuk Dzong, 12000ft, 21 v 1947, Ludlow, Sherriff & Elliot 13746 (holo. E; iso. BM).
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: pink, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):370
Shrub, 0.3—4(-7.5)m; shoots densely rufous- or white-tomentose. Leaves usually coriaceous, elliptic to obovate, 6.5-11 x 2.5-4.2cm, 2-3(-3.5) x as long as broad, apex rounded, apiculate, base rounded, upper surface with lamina glabrous or with a floccose indumentum that in most specimens persists over the midrib, lower surface with a dense, usually thick ± crisped tomentum composed of dendroid hairs, whitish when young, maturing to a deep rufous-brown or mid coffee-brown; petioles c.lcm, densely tomentose. Inflorescence 5- 10-flowered; rhachis 3- 10mm; pedicels 10-20mm, densely white- to brown-tomentose. Calyx c.lmm, tomentose. Corolla campanulate, creamyyellow, with crimson flecks, 32-50mm. Ovary densely rufous-tomentose. Capsule 15-25 x 4-8mm, curved.
Habitat: Abies forests, scrub, cliffs, etc.
Distribution: NE India (Sikkim, Arunachal Pradesh), Bhutan, China (S Xizang)
Altitude: 3000-4500m
Illustrations:
A species with considerable local geographical variation. Material from Sikkim in general matches the type in having a thick, coffee-coloured leaf indumentum. However, specimens from around Bumthang in C Bhutan have a thinner, more crisped rufous leaf indumentum and sometimes have pinkish flowers. These include the type of R. flinckii (see above), also Cooper 2148, 3987 & Ludlow, Sherriff & Elliot 18890, 18998. Plants from W Bhutan are intermediate in these characters. Specimens from S Xizang (R. luciferum) often have relatively narrow leaves (c.3 x as long as broad) with a thick, mid-brown indumentum, although one plant Ludlow & Sherriff 1608, from Yarap, approaches R. circinnatum in its more crisped, thinner leaf indumentum. Field studies are required before this species is further subdivided.
R. lanatum apparently hybridises with R. tsariense where the ranges of the two species overlap.
Type: N India, Sikkim, common at Jongri and Chola, 10-12000ft, Hooker (holo. K; iso. A, E)
Synonymy: R. lanatum Hooker f. var. luciferum Cowan in Notes R.B.G. Edinb. 19:228 (1937). Type: China, S Xizang, Tsari, Bimbi La, 3 vi 1936, Ludlow & Sherriff 1162 (holo. BM). R. luciferum (Cowan) Cowan, Notes R.B.G. Edinb. 21: 145 (1953). R. flinckii Davidian, Quart. Bull. Amer. Rhododendron Soc. 25: 143 (1975). Type: Bhutan, Kopub, Pumthang, 10000ft, 18 vi 1915, Cooper 3990 (holo. E)
Occurs in Countries: BT, CN, IN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: cream, crimson
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):369
Shrub to 1.2m. Twigs 2–3mm in diameter, green, rounded, smooth apart from a fine covering of pale brown scales becoming glabrescent; internodes 3.5–8cm. Leaves 3–7 large, together with several very slender scale leaves in well-marked pseudowhorls at the upper 1–3 nodes. Blade 70–120 x 25–45mm, narrowly ovate to elliptic, sub-sessile; apex acuminate, acute, often slightly curved; margin entire, flat or weakly revolute; base obtusely tapering to rounded and highly rugose; very densely scaly on both sides when young, above the scales, sparse and becoming glabrescent but leaving a pitted surface, beneath sub-densely and persistently scaly, especially at the base of the blade. Scales small, thin and flat, the marginal zone irregularly sub-stellately lobed; centre minute and shallowly impressed, leaving dark pits. Mid-vein broad and prominent and often coloured red in the proximal ½ above, but flat or slightly raised beneath; lateral veins 7–12 per side, very fine and obscure, wide-spreading, almost at right angles, curved and anastomosing before the margin, the lamina often thrown into folds on either side of the mid-vein, reticulation inconspicuous above, obscure below. Petiole 2–3 x 2–3mm, scaly, obscurely defined, (the leaves being almost sessile), without a groove, reddish in colour. Flower buds (see p.327) to 25 x 15mm, sub-spherical with a broadly pointed apex, brown with the bract tips spreading. Outer bracts subulate to ovate-acuminate, inner ones obovate to spathulate, apiculate, all sub-densely scaly outside. Bracteoles to 15mm, subulate-linear, scaly. Inflorescence 4–10-flowered in an open umbel. Flowers c.24 x 22mm, white, sometimes scented, horizontal or half-hanging. Pedicels 20–30 x 1–2mm, densely brown-scaly and shortly white-hairy. Calyx c.4mm in diameter, disc-shaped, with distinct, very short blunt lobes, scaly and hairy outside. Corolla sub-campanulate, lobed to 2⁄3; tube 7–10 x 4–6 x 10–15mm, densely scaly, glabrous or slightly hairy inside, with broad grooves in the proximal ½; lobes 12–16 x 8–13mm, sub-obovate, erect, not reflexing back, scaly outside where the lobes were not overlapping in bud, variously overlapping ¼–¾. Stamens spreading regularly all round the flower, slightly dimorphic; filaments white, hairy for ¾ of their length, c.10 and 12mm; anthers 3–4 x c.1mm, white, curved, narrowed towards the pores, base obtuse or very shortly bilobed. Disc of 10 rounded, greenish yellow lobes, hairy on the upper side. Ovary 4–5 x 3–3.5mm, conical, green but covered with white hairs but without scales, ridged in the proximal ½, obtusely contracted distally; style c.5mm, green, hairy in the proximal ½, straight in young flowers but bending to place the stigma at the side of the flower; stigma green, 1.5mm in diameter. Fruit c.25 x 5mm, not seen mature.
Habitat: Grows as an epiphyte in the shade of wet mossy forest or occasionally on the ground in open peaty situations
Distribution: Malaysia (Borneo), Sarawak, Mt Batu Lawi at Upper Limbang R., Mt Mulu and Mt Murud, Batu Tiban (7th Div.). Sabah, from the Long Pa Sia area. Indonesia, W Kalimantan (Borneo), on Mt Batu Tiban (G. Tiboeng) (as R. partitum).
Altitude: 1000-1600m
Latin – lanceolatus – shaped like a spear-head, referring to the shape of the leaves.
Rhododendron partitum was reduced to synonymy by Sleumer (1966) and in almost all respects agrees with R. lanceolatum as understood here. It was however described (possibly in error) as having orange-yellow flowers, which R. lanceolatum apparently never does. This is a very distinct species with short, almost campanulate flowers, which are a dirty white due to the small but dense brown scales on the outside of the corolla. It has relatively large, nearly sessile leaves which are distinctly rugose at the base and it possesses numerous slender scale leaves associated with the pseudowhorls of normal leaves. Pollinators have not been recorded and hybrids with other species are unknown. Curiously the flowers are distinctly pleasantly scented, unpleasantly scented or quite without scent to different observers of the same plant.
Type: Moulton s.n., 29 May 1911. Borneo, Sarawak, Mt Batu Lawi, Upper Limbang R., c.1125m (SAR, L).
Synonymy: R. partitum J.J.Sm., Bull. Jard. Bot. Buit. III, 1935. 13: 453.
Occurs in Countries: ID, MY Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:270
Shrub or tree, 2.7-6m. Leaves elliptic to oblanceolate, 16-22 x 5-7cm, 3.3—4 x as long as broad, upper surface rugulose and ± glabrous at maturity though often with traces of indumentum along the midrib, lower surface with a dense whitish to fawn lanate-dendroid tomentum, that overlies a compacted lower layer of indumentum; petioles 1.5-2cm, velutinous. Inflorescence 20-25-flowered, dense; rhachis c.20mm; pedicels c.lOmm, glabrous. Calyx fleshy, c.2mm, with minute teeth, glabrous. Corolla campanulate, deep pink to rosy purple, with darker nectar pouches, 35mm. Ovary with a dense tomentum. Capsule shortly cylindrical, c.20 x 7mm.
Habitat: Ridges, etc.
Distribution: China (S Xizang) and adjacent NE India (Delei Valley)
Altitude: 2550-3350m
Type: NE India, Arunachal Pradesh, Delei Valley, 10-11000ft, v 1928, Kingdon-Ward 8251 (iso. E).
Synonymy: R. silvaticum Cowan, Notes R.B.G. Edinb. 19: 185 (1936). Type: SE Xizang, Pemako, 9-10000ft, 24 x 1924, Kingdon-Ward 6258 (holo. E).
Occurs in Countries: CN, IN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: pink, purple
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):332
Much branched prostrate or erect shrub to 1 m. Leaves 4-20(-25) x 2-7(-9) mm, oblong-elliptic to elliptic-ovate, apex obtuse or rounded, mucronate (sometimes obscurely so), base cuneate, undersurface fawn to ferrugineous, the contiguous scales bicolorous, either straw-coloured to fawn, or ferrugineous, the two colours occurring in various proportions. Inflorescence 3-6-flowered, pedicels lepidote, 3-12 mm. Calyx 1-2 mm, lobes deltoid, variably lepidote, margin ciliate. Corolla violet-rose to purple or sometimes white, broadly funnel-shaped, pubescent in the throat, (6-5-)7-5-14(-15) mm, tube (1-5-)2-5(-6) mm. Stamens 5-10, filaments pubescent towards the base. Ovary lepidote, style 10.5-15 mm, exceeding the stamens, glabrous. Capsule ovoid, 4-6 mm, lepidote.
Distribution: Scandinavia, ussr (Siberia), usa (Alaska), Canada, Greenland, with outliers in c USA and Canada (British Columbia)
Synonymy: Azalea lapponica Linnaeus, Sp. PI. 151 (1753). Described from Lapland. A. ferruginosa Pallas, Fl. Ross. 2: pi. 70 fig. 1A, B (1788). R. parvifolium Adams, Nouv. Mem. Soc. Nat. Mosc. 9:237 (1834). R. palustre Turczaninow in Bull. Sci. Nat. Mosc. 11:96 (1838). R. parviflorum F. Schmidt, Fl. Sachal. 158 (1868).. Azalea parvifolia (Adams) Kuntze, Rev. Gen. 2:387 (1891). R. confertissimum Nakai, Bot. Mag. Tokyo 31:239 (1917)
Occurs in Countries: CA, GL, RU, US Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: purple, white
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):107
Shrub, l-2m; young shoots densely clothed with a mixture of adpressed villose and flattened strigose hairs. Leaves dimorphic, deciduous to ± persistent, subcoriaceous; spring leaves obovate to elliptic, 2~~4 x 1.2-2cm, 1.7-2.5 x as long as broad, apex rounded to acute, mucronate, base cuneate, margin entire, both surfaces with sparse adpressed greyish-brown strigose hairs; summer leaves oblong-obovate to oblan-ceolate, 13-40 x 4-20mm, up to 4 x as long as broad, otherwise as for spring leaves; petioles 2~4mm, adpressed-strigose. Inflorescence 2-3-flowered; pedicels c.5mm, densely covered with whitish flattened hairs. Calyx 2-3mm, densely strigose, lobes 1-3mm. Corolla funnel-shaped, pink, c.20mm; tube c.7mm long, glabrous. Stamens 10, c. as long as corolla, filaments papillate below middle. Ovary densely strigose; style strigose below. Capsule ovoid, c.8mm, strigose.
Habitat: Mountain sides
Distribution: China (Taiwan)
Altitude: 2375-3350m
This species is allied to R. rubropilosum but differs in its larger, often obovate, leaves, etc.
The type specimen of R. sasakii was said to be red-flowered whereas the flowers of R. lasiostylum are pink. However, the type specimen of R. lasiostylum is poor, making its true identity uncertain. We therefore follow Wilson's concept of the species that is apparently based on Wilson 10020 (BM!, K!).
Type: Taiwan, in monte Randaisan, vi 1911, Mori s.n. (holo. TI, n.v.)
Synonymy: R. sasakii Wilson, J. Arnold Arb. 6: 181 (1925). Type: Taiwan, Nanto Prov., Horisha, planted in a hotel garden, apparently collected in the wild (holo. A).
Occurs in Countries: CN, TW Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: pink
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):124
Shrub to 7 m high, young branches glabrous. Leaves glabrous; blades broadly elliptic or obovate to elliptic-lanceolate, 50-100 x 18-50mm, base cuneate, apex shortly or long acuminate, coriaceous; petiole 5-12 mm long. Inflorescence buds lateral, 1-flowered, clustered near the ends of leafy shoots; outer bud scales short, inner elongate (c.20mm long), shining, glabrous except for minute hairs or glands on the margin and apex, persistent; pedicels glabrous, c.20 mm long. Calyx lobes 5, minute, glabrous. Corolla pink with darker spots on the upper lobe, glabrous, with a short tube (c.lOmm long) and broad spreading lobes (c.27mm long). Stamens 10, filaments slightly villose near the base, exserted. Ovary cylindric, c.7mm long, glabrous, 5-locular; style c.30mm long, glabrous. Capsule narrowly cylindric, falcate, c.30-40 x 4-5 mm.
Distribution: China (Hubei, Guizhou, Hunan, Guangdong, Fujian, Jiangxi, Thejiang), Japan (Ryukyu Islands).
The original localities of R. latoucheae and R. wilsonae were far apart (Fujian and Hubei respectively) so that the presence or absence of a fringe of glandular hairs on the margins of the flower bud-scales was regarded as adequate specific distinction. However, their combined ranges are now known to stretch over seven adjacent provinces. Consequently, this small difference is not considered to justify the separation of R. wilsonae as a species as no other distinctive character can be recognized in support of it. For notes on R. latoucheae and R. wilsonae see Fang (1939).
We record this species from the Ryukyu Islands on the basis of a specimen collected on Ishigaki Id, Mt Omotodake by Idzumi & Togashi s.n. This has the typical 1-flowered inflorescence and short tube of this species. The resemblance to R. latoucheae of some 1 -flowered specimens from Taiwan has been commented on (see Hui-Lin Li, 1963). It is possible, therefore, that this species also occurs in Taiwan. We have not seen the type of R. amamiense (also from the Ryukyu Islands) but it is treated as a synonym of R. latoucheae because of its 1-flowered inflorescence and short corolla tube. We are grateful to Dr John Rouse of Melbourne for information about this plant which he has in cultivation.
Type: China, Fujian, les montagnes autour de Kuatin, M & Mme de la Touche, n.v. Syn.: R. wilsonae Hemsley & Wilson, Kew Bull. 1910:116 (1910). Type: China, Hubei, in woods, 1700-2000m, Wilson 317 (holo. K). R. amamiense Ohwi, Acta Phytotax. Geobot. 6:49 (1937). Type: Japan, Ryukyu Islands, Mt Eboshidake, Amamioshima, Z. Tashiro (holo. KYO-n.v.).
Occurs in Countries: CN, JP Subgenus: Azaleastrum Habit: Non-Tree
Philipson, W.R. & Philipson, M.N. (1986) A Revision of Rhododendron III. Subgenera Azaleastrum, Mumeazalea, Candidastrum and Therorhodion. Notes from the Royal Botanic Garden Edinburgh 44(1):11
Small shrub, usually up to 0-6 m, rarely taller; leaf-bud scales usually persistent but not very conspicuous. Leaves oblong to ovate or almost orbicular, 11-17 x 6-9 mm, rounded or tapered to the base, rounded to the slightly mucronate apex, dark green or brownish and elepidote above, dark chocolate-brown beneath with dense, overlapping scales borne in 2-3 tiers, those of the lowermost tier as dark as, or darker than, the others. Inflorescence dense, many-flowered. Calyx lobes 5-6 mm, oblong, narrowly elliptic or obovate, densely lepidote outside, ciliate with long, loriform cilia and pubescent inside. Corolla white or pink, rarely yellowish, tube 4.5-11 -5 mm, lobes 3.5-6 mm, tube laxly to densely pilose outside, mouth of the tube densely pilose inside. Stamens 5-6. Ovary lepidote or lepidote and rather sparsely puberulent. Capsule very small
Two rather intergrading varieties can be distinguished
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: pink, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):160
Habitat: Rocky hillsides
Distribution: China (SE Xizang)
Altitude: 4250-4550m
Type: China, S Tibet, Tsari, Lapu, 15000 ft, Ludlow <& Sherriff 2160 (holo. BM, iso. E)
Habitat: Moraines and open slopes
Distribution: China (SE Xizang)
Altitude: 2900-4700m
Type: China, S Tibet, Doshong La, 12-13000 ft, 24 vi 1924, Kingdon Ward 5848 (holo. E)
Shrub, c.3m; young shoots setulose. Leaves broadly oblong, 4.5-6 x 2.5-3cm, 1.8-2 X as long as broad, apex rounded, apiculate, base rounded to sub-cordate, lower surface with lamina glabrous though probably with a few scattered glands, midrib setulose, at least below; petioles 5-10mm, with a dense setulose, probably also glandular, tomentum. Inflorescence 3-flowered; rhachis minute; pedicels 12-15mm, densely setulose-tomentose. Calyx c.3mm, tomentose. Corolla open-campanulate, purple, 30-35mm. Stamens with filaments coarsely papillate below. Ovary densely setulose-tomentose; style glabrous. Capsule not known.
Distribution: China (E Guizhou). Only known from the type
This interesting new species is probably most closely allied to R. williamsianum, though with a dense indumentum on the petioles and the lower surface of the leaf midribs as in subsection Maculifera, that is however not as dendroid and matted as is usual in that subsection.
Type: China, Guizhou, Leishan Xian, Leishan, 1850m, 29 iv 1959, Cao, S. Y. 909 (holo. SZ)
Occurs in Countries: CN Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: purple
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):261
Shrub 0-5-1-5 m. Young growth lepidote and densely loriform-setose. Leaves evergreen, coriaceous, revolute, with long-persistent bluish bloom, obovate or obovate-elliptic, ± rounded at apex and base, 30-35 x 15-18 mm, loriform setose with straight setae beneath and on margins and petiole; scales equal, golden, distant, upper surface glabrous and elepidote. Inflorescence 2(-3)-flowered, pedicels c. 20 mm, loriform-setose and lepidote. Corolla 20-33 mm, tube 10-12 mm, clear yellow, sometimes with orange spots, lepidote and sparsely loriform-setose outside. Ovary densely setose as well as lepidote, style lepidote at the base or more usually elepidote. Capsule cylindric, c. 10 mm, the loriform setae usually persistent at least in part.
Habitat: Boulders, cliffs and ledges
Distribution: China (SW Yunnan)
Altitude: 3050-3650m
Illustrations:
The bluish, coriaceous leaves make this the most easily recognised species of the subsection. In the type the style is slightly lepidote at the base; in other specimens it is completely elepidote.
Type: China, Yunnan, summit of Jangtzow shan, Shweli/Salween Divide, 11-11500 ft, vi 1919, Forrest 18143 (holo. E)
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: orange, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):152
Small, evergreen shrub to 2 m. Young shoots densely lepidote. Leaves narrowly elliptic, obovate or rarely lanceolate, coriaceous or subcoriaceous, (6-)10-24(-30) x (3-)4-12(-16) mm, dark green and usually densely lepidote with variably persistent scales above, pale greyish green beneath with distant to overlapping, large, brownish scales with translucent rims. Inflorescences 1-2-flowered, pedicels lepidote, (10-)12-25 mm. Calyx lobes variable in shape, ovate or oblong, rarely spathulate, rounded, (2-)3-4 mm, greenish or reddish, lepidote. Corolla white, yellow, pink, red or various shades of purple, often spotted darker, (10-)12-15(-17) mm, tube to 7(-8) mm, usually densely lepidote outside. Ovary lepidote. Style very short, deflexed. Capsule lepidote, ± cylindric, 4-6 mm.
Habitat: Moorland, slopes, open forest
Distribution: India (Kashmir, Punjab, Himachal & Uttar Pradesh, Sikkim, W Bengal, Assam, Arunachal Pradesh), Nepal, Bhutan, ne Burma, China (NW & NW Yunnan, S & SE Xizang)
Altitude: 2450-4550m
Illustrations:
A very widespread and variable species. Leaf size and shape are particularly variable, and a number of segregates have been described on the basis of these characters: R. obovatum with large, obovate leaves, R. elaeagnoides with small, elliptic leaves, and R. salignum with long, narrow leaves. Hooker was uncertain about their distinctness when he described them, and the copious material now available shows that the various forms are linked by numerous intermediates and that the variability follows no geographical pattern; nor does it correlate with the equally wide variation in corolla colour.
Type: Nepal, Gossainthan, Wallich (holo. K, iso. E)
Synonymy: R. elaeagnoides Hooker, Rhodo. Sikkim Himalaya t. 23 (1849). Type: mountains of Sikkim Himalaya, 14-15000 ft, Hooker (holo. K, iso. E). R. ohovatum Hooker, op. cit., consp. 6. Type: Sikkim Himalaya, Lachoong valley, 12000 ft, Hooker (holo. K, iso. E). R. salignum Hooker, op. cit. t. 23A. Type: Sikkim Himalaya, above Choongtam, 7000 ft, Hooker (holo. K, iso. E). R. sinolepidotum Balfour f., Notes R.B.G. Edinb. 10:155 (1917). Type: China, Yunnan, Likiang, Delavay 18 (holo. E). R. cremnastes Balfour f. & Farrer, Notes R.B.G. Edinb. 13:253 (1922). Type: NE Upper Burma, Chimili, 11000 ft, Farrer 1196 (holo. E)
Occurs in Countries: BT, CN, IN, MM, NP Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: pink, purple, red, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):149
Shrub to 3m, with thick roots and often hanging branches. Twigs c.1.5mm in diameter, slender, densely covered with red-brown, stellate scales when young, glabrescent and a little rough in older parts; internodes 2–12cm. Leaves mostly 3–4 together in tight pseudowhorls. Blade 25–65 x 14–30mm, ovate or broadly elliptic; apex broadly acute, obtuse or rounded; margin entire, flat or weakly revolute; base rounded, to sub-cordate; equally sub-densely scaly on both sides. Scales small, deeply stellately divided and shortly dendroid, each on top of minute paler, often nearly white tubercles beneath, the tubercles less distinct on the upper surface, quickly glabrescent above, more slowly beneath. Mid-vein weakly impressed above, strongly prominent beneath; lateral veins 5–7 per side, straight, anastomosing near the edge, slightly impressed above, somewhat raised beneath, reticulation lax, visible above, smooth to distinctly raised or inconspicuous beneath. Petiole 2–5 x 2–3mm, grooved above, densely brown-scaly. Flower buds ovoid, to 14 x 8mm, predominantly green with all the bract tips appressed, with a few brown scales outside near the apices and along the midline of the bracts especially near the base of the bud. Bracts to 12 x 6mm, ovate to spathulate; outer smaller ones sub-subulate, upper ones mucronate. Bracteoles to 15 x 2mm, linear-spathulate, glabrous. Inflorescence 2–5-flowered, in open one-sided umbels, the flowers semi-erect to half-hanging. Pedicels 7–15 x 1.5–2mm, pale green but densely brown-scaly. Calyx to 5mm in diameter, a low circular disc, or very shortly obtusely 5-toothed. Corolla 25–35 x 25–35mm, tubular, zygomorphic, deep pink; tube 25–30 x 7–8 x 10–13mm, curved, laxly to sub-densely, stellately scaly outside, glabrous inside; lobes 12–15 x 10–15mm, broadly spathulate to sub-circular, mostly emarginate, often with scales on the central basal areas outside. Stamens clustered on the upper side of the corolla, exserted c.8mm; filaments red, narrowly linear, glabrous or with some scattered hairs; anthers c.1.6 x 1mm, brown or dark purple. Disc glabrous. Ovary 5–6 x 2–3mm, elongate-conical, densely brown-stellate-scaly, gradually tapering distally; style held on the upper side of the corolla tube, pink, stellate scaly almost to the top; stigma broadly club-shaped, becoming exserted to c.6mm, positioned on the upper side of the tube. Fruit 30–40 x 4–6mm, fusiform, often curved, densely brown stellately scaly. Seeds 8mm, without tails c.1mm, the longest tail 4mm.
Habitat: Terrestrial on rocks or exposed cliff faces, epiphytic on big branches of high trees or growing on fallen trunks in mossy forest. Sometimes common.
Distribution: Papua New Guinea, Madang to Milne Bay Districts.
Altitude: 1370-2250m
Greek – leptos – thin; anthos – flower. Thin flowered.
Type: McGregor 1889. New Guinea (E), Southeastern part, Central District, Summits of Owen Stanley Range (MEL).
Occurs in Countries: PG Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: pink
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:90
Shrub or small tree with slender branches to 3m. Twigs rounded, 1.5–3mm in diameter, laxly silvery scaly, becoming glabrescent, often pink when fresh, whitish in dry specimens, with distinctive slender, acutely pointed lateral buds with subulate tips to the scales; internodes 3.5–12cm. Leaves 4–7 together in tight pseudowhorls at the upper 1–2 nodes, 1–2 additional sometimes on the internodes. Blade 55–90 x 18–28mm, narrowly elliptic; apex shortly acuminate, acute; margin entire, flat or only very slightly revolute; base acutely tapering, densely scaly on both sides when young, glabrescent and minutely blackish punctate above with age, more persistently and laxly scaly beneath. Scales small, with a relatively wide marginal zone which quickly disintegrates, sub-stellately lobed; centre minute and slightly impressed, blackish with age. Mid-vein narrow and impressed above, strongly and obtusely prominent beneath, often pale whitish; lateral veins 6–10 per side, irregular, spreading, obscurely arching inwards, with additional shorter intermediate veins all minutely impressed, inconspicuous above, more distinct beneath. Petiole 10–20 x 1.5–1.8mm, compressed and weakly grooved above, scaly. Flower buds to 20 x 11mm, ovoid, or narrowly ovoid, smooth, bright red. Outer bracts to 20 x 10mm, ovate to ovate-oblong, inner ones spathulate, very densely hairy outside, glabrous except for the sparsely hairy base inside. Bracteoles 15–20 x c.0.6mm, linear, densely hairy. Inflorescence 4–10-flowered, an open umbel, the flowers half-hanging. Pedicels 10–24 x c.1.25mm, pink, slender, laxly scaly, without hairs. Calyx 3–4mm in diameter, obliquely disc-shaped, shallowly 5-lobed, densely scaly outside. Corolla 30–40 x c.30mm, tubular, bright glossy red; tube 25–27 x 6–8 x 6–8mm, cylindrical, straight, very prominently and deeply sulcate in the proximal ½, laxly or very laxly scaly especially towards the base outside, sub-densely very shortly hairy inside; lobes 10–14 x 9–11mm, broadly obovate or sub-circular, 1⁄3–½ overlapping, half-spreading. Stamens irregularly arranged, exserted to c.10mm; filaments linear, pink, densely sub-patently hairy in the proximal 2⁄3, glabrous distally; anthers 2–3 x c.1mm, obovate-oblong. Disc prominent, glabrous. Ovary 4–6 x 2–3mm, sub-ovoid-cylindrical, densely sub-patently hairy and scaly, tapering distally; style slender, pale pink, nearly as long as the stamens and depressed to the lower side of the tube, hairy in the proximal ½, sparsely, or not scaly; stigma globose. Fruit 20–30 x 5–6mm, cylindrical, slightly curved, sub-densely hairy and scaly. Seeds 3.8mm, without tails 0.8–1mm, the longest tail 1.8mm, the tails highly crimped.
Habitat: In mossy forest, locally common.
Distribution: Indonesia, Sulawesi (C), Mt Pokapindjang, Mt Rantemario.
Altitude: 2000-3000m
Greek – lepto – thin or slender; brachium – arm. Described as having slender branches.
Type: Eyma 647, 16 June 1937. Celebes (C): Enrekang, Pokapindjang-Tinábang (L, A, BO, K, SING).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:289
Shrub to 2m. Twigs 5mm in diameter, densely stellate-scaly at first, glabrescent and smooth later. Leaves c.4 together in pseudowhorls. Blade 20–30 x 7–10mm, narrowly elliptic or elliptic; apex shortly acuminate, sub-acute; margin cartilaginous, slightly revolute, wavy and sub-crenulate; base tapering; glabrescent and rugulose above at maturity, brown and sub-densely scaly beneath. Scales flat, irregularly crenate or sub-stellately lobed in the marginal zone; centre large and impressed. Mid-vein very narrowly impressed proximally on the upper surface, prominent beneath; lateral veins darker coloured, inconspicuous. Petiole 3–5 x c.0.8mm, nearly rounded, scaly. Flowers solitary. Pedicels 15–20 x c.0.6mm, densely stellate-scaly, less densely shortly hairy. Calyx c.4mm in diameter, disc-shaped, membranous, reflexed and obscurely lobed. Corolla 30mm, tubular, scarlet, slightly oblique; tube 19–22 x c.6 x c.10mm, almost straight, lobed at the base, glabrous or with a few stellate scales at the base outside, glabrous inside; lobes 8–10 x 7–9mm, broadly obovate-spathulate to sub-circular. Stamens exserted to c.5mm, unequal; filaments linear below, filiform distally, glabrous; anthers c.2.5 x 1.2mm, broadly oblong. Disc prominent, glabrous. Ovary c.4 x 1.8mm, sub-cylindrical, densely shortly yellowish hairy, no scales visible, gradually tapering distally; style c.23mm, thick, glabrous, slightly exceeding the stamens; stigma rounded.
Habitat: Terrestrial shrub on the summit
Distribution: Indonesia, Sulawesi, Poso area, Mt Lumut.
Altitude: Around 2280m
Greek – lepto – thin; morphe – form. Both the plant and the flowers are described as slender on the collecting label.
Known only from the type collection.
Type: Eyma 3617, 5 Sept. 1938. Celebes (E), Menado, O. a Poso, Mt Loemoet, pilaar-top en W. bijtop (summit), c.2280m (BO, L, fragment).
Occurs in Countries: ID Altitude Ranges: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: scarlet
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:212
Shrub or small tree, 6-9m. Leaves oblanceolate, 9-14 x 3-4cm, 3-3.7 X as long as broad, apex acuminate, base rounded, margin not undulate, upper surface glabrous when mature, lower surface with a veil of persistent dendroid hairs embedded in a surface film, with numerous red punctate hair-bases overlying the veins; petioles 1-1.5cm, glabrous. Inflorescence c.lO-flowered; rhachis c.5mm; pedicels c.20mm, stipitate-glandular. Calyx 4-6mm, lobes rounded, sparsely glandular. Corolla campanulate, glabrous within, white flushed rose to rose, with crimson flecks, 40-45mm. Ovary glandular but not tomentose; style glabrous. Capsule not known.
Habitat: Rhododendron forests
Distribution: China (NW Yunnan)
Altitude: Around 3000m
Close to R. tanastylum var. pennivenium but sufficiently distinct to be maintained as a separate species.
Type: China, Western NW Yunnan, Mekong/Salween divide, 13000ft, v 1918, Forrest 16352 (holo. E; iso. K)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: crimson, rose, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):302
Shrub to 8 m, minutely puberulous on the young branches, petioles and upper mid-ribs. Leaves narrowly elliptic to lanceolate, rounded or cuneatc at the base, tapering to a sub-acute or emarginatc apex, mucronate, 35-120 x 17-36 mm, slightly coriaceous, reticulation of veins evident; petiole 10-15 mm long. Inflorescence buds lateral, 1-flowered, clustered near the ends of the leafy shoots; outer bud scales short, inner elongate (c. 12-14 mm long); pedicel c. 15-25 mm long, puberulous and with glandular hairs. Calyx lobes usually oblong, obtuse, or ovate (3-5-)6-8 x (2-5-)3-4mm, variously fringed with fine hairs and/or glandular hairs or almost glabrous. Corolla rose to magenta purple with darker markings, glabrous or the tube minutely puberulous on the outside and/or within, rotate with a short tube and spreading lobes, up to c.50mm across. Stamens 5, filaments hairy below. Ovary subglobose, c.2 ï 5 mm high, with setose and glandular hairs, 5-locuIar; style glabrous. Capsule broadly ovoid, 6-8 x 5-6 mm, verrucose.
Habitat: In open scrubland and in deciduous and pine forests
Distribution: China (NW Yunnan, adjacent parts of Sichuan and Xizang), NE Upper Burma.
Altitude: 2250-3550m
Illustrations:
The limited range of R. leptothrium is well separated both geographically and altitudinally from that of R. ovatum. Its range in the south-cast overlaps with that of R. ngawchangense; see under that species for distinguishing features.
Type: China, Yunnan, Litiping, 11 000 ft, vi 1917, Forrest 13881 (holo. E)
Occurs in Countries: CN, MM Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Azaleastrum Habit: Non-Tree Fl. Colour: magenta, purple
Philipson, W.R. & Philipson, M.N. (1986) A Revision of Rhododendron III. Subgenera Azaleastrum, Mumeazalea, Candidastrum and Therorhodion. Notes from the Royal Botanic Garden Edinburgh 44(1):5
Shrub to 1 m. Young shoots densely loriform-setose, the setae straight, not twisted and matted. Leaves broadly elliptic, 30-45 x 18-22 mm, apex obtuse, base cuneate, ± persistently loriform-ciliate, upper surface densely loriform-setose, lower surface with vesicular scales sunk in crenulately margined pits, inflorescence 1-2-flowered, pedicels lepidote, short, sometimes sparsely loriform-setose and pubescent. Calyx lobes obovate, 7-8 mm, greenish or often reddish, loriform-ciliate, not or scarcely iepidote except on the tube. Corolla very broadly campanulate to almost rotate, white, often tinged pinkish, 25-30 mm, tube 8-11 mm, lepidote outside, particularly on the lobes, pilose within. Ovary lepidote. Capsule lepidote, up to 10 mm.
Habitat: Grassy, scrubby slopes, rarely epiphytic
Distribution: China (S Xizang—Tsangpo gorge)
Altitude: 2450-3050m
Illustrations:
Type: A cultivated specimen said to be derived from seed of Kingdon Ward 6273 (iso. E)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Rhododendron Habit: Epiphyte, Non-Tree Fl. Colour: pink, white
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):138
Shrub to 3m, erect, few-branched. Twigs 5–12mm in diameter, densely stellate-scaly at the new shoots, early glabrescent; internodes 3–20cm. Leaves 3–6 together in pseudowhorls, spreading. Blade 180–280 x 60–105mm, elliptic, narrowly elliptic or slightly obovate; apex broadly acute, obtuse or rounded; margin entire, narrowly cartilaginous and revolute; base truncate to cordate; when young, stellately scaly, becoming glabrescent on both sides. Scales of two different types: sub-dendroid, stellately lobed, reddish-brown fragile ones, and flat, smaller, paler, less deeply dentate and longer persistent ones, the impressions of these small ones found on the mature leaves beneath. Mid-vein raised above in the proximal ½ and grooved, flat or slightly impressed distally, below strongly raised for most of the length, tapering gradually; lateral veins 9–12 per side, narrowly grooved above, becoming slightly raised when dry, beneath flat or very slightly raised, curved-ascending, joining before the margin, reticulation obscure when fresh, prominent above when dry. Petiole 7–20 x 4–5mm, somewhat flattened, not grooved above, scaly when young, upwardly directed, close to the stem to make the leaves appear sub-sessile. Flower buds to 80 x 40mm, ovoid, dark purple. Bracts to 80 x 40mm, outer bracts ovate, apiculate, inner ones obovate to spathulate, covered with short, appressed hairs and scales outside, and by longer hairs inside. Bracteoles to 85 x 1–2mm, densely hairy at the base, becoming laxly hairy and glabrous distally, also laxly scaly with long-stalked fragile scales, linear, pink. Inflorescence 5–8-flowered, an open umbel, the flowers semi-erect to half-hanging. Pedicels 10–15 x 5–6mm, densely scaly. Calyx 7–9mm in diameter, rim-like, scaly and hairy on the margin, sometimes with irregular linear lobes up to 8 x 2mm. Corolla 7-lobed, c.140mm, tubular-funnel-shaped, white with pale pink on the tube and at the junctions of the lobes, strongly scented; tube 60–100 x 8–12 x 30–35mm, straight, sub-densely to sparsely stellate-scaly outside, densely hairy inside; lobes 50–60 x 25–40mm, spreading, obovate, apex emarginate or rounded, edge crenulate. Stamens 14, exserted to 10mm; filaments hairy; anthers 7–12 x c.1.5mm, linear, base obtuse. Disc densely hairy. Ovary 15–18 x 6–10mm, cylindrical, dense hairs covering scales; style c.70 x 2mm, hairy and scaly in the proximal ½ the hairs becoming laxer distally, densely scaly only in the distal ½, sometimes with a short, glabrous zone below the stigma. Fruit 140–160 x 10–18mm, fusiform, densely covered with hairs and scales; stigma large, 7-lobed. Seeds 8–9.5mm, without tails 1.5–2mm, the longest tail 4.5mm.
Habitat: Epiphytic on tree trunks in riverine forest or in sub-mossy Nothofagus forest. Said to be common locally.
Distribution: Indonesia, New Guinea (W), Cycloop Mts. Papua New Guinea, Hunstein Range?
Altitude: 1000-1500m
Greek – leuco – white; gigas – a giant. Alluding to the enormous flowers.
The original description of the species described the bracteoles as glabrous; the Edinburgh plant which was from Sleumer’s original collection has distinctly hairy bracteoles as has the specimen grown at Boskoop. The scales which are described as being of two types are mostly from a completely level epidermis but some are from minutely elevated protuberances similar to, but much smaller than, those generally found in section Phaeovireya.
Type: Royen & Sleumer 5981, 24 June 1961. New Guinea (N), Cycloop Mts, S slope of the central part along path Ifar-Ormu, camp site, 1220m (L).
Occurs in Countries: ID, PG Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:316
Shrub, 3-4 m. Leaves oblong-obovate, broadly tapered to the base, truncate at the apex, 60-65 x 28-30 mm, petiole and at least the lower part of the margin loriform-setose, lower surface brownish with rather dense, sub-contiguous, slightly unequal golden scales. Inflorescence 1-3-flowered, pedicels lepidote, c. 10 mm. Calyx conspicuous, deeply 5-lobed, the lobes oblong, obtuse to rounded, c. 8 mm, sparsely lepidote outside. Corolla white, funnel-campanulate, c. 45 mm, the tube 20 mm, sparsely lepidote outside. Stamens 10, filaments pubescent towards the base. Ovary densely lepidote, tapering into the style which is lepidote at the base. Capsule unknown.
Habitat: Hillsides and rock crevices,
Distribution: China (Guangdong)
Altitude: Around 950m
Illustrations:
Type: China, Kwangtung, Loh Fau Mt., c. 950 m, Merrill 10952; ibid., CCC (Levine) 1330 (isosyntype E)
Occurs in Countries: CN Altitude Ranges: 0 - 1,000m Subgenus: Rhododendron Habit: Non-Tree
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):40
Named after the island on which it was first found.
Type: Ramos B.S. 15252, 23 Aug. 1912. Philippines, Leyte, Mt Ibuni, back of Dagami (PNH†, BM, E, K, L, P).
Synonymy: R. flaviflorum Elmer ex Merr., En. Philip. 1923. 3: 244, in obs. pr. R. leytense.
Occurs in Countries: PH Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Vireya Fl. Colour: yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:282
Shrub to 2m. Twigs 3–4mm in diameter, rounded, green, laxly to densely covered with brown scales, glabrescent; internodes 1.5–5cm. Leaves 3–6 together in dense to lax pseudowhorls. Blade 40–100 x 15–38mm, elliptic to sub-obovate-elliptic; apex shortly and bluntly acuminate; margin entire, flat, often red; base tapering, sometimes slightly decurrent; laxly sub-stellately scaly on both sides at first, glabrescent above, laxly and sub-persistently scaly beneath, the scales denser along the mid-vein. Scales small, marginal zone deeply and irregularly lobed; centre shallowly impressed. Mid-vein slightly prominent in the proximal ½ above, and minutely hairy, becoming glabrous, smooth or narrowly impressed into a groove distally, beneath shallowly and broadly raised for most of its length; lateral veins 5–8 per side, straight or ascending, inconspicuous especially beneath, reticulation not visible. Petiole 6–16 x 2–3mm, not grooved, scaly, densely shortly hairy above and sometimes with a few minute papillae, slightly flattened. Flower buds to 30 x 20mm, narrowly ovate, acute, pale green. Bracts ovate, acuminate, glabrous, to 25 x 10mm. Bracteoles linear, to 11 x 0.5mm, glabrous. Inflorescence an open umbel of 3–5 flowers, held semi-erect to horizontal. Pedicels 10–15 x 2mm, shortly hairy, without, or with just the occasional scale. Calyx c.3mm in diameter, rim-like, densely short-hairy. Corolla 33–35 x 35–40mm, broadly tubular-funnel-shaped or sub-campanulate, yellow, without scent, lobed c.1⁄3–½; tube 20–21 x 5–6 x 12–15mm, straight, sulcate near the base, glabrous outside, very laxly hairy proximally inside; lobes 15–18 x 12–15mm, obovate, overlapping 1⁄3–½, spreading, the distal ½ reflexed. Stamens 27–30mm, irregularly arranged all round the mouth or sometimes in two groups on either side towards the lower side of the mouth, unequal, exserted to c.10mm; filaments broad and hairy at the base or up to 1⁄3, filiform and glabrous distally; anthers 2–2.5mm, oblong, yellow, base rounded or minutely apiculate. Disc hairy on the upper side or occasionally all over. Ovary c.7 x 2mm, sub-cylindrical, tapering distally, densely short-hairy and with minute scales hidden by the hairs; style hairy and scaly in the lower ¼, glabrous distally or completely glabrous, lying on the lower side of the mouth; stigma c.2mm in diameter, rounded or deeply 5-lobed. Fruit 30 x 6mm, fusiform, the valves spreading and twisting. Seeds 7mm, without tails 0.9mm, the longest tail c.3mm.
Habitat: Mossy forest, and open shrubberies, both terrestrial and epiphytic
Distribution: Philippines, Luzon, Leyte, Mt Lobi near Dagami; Mindanao, Camiguin Island, Mt Hibok-hibok.
Altitude: Around 1000m
Differs from the type by the shorter corolla, only c.30mm long, and anthers with appendages at the base.
Distribution: Philippines.
Named after the collector, August Loher, a German who lived for many years in the Philippines and made many collections of plants there.
Known only from the type collection.
Type: Loher 14769, 27 March 1913. Philippines, Luzon, Rizal, Guinuisan (PNH†, E, UC).
Shrub to 3 m or more. Leaves oblong-elliptic or narrowly oblong-elliptic, tapering to a rather abruptly rounded apex, narrowing to the base, 100-130x 31-50 mm, petioles loriform-setose when young, the setae variably deciduous, undersurface brownish or greyish green with unequal brownish scales about their own diameter apart. Inflorescence 2-3-flowered, pedicels 10-15 mm, apparently accrescent in fruit, densely lepidote. Calyx conspicuous, lobed from Vi-lA of its length, the lobes broadly deltoid or oblong, rounded at the apex, 10-12 X 6 mm, accrescent in fruit and becoming papery, lepidote at the base only. Corolla narrowly funnel-campanulate, white, 60-80 mm, tube 40-55 mm, the whole rather densely lepidote outside. Stamens 10, filaments pubescent in the lower part. Ovary lepidote, tapered into the style which is lepidote in the lower part. Capsule lepidote, cylindric-fusiform, 30-35 x 12 mm, exceeding the persistent calyx, weakly 5-ridged.
Habitat: Scrub, rocky slopes, open forest
Distribution: China (Guizhou, Guanxi)
Altitude: 600-1400m
Illustrations:
I have seen no material of R. chunienii Chun & Fang, Acta Phytotax. Sinica 6:169, 1957 (Type: Kwangsi, Lingshan hsien, Tati hsiang, Tienping chuen, 20 v 1955, Kwangfu Exped. 235). From the description and photograph of the type (op. cit. t. 40), it is very similar to R. liliiflorum, but is described as having only 5 stamens.
Type: China, Kouy-Tcheou, Pin-fa, Juin-ou-chan, 3 vi, 15 vii 1902, Cavalerie 54 (holo. E)
Occurs in Countries: CN Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: white
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):38
Named after G. Lindau, German botanist.
Type: Römer 1043, 30 Nov. 1911. New Guinea (W), Hellwig Mts, Erica Top, c.2500m (BO, lectotype, L, fragment).
Occurs in Countries: ID, PG Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Fl. Colour: pink, red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:59
Differs from the typical variety by longer calyx lobes (c.1mm) which are appressed to the corolla. Corolla lobes not ciliate.
Habitat: Summits, in brushwood
Distribution: Indonesia, Sulawesi, (SW) Mt Bantaeng (Peak of Bonthian), Mt Bawakraeng
Altitude: 2800-2890m
Named after the mountain on which it was first collected.
Type: Bünnemeijer 12250, 17 June 1921. Celebes, SW, G. Bantaeng (Peak of Ponthain), 2890m (BO, L).
Shrub to 3m. Twigs rounded, slender, tips densely covered with stalked scales, lower parts rough with the remaining scale stalks. Leaves densely spirally arranged, or in loose to tight pseudowhorls. Blade 8–25 x 5–15mm, obovate to spathulate or elliptic-obovate; apex rounded, often slightly retuse; margin strongly revolute, the lamina often convex; base tapering, dark green above, greyish green below, shiny and laxly scaly becoming glabrescent above, persistently laxly scaly beneath. Scales red-brown, disc-shaped; marginal zone narrow, entire; centre thick, not or slightly impressed. Mid-vein distinctly impressed above, prominent beneath; lateral veins 3–5 per side, the lower 1–2 ascending, upper ones spreading, anastomosing, faintly impressed above, somewhat raised beneath, sometimes hardly visible. Petiole 1.5–2.5mm, scaly and rough. Bracts to 7 x 4mm; outer ones narrowly ovate, sub-acute, scaly outside, inner ones larger, broadly ovate to sub-circular, scaly and/or with grey hairs outside in the distal part and ciliate margins. Bracteoles 6–7 x 1–1.5mm, linear to spathulate, hairy towards the apex. Inflorescence of solitary flowers, or up to 3 together, half-hanging to hanging. Pedicels 7–12mm, slender, densely scaly and often laxly short hairy. Calyx oblique, scaly, obtusely 5-lobed to c.5mm, the lobes spreading, reflexed or appressed to the corolla, sometimes shortly ciliate. Corolla 16–24mm, deep red to pink, tubular, slightly zygomorphic; tube 16–20 x c.2.5 x 4–5mm, laterally compressed, straight, somewhat pouched at the base, laxly scaly all over outside, glabrous inside; lobes 3–5 x c.2.5mm, ovate-elliptic, obtuse, erect or half-spreading, overlapping ¼–½, often with minute hairs near the apex outside and ciliate. Stamens clustered on the lower side of the mouth, slightly, or not, exserted, unequal; filaments filiform, glabrous; anthers 1–1.5mm, blackish purple or brown, oblong-ovate. Disc glabrous or rarely slightly hairy. Ovary c.2.5 x 1.5mm, narrowly ovoid-conical, densely scaly, gradually tapering distally; style 10–13mm, becoming exserted as the flower ages, glabrous, swollen distally to a club-shaped, shortly and irregularly 10-lobed stigma. Fruit 10–18 x 3–4mm, sub-cylindrical, longitudinally grooved.
Habitat: In forests, generally epiphytic, but also terrestrial in swampy or alpine shrubberies, on exposed summits, on poor clay or sandy soil
Distribution: Indonesia and Papua New Guinea. New Guinea from the Arfak Mts in the west to Mt Saruwaged in the east.
Altitude: 1250-3200m
This is a widespread and variable species. The differences between R. lindaueanum and R. erosipetalum do not appear to be significant but there are considerable differences between the west New Guinea and east New Guinea specimens of this species. West New Guinea specimens of R. lindaueanum have larger leaves (more than 15mm), usually in loose to tight pseudowhorls. East New Guinea specimens have much smaller leaves (less than 10mm) which are spirally arranged. More detailed work is required to better understand this problem.
Synonymy: R. lindaueanum var. latifolium J.J.Sm., Nova Guinea 1914. 12(2): 130, t.29A. R. retusum [non (Blume) Benn.] Wernham, Trans. Linn. Soc. London, II, Bot. 1916. 9: 94. R. fuchsioides Schltr., Bot. Jahr. 1918. 55: 147. R. lindaueanum var. psilacrum Sleumer, Reinwardtia 1960. 5: 58. R. lindaueanum var. cyclopicum Sleumer, Reinwardtia 1960. 5: 59.
Epiphytic shrub, 1-4 m. Leaves 85-130 x 29-46 mm, narrowly elliptic to oblong-elliptic, rarely somewhat obovate, tapered or rounded to the base, apex obtuse or rounded, lower surface greyish green with rather distant, somewhat unequal, reddish brown scales. Inflorescence 2-3(-5)-flowered, pedicels 10-17(-25) mm, rather sparsely lepidote. Calyx large, conspicuous, deeply 5-lobed, the lobes pinkish or green, thin, becoming papery in fruit, tube densely lepidote, the lobes narrowly ovate-oblong, rounded at the apex, 11-18 x 5-8(-10) mm, rather prominently veined, conspicuously and persistently filiform-acicular-ciliate, elepidote. Corolla openly funnel-campanulate, (65-)70-95 mm, tube (45-)50-60 mm, white or cream with an orange-yellow blotch at the base, sometimes suffused pink in bud, elepidote or very sparsely lepidote, glabrous or finely pubescent at the base. Stamens 10, filaments pubescent in the lower part. Ovary densely lepidote, tapering into the style, which is lepidote in the lower part. Capsule cylindric-fusiform, weakly 5-ridged, c. 40 mm, much exceeding the persistent calyx.
Habitat: Mostly epiphytic, rarely on rocks, in forests
Distribution: Nepal, India (W Bengal, Arunachal Pradesh, Manipur), Bhutan, China (S Xizang)
Altitude: 2000-2750m
Illustrations:
Type: Bhutan'(i.e. India, Arunachal Pradesh, cf. Ludlow, Trans. Bot. Soc. Edinb. 41:351-363, 1972), Booth (holo. K)
Synonymy: R. bhotanicum C. B. Clarke in Hooker, Fl. Brit. India 3:475 (1882). Type: as for R. lindleyi.
Occurs in Countries: BT, CN, IN, NP Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Rhododendron Habit: Epiphyte, Non-Tree Fl. Colour: cream, orange, pink, white
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):37
Shrub to 2m. Twigs slender, rounded, densely brown-scaly; internodes 1.5–6cm. Leaves 3–7 together in loose pseudowhorls or spirally arranged. Blade 18–30 x 4–7mm, linear to narrowly elliptic, gradually tapering in the distal 1⁄3, the extreme apex obtuse; margin flat or revolute in dry specimens slightly irregular; base broadly tapering to rounded, silvery scaly but quickly glabrescent above, the surface then green; densely brown-scaly beneath. Scales large, of a more uniform size than is typical of species in this section; although larger ones are present, the majority are spaced about one diameter apart with relatively few overlapping. Mid-vein strongly impressed above, slightly prominent beneath (more so in dry specimens); lateral veins obscure. Petiole 2–4 x 1mm, grooved above, densely scaly. Flower buds 7–15 x 4–6mm, ovoid; apex obtuse, bracts all closely appressed. Outer bracts narrowly ovate, inner ones obovate to sub-spathulate, with a broad triangular area of dense brown scales in the centre outside and with green, glabrous marginal areas, margins white ciliate. Bracteoles narrowly linear, ciliate at the top, to 12mm. Inflorescence of 2–6 flowers in an open umbel, the flowers held horizontally to half-hanging. Pedicels 8–10 x 1mm, covered with brown scales. Calyx c.2mm in diameter, small, oblique, disc-shaped, obscurely lobed, densely scaly. Corolla 22 x 27mm, bright yellow but with prominent orange-brown spots from the large scales outside; tube c.10 x 5 x 11mm, but constricted in the middle to 4mm where it is longitudinally fluted, covered in prominent brown scales outside, glabrous inside, straight; lobes 15 x 11mm, brown scaly outside in a broad roughly triangular area from the tube and tapering distally, spreading to c.45°, the upper lobes overlapping to 1⁄3, the two lower, not overlapping. Stamens loosely and irregularly arranged all round the flower, or on the lower side; filaments pale yellow, filiform above, dilated towards the base, densely white-patent-hairy in the proximal 3mm; anthers brown, exserted to c.10mm, c.3 x 0.5mm, cells pointed at the base. Disc thick, glabrous. Ovary 4–5 x 1.5–2mm, sub-cylindrical, densely scaly, gradually tapering distally; style thick, translucent pale yellow and almost as long as the corolla, scaly in the proximal ½, glabrous distally; stigma thick, pale yellow, curved to the lower side of the flower, 5-lobed. Fruit 15–25 x 3–3.5mm, cylindrical, densely brown-scaly; valves reflexing back against the pedicel and often twisting; placentae splaying out and often breaking away from the base. Seeds 58–63mm, without tails 0.9–1mm, the longest tail 25–27mm, the tails very slender, filiform, sometimes crimped.
Habitat: A high epiphyte in dipterocarp and mossy forest, occasionally on moss-covered ground
Distribution: Widespread in western Borneo. Presently recorded from: Malaysia, Sarawak, Mt Buri, Mt Dulit, Mt Lupar, Bt Sagan, Mt Mulu. Brunei, Bt Bedawan.
Altitude: 360-1230m
Latin – linearis – a long and narrow parallel-sided shape, alluding to the leaves.
A dainty species in cultivation, first introduced in 1982 from Mt Buri in Sarawak by Ian Sinclair. It is of weak growth but always admired with its relatively large bright yellow flowers which are prominently spotted with large brown scales outside. It flowers irregularly about twice a year in spring and autumn with the flowers opening in succession.
Type: Native Collector, B.S. 1161. Sarawak, without locality (PNH†, K).
Occurs in Countries: MY Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: orange, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:120
Shrub to 1.5m. Twigs c.5mm in diameter, rounded, glabrous or sparsely scaly, with large flat fragile scales. Leaves spirally arranged with conspicuous, spherical buds in the upper axils. Blade 100–120 x 40–60mm, elliptic, apex sometimes shortly acuminate, broadly acute to obtuse; margin narrowly but distinctly revolute; base broadly tapering, occasionally rounded, glabrescent above at maturity; laxly and more persistently scaly beneath. Scales small, marginal zone irregularly lobed; centre weakly or not impressed. Mid-vein strong, raised above in the proximal ½, smooth distally, raised beneath throughout, as broad as the petiole proximally, gradually narrowed upwards; lateral veins 12–15 per side, at an acute angle, indistinctly anastomosing, prominent or barely distinct on both sides, reticulation mostly visible beneath only. Petiole 10–20 x 2.5–3mm, without a groove, scaly, somewhat flattened. Flower buds to 40 x 20mm, shortly ovoid, shortly pointed, pale yellowish-green, smooth with the bracts appressed. Bracts broadly ovate, glabrous except for minute, fragile scales on the margins. Inflorescence 4–7-flowered, in slightly open umbels. Pedicels 10–20 x c.2mm, expanded to c.5mm just below the calyx, glabrous to laxly scaly. Calyx 4–5mm in diameter, disc-like, margin thickened, wavy and faintly lobed, glabrous. Corolla 35–40 x 50–60mm, funnel-shaped, held horizontally to semi-erect, yellow, without scent; tube 20–22 x 9–11 x 24–30mm, glabrous on both sides; lobes 20–29 x 20–24mm, unequal, oval, reflexed to horizontal, overlapping to c.½. Stamens irregularly arranged, exserted 5–8mm, slightly dimorphic; filaments linear, glabrous, c.25mm; anthers 4 x 1mm, strongly incurved, yellow, oblong, base obtuse. Disc glabrous or with a few sparse hairs, deeply lobed. Ovary 7–10 x 3–5mm, sub-obovoid-cylindrical, glabrous or with a few scattered scales, abruptly contracted distally; style 13–17 x 1.25mm, glabrous; stigma 5mm in diameter, yellow, circular, thick and lobed. Fruit 25–45 x 6–9mm, fusiform. Seeds 6–7mm, without tails c.1.2mm, the longest tail 3.8mm.
Habitat: Epiphytic or terrestrial.
Distribution: Philippines, Luzon, Batangas Province, Lobo Mts; Camiguin Island, Mt Hibok-hibok, Misamis Oriental Province; Mt Halcon, Mindoro.
Named after the Lobo Mts where it was first collected.
The description above has been greatly amplified with the additional recent collections from locations far removed from that of the type collection but it remains a poorly known species. The differences between the three known locations do not appear to warrant any subspecific recognition. It is very similar to R. leytense and differs chiefly in the lack of hairs on the ovary. It is hardly distinguishable from the R. javanicum complex but retained here as the number of collections is still very limited. It has been in cultivation in Edinburgh since 1997 and has flowered so far in September, with handsome yellow flowers.
Type: Mabesa F.B. 28045. Philippines, Luzon, Batangas, Lobo Mts (PNH†, A, E).
Occurs in Countries: PH Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:282
Shrub or small tree to 6.5m. Twigs 2–4mm in diameter, rounded, sub-densely to laxly scaly, quickly glabrescent; internodes 1–10cm. Leaves 3–5 together in tight pseudowhorls. Blade 50–90 x 30–50mm, broadly elliptic, occasionally sub-obovate; apex acute to rounded or sometimes minutely emarginate, with a small pale gland which rarely slightly protrudes; margin entire, flat or weakly revolute; base broadly tapering to rounded; laxly scaly and quickly glabrescent above; sub-densely and more persistently brown-scaly below. Scales round or weakly lobed with a broad flange and relatively small centre, impressed. Mid-vein impressed above in the proximal ½, smooth distally; below raised proximally, gradually becoming less so and finally smooth in the distal ¼; lateral veins 5–9 per side, minutely impressed above, smooth below, looping and joining before the margin, reticulation loose and weak, more clearly visible beneath. Petiole 10–20 x 2–3mm, distinctly grooved above, especially distally, densely brown scaly. Inflorescence a 2–6-flowered open umbel, the flowers mostly semi-erect. Pedicels 10–40 x c.1.5mm, scaly often more densely so distally. Calyx a disc or 5-lobed up to 8 x 3.5mm, pink. Corolla 25–55 x 35–45mm, red or pink, without scent; tube 25–40 x 7–11 x 10–20mm, scaly outside, glabrous inside; lobes 15–20 x 15–22mm, spreading horizontally, to slightly reflexed, overlapping ½–2⁄3. Stamens loosely clustered on the upper side of the mouth, not or hardly exserted, slightly dimorphic; filaments 22–31 and 21–30mm, glabrous; anthers c.2mm, oblong, pale brown. Disc green, glabrous or hairy. Ovary 3.5–5 x 2–3mm, sub-cylindrical, tapering distally, densely scaly and sometimes hairy; style scaly and sometimes hairy as well in the proximal 1⁄3–½, glabrous distally, held on the upper side of the tube; stigma rounded. Fruit 20–25 x 4–5mm, fusiform. Seeds 2.5–3mm, including the tails.
Habitat: Terrestrial in stunted montane forest and shrubberies amongst rocks.
Distribution: Australia, Bellenden Ker Range, also probably on Bell Peak in the Malbon Thompson Range.
Altitude: 1200-1520m
Named after Lady Loch, wife of the governor of Victoria, in recognition of her patronage to Victorian horticulture.
Type: Sayer 135, 1887? Mt Bellender-Ker, Queensland, Australia (MEL, K).
Synonymy: Azalea lochae (F.Muell.) Kuntze, Rev. Gen. Pl. 1891. 387. R. notiale Craven, Edinb. J. Bot. 1996. 53(1): 33.
Occurs in Countries: AU Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Tree Fl. Colour: pink, red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:324
Erect shrub to 2.5m. Twigs spreading, rounded, tips sub-densely covered with flat sub-stellate scales, lower down glabrescent and smooth; internodes 2–10cm. Leaves in loose pseudowhorls, 3–5 together. Blade 60–120 x 23–44mm, narrowly elliptic to elliptic; apex shortly acuminate, sub-acute, rarely obtuse; margin narrow, cartilaginous and revolute; base broadly acutely tapering; initially scaly on both sides, glabrescent above, more persistently scaly beneath. Scales sub-dense, small, reddish-brown, the narrow marginal zone variously lobed or sub-stellate; centre dark, distinctly impressed, leaving black pits when the scales have gone. Mid-vein narrow and slightly impressed above, thick and obtusely prominent beneath; lateral veins 8–10 per side, spreading, anastomosing before the margin, faintly impressed above, slightly raised beneath, reticulation inconspicuous. Petiole 4–10 x 1.5–2mm, compressed and grooved above. Flower buds 18 x 8mm, ovoid, smooth, often lateral at the base of older inflorescences. Bracts to 17 x 11mm, ovate, inner ones obovate, obtuse or mostly apiculate, glabrous except for scales on the upper part of the outside and fragile marginal scales. Bracteoles 7–10 x 0.5–1mm, linear below, spathulate at the apex, glabrous. Inflorescence 3–9-flowered. Pedicels 20–25mm, slender, densely stellate-scaly, without hairs. Calyx c.3mm in diameter, obliquely round or cup-shaped, scaly outside, with unequal triangular teeth up to 3mm. Corolla 22–30mm, tubular, expanded at the lobes, scarlet; tube 15–22 x 4–5 x 7–8mm, sparsely scaly outside, hairy in the proximal ½ inside; lobes 9–13 x 6–10mm, obovate, sub-equal. Stamens as long as the corolla tube; filaments linear, sub-densely covered with long, patent hairs in the proximal 3–5mm, glabrous distally; anthers 1–1.5mm, obovate, apex truncate, base sub-acute. Disc prominent, glabrous. Ovary 5–7 x c.3mm, sub-cylindrical-conical, abruptly contracted distally, densely scaly, and with just a few scattered hairs, especially proximally between the scales; style thick, glabrous, nearly as long as the stamens; stigma rounded, with thick lobes. Fruit 20–23 x c.5mm, cylindrical, 5-angular, densely scaly. Seeds c.6mm including the tails.
Habitat: In grassland or shrubberies on dry but fertile soil, very rich in humus, apparently rare
Distribution: Indonesia, C Java, Kedu: Mts Tlerep and Sumbing.
Altitude: 1800-2000m
Named after the collector, a German who collected extensively in the Dutch East Indies.
The lateral flower buds on such a large-leafed species are very curious and it would be interesting to have more material of this species. Not recently recollected and never cultivated.
Type: Loerzing 594, 10 Aug. 1912. Java, Central, Kedu, G. Tlerep, NE slope, Blintjung ridge, 1800m (BO, L).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: scarlet
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:253
Shrub. Twigs rounded, 2.5–4mm in diameter, densely scaly when young, becoming glabrescent; internodes 2.8–9cm. Leaves 4–7 together in pseudowhorls. Blade 70–105 x 28–44mm, elliptic-ovate; apex gradually acuminate, broadly acute; margin flat or weakly revolute; base rounded; initially densely scaly on both sides, glabrescent above at maturity, persistently and sub-densely scaly beneath. Scales flat, small marginal zone irregularly lobed; centre slightly impressed. Mid-vein broad proximally, flat above, strongly raised beneath; lateral veins 8–12 per side, spreading, straight at the base, curved upwards and arching inwards distally; a little raised above, more distinctly so beneath, reticulation indistinct above, densely and minutely prominent beneath. Petiole 6–12 x 1.5–2mm. Bracts to 30 x 15mm, circular to broadly ovate-acuminate, scaly and shortly hairy near the base outside, scaly on the margins, becoming glabrescent but remaining a little rough. Inflorescence a 6-flowered umbel. Pedicels 12–16mm, thick, sub-densely scaly, without hairs. Calyx c.3mm in diameter, inconspicuous, disc-shaped, oblique. Corolla tubular below, funnel-shaped distally, white; tube 26–31 x 4–5 x 5–6mm, strongly 5-lobed at the base, glabrous outside, hairy inside; lobes c.15 x 12–13mm, obovate, half-spreading. Stamens somewhat exserted; filaments linear, densely hairy in the proximal 2⁄3, glabrous distally; anthers c.3 x 1mm, oblong, base obtuse. Disc glabrous below but with short white hairs on the upper margin. Ovary c.9 x 2mm, cylindrical-conical, 5-angled, appressed-hairy, the hairs covering scales, gradually tapering distally; style c.20mm, densely hairy and laxly scaly in the proximal 2⁄3, glabrous distally; stigma large, 5-lobed.
Distribution: Indonesia, Sulawesi (C), Mt Lompoh.
Lompoh – the mountain on which this was found; ense – the place of origin.
An intermediate specimen between this and R. bloembergenii at Kew casts doubt on the distinctness of this species.
Type: Rachmat 943, Dec. 1913. Indonesia, Celebes (C), G. Lompoh (BO, L).
Occurs in Countries: ID Subgenus: Vireya Habit: Non-Tree Fl. Colour: white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:293
Shrub, c.3m; young shoots densely rufous-tomentose. Leaves elliptic to oblanceolate, 6-11 x 2-3.5cm, c.3x as long as broad, apex shortly cuspidate, base ± cuneate, upper surface shortly stipitate-glandular and rufous-tomentose when young, indumentum composed of flagellate hairs and restricted to the midrib by maturity, lower surface with lamina glabrous when mature although with midrib rufous-tomentose; petioles 1-1.5cm, densely rufous-tomentose. Inflorescence dense, 4-6-flowered; rhachis minute, to 2mm; pedicels 15-20mm, densely stipitate-glandular. Calyx 6-iOmm, stipitate-glandular, lobes Ungulate. Corolla open-campanulate, rose-pink, 40-45mm. Ovary and lower half of style stipitate-glandular. Capsule not known.
Habitat: Woodland
Distribution: China (Sichuan)
Altitude: 2300-3350m
Illustrations:
A distinctive species on account of its well-developed calyx, etc.; without close allies.
Type: China, W Sichuan, Tatsienlu, vii 1903, Wilson 3973 (holo. HBG, n.v.; iso. A, BM, K, Herb. Inst. Bot. Guangzhou)
Synonymy: R. brettii Hemslcy & Wilson, Kew Bull. 1910: 106 (1910). Type as above.
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: rose
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):268
Latin – longus – long; florum – flower. The long-flowered rhododendron.
Type: J. Hort. Soc. Lond. 1848. 3: f.89.
Synonymy: R. tubiflorum Low ex Lindl., J. Hort. Soc. Lond. 1848. 3: 88. R. lobbii Veitch, Cat. 1870. 22. R. javanicum (Blume) Benn. var. tubiflorum Hook., Bot. Mag. 1885. t.6850. R. orion Ridl. var. aurantiacum Ridl., Fl. Mal. Pen. 1923. 2: 217.
Occurs in Countries: ID, MY, TH Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Vireya Fl. Colour: orange, pink, red, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:240
Leaves elliptic or broadly elliptic. Petiole 9–20 x 1.5–2mm. Bracts densely hairy outside. Corolla 20–25mm, tube straight, base 2.5–3mm in diameter, widened to 3.5–4.5mm distally, lobes 15–16 x 8–10mm, obovate-spathulate. Stamens c.35mm, anthers 2.5 x 1mm. Ovary c.4 x 2mm; style 23mm. Differs from var. longiflorum mainly by smaller flowers and longer petioles.
Distribution: Indonesia, Bangka Is., top of Mt Maras, Menumbing, and R. Liat.
Altitude: 425-700m
Named after the island from which it was described.
Type: de Leeuw 2, 22 Sept. 1928. Bangka, Top of G. Maras, 600–700m (L, A, BO).
Shrub to 3m. Twigs rounded, initially laxly brown-scaly, quickly glabrescent; internodes 2–12cm. Leaves 4–5 together in tight pseudowhorls at the upper 1–3 nodes. Blade 40–90 x 20–40mm, narrowly obovate, obovate-elliptic, or elliptic; apex shortly and bluntly tapering or sub-acuminate; margin flat or very slightly revolute, often slightly convex; base tapering to rounded, rarely sub- cordate, at first densely scaly on both sides, later glabrescent above, laxly and more persistently scaly beneath. Scales small, marginal zone irregularly sub-stellately lobed; centre deeply impressed. Mid-vein slightly impressed above, prominent in its proximal part beneath; lateral veins 5–6 per side, faintly impressed above, smooth beneath, often obscure. Petiole 3–25 x 1.5–2mm, flattened, grooved above, brown-scaly. Flower buds to 12 x 8mm, conical, brown, smooth. Outer bracts ovate to sub-circular, inner ones broadly spathulate, all laxly scaly and sometimes also minutely hairy outside. Bracteoles to 15mm, filiform to linear-spathulate. Umbels open, 5–10-flowered, the flowers horizontal to semi-erect. Pedicels 10–30 x c.2mm, mostly laxly, rarely densely hairy and laxly scaly. Calyx a thin oblique, very short rim. Corolla 40–60 x 30mm, orange, pink or red often with a yellow throat; tube 30–40 x 3–5 x 7–12mm, scaly outside, hairy inside in the proximal ½, curved upwards; lobes 13–21 x 7–12mm, obovate to sub-circular, not or only shortly overlapping, spreading and becoming reflexed, mostly hooded at the apex. Stamens spreading irregularly around the mouth, exserted for 10–15mm, reflexing back in old flowers; filaments to 55mm, linear and sub-densely to laxly hairy in the proximal 1⁄3, glabrous and nearly filiform distally; anthers 2.8–3 x 1mm, oblong. Ovary 6 x 2mm, elongate-conical, densely covered with sub-appressed hairs which cover scales; style to c.50mm, exserted, densely hairy in the proximal ½; stigma lobed, c.3mm in diameter. Fruit 30–40 x 5–6mm, cylindrical, with longitudinal grooves. Seeds 3.5mm, without tails 1mm, the longest tail 1.5mm.
Habitat: Terrestrial or epiphytic, often on tall trees in primary or secondary forest, along rivers and in mangrove, quartzite rocks, sandstone pavement, limestone hills or sandy clay; in heath-forest (kerangas)
Distribution: Thailand, Yala Province, Betong District. Malaysia, Peninsula; Sabah, Sarawak (Borneo). Brunei. Indonesia, Sumatra, Karimata Arch., Mentawei Is.; Kalimantan (Borneo).
Altitude: 0-1500m
Hybridising with R. jasminiflorum ssp. heusseri in the Samosir Peninsula, Sumatra (see under that subspecies). Specimens from West Malaysia, especially from Mt Tahan, are distinct in having short, thick petioles and large flowers. They may warrant description as a distinct form.
Leaves as in var. longiflorum. Corolla c.52 x 70mm, tube 40 x 8 x 15mm, straight; lobes 35 x 20mm.
Habitat: Epiphyte in lowland forest.
Distribution: Malaysia (Borneo), Sabah, Crocker Range, Sinsuron Road; Mt Madalon.
Altitude: 760-1060m
Latin – longus – long; petalum – petal. Referring to the very long petal lobes.
This variety was first collected along the Sinsuron Road where the forest has been very much reduced, and it is likely to be extinct here. It is an area where R. javanicum ssp. brookeanum is common and it is possible that this variety is a hybrid between this species and R. longiflorum; however, the leaves are typical of R. longiflorum var. longiflorum.
Type: Phillipps & Ampal 1337, 21 Feb. 1980. Sabah, Sinsuron Rd. (E).
Vegetatively as in the type variety. Corolla tube straight, not curved, lobes spreading not becoming reflexed, overlapping at the base and rarely hooded at the apex.
Habitat: Terrestrial and epiphytic in heath-forest.
Distribution: Malaysia (Borneo), Sarawak, Batang Lupar, Tian Laju. Sabah, near Nabawan
Altitude: 700-1000m
Latin – sub – somewhat; cordatus – heart-shaped. Referring to the rounded lobes of the leaf base.
Type: Beccari P.B. 3231. Borneo, Sarawak, Batang Lupar, Tian Laju, c.1000m (FI, K).
Synonymy: R. subcordatum Becc., Malesia 1878. I: 203.
Erect shrub, young shoots densely clothed with adpressed flattened hairs. Leaves dimorphic, sub-persistent, chartaceous; spring leaves ovate to ovate-lanceolate, 1-3 x 0.5-1.5cm, 1.7-2 x as long as broad, apex acute, base cuneate, margin entire, upper surface sparsely strigose, lower surface densely strigose, especially on midrib and veins; summer leaves up to 10 x 6mm, otherwise as for spring leaves; petioles 1-2mm, strigose. Inflorescence 1-3-flowered; pedicels c.l2mm, stout, densely clothed with shining adpressed rufous hairs. Calyx indumentum as for pedicels, lobes c.2mm, acute. Corolla funnel-shaped, scarlet, c.30mm; tube c.20mm. Stamens 9-10, included within tube, sparsely pilose towards base. Ovary densely pilose; style glabrous. Capsule pubescent, 8-15mm long.
Habitat: Grasslands
Distribution: Taiwan
Altitude: 700-1000m
Apparently allied to R. kanehirai but differing in its shorter, broader leaves and smaller flowers.
Type: Taiwan, Mt Daiton, viii 1910, Shimada, (holo. TI)
Occurs in Countries: TW Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: scarlet
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):119
Shrub or small tree, l-10m. Leaves obianceolate, 5-11 x 1.5-3cm,c.3.3 x as long as broad, apex cuspidate, glabrous above, with a felted to compacted, fawn to brownish indumentum beneath, intermixed with a few stipitate glands; petioles clem, narrowly winged, floccose to ± glabrescent. Inflorescence lax, 8-15-flowered; rhachis c.lOmm; pedicels 20-30mm, floccose and sparsely stipitate-glandular. Calyx l-2mm, floccose, lobes triangular, minute. Corolla funnel-campanulate, pinkish to pale purple, with darker flecks, 30-35mm. Ovary rufous-tomentose and glandular; style glabrous. Capsule 20-25mm, cylindrical and curved.
Habitat: Thickets
Distribution: China (W & C Sichuan, Guizhou)
Altitude: 2000-2900m
Occurs in Countries: CN Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: pink, purple
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):319
Leaves with a thicker, more spongy, felted indumentum.
The only significant difference between the two taxa is in the degree of development of the indumentum and this does not merit more than varietal rank. Closely allied to R. simiarum.
Synonymy: R. chienianum Fang, Contr. biol. Lab. Sci. Soc. China, Bot. ser. 12: 28 (1939). Syntypes: China, Sichuan, Nan Chuan hsien, Kin-shan, 19 viii 1926, Hwang 175, fr. (SZ); Kwan-toun-shan, 2300m, 19 vi 1930, Chang 251, f. (E, SZ)
Leaves with a thin compacted indumentum.
A specimen from Guizhou, Tsiang 7459, with broader leaves than is usual in R. longipes, may be intermediate between this variety and R. simiarum.
Type: China, W Sichuan, Ching-chi Shien, Ta-hsiang long, 2000-2900m, 16 v 1907, Wilson 3424 (holo. A; iso. E, K)
Shrub, 0.5-2 m. Young growth sparsely lepidote and usually puberulent. Leaves obovate or oblong-obovate, 35-52 x 9-15 mm, acute at the apex, tapered to the base, lower surface pale green with distant, unequal, golden and brown scales with broad rims, upper surface sparsely but persistently lepidote, puberulent along the main vein. Inflorescences (l-)3-flowered, pedicels lepidote and puberulent, 10-15 mm. Calyx lobes narrowly triangular, obtuse, up to 3-5 mm, fringed with scales, tube lepidote and slightly puberulent. Corolla white, narrowly funnel-shaped or funnel-campanulate, c. 20 mm, tube 12 mm, glabrous and elepidote outside, pilose within at the base of the tube. Stamens 10, filaments pilose towards the base, much exserted from the corolla. Ovary lepidote and puberulent at the apex, style impressed, glabrous, much exserted from the corolla. Capsule lepidote, broadly cylindric, c. 6 mm
Habitat: Cliffs
Distribution: China (C Sichuan)
Altitude: 1300-2300m
Illustrations:
Known only from a few collections from near Wen chuan hsien, and material in cultivation
Type: China, western Szechuan, west and near Wen chuan hsien, 2300 m, vii & x 1908, Wilson 1204 (iso. E)
Occurs in Countries: CN Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Rhododendron Habit: Non-Tree
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):129
Shrub; young shoots covered with adpressed strigose hairs. Leaves dimorphic, coriaceous; spring leaves lanceolate to oblong-lanceolate, 4.5-5.5 x 1.2-1.6cm, c.3.5 x as long as broad, apex acute, base narrowly cuneate, margin entire, revolute, upper surface sparsely strigose, lower surface with a felted red-brown strigose indumentum; summer leaves 15-20 x 5~7mm, otherwise as for spring leaves; petioles c.6mm, densely strigose. Inflorescence 4-5-flowered; pedicels c.8mm, strigose. Calyx densely strigose, lobes triangular, c. 1.5mm. Corolla tubular-campanulate, pale reddish-purple, c.35mm; tube 18-25 x 3mm at base, widening to 7mm below lobes, hairy within. Stamens 5, puberulent in lower half. Ovary covered with reddish-brown strigose hairs; style strigose at base. Mature capsule not known.
Habitat: Open woodlands
Distribution: China (Fujian)
Illustrations:
Closely allied to R. mariae but with larger corollas, the tubes of which are hairy within.
Type: China, Fujian, Anxi Xian, Lutin, 20 iv 1974, L.G. Li (L.K. Lee) 740123 (holo. Inst. Mat. Med. Fujian)
Occurs in Countries: CN Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: red
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):104
With flowers like a Loranthus (Loranthaceae).
Type: Kajewski 2045, 8 Aug. 1930. Solomon Is., Bougainville, Koniguru, Buin, 1000m (BRI, E, L, fragment).
Synonymy: R. subpacificum Sleumer, Blumea 1963. 12: 105.
Occurs in Countries: PG Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Vireya Fl. Colour: white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:187
Distinguished from the type subspecies by the style exclusively scaly distally.
Habitat: Epiphytic in lowland forest
Distribution: Papua New Guinea, Gulf Province, Lakekamu, E branch of the Avi Avi R.
Altitude: Around 175m
Named after Lakekamu, where it was found.
Epiphytic in lowland forest at the extraordinarily low altitude of 175m, this was, when described, a surprising extension of the range of the species to the New Guinea mainland.
Type: Takeuchi & Julang 11503, 31 Oct. 1996. Papua New Guinea, Gulf Province, Lakekamu, east branch of the Avi Avi R., 175m (LAE, A, BRIT, E, K, L, NY).
Epiphytic, much-branched shrub. Twigs smooth, older rounded and often whitish, tips sub-angular or flattened and densely brown-scaly; internodes 1.5–12cm. Leaves 3–6 together in tight pseudowhorls. Blade 25–60 x 15–25mm, obovate; apex broadly obtuse or rounded; margin entire, very slightly revolute; base tapering, scaly on both sides initially, glabrescent above, sub-densely and persistently scaly beneath. Scales thin, irregularly and shallowly dentate or lobed at the margin; centre slightly impressed, sub-revolute. Mid-vein narrowly and shallowly impressed above in the proximal 2/3, broadly and shallowly prominent beneath in the proximal ½, distally smooth; lateral veins 3–5 per side, indistinct on both sides, reticulation obscure. Petiole 3–8 x 1–2mm, weakly to distinctly grooved above, scaly. Flower buds to 10 x 6mm, ellipsoid to slightly obovoid, smooth in outline with all except the very basal bracts appressed, brownish-green, with a few scales outside. Bracts triangular at the base passing to broadly rounded, concave, the apex retuse often with a minute point, brown-scaly along the central line towards the apex, the margin entire but fringed with scales in the apical part. Bracteoles to 6mm, filiform, glabrous. Inflorescence with 3–7 flowers in a loose, open umbel, held semi-erect to half-hanging. Flowers white, faintly scented. Pedicels 10–22 x c.1.5mm, laxly brown-scaly, without hairs. Calyx 3–4mm in diameter, green, disc-shaped. Corolla 35–42 x 25–35mm, tubular-trumpet-shaped, white; tube 25–35 x 5–9 x 6–7mm, cylindrical, straight or very slightly curved, densely scaly outside, laxly papillose hairy in the proximal ½ inside; lobes 10–12 x 9–10mm, broadly elliptic, obovate or rounded, spreading to weakly reflexed, overlapping c.halfway, scaly outside, glabrous inside. Stamens at first exserted to 7mm in a group centrally, or slightly deflected to the lower side of the mouth, later the filaments curving and the anthers irregularly spreading back against the corolla lobes, weakly dimorphic; filaments filiform, shortly hairy in the lower 2/3; anthers c.1.5mm, oblong, base obtuse. Disc low, glabrous or densely hairy on the upper margin. Ovary c.6 x 1.5mm, sub-cylindrical, slightly 5-ribbed, densely scaly, the scales thick and sub-entire, also very shortly patently or with distally directed hairs, gradually tapering distally; style 35–40mm, scaly and hairy in the proximal part, then hairy or scaly and finally glabrous distally; stigma c.2mm in diameter, at the mouth when the flower opens, becoming exserted to 7mm as the flower ages. Fruit 40–45 x c.3mm, cylindrical, slender, curved, tapering apically, 5-ribbed, densely brown-scaly and shortly hairy.
Habitat: An epiphyte in high rain forest and in stunted forest on a crater rim. Locally common.
Distribution: Papua New Guinea, New Britain: headwaters of Matabunu Creek. Solomon Is.: Bougainville, near Koniguru, Buin, New Georgia Group, Vangunu I.
Altitude: 180-1500m
Shrub or small tree to 10m, often with long unbranched stems. Twigs 5–10mm in diameter, green but covered in pale brown lobed scales, round; internodes 4–100cm. Leaves evenly spirally arranged along the stems, rarely in pseudowhorls of 4–6 leaves. Blade 100–200 x 45–100mm, broadly elliptic to elliptic, sub-obovate or broadly ovate; apex obtuse, to rounded; margin entire, flat, often slightly irregularly wavy; base broadly rounded to cordate; initially very densely scaly on both sides, glabrescent above, more persistently scaly below. Scales stellate, irregularly lobed with broad flanges and small centres, not or shallowly impressed. Mid-vein broad, raised in the proximal ½ on the upper side of the leaf, not raised below; lateral veins 9–15 per side, broadly spreading, with distinct reticulation which is smooth above and below. Petiole 5–22 x 4–8mm, ungrooved and rounded on the upper side, distinctly flattened below, scaly, green sometimes flushed with red. Flower buds to 60 x 40mm, smooth with the bracts appressed, ovoid-conical, pale green. Outer bracts ovate, obtuse, often splitting to become emarginate, inner ones ovate, shortly acuminate, innermost ones obovate, obtuse, all membranous, glabrous and shiny outside. Bracteoles 30 x 2mm, linear below, sub-spathulate distally. Inflorescence a full umbel, 8–15-flowered, flowers erect to horizontal. Pedicels 20–50 x 2–4mm, laxly sub-stellately scaly, without hairs, yellow or flushed with red or orange. Calyx 5–6mm in diameter, a low wavy ring or obscurely 5-lobed, sub-glabrous. Corolla 60–110 x 70–80mm, funnel-shaped (wax-like when fresh), yellow or orange, sometimes flushed with orange or pink, scentless or delicately scented, glabrous outside; tube 30–35 x 6–8 x 12–15mm, straight; lobes 35–56 x 40–50mm, spreading to slightly reflexed, broadly obovate, sometimes retuse, overlapping 1⁄3–½. Stamens usually all on the lower side of the flower, somewhat irregular, exserted to c.15mm; filaments linear, long hairy in the proximal 1⁄3, sub-filiform and glabrous above; anthers c.6 x 2mm, cream, curved, with the pores turned upwards and with minute basal appendages. Disc thick, very prominent, glabrous or shortly hairy on the upper margin. Ovary 12 x 5.5mm, columnar, but tapering more gradually proximally than distally, covered with white hairs and densely scaly, although most scales are hidden by hairs; style 20–25mm, thick, glabrous, or with some hairs at the base; stigma 3–8mm in diameter, obtusely lobed. Fruit 30–80 x 8–12mm, fusiform, shortly hairy to glabrescent, with scattered, minute, elliptic-oblong, lenticel-like warts. Seeds 5–6mm, without tails c.1mm, the longest tail c.2.2mm.
Habitat: Terrestrial in gullies in mossy forest and on open shrubberies on rocky ridges
Distribution: Malaysia (Borneo), Sabah, Mt Kinabalu, Mt Trus Madi and Mt Alab.
Altitude: 2700-3650m
Named after H. Low, the collector.
Old reports of this species from New Guinea are without foundation and reports from Mt Monkobo are now referable to R. monkoboense (for differences see under that species).
Type: Low s.n. North Borneo, Mt Kinabalu, 2440–3350m (K, CGE).
Occurs in Countries: MY Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Tree Fl. Colour: orange, pink, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:276
Small, creeping shrublet up to 25 cm. Stems loriform-setose and filiform-acicular pubescent. Leaves deciduous, thin, narrowly elliptic to oblanceolate, rounded at the mucronate apex, tapered to the base, 15-25 x 6-11 mm, margins slightly crenate and loriform-ciliate, upper surface dark green and filiform-acicular pubescent, very sparsely lepidote with dried-out scales, lower surface pale green, lepidote with distant, yellow scales with broad, translucent margins. Inflorescence 1-2-flowered, pedicels 15-20 mm, somewhat accrescent and rigid in fruit, usually loriform-setose and sparsely lepidote. Calyx lobes oblong-ovate, rounded, greenish or reddish, sparsely lepidote, loriform and filiform-acicular ciliate, 2-5-3-5 mm. Corolla yellow, sometimes spotted or streaked with red, 13-15 mm, outside of the tube sparsely to densely lepidote. Ovary lepidote. Capsule cylindric, sparsely lepidote, c. 5 mm.
Habitat: Rock crevices, ledges and peaty banks
Distribution: Nepal
Altitude: 3800-4550m
Illustrations:
Type: Nepal, Marsiandi valley, 13500 ft, 2 vii 1950, Lowndes 1174 (holo. BM, iso. E)
Occurs in Countries: NP Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: red
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):149
Small, spreading shrub to 0.3 m. Young growth lepidote with somewhat stalked scales, glabrous. Leaves 15-16 x 9-10 mm, broadly obovate or oblong-obovate, very obtuse at the apex, rounded to the base, margins crenate, lower surface pale green or brownish with prominent venation and distant, brown, flat, rather narrowly rimmed scales. Inflorescence 1-flowered, pedicels 15-20 mm in flower, lepidote. Calyx with conspicuous, oblong, rounded, lepidote and sparsely filiform-acicular-ciliate lobes, c. 7 mm. Corolla yellow, drying greenish yellow, sometimes with red spots inside the tube, 20-23 mm, tube c. 14 mm, broadly funnel-campanulate to almost bowl-shaped, densely pubescent and lepidote all over the outer surface. Stamens 10, filaments pubescent towards the base. Ovary lepidote, style impressed, glabrous, exceeding the stamens. Capsule unknown.
Habitat: Open rocky hillsides,
Distribution: China (S Xizang)
Altitude: Around 4000m
Illustrations:
Known only from the type collection and material in cultivation.
Type: China, SE Tibet, Pachakshiri District, Lo La, 13500 ft, 2 vii 1936, Ludlow & Sherriff 1895 (holo. BM, iso. E)
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: green, red, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):122
Free-growing shrub to 1.5 m. Young branches not loriform-setose. Leaves obovate, rounded at the apex, tapered to the base, 30-70 x 15-35 mm, upper surface brownish green, lower surface lepidote with rather dense, but not overlapping, brownish scales; petiole sometimes loriform-ciliate. Inflorescence 2-3-flowered, pedicel lepidote and minutely puberulous. Calyx very small, disc-like, obscurely lobed, margins loriform-ciliate. Corolla funnel-campanulate, white and pink, c. 65 mm, tube c. 33 mm, sparsely pubescent over most of the surface, the lobes lepidote. Stamens 10, filaments pubescent towards the base. Ovary lepidote, tapered into the style which is lepidote and minutely pubescent in the lower third. Capsule unknown.
Habitat: Ridges
Distribution: Thailand (Dayap province)
Altitude: 1600-2180m
Illustrations:
Type: Siam, Dai Djieng Dao, Kalkgipfel III, 6600 ft, 17 ii 1905, Hosseus 401 (holo. B—n.v., iso. K)
Occurs in Countries: TH Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: pink, white
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):57
Shrub or small tree, l-7.5m. Leaves coriaceous, elliptic to oblanceolate, 8-16.5 x 3-5.2cm, 2.5-4 x as long as broad, apex acuminate, base ± cuneate, margin undulate, lower surface of mature leaves glabrous except for numerous red punctate glands overlying the veins; petioles 1-1.8cm, glabrous. Inflorescence 6-15-flowered; rhachis 5-10mm; pedicels c.lOmm, sparsely stellate-tomentose, eglandular. Calyx c.2mm, sparsely ciliate. Corolla tubular-campanulate, glabrous within, pale to deep magenta rose, darker on the lobe margins, with purple flecks and usually a basal blotch, 40-45mm. Ovary glabrous to sparsely rufous-tomentose; style glabrous. Capsule 19-27 x 3—5mm.
Habitat: Open rocky slopes, mixed woodland
Distribution: China (NW Yunnan, SW Sichuan, SE Xizang)
Altitude: 2100-3350m
Closely allied to R. irroratum but differing in the glabrous style. Vegetatively there is little to distinguish R. lukiangense from R. araiophyllum, R. irroratum, or indeed R. tanastylum. The last is however unlikely to be confused as it has a more southerly distribution.
Type: W NW Yunnan, Tseku, Loukiang Valley, 16 iii 1895, Soulie 1000 (iso. E, K)
Synonymy: R. gymnanthum Diels, Notes R.B.G. Edinb. 5: 211 (1912). Type: China, W NW Yunnan, NW of Tseku, 13000ft, viii 1904, Forrest 5071 (holo. E). R. ceraceum Balfour f. & W. W. Smith, Trans. Bot. Soc. Edinb. 27: 187 (1917). Type: W NW Yunnan, Tseku, Mombeig 166 (holo. E; iso. BM, K). R. admirabile Balfour f. & Forrest, Notes R.B.G. Edinb. 13: 27 (1920). Type: China, SW Sichuan, 10-11000ft, vi 1918, Forrest 16378 (holo. E; iso. K). R. adroserum Balfour f. & Forrest, ibid. 13: 28 (1920). China, W NW Yunnan, Mekong/Salween divide, iv 1917, Forrest 16353 (holo. E)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: magenta, purple, rose
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):299
Named after the lake around which it was collected.
Type: Kajewski 2064. Solomon Islands, Bougainville, Lake Luralu, 1500m (B†, A, BM, BRI, E, fragment, P).
Occurs in Countries: PG Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Vireya Habit: Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:312
Shrub or tree to 9m. Twigs rounded, 2–3mm in diameter, laxly scaly at first, later glabrescent; internodes 3.5–8cm. Leaves 4–7 together in tight pseudowhorls. Blade 35–60 x 20–30mm, obovate-elliptic to elliptic; apex broadly acute to obtuse, or occasionally rounded, sometimes apiculate; margin narrowly recurved; base broadly tapering; glabrescent above, laxly and more persistently scaly beneath. Scales small, marginal zone fragile, irregularly lobed; centre dark, slightly impressed. Mid-vein broad and impressed in the proximal ½ above, broadly and obtusely prominent beneath; lateral veins 4–6 per side, irregular, spreading, inconspicuously arching inwards before the margin, faintly impressed or obscure above, slightly prominent beneath, reticulation lax, slightly raised beneath only. Petiole 3–5 x 1–1.5mm, grooved above. Bracts to 12 x 6mm; outer bracts ovate-acuminate, inner ones obovate to spathulate, glabrous or laxly scaly apically outside. Bracteoles c.10mm, filiform, glabrous. Inflorescence of 3–6-flowered open umbels. Pedicels c.13 x 1.5mm, laxly sub-stellate-scaly, more densely so towards the apex. Calyx c.3mm in diameter, oblique, disc-shaped, very shortly 5-lobed. Corolla 35–45 x c.50mm, funnel-shaped, white; tube 15–20 x c.4 x 7–9mm, sparsely scaly outside, very laxly and shortly hairy inside; lobes 10–15 x 10–14mm, obovate-sub-circular, spreading. Stamens exserted to c.6mm; filaments linear and densely hairy proximally, filiform and glabrous distally; anthers c.2.5mm, oblong. Disc prominent, glabrous. Ovary c.4 x 1.8mm, sub-cylindrical, densely white-hairy and scaly (the hairs covering the scales), abruptly contracted distally; style slender, slightly shorter than the stamens, sub-densely to laxly hairy and scaly proximally to c.¾; stigma rounded.
Habitat: Epiphytic shrub in rain forest, or tree in stunted vegetation, locally common
Distribution: Papua New Guinea, Bougainville Island, Crown Prince Range.
Altitude: 900-1500m
Named after T.C. Whitmore, famous tropical botanist who collected the type specimen.
A ceteris subspeciebus R. loranthifloro stylo per c.4mm (styli c.1⁄5 longitudinis) proximaliter tantum piloso lepidotoque (nec per 12–15mm vel styli ¾ longitudinis) differt.
Differing from the type subspecies of R. luraluense as the style is hairy and scaly for only c.4mm (about 1⁄5) proximally, not 12–15mm (¾ of the style).
Type: Whitmore 6360, 27 Aug. 1965. British Solomon Islands Protectorate, New Georgia Is., SW summit peak of Kolombangara, 1680m (K).
Very similar to R. glaucophyllum var. glaucophyllum, differing as follows: leaves elliptic, obtuse at the apex, not or scarcely lepidote above, sparsely so beneath, calyx lobes rounded at the apex, not loriform-ciliate and without a tuft or hairs inside at the apex; corolla campanulate, bright, clear yellow, 20-22 mm, tube c. 12 mm.
Habitat: In thickets and on exposed ridges
Distribution: ne Burma
Altitude: 3050-3350m
Illustrations:
Synonymy: R. glaucophyllum var. luteiflorum Davidian, Journ. Roy. Hort. Soc. 85:369 (1960). Type: N Burma, N Triangle, Uring Bum above Akhail, 10000 ft, 4 xi 1953, Kingdon Ward 21556 (holo. BM)
Occurs in Countries: MM Altitude Ranges: 3,000 - 4,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):141
Straggling shrub up to 6 m, with grey bark. Leaves sometimes subdeciduous, lanceolate or ± oblong, apex acuminate into a long and conspicuous drip-tip, base rounded, margins somewhat distantly crenulate, 50-90 x 13-26(-37) mm, upper surface variably lepidote, midrib usually glabrous, lower surface with large, distant, broadly rimmed, golden scales. Inflorescences mostly axillary, terminal inflorescence often lacking, pedicels 6-15 mm, lepidote and sometimes puberulent at the base. Calyx undulate or obscurely 5-lobed, lepidote, sometimes loriform-ciliate. Corolla pale yellow with greenish spots on the inside of the upper lobes, 18-25 mm, tube up to 11 mm, pubescent outside with retrorse hairs, their density variable. Stamens 10, filaments densely pubescent towards the base. Ovary lepidote, often pubescent at apex. Style glabrous or pubescent at base. Capsule lepidote, narrowly cylindric, 9-11 mm.
Habitat: Hillsides, slopes and forest margins, (550-)1750-3000 m
Distribution: China (C Sichuan, widely distributed but scattered)
Illustrations:
R. lutescens is a very scattered species, and has an immense altitudinal range, if the altitudes on some of Maire's specimens (e.g. the type of R. biinii) are credible.
Type: China, Szechuan, Moupine in sylvis regionis mediae, David (holo. P—n.v.)
Synonymy: R. costulatum Franchet, Journ. de Bot. 9:399 (1895). Type: China, Szechuan, Kiala, Soulie 492 (holo. P—n.v., iso. E). R. lemeei Leveilie, Feddes Rep. 13:339 (1914). Type: China, Yunnan, monts de Ta tchai, 3000 m, iv 1913, Maire (holo. E). R. biinii Leveilie, Bull. Acad. Geogr. Bot. 24:21 (1915). Type: China, Yunnan, braisse de coteaux a Tscheu-fong-tchan, 550 m, v 1912, Maire (holo. E)
Occurs in Countries: CN Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: green, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):79
Shrub or small tree to 2m tall, usually non-rhizomatous; young twigs red-brown, rarely yellow-brown, densely covered with unicellular hairs and multicellular gland-tipped hairs, rarely also with multicellular eglandular hairs, or with only multicellular gland-tipped and eglandular hairs. Vegetative bud scales glabrous, rarely sparsely covered with unicellular hairs abaxially; margin glandular ciliate. Leaf blade membranaceous, ovate or obovate to elliptic, (6.4-)7.6-12.0(-14.6) x (1.6-)2.1-3.4(-4.2)cm; base acute to oblique; apex acute to obtuse, often mucronate; adaxial surface sparsely to densely covered with multicellular gland-tipped hairs, or rarely with multicellular eglandular hairs, the midvein densely covered with unicellular hairs; abaxial surface glabrous, occasionally glaucous, the veins raised and prominent beneath, rarely sparsely to densely covered with unicellular hairs, or with multicellular gland-tipped and eglandular hairs, or all three types of hairs, the midvein sparsely to densely covered with unicellular and multicellular gland-tipped hairs, rarely lacking the unicellular hairs; margin entire, ciliate with multicellular eglandular hairs above and gland-tipped hairs below; petiole 0.3-0.6(-0.8)cm long, densely covered with unicellular hairs and multicellular gland-tipped hairs, rarely with multicellular eglandular and glandular hairs. Flower bud scales chestnut brown; abaxial surface glabrous, occasionally sparsely to densely covered with unicellular hairs; margin glandular. Flowers appearing before or with the leaves; inflorescence a shortened raceme of 9 to 17 flowers. Pedicels (0.8-)0.9-1.8(-2.4)cm long, densely covered with multicellular gland-tipped hairs, occasionally with unicellular hairs and multicellular gland-tipped hairs. Sepals less than 0.1-0.4(-0.7)cm long, varying in length on the same flower; margins glandular-fimbriate; abaxial surface sparsely covered with multicellular gland-tipped hairs, occasionally with unicellular hairs, rarely glabrous. Corolla yellow with a darker yellow blotch on the upper corolla lobe, fragrance sweet, the tube longer than the limb and gradually expanding into it; upper corolla lobe (1.3-)1.4-2.0(-2.4) x (0.8-)0.9-1.5(-2.0)cm wide; lateral lobes (1.3-)1.6-2.2(-2.5) x (0.5-)0.7-l.l(-1.2)cm; corolla tube (1.2-)1.3-2.0(-2.4)cm long, 0.2-0.4(-0.5)cm wide at base; outer surface of corolla sparsely to densely covered with multicellular gland-tipped hairs, or also with unicellular hairs, the gland-tipped hairs continuing up the corolla lobes; inner surface of corolla glabrous, rarely sparsely covered with unicellular hairs. Stamens (3.2-)3.4-4.4(-5.0)cm long, with dense terete or flattened unicellular hairs on proximal (1.6-)1.7-2.3(-2.5)cm of filament, exserted (1.4-)1.8-2.7(-3.0)cm beyond throat of corolla. Style (3.5-)3.7-5.0(-5.4)cm long, exserted (2.2-)2.4-3.8(-4.2)cm beyond throat of corolla, with dense unicellular hairs on proximal 0.2-0.6(-l .0)cm of style; stigma 0. l-0.2cm wide. Ovary (0.2-)0.3-0.4cm long, (0. l-)0.2-0.3cm wide at the base, sparsely covered with multicellular hairs, often with flattened or terete unicellular hairs in a tuft at the apex. Capsules (1.3-)1.5-2.1(-2.2) x 0.4-0.7(-0.8)cm, broadly ovate, sparsely covered with unicellular hairs and sparsely to moderately covered with multicellular gland-tipped hairs. Seeds pale to dark chestnut brown, ovate or effiptic to fusiform, (2.4-)2.8-3.8(-4.8) x (0.5-)0.7-l .2(-l .5)mm, body (1.1-) 1.3-1.8(-2.0) x (0.3-)0.4-0.6(-0.7)mm; testa expanded and dorsiventrally flattened, surrounding the body, the cells elongate, with tapered end-walls
Habitat: Open wooded slopes, along streams and in swampy areas, shores of the Black Sea
Distribution: Caucasus: Former Soviet Union, Turkey, and isolated populations in Poland and former Yugoslavia.
Altitude: 0-2300m
Illustrations:
Rhododendron luteum exhibits a typical Tertiary relict distribution in Europe (Szafer, 1975). It is variable primarily in leaf shape and unicellular Indumentum of the floral bud scales.
The name R. luteum Sweet has priority over Azalea pontica L. since Linnaeus (1753) recognized the deciduous species of Rhododendron as a distinct genus (Azalea) from the evergreen species (Rhododendron). Transfer of the epithet 'pontica'to Rhododendron would result in a later homonym, since Linnaeus described the evergreen R. ponticum L. from the Caucasus in 1753.
Rhododendron luteum is most closely related to R. austrinum from which it can be distinguished by its broader, more glabrous fruits and its entirely yellow corolla with a deeper yellow blotch on the upper corolla lobe. The most noticeable difference between R. luteum and R. austrinum is the shape of the testa cells (Fig. 8). Rhododendron luteum possesses seeds with elongate testa cells with tapered end-walls, whereas R. austrinum possesses seeds with short testa cells with transverse end-walls.
Chromosome number: 2n = 26 (Sax, 1930; Janaki-AmmaletaL, 1950)
Synonymy: AzaleaponticaL.,Sp.Pl.ed. 1,1:150 (n53).Anthodendronponticum(L.)Rchb. in Mossier, Handb. Gewachsk. 1: 309 (1827). Rhododendron ponticum (L.) Schreb. ex DC, Prodr. 7: 718 (1839), non L., Sp. PI. ed. 1,1: 154 (1753). Type: Elus. in Buxbaum, Plant. Minus Cogni. Cent. 5: 36, fig. 69 (1740). RhododendronflavumG. Don, Gen. Syst. 3: 847 (1834), nom. illeg.; based on Azaleapontica L. (1753) [ = R. luteum Sweet (1830)]. Azalea flava Hoffmanzegg, Verz. Pflanzenkult. Nachtr. 2: 62 (1826). Type: n.v. Azalea pontica L. var. autumnalis C Koch, Linnaea 17: 281 (1843). Type: n.v. Rhododendron flavum G. Don var. macranthum Bean, Trees and Shrubs Brit. Isles 2: 357 (1914). R. luteum Sweet var. macranthum Wilson, Monogr. Azaleas 105 (1921). Type: n.v.
Occurs in Countries: PL, TR Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Pentanthera Habit: Tree Fl. Colour: yellow
Kron, K.A. (1993) A Revision of Rhododendron Section Pentanthera. Edinburgh Journal of Botany 50(3):314
Shrub to 2 m. Young shoots loriform-setose, the setae persistent for at least one year. Leaves narrowly obovate, 70-80 x 25-30 mm, tapering to the base, bluntly acute at the apex, lower surface brown with dense but not contiguous scales. Inflorescence (2-)3-4-flowered. Calyx obscurely lobed or undulate, persistently loriform-setose. Corolla white, funnel-campanulate, c. 55 mm, tube c. 30 mm, pilose at the base, the whole surface sparingly lepidote. Capsule ± cylindric, tapering, lepidote, c. 25 mm
Habitat: Forest, altitude unknown.
Distribution: China (Guizhou), Vietnam, Laos
Illustrations:
Possibly also occurring in Thailand and elsewhere.
Type: China, Kweichow, Gan tchouen, iv 1912, Cavalerie 3883 (holo. E)
Synonymy: R. leptocladon Dop in Lecomte, Fl. Gen. Indo-chine 3:745 (1930). Type: Tonkin, prov. Lao-kay, massif de Lo-sui-tong, 2200 m, Poilane 12680 (holo. P). R. saravanense Dop, loc. cit. Type: Laos, prov. Saravane, sommet de Pou Set, 1400 m, Poilane 16165 (holo. P)
Occurs in Countries: CN Subgenus: Rhododendron Habit: Non-Tree
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):53
Tree, up to 15m. Leaves broadly ovate to broadly elliptic, 14-25 x 9- 18.5cm, 1.3-1.8 x as long as broad, apex rounded to retuse, sometimes also minutely apiculate, base rounded (in cultivation leaves up to 31 x 13cm, 2.3 x as long as broad, base cuneate), upper surface glabrous when mature, reticulate with impressed veins, lower surface with a dense bistrate indumentum, the lower layer compacted, whitish, the upper lanate-tomentose, composed of largely rosulate though with some ramiform hairs; petioles 2-2.5cm, terete, slightly winged, floccose-tomentose, especially below. Inflorescence dense, 15—25-flowered; rhachis to c.35mm; pedicels 25—40mm, densely whitish-felted tomentose. Calyx c.lmm, tomentose, lobes triangular. Corolla 8-lobed, tubular-to narrowly funnel-campanulate, lemon yellow with a purple blotch in the throat, c.50mm. Stamens 16. Ovary densely rufous-tomentose. Capsule 20-40 x c.8mm, curved.
Habitat: Forming dense stands on the summits of hills, also scattered through mixed woodland
Distribution: NE India (Manipur, Nagaland)
Altitude: 2500-3000m
Illustrations:
Plants raised from seed (Kingdon- Ward1124) have proved somewhat variable in cultivation with respect to leaf shape. Some plants have larger, narrower leaves than the wild-collected specimens but otherwise match the type well.
Type: NE India, Manipur, Japvo, Naga Hills, 8000-9000ft, Watt 6212 (nolo. E; iso. K)
Occurs in Countries: IN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: lemon, purple, yellow
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):251
Shrub or tree to 15m. Twigs 2–4mm in diameter, rounded, sparsely scaly, quickly glabrescent; internodes 2–10cm. Leaves 3–7 together in tight pseudowhorls. Blade 40–140 x 25–50mm, elliptic, ovate-elliptic, or obovate-elliptic; apex shortly acuminate, acute or obtuse to rounded; margin entire, flat or weakly and narrowly revolute; base tapering to broadly tapering, laxly scaly and quickly glabrescent above; laxly to sub-densely scaly below. Scales rounded to weakly sub-stellately lobed, flat, with a broad margin and small slightly impressed centre. Mid-vein narrowly impressed above, weakly to strongly raised below; lateral veins 4–10 per side, spreading at 45–90°, curving before the margin, minutely impressed above, and smooth to weakly raised below, reticulation obscure to faintly visible on both sides. Petiole 5–12mm, grooved above, scaly. Flower buds to 15 x 12mm, spherical, often with an outer collarette of narrow subulate spreading or reflexed bracts, these often disappearing near maturity so that the bud is then smooth. Outer bracts ovate, inner ones sub-circular, obovate to spathulate with rounded or apiculate apices, all laxly scaly and minutely hairy outside and fringed with scales. Bracteoles to 15 x 1mm, linear to filiform, sub-spathulate distally, very laxly hairy or glabrous. Inflorescence of 5–15 flowers in a complete umbel. Pedicels 25–50 x c.1mm, slender, sparsely scaly, normally without hairs, but sometimes laxly covered with very fine, short hairs. Calyx 2–3mm in diameter, oblique, rounded, the lobes indistinct, margin often scaly. Corolla 10–25 x 20–30mm, shortly tubular or tubular-campanulate, light yellow to orange or yellow at the tube and/or centre, reddish orange at the lobes, variable in size, mostly scentless; tube 10–12 x 3–5 x 4–6mm, straight, 5-angular, lobed at the base, laxly scaly outside, densely hairy inside; lobes 12–20 x 8–14mm, broadly obovate-spathulate, laxly scaly outside, glabrous inside. Stamens strongly exserted to 15mm, spreading around the mouth of the flower, unequal; filaments linear and densely covered with spreading hairs in the proximal ½, glabrous and narrower distally; anthers 2.5–3.2 x c.1mm. Disc with thick lobes, mostly glabrous, rarely shortly hairy in the upper ½. Ovary c.4 x 1.8mm, elongate-conical, densely covered with sub-appressed hairs, which completely cover scales, tapering distally; style 10–15mm, densely to laxly hairy and scaly in the proximal ½, glabrous distally; stigma rounded to distinctly lobed. Fruit 35–45 x 3–5mm, fusiform, often slightly curved, strongly 5-ribbed, hairy and scaly. Seeds c.4mm including the long tail at both ends.
Habitat: Common and locally abundant, sometimes colouring hillsides with its flowers, mostly terrestrial, occasionally epiphytic, both in primary mossy forest, secondary shrubberies and often persisting in anthropogenic grassland in dry sunny situations.
Distribution: Indonesia and Papua New Guinea. Widespread over the whole mainland of New Guinea.
Altitude: 120-3000m
Named after Lady MacGregor, wife of the former Administrator of New Guinea and Lieutenant Governor of Papua, explorer and collector of natural history objects who promoted the expedition on which this species was first collected.
This species is well known to the local people in many places as poisonous to grazing animals and therefore it is often removed. A bizarre use was recorded by Clyde Smith (1984) who stated that the local people in the Western Highlands were mixing parts of R. macgregoriae with sweet potato and using this mixture to poison rats. He notes that the flowers are considered particularly poisonous. Natural hybrids are common, especially with R. zoelleri, the two species sometimes forming hybrid swarms in disturbed areas where the forest has been cleared. These hybrids have intermediate-sized flowers between those of the parents. Hybrids with longer tubes and scented flowers have been attributed to crossing with R. herzogii. Records of this species with pink flowers and corollas which are glabrous inside are now referable to R. glabrifilum; plants with pink flowers and hairy corollas may be hybrids with that species but more careful observations are needed.
Type: Bedford s.n., 1891. New Guinea (E), Mt Yule, top, c.3350m (MEL, BM, K).
Synonymy: R. hansemanni Warb., Bot. Jahr. 1892. 16: 26. R. vonroemeri Koord., Nova Guinea 1912. 8: 879, t.155. R. lauterbachianum Foerster, Fedde Rep. 1914. 13: 224. R. calceolarioides Wernham, Trans. Linn. Soc. London, II, Bot. 1916. 9. R. gorumense Schltr., Bot. Jahr. 1917. 55: 142.
Occurs in Countries: ID, PG Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Epiphyte, Tree Fl. Colour: orange, red, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:305
Shrub, 2-4m; young shoots soon ± glabrous. Leaves broadly elliptic, (6.5-)8.5-12(-17) x 3-5.2(-7.5)cm, 2.5-2.8 x as long as broad, apex acute to minutely apiculate, base cuneate, upper and lower surfaces glabrous when mature; petioles l-2(-3)cm, glabrous. Inflorescence 10-20-flowered; rhachis 15-30mm; pedicels glabrous, 30-60mm in flower, hardly elongating in fruit. Calyx c.lmm, glabrous. Corolla broadly campanulate, white to pink with yellowish flecks, 30-40mm. Ovary densely rufous-pilose; style glabrous. Capsule c.25 x 7mm.
Distribution: Western Seaboard of USA from the Canadian border to California. Forest margins, etc.
Altitude: 0-150m
Map in Little, Atlas United States Trees 3: map 152 (1976)
Allied to R. maximum
Type: NW Coast of N America, Menzies (iso. BM?)
Synonymy: R. californicum Hooker f., Bot. Mag. 81: t.4863 (1855). Type: W N America, mountains of California, Lobb (iso. BM, K).
Occurs in Countries: US Altitude Ranges: 0 - 1,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: pink, white, yellow
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):317
Low shrub, 0.3-lm; young shoots covered with greyish spreading-pilose, sometimes glandular hairs, also with a few bristles. Leaves dimorphic, ± deciduous, chartaceous; spring leaves ovate-elliptic, 2.5-7 x 1.5-2.5cm, 1.7-2.5 x as long as broad, apex acute, base cuneate, margin entire, upper surface sparsely glandular-pilose, lower surface more densely pilose, with a few setose hairs on midrib and main veins; summer leaves oblanceolate, 12-20 x 3-6mm, otherwise as for spring leaves; petioles c.5mm, densely pilose, also with a few flattened spreading setae. Inflorescence 2-10-flowered; pedicels 10-25mm, covered with long spreading pilose, partly glandular hairs. Calyx glandular-pilose, lobes lanceolate to broadly oblong, 15-30mm. Corolla broadly funnel-shaped, lilac-pink to rose-purple, with purple flecks on upper lobe, 35-50mm; tube 15-20mm, glabrous. Stamens 5(-7), slightly shorter than corolla, filaments pubescent below middle. Ovary glandular-setose, style glabrous. Capsule ovoid, c.lOmm, setose.
Habitat: Thickets, open forest
Distribution: Japan (Honshu, Shikoku)
Altitude: 150-400m
Illustrations:
27*. R. x enomotoi Yamazaki, J. Jap. Bot. 51: 31 (1976)óR. macrosepalum x R. indicum. Type: Japan, Prov. Aichi, Kitashidara-gun, cult., 27 v 1974, F. Yamazaki 974 (holo. TI, n.v.). This hybrid will key down to R. macrosepalum but differs in its smaller, 5-7mm, calyx, etc.
Possibly hybridizing with R. kaempferi (q.v.). R. macrosepalum may be the wild species from which R. linearifolium is derived.
Type: Two plants cultivated by Maximovicz, originating in Japan, 'in alpe altissime Nikkoo'(n.v.).
Synonymy: R. linearifolium Sieb. & Zucc. var. macrosepalum (Maxim.) Makino, Bot. Mag. (Tokyo) 27: 108 (1913). R. hortense Nakai in Nakai & Koidz., Trees Shrubs Japan ed. 1: 122(1922).
Occurs in Countries: JP Altitude Ranges: 0 - 1,000m Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: lilac, purple, rose
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):113
Shrub to 4m. Twigs thick, scaly, often white; internodes 6–9cm. Leaves 4–5 together in pseudowhorls. Blade 70–100 x 40–60mm, obovate-elliptic; apex broad to very broadly obtuse to rounded, sometimes apiculate; margin entire, flat; base tapering, slightly decurrent, glabrescent above with age, densely scaly beneath. Scales minute, the thin silvery, fragile marginal zone variously stellately lobed; centre thick, small, deeply impressed, flat. Mid-vein narrowly impressed above; beneath as thick as the petiole and very prominent proximally, decreasing upwards; lateral veins 6–7 per side, irregular, with shorter ones between them, all spreading and anastomosing, strongly impressed above, hardly raised beneath, reticulation faintly impressed above, slightly prominent or sometimes obscure beneath. Petiole 20–25 x c.3mm, grooved above, densely scaly, semi-rounded. Inner bracts elongate-spathulate, hairy on both sides, up to 30mm. Bracteoles linear, glabrous, up to 25mm. Inflorescence 8–10-flowered. Pedicels 40–80 x c.1.5mm, very densely scaly. Calyx 5–6mm in diameter, obliquely disc-shaped, irregularly 5-lobed, densely scaly outside. Corolla tubular below, abruptly expanded to the lobes, white; tube 60–70 x 5–6 x 10–15mm, sub-densely or laxly scaly outside and with dense appressed white retrorse hairs inside; lobes 25–30 x 25–30mm, sub-spathulate-obovate or sub-circular. Stamens exserted to 15mm; filaments linear, and densely covered with retrorse hairs proximally, more laxly hairy and slender upwards, glabrous and filiform for the distal 15mm; anthers 7–8 x 1.5mm, elongate-oblong, each cell narrowed into a distinct basal apiculus to c.1mm. Disc thick, 10-lobed, more densely hairy at, than between, the lobes. Ovary c.15 x 3mm, cylindrical, densely covered with coarse yellowish, distally directed hairs which cover scales, gradually tapering distally; style 1.5–2mm diameter proximally, gradually narrowing upwards, hairy for the proximal 2/3, more laxly hairy and scaly distally, glabrous for the ultimate 10mm; stigma c.2mm in diameter, globose, with thick lobes.
Habitat: Originally from a depression on peaty ground in primary forest, also from secondary vegetation. Locally common.
Distribution: Indonesia, New Guinea (W), Star Mts: near the mouth of the Minam R. into the Bon R., also from Koruppen Valley (139°38'E 4°28'S). Papua New Guinea, Hong Kong Hill, Ok Tedi headwaters, Kiunga, Western District.
Altitude: 1500-2000m
Greek – macro – long or great; siphon – relating to a tube. Alluding to the tube-shaped flowers.
Leaves similar to those of R. scabridibracteum in form and nervation. Said to be similar to R. carringtoniae and R. carstensense but differing in the more dilated corolla tube and larger lobes.
Type: Kalkman 4353, 2 July 1959. New Guinea (C), Star Mts, 1km east of the mouth of the Minam R. into the Bon R., 1500m (L).
Occurs in Countries: HK, ID, PG Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:173
Shrub or small tree, l-10m; young shoots with an evanescent tomentum. Leaves elliptic or oblong to obovate, 5-10 x 2.7-4.2cm, 1.5-3 x as long as broad, apex rounded, apiculate, base rounded, margin sometimes ciliate with shaggy hairs near the base, lamina of upper and lower surfaces glabrous at maturity, midrib covered with a thick tomentum composed of folioliferous hairs; petioles c. 1.5cm, tomentose at first, soon glabrescent. Inflorescence lax, 5-10-flowered; rhachis 2-3mm; pedicels 13-20mm, glabrous or tomentose. Calyx c.lmm, glabrous to tomentose, lobes rounded. Corolla open-campanulate, without nectar pouches, white, sometimes suffused with pale pink, with a purple blotch and a few flecks, 25—30mm. Ovary densely rufous-tomentose to glabrous. Capsule c.20 x 6mm, curved.
Habitat: Cliffs, woods, etc.
Altitude: 1200-3000m
The tomentum on the ovaries, calyx and pedicels is apparently the only reliable character separating subsp. maculiferum from subsp. anhweiense, a difference that does not merit maintaining them as separate species. The leaves of the latter are consistently small while those of the former are usually larger, though not always so. The present species is allied to R. pachytrichum.
Occurs in Countries: CN Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: pink, purple, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):272
Pedicels, calyx and ovary glabrous
Distribution: China (Jiangxi, Anhui, Zhejiang)
Synonymy: R. anhweiense Wilson, J. Arnold Arbor. 6: 163 (1925). Type: China, Anhui, Wang Shan, 29 viii 1923, !p, H. K. 4784, n.v.
Pedicels, calyx and ovary tomentose
Distribution: China (Sichuan, Guizhou, Guangxi, Gansu, Hubei, Shaanxi)
A variable taxon with respect to leaf shape though usually with an apiculate apex. A plant from Guizhou (Tu 3739) has smaller leaves than is usual in subsp. maculiferum; the calyx, pedicels and ovary are however densely tomentose.
Type: China, Sichuan, environs 'de Tchen-keou-tin, Farges 762 (iso. E, K)
Shrub up to 2 m, sometimes epiphytic. Leaves 60-160(180) x 28-60 (-80) mm, elliptic or broadly obovate, rarely somewhat ovate, acute to obtuse at the apex, cuneate at the base, elepidote above, densely lepidote beneath, the surface often brownish. Inflorescence (l-)2-5(-7)-f!owered, pedicels 5-15(-20) mm, lepidote. Calyx usually deeply 5-lobed, the lobes oblong to oblong-lanceolate, margins erose, usually glabrous, (2-5—)5—12(—16) mm. Corolla white, often flushed pink or purplish, more rarely wholly pink, usually with a yellowish blotch at the base, at first narrowly funnel-campanulate, later ± funnel-campanulate, (35-)60-85(-100) mm, the tube (20-)30-50(-60) mm, densely lepidote outside, the scales conspicuous on the tube and middle of the lobes. Stamens (15-)17-25(-27), filaments glabrous or sparsely pilose towards the base. Ovary (8-)10(-12)-Iocular, densely lepidote, tapering into the style which is lepidote over most of its length. Capsule 10-20 mm, (8-)10(-12)-ridged, lepidote, ovoid-globose to oblong-cylindrical.
A complex and very variable species (see below), which can be divided into two highly intergrading subspecies.
R. maddenii, as treated here, is the result of the amalgamation of all the six species of subseries Maddenii recognised by Hutchinson in his 1919 revision plus the later-described R. odoriferum. R. excellens, included by Hutchinson in subseries Maddenii in his Species of Rhododendron account, is excluded, as its affinities lie with R. dalhousiae and R. nuttallii. Although R. maddenii is variable in a large number of characters, it is impossible to distinguish species within it, as most of the variation is uncorrelated. For in-stance, stamen number, on which Hutchinson lays such stress, shows continuous variation from 15-25, and individual flowers occur which have 27. Different flowers on the same specimen may have different numbers of stamens. Hutchinson records 25 for the type of R. polyandrum (Cooper 1494); two further flowers dissected during this study had 17 and 19 stamens respectively. The number of stamens, on average, seems to increase from west to east, from Sikkim to western China '(S Xizang), and then to decrease further south and east into China. Similarly, there seems to be a cline in filament indumentum, from glabrous in the west (Sikkim and Bhutan) to the east (China), where all specimens examined had pubescent filaments. The density of the scales on the lower leaf surface is another character showing great variability, but not linked in any perceptible way with geography. Corolla size is also variable, even on an individual plant; for instance, one flower of Forrest 27150 is 47 mm long, whereas another is 87 mm. Similar, though less spectacular, differences occur in other collections, and, as a whole, corolla size shows continuous variation. Corolla shape varies with the age of the flower, the younger flowers being more tubular than the older. The only characters whose variability appears to have any taxonomic usefulness are leaf breadth and fruit shape, and even these are neither clear-cut nor completely correlated; hence the recognition of subspecies here.
Occurs in Countries: BT, CN, IN, MM Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: pink, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):33
Leaves more than 40 mm broad, usually 90-150(-180) x (4O-)55-80 mm, usually ± elliptic; capsules oblong-cylindrical, abruptly rounded to almost truncate at the apex; filaments usually pubescent.
Habitat: Cliffs, slopes, scrub and thickets
Distribution: India (Manipur), Burma, China (N, NW, W & SW Yunnan, SE Xizang), Vietnam
Altitude: 2400-3650m
Illustrations:
Synonymy: R. crassum Franchet, Bull. Soc. Bot. Fr. 34:282 (1887). Type: China, Yunnan, in dumetis ad Hou-tien-pa in monte Tsang-chan supra Tali, alt. 2500 m, Delavay 2112 (holo. P). R. maddenii var. obtusifolia Hutchinson, Bot. Mag. 134: t. 8212 (1908). Type: Manipur, Japvo, 8000-10000 ft, 9 iii 1882, Watt 6461 (iso. E). R. manipurense Balfour & Watt, Notes R.B.G. Edinb. 10:119 (1917). Type: as for R. maddenii var. obtusifolia. R. odoriferum Hutchinson, Gard. Chron. 82:30-32 (1927). Type: a cultivated specimen (holo. K). R. chapaense Dop in Lecomte, Fl. Gen. Indo-Chine 3:743 (1930). Type: Indochina, Tonkin, massif de Lo-sin-tong pres de Cha-pa, Poilane 12672 (holo. P)
Leaves less than 40(-55) mm broad, usually 60-110(-150) x 28-40(-55) mm, often obovate; capsule ovoid-globose, rounded to the apex; filaments often glabrous
Habitat: Hillsides, scrub, damp forest
Distribution: India (Sikkim, Arunachal Pradesh), Bhutan, China (SE Xizang)
Altitude: 1900-2600m
Illustrations:
Subsp. maddenii is extremely variable in corolla shape, stamen number and filament indumentum, all of which require further study in natural populations.
Type: Sikkim Himalaya, in thickets by the Lachen and Lachung rivers at Choongtam, 6000 ft, fl. vi-viii, fr. ix, Hooker (holo. K)
Synonymy: R. jenkinsii Nuttall, Hooker's Kew Journ. 5:361 (1853). Type: 'Bhutan' (i.e. India, Arunachal Pradesh, cf. Ludlow, Trans. Bot. Soc. Edinb. 41: 351-363, 1972), southern slopes of Oola mountain, 6-7000 ft, Booth (holo. K). R. calophyllum Nuttall, op. cit.: 362. Type: 'Bhutan', Booth (holo. K). R. macranthum Griffith, Notulae 4:303 & t. 520 (1854). Type: Bootan, Tongse, Griffith (n.v.). R. maddenii var. longiflora Watson, Gard. Chron. 15:684 (1894). Type: none cited. R. brevitubum Balfour f. & Cooper, Notes R.B.G. Edinb. 12:24 (1919), non J. J. Smith, Ic. Bogor. 4:253 (1914). Type: Bhutan, Punakka, 6-7000 ft, 27 vi 1915, Cooper 3936 (n.v.). R. brachysiphon [Balfour ex] Hutchinson, Notes R.B.G. Edinb. 12:24 (1919). Type: Bhutan, Punakka, 6-7000 ft, 27 vi 1915, Cooper 3936 (n.v.). R. polyandrum Hutchinson, op. cit.: 25. Type: Bhutan, Chapcha Thimpu, 8500 ft, 8 vii 1914, Cooper 1454 (holo. E)
Shrub to 1.5m. Twigs rounded, distinctly brown-scaly and minutely hairy, becoming glabrescent; internodes 2–10cm. Leaves 10–14 in loose pseudowhorls. Blade 40–80 x 13–40mm, narrowly to broadly elliptic, occasionally obovate; apex broadly acute, obtuse or rounded; margin entire, slightly revolute and with a narrow cartilaginous edge; base narrowly to broadly tapering, often decurrent; above with silvery small scales but quickly glabrescent; below with brown, more persistent impressed scales. Scales laxly arranged, rounded to weakly lobed, with a broad, striate marginal flange and a relatively large, slightly swollen centre. Mid-vein grooved and slightly raised or impressed in the proximal part, distally shallowly impressed above, slightly raised beneath and distinct to the apex; lateral veins 4–8 per side, spreading at 45–90°, moderately distinct and minutely impressed above, obscure to invisible beneath, reticulation inconspicuous. Petiole 3–8 x 1–3mm, distinctly grooved above, brown-scaly. Flower buds (see p.327) to 50 x 30mm, green or green strongly flushed with red, the outer bracts recurving but with the lateral margins strongly inrolled distally, appearing acute but slightly retuse if flattened out, with a few scales outside in the proximal ½, mainly in the central area. Inner bracts to 50 x 17mm, glabrous except for marginal scales near the apex, standing out vertically away from the bud to completely enclosing and ensheathing, ovate to elliptic with hooded apices. Pedicels 25–28 x 2–3mm, green to strongly flushed with red, especially in the proximal ½, scaly and shortly white-hairy. Inflorescence of 5–10, semi-erect to slightly hanging flowers in an open umbel. Flowers white with a greenish tinge on the tube or flushed very pale pink, without scent. Corolla 50–56 x 65–70mm; tube 30–33 x 6–8 x 16–20mm, glabrous outside, or with some short hairs near the base, hairy inside; lobes 30–36 x 23–29mm, at first semi-erect, later spreading horizontally, overlapping to c.¼, often with an irregular margin and retuse at the apex. Stamens mostly clustered in the lower 2⁄3 of the flower, sometimes arranged all round the mouth, exserted to c.6mm; filaments c.35mm, white with distally pointing hairs in the basal 1⁄3; anthers c.3 x 1mm, cream, becoming pale brown with age. Disc 10-lobed, with dense, white, erect hairs on the upper side. Ovary c.10 x 3mm, covered in short, white, slightly distally pointing hairs and pale translucent scales; style up to 25mm, glabrous except for the proximal 1–2mm which is densely hairy; stigma 3–5mm in diameter, white, 5-lobed, at first on the lower side of the mouth, rising to central position as it becomes receptive. Fruit 35–40 x 6–8mm, fusiform, often slightly curved and shallowly longitudinally grooved, green to purplish-red.
Habitat: Common in sub-montane shrubbery on ultramafic rocks.
Distribution: Philippines, Palawan, Mt Mantalingajan
Altitude: 1600-1800m
Named after Domingo Madulid, Chief of the Division of Botany in the National Museum, Manila, who greatly facilitated the collection of this species.
Known only from the type locality.
Type: Argent GAM 4 (19922782). Philippines, Palawan, Brooks Point, Mt Mantalingajan, 1600–1800m (PNH, E).
Occurs in Countries: PH Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:285
Tree, 13-18m. Leaves broadly obovate, 20-32 x 10-14(-17)cm, 1.7-2.3 x as long as broad, apex rounded, base cuneate, upper surface glabrous, lower surface with a thin but continuous, apparently bistrate indumentum, the lower layer compacted, the upper arachnoid; petioles 2-3.8cm, slightly flattened, narrowly winged, glabrous when mature. Inflorescence up to c.30-flowered; rhachis c.40mm; pedicels 8-15mm, stout, rufous-tomentose. Calyx c.lmm, rufous-tomentose, lobes triangular. Corolla 8-lobed, funnel-campanulate, rosy purple with darker nectar pouches, 45-60mm. Stamens c.16. Ovary densely rufous-tomentose. Capsule not known.
Habitat: Rain forest
Distribution: NE Upper Burma, China (adjacent parts of W Yunnan)
Altitude: 1800-2500m
Illustrations:
Only known for certain in the wild from the specimens cited above though the a specimen from Phyet in NE Burma (Toppin 6232) may also be this species. The origin of plants in cultivation is not certain though it is assumed that they have been raised from seed collected by Kingdon-Ward. These plants apparently have narrower leaves, c.3 x as long as broad, but clearly have the typical funnel-campanulate corollas, a character that suggests a close affinity with R. protistum and R. macabeanum.
Type: Burma-Tibet frontier, Adung Valley, 6000-8000ft, Kingdon-Ward9200 (holo, BM; iso. E) also Kingdon-Ward 9301, n.v.
Occurs in Countries: CN, MM Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: purple
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):250
Shrub to 2m. Twigs 3–5mm in diameter, rounded, tips laxly scaly; internodes 6–14cm. Leaves 6–10 together in well-marked pseudowhorls. Blade 50–90 x 22–40mm, elliptic; apex broadly tapering, obtuse; margin slightly revolute; base broadly tapering to rounded; sub-densely minutely impressed-spotted above with age, sub-densely and persistently scaly beneath. Scales dark, marginal zone coarsely dentate; centre slightly impressed. Mid-vein weakly impressed above, strongly prominent beneath, though more slender towards the apex of the lamina; lateral veins 9–10 per side, the lower 4–5 slightly curved, upper ones straight, all branched distally and anastomosing with each other and slightly impressed above, prominent beneath; finer reticulation dense and visibly prominent beneath. Petiole 4–10 x c.1.5mm, scaly. Flower buds to 30 x 15mm, ovoid, apiculate, reddish-brown, the tips of the bracts spreading to revolute. Outermost bracts narrowly triangular, reflexed becoming rolled back, inner bracts to 20 x 13mm, ovate, broadly reflexed, apiculate densely scaly and shortly semi-appressed hairy in the distal ½ and along the midline outside, densely brown scaly and minutely patently hairy inside in the reflexed apical portion, glabrous below, densely fringed with brown scales, the innermost (floral) bracts narrowly spathulate. Bracteoles 20 x 0.5mm, linear, white with just a few scattered scales. Inflorescence of (5)12–15 mostly horizontal flowers in an open umbel. Pedicels 10–25 x 2mm, thickened distally, sub-densely covered with thin reddish-brown scales. Calyx c.6mm in diameter, with irregular, triangular, obtuse or acute teeth, one of them often longer (up to 2mm). Corolla 70–90 x 25–30mm, trumpet-shaped, white, or white with a pink tube, sometimes darkening to red at the base, carnation-scented; tube 70–75 x 4–5 x 6–7mm, widest (7–8mm) at about ¾ of the distance from the base, slightly curved, laxly appressed-scaly outside, inside densely retrorse hairy in the proximal part, more laxly so in the upper part; lobes 12–14 x 10–17mm, obovate to circular, irregularly undulate at the margin, reflexing to right angles, the tips slightly more, glabrous except for some scales at the sinuses or the base of the lobes, overlapping ½–¾. Stamens at first clustered tightly at the upper side, exserted 7–8mm, later more irregular and spreading; filaments linear, laxly hairy in the proximal ½, gradually less hairy to become completely glabrous distally; anthers 3.5 x 1mm, narrowly oblong, base obtuse. Disc laxly appressed hairy or almost glabrous. Ovary 9–12 x 2mm, cylindrical or elongate-conical, tapering gradually distally, densely covered with coarse white or yellowish hairs, which cover the scales; style 50–55mm, densely patently hairy proximally, laxly hairy and scaly in the middle, glabrous in the upper 1⁄3; stigma globose-conical, crenulate.
Habitat: Terrestrial or epiphytic, in open places or on stream banks within the mossy forest.
Distribution: Indonesia, New Guinea (W), Hubrecht Mts, Lake Habbema and Mt Jaya. Papua New Guinea, Marafunga and a form on Mt Wilhelm with 5-flowered umbels.
Altitude: 2770-3000m
Latin – maius – large, alluding to the larger flowers than those of R. carringtoniae.
Sleumer’s adoption of the name as ‘maius’ cannot be maintained under the existing Code and the name reverts to J.J. Smith’s original spelling ‘majus’.
Type: Pulle (Versteeg) 2422, 7 Feb. 1913. New Guinea (W), Hubrecht Mts, 3200m (L).
Synonymy: R. carringtoniae F.Muell. var. majus J.J.Sm., Nova Guinea 1917. 12: 511.
Occurs in Countries: ID, PG Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: pink, red, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:176
Of Malaya – a general term for a wide area of the SE Asian archipelago at the time and indicating the place of origin.
Type: Jack s.n., Mt Bunko, 915m (destroyed, not yet lectotypified).
Synonymy: Vireya tubiflora Blume, Bijdr. 1826. 855. R. malayanum var. axillare J.J.Sm., Ic. Bog. 1919. 4: 74.
Occurs in Countries: ID, MY, TH Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Vireya Habit: Tree Fl. Colour: green, pink, red, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:121
Leaves broadly elliptic to ovate, the base rounded, the apex shortly obtusely tapering, base truncate-obtuse, 90–150 x 40–80mm.
Distribution: Malaysia (Borneo), Sarawak. Brunei. Indonesia, C and SE Kalimantan.
Altitude: 200-1500m
Type: Endert 3978. Borneo, SE Kalimantan, W Kutei, top of Mt Kemel, 1800–1850m (A, BO, L).
Erect shrub or small tree to 5m. Twigs rounded, slender, brown, with the tips very densely covered with flat, rounded or lobed persistent scales, quite distinct to the naked eye; internodes 2–10cm. Leaves 3–6 together in tight pseudowhorls. Blade 40–190 x 10–40mm, elliptic, or narrowly ovoid, variable in shape and size, tapering at both ends; apex mostly gradually shortly acuminate, the extreme point obtuse with a small gland, entire or indistinctly and irregularly denticulate in the upper ½; margin often slightly revolute especially proximally; base acutely tapering, scales very dense, silvery and glabrescent above, brown and forming a coherent, persistent overlapping layer beneath. Scales with the marginal zone thin, brown, becoming silvery with age, irregularly and mostly deeply crenate or lobed; centre dark-brown to almost black, large in relation to the marginal zone, leaving a small dark pit when the scale has gone. Mid-vein impressed above, prominent beneath proximally, less so distally; lateral veins 5–8 per side, irregular, mostly straight, anastomosing before the margin, obscure above, slightly raised beneath, reticulation obscure. Petiole 10–22 x 2–3mm, grooved above, semi-rounded in section, densely scaly. Flower buds both terminal and lateral, narrowly ellipsoid, to 15 x 6mm, the bracts fully appressed, totally brown-scaly except for the white, ciliate, margins and sometimes glabrous in a marginal strip. Bracts ovate-triangular or ovate to spathulate, densely scaly outside, glabrous green inside and densely white ciliate on the margins. Bracteoles to 15mm, filiform, slightly dilated at the apex, sometimes with a few small scales and with sparse white hairs in the upper ½ which become denser towards the apex. Pedicels slender, 6–10mm, moderately short-hairy, the hairs often completely covered by the scales. Flowers in open umbels of 1–5 which hang vertically down, without scent. Calyx oblique, small, 5-lobed, densely scaly, the lobes obtuse, sometimes up to 1mm. Corolla 15–30 x 17–22mm, waxy and glossy, bright red or purplish, to pink, or in albino forms greenish-white; tube 17–23 x 4–5 x 5–5.5mm, cylindrical, straight or slightly curved but laterally compressed, and often deeply grooved at the base, slightly dilated distally, sub-densely to sparsely scaly outside, glabrous inside; lobes 7–10 x 5mm, not or only very slightly overlapping at the base, mostly half-spreading. Stamens exserted to 6mm, unequal, loosely clustered on the lower side of the flower and turning downwards as the flower ages; filaments linear, nearly filiform above, glabrous; anthers 1.2–1.6mm, broadly oblong. Disc without hairs but covered with scales on the upper side. Ovary 4–5 x 1.5–2mm, oblong-conical, densely scaly, tapering distally; style 10–20mm, slender, equalling or slightly longer than the stamens and lying on the lower side of the corolla, mostly scaly in the proximal ¼–1⁄3, rarely so to ½, or glabrous except at the very base, green or white; stigma shortly club-shaped, hardly wider than the style. Fruit 22–33 x 3–4mm, fusiform, brown-scaly, the valves splitting and curling right back against the pedicel, the placentae breaking away from the base and weakly spreading. Seeds 7.5mm, without tails 0.8mm, the longest tail 3.5mm.
Distribution: Thailand (the extreme south). Malaysia, Peninsula; Sarawak, Sabah (Borneo). Indonesia, Kalimantan (Borneo), Sumatra, W Java, Sulawesi, Maluku.
This was the first vireya to be described, is the most widespread species in the subgenus and is subtly variable. Rhododendron vinicolor might be considered an extreme form differing in its linear leaves but otherwise having identical flowers, and R. micromalayanum similarly has identical flowers although smaller leaves (however, this leaf size can be approached in high altitude exposed forms of R. malayanum from both the Malay Peninsula and Seram). Professor Sleumer was mistaken to assert (1966) that only the Bornean forms produced lateral inflorescences; those in the Malay Peninsula often produce these also, both in the wild and in cultivation, and this character is not considered of great significance. Thus var. axillare has been included within the type variety. An odd form from West Malaysia has produced both terminal flowers and lateral inflorescences from bare leafless stems, thus being ramiflorous. The flowers of R. malayanum are recorded as constantly somewhat larger in Sulawesi compared with those of other islands, although it must be noted that R. nortoniae (Philippines) essentially differs from this species only in its larger flowers. The best colour forms of R. malayanum come from West Malaysia where it is decidedly montane in its ecology and occurs with deep reddish-purple glossy flowers which, although small, can be produced in great profusion in cultivation, making it an attractive plant when in full flower. In Borneo it can also be montane in its ecology but large-leafed forms come down almost to sea level in the heath (kerangas) forests, usually on peaty accumulations over white sand, where it can be a common and dominant feature of the vegetation. These large-leafed forms (forma latifolium) often have truncate or rounded leaf bases; they are undoubtedly different in physiology and have proved difficult to cultivate successfully. This species was one of the earliest in cultivation, although we are lacking precise records of its first appearance and the provenance of the plants first grown. It was one of the parents of the early ‘Veitch’ hybrids, and Henslow (1891) lists the horticultural hybrid ‘Little Beauty’ made by crossing a complex vireya hybrid with R. malayanum (probably of West Malaysian origin) which resulted in an improved type of R. malayanum which has long since disappeared from cultivation.
Wild hybrids are not recognised as common but see under var. pilosifilum, R. x hybridogenum and R. x wilhelminae. The hybrid between R. malayanum and R. vinicolor was collected on Mt Bandahara, exactly intermediate in leaf shape and growing between the two parent species. It is now thought that R. variolosum in southern Sarawak is the hybrid between R. malayanum and R. jasminiflorum.
Filaments laxly to sub-densely hairy in the proximal ½.
Habitat: On peat moor and light summit forest on limestone
Distribution: Malaysia (Borneo), Sarawak. Indonesia, Kalimantan (Borneo) near the Sarawak border; Maluku, C Seram and Buru
Altitude: 1075-1830m
The Bornean forms at least would suggest that var. pilosifilum represents hybrids with R. durionifolium or R. fallacinum: both species have hairy filaments and broad rounded leaf bases which could account for the broader leaf characteristics. The Kinabalu record of Sleumer (1966) has not been traced and has been discounted (Argent et al. 1988). A hybrid between this variety and R. ruttenii was collected above the village of Kanikeh in the Manusela National Park, Seram.
Type: Toxopeus Aa, Maluku, Buru, Kunturun (BO, L).
Synonymy: R. malayanum var. infrapilosum Sleumer, Reinwardtia 1960. 5: 103.
Corolla shortly hairy both inside and out, 30mm. Filaments hairy proximally. Leaves 80–120 x 25–50mm.
Distribution: Indonesia, Maluku, W Seram, Ora Mts, rare on steep limestone ridge, one record at 1000m.
Altitude: Around 1000m
Type: Stresemann 14, 2nd Freiburger Molukken Expedition (L, A).
Shrub or small tree, 1.5—6.5m, usually with a well-defined trunk; young shoots densely rufous-tomentose. Leaves broadly oblanceolate to obovate, 10-13 x 4.5-6.3cm, 1.8-2.3 x as long as broad, apex rounded, apiculate, base ± rounded, upper surface glabrous when mature except for the tomentose midrib, rugulose; lower surface covered with a dense rufous dendroid lanate tomentum; petioles 2-2.5cm, densely tomentose. Inflorescence 7-14-flowered; rhachis c.lOmm; pedicels 10-15mm, densely tomentose. Calyx 2—3mm, tomentose. Corolla fleshy, tubular-campanulate, crimson, 40-45mm. Ovary densely rufous-tomentose. Capsule c. 12 x 8mm, persistently tomentose.
Habitat: Cliffs, rocky slopes, thickets
Distribution: NE Upper Burma, China (W Yunnan)
Altitude: 3350-3650m
Illustrations:
Type: E Upper Burma, Hpimaw, 11-12000ft, 19v 1914, Kingdon-Ward 1567 (holo. E).
Synonymy: R. aemulorum Balfour f., Notes R.B.G. Edinb. 12: 86 (1920). Type: China, W Yunnan, eastern flank of the N'Maikha/Salween divide, 26°N, 11000ft, iv 1919, Forrest 17853 (holo. E)
Occurs in Countries: CN, MM Altitude Ranges: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: crimson
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):386
Shrub l-3m; young shoots covered with adpressed flattened reddish-grey hairs. Leaves dimorphic, coriaceous; spring leaves elliptic, 2-9.5 x l-4cm, 2-2.5 x as long as broad, apex acute, mucronulate, base cuneate, margin entire, upper surface + glabrescent, lower surface with scattered adpressed rufous hairs; summer leaves obovate, 10-40 x 5-20mm, otherwise as for spring leaves; petioles 2~4mm, densely covered with reddish strigose hairs. Inflorescence 7-12-flowered; pedicels 4-6mm, densely strigose. Calyx minute, covered with shining red-brown hairs, lobes inconspicuous. Corolla tubular-campanulate, lilac-pink, apparently without flecks, c.20mm, lobes spreading; tube c.lOmm, c.3mm wide at base, c.4mm wide below lobes, glabrous. Stamens 5, filaments glabrous. Ovary densely covered with shining rufous-brown hairs; style glabrous. Capsule ovoid, 6-8 x c.2mm, densely strigose.
Habitat: Open scrub, stream-sides, to 300m (1450m in subsp. kwangsiense)
Distribution: China (Guizhou, Guangxi, Guangdong, Hunan)
Type: China, Guangdong, circa coenobium Fi-loi-tsz, ad angustias Tsing-un, fl. North River, 2 iv 1882, Henry (Hb. Hance 22025) (holo. BM)
Occurs in Countries: CN Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: lilac
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):105
Leaves 4-5.5 x 1.5-1.8cm; corolla tube c.2mm at base
R. mariae is allied to R. chrysocalyx and R. meridionale but generally has broader leaves than either.
We consider that the varieties described by Tan are not worthy of formal recognition. Subsp. kwangsiense tends to have a more westerly distribution than does subsp. mariae but there is considerable overlap between the two subspecies.
Synonymy: R. kwangsiense [Hu ex] P.X. Tan, Survey Gen. Rhododendron S. China 105, f.7 (1983). Type: China, Guangxi, Longsheng Xian, 1450m, 31 iii 1955, Kwangju Exp. 353 (holo. IBSC, iso. KUN). R. kwangsiense P.X.Tan var. salicinum Tan, loc. cit. (1983). Type: China, Guangxi, Lingui Xian, 1952, C.F. Liang 30202 (holo. IBSC). R. kwangsiense P.X.Tan var. subfalcatum P.X.Tan, loc. cit. (1983). Type: sine loco, 13 vi 1928, R.C. Ching 5937 (holo. IBSC). R. kwangsiense P.X.Tan var. obovatifolium P.X.Tan, loc. cit. (1983). Type: China, Guangdong, Xinyi Xian, 1931, X.P. Gao (S.P.Ko) 51190 (iso. KUN).
Leaves (4.5-)6-8 x 2-3.7cm; corolla tube c.1mm at base
R. papyrociliare is described as differing from subsp. mariae in its thinner leaves and shorter calyx lobes. These two characters however, apparently vary independently from one another.
Synonymy: R. papyrociliare P.X.Tan, Guihaia 3: 179 (1983). Type: China, Guangxi, Singan Hsin (Xingan Xian), Guangxi PL Exp. 583 (holo. IBSC)
Shrub or small tree, l-3m; young shoots at first covered with adpressed yellowish hairs, becoming glabrous and grey. Leaves deciduous, ovate-lanceolate, sometimes broadly ovate, 3-7.5 x 2-4.5cm, apex acute, upper surface dark green, lower surface pale; petioles 5-~20mm, glabrous. Inflorescence 1-2-flowered, flowers appearing before leaves; pedicels 5-8mm, enclosed by bud scales, villose. Calyx minute, covered with grey/yellowish adpressed hairs. Corolla funnelform, 25-30mm, rose-purple, upper lobe spotted, 20-25mm, oblong. Stamens 10, equal, glabrous. Ovary yellowish-grey-villose; style glabrous. C´R._/ec.l0mm, cylindric, villose.
Habitat: Cliffs and thickets
Distribution: China (W Hubei, E Sichuan, Guizhou, Guangxi, Guangdong, Fujian, Hunan, Jiangxi, Zhejiang, Auhui), Taiwan
Altitude: 200-1300m
Differing from R.farrerae in its larger leaves and longer, glabrescent petioles and pedicels. Specimens from E Sichuan and W Hubei have broader, ovate-lanceolate leaves that apparently flush while the flowers are open; the remainder of the material has rhombic leaves that apparently flush after the flowers have opened. However, there are no other morphological differences between these two groups of plants so we arc hesitant to describe them as separate entities without further field studies.
Type: China, Hubei, 200-600m, Wilson 29 (E); Chongyang, Henry 5274 (E), 5947 (K); Badong (Paling), Henry 1422 (K); Nanto, Henry 3829 (K); Jiangxi, Kiukiang (Jiujiang ?), Maries, n.v.
Synonymy: Syn.: R. umbelliferum Levi., Repert. Spec. Nov. Regni Veg. 12; 102 (1913). Type: China, Guizhou, Pin fa, 2 iv 1902, Cavalerie 10 (holo. E). R. shojoense Hayata, J. Coll. Sci. Imp. Univ. Tokyo 30: 174 (1911). Type: Taiwan, Nantou, Kawakami & Mori 1160, n.v. R. gnaphalocarpum Hayata, Ic. PI. Formosan. 3: 132 (1913). Type: China, Fujian, Isan, 1910, Nagasawa 239, n.v.
Occurs in Countries: CN, TW Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Tsutsusi Habit: Tree Fl. Colour: rose
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):144
Much-branched shrub, 0.8-2m; young shoots usually stipitate-glandular or setose-glandular, occasionally glabrous. Leaves elliptic to obovate, 4.5—5 x 1.4-2.4cm, 2—2.3 x as long as broad, apex rounded, apiculate, base rounded, upper surface glabrous, lower surface punctulate, otherwise glabrous, occasionally with a few tufts of hairs even at maturity, glaucous; petioles 0.5-0.7 cm, with a few setulose glands or ± glabrous at maturity. Inflorescence lax, 1 —4-flowered; rhachis c.3mm; pedicels 20-30mm, glandular-setulose. Calyx 1—3mm, stipitate-glandular, lobes rounded. Corolla funnel-campanulate, pale yellow or white flushed rose, to pink, usually dark pink in bud, with or without purple flecks, c.30mm. Ovary and style-base densely stipitate-glandular. Capsule 20-25 x c.5mm, curved.
Habitat: Among scrub, forest margins, open pasture
Distribution: China(NW Yunnan, SE Xizang), ne Upper Burma.
Altitude: 3000-4250m
Closely allied to R. selense (q.v.)
Type: China, W NW Yunnan, Mekong/Salween divide, 28°10'N, 11000ft, ix 1914, Forrest 13301 (holo. E; iso. BM).
Occurs in Countries: CN, MM Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: pink, purple, rose, white, yellow
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):281
Shrub or small tree, 1.3-3.5m; young shoots tomentose and stipitate-glandular, soon glabrescent. Leaves oblanceolate to elliptic, 10-16 x 3-5cm, 3.3-4 x as long as broad, apex acute to shortly and bluntly cuspidate, base cuneate, upper surface glabrous when mature, lower surface with a thin fug-aceous indumentum that is embedded in a thin surface film and usually persists towards the base of the leaf, especially near the midrib; petioles 2-3cm, usually sparsely tomentose, even when mature. Inflorescence 14-25-flowered; rhachis 10-30mm; pedicels sparsely stipitate-glandular, 20-30mm in flower, up to 60mm in fruit. Calyx 3-5mm, stipitate-glandular, lobes rounded. Corolla campanulate, white to rose-purple, with yellowish-green flecks, 25-30mm. Ovary stipitate-glandular and pilose; style glabrous. Capsule 17-20 x 4-6mm.
Habitat: Upland woods
Distribution: Eastern USA & CANADA(from Nova Scotia to N Georgia)
Altitude: 300-1700m
Illustrations:
Map in Little, Atlas United States Trees 4: map 119 (1977)
Allied to R. macrophyllum
Type: USA, Virginia, Collinson, n.v.
Synonymy: R. procerum Salisbury, Prodr. 287 (1796), superfluous name. R. maximum L. var. purpureum Pursh & var. album Pursh, Fl. Amer. Sept. 1:297(1814). 1R. latifolium Hoffmannsegg, Verz. Pfl.-Kult. Nachtr. 2: 195 (1826). R. purpureum (Pursh) G. Don, Gen. Syst. 3: 843 (1834). R. purshii G. Don, ibid. 3: 843 (1834). Type: USA, Cedar swamps in New Jersey and Delaware, n.v. R. ashleyi Coker, J. Elisha Mitchell Sci. Soc. 51: 189, t.53, 54 (1935). Type: USA, N Carolina, Ashe Co., 2 miles from Lansing, 19 vi 1935, Ashley, n.v.
Occurs in Countries: CA, US Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: rose, white, yellow
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):316
Shrub to 2m. Twigs rounded, or fluted with longitudinal grooves in the youngest parts, 3–4mm in diameter, with small brown indistinct scales; internodes 2–9cm; lateral buds conspicuous, 3mm, conical. Leaves 3–5 large, and a few smaller together in distinct pseudowhorls. Blade 65–100 x 30–50mm, obovate or elliptic; apex rounded or retuse; margin slightly recurved; base broadly tapering; glabrescent above, laxly scaly but also often glabrescent beneath. Scales small, marginal zone variously lobed; centre dark, persistent, deeply impressed. Mid-vein strongly impressed above and raised below throughout its length; lateral veins 5–7 per side also slightly impressed above and raised below, dark-green above, paler green below. Petiole 7–12 x 4–6mm, strongly grooved above, initially with fine brown scales, green. Flower buds 14 x 9mm, ellipsoid, green or yellowish-green, with appressed, rounded or shortly apiculate bud scales. Inflorescence with 11–14 flowers held horizontally or half-hanging in an open umbel. Pedicels green or bright-red, densely scaly, sometimes also with hairs. Calyx a low ring covered in scales. Corolla c.26 x 30mm, shortly funnel-shaped, pale-yellow, often lightly flushed with pink outside on the tube, very strongly and sweetly scented; tube c.12 x 6 x 9mm, covered in scales and hairy inside at the base; lobes c.16 x 17mm, densely scaly outside, overlapping to c.halfway and broadly spreading nearly to the horizontal. Stamens evenly arranged in a circle at the mouth of the tube; filaments c.13mm, with patent hairs in the proximal 1⁄3; anthers 2.5–3.3 x c.0.8mm, oblong. Disc hairy at the upper margin. Ovary c.4 x 2.5mm, sub-conical, densely hairy and scaly; style 4–6 x c.2mm, patently hairy near the base only, cream; stigma c.2mm in diameter, green. Fruit c.15 x 7mm, ovoid-cylindrical. Seeds 2.3–2.6mm, without tails 1.0mm, the longest tail 0.8mm.
Habitat: Mossy sub-montane forest. On Kinabalu it is common in the zone of ultramafic soils dominated by bamboo; it usually grows on emergent trees although seedlings can be commonly found on the ground or amongst moss on tree trunks.
Distribution: Malaysia (Borneo), Sabah, Mt Kinabalu.
Named after Mr D.R. Maxwell, Assistant District Officer for North Keppel, who accompanied Miss Gibbs on her ascent of Mt Kinabalu in 1910 when she discovered this species.
Rhododendron maxwellii remains one of the Kinabalu endemics and has yet to be found anywhere else. This species appears to hybridise with R. rugosum giving rise to forms with pink, less strongly scented flowers but leaves very similar to those of pure R. maxwellii. These pink forms always occur on open ridges amongst R. rugosum but very close to forest containing typical R. maxwellii and it seems reasonable to regard them as hybrids. A beautifully scented plant with extra large flowers and intermediate leaves found on Kinabalu’s Eastern Ridge recently is thought to be a hybrid with R. lowii.
This species is the most strongly scented Bornean rhododendron and the flowers can often be smelled before they can be seen.
Type: Gibbs 4254. North Borneo, Mt Kinabalu, 1830–2440m (BM).
Occurs in Countries: MY Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:273
Shrub; young shoots glabrous. Leaves ovate-rhombic, 2.5-3 x 1.5-1.7cm, apex acute, upper surface at first hairy, lower surface with lamina glabrous, veins and midrib with brown hairs, especially towards base; petioles very short. Inflorescence 1-flowered, flowers appearing before leaves; pedicels 10-15mm, densely brownish setose-pubescent. Calyx inconspicuous. Corolla open funnel-campanulate, c.25mm, deep magenta, spotted, lobes c.20mm, oblong. Stamens 10, unequal, filaments glabrous. Ovary densely brownish setose-strigose; style glabrous. Capsule 8 x 3mm.
Habitat: Wooded hillsides
Distribution: Japan (S Kyushyu)
Altitude: 600-1000m
Illustrations:
Close to R. nudipes but differing in the less hairy leaf undersurfaces and the densely pubescent pedicels. Var. obsumiense is supposed to differ in the sparsely hirsute lower surface of its leaves. We do not consider this to be a sufficient difference to merit recognition.
Type: Japan, Kyushyu Prov., Higo, in Mt Kurobaru, 1017m, 24 iv 1927, Mabare 2159, n.v.
Synonymy: R. nudipes var. mayebarae Nakai & Hara in Acta Phytotax. Geobot. 25 (2-3): 37 (1972). R. mayebarae Nakai var. obsumiense Yamazaki, J. Jap. Bot. 59: 209 (1984). Type: Japan, Pref. Kagoshima, Aranishiyama, 800-900m, 21 ix 1977, Takeda (holo. TI, n.v.).
Occurs in Countries: JP Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Tsutsusi Habit: Non-Tree
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):149
Shrub, l-2.3m; bark shghtly rough; young shoots glabrous. Leaves obovate to broadly elliptic, 8—11(—15) x 4.5-5.2(-8.2)cm, 1.8-2.4 x as long as broad, apex retuse to apiculate, base rounded to ± cuneate, entirely glabrous, lower epidermis epapillate, green; petioles 1 —1.5cm, glabrous. Inflorescence 6-10-flowered; rhachis c.5mm; pedicels 10-20mm, glabrous. Calyx 3—12(— 18)mm, fleshy, cupular, reddish, glabrous, lobes rounded, broad. Corolla fleshy, tubular-campanulate, deep rose to deep blackish crimson, 40—65mm. Ovary glabrous to densely glandular and viscid. Capsule 15-20 x 6—7mm.
Habitat: Open rocky slopes, Rhododendron thickets
Altitude: 2700-3600m
One specimen, Forrest 18073, is intermediate between the two varieties. Var. atrokermesinum has a more northerly distribution than does var. meddianum though there is some overlap.
Occurs in Countries: CN, MM Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: black, crimson, rose
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):423
Ovary densely glandular and viscid
Distribution: NE Upper Burma
Type: NE Upper Burma, western flank of the N'Maikha/ Salween divide, 10000ft, iv 1925, Forrest 26499 (holo. E)
Ovary ± glabrous
Distribution: China (W Yunnan) & NE Upper Burma.
Illustrations:
Type: China, W Yunnan, Shweli/Salween divide, 10-11000ft, vi 1917, Forrest 15767 (holo. E; iso. K)
Shrub of 1 -3-5 m. Leaves elliptic to obovate, tapering to the somewhat rounded base, the apex very rounded, 100-160 x 45-75 mm, lower surface brownish with heteromorphic, subcontiguous scales, the smaller rimless, deeply sunk in pits, the larger with rims and less deeply sunk, all golden or brownish. Inflorescence 2-6-fIowered, pedicels 15-32 mm, accrescent and divaricate-reflexed in fruit, glabrous and elepidote or rarely slightly lepidote. Calyx very large, lobed from half to almost its total length, cuplike, reddish, lobes broadly elliptic, rounded at the apex, 22-30 x 14-20 mm, glabrous and elepidote, accrescent and becoming papery in fruit, whitish pruinose. Corolla white or cream, rarely flushed pinkish purple, funnel-campanulate, mouth very oblique, 65-95 mm from base to apex of the longest lobe, tube c. 50 mm, very sparsely lepidote outside. Stamens 10, filaments pubescent in the lower part. Ovary densely lepidote, tapering into the style, which is lepidote at the base. Capsule 20-25 x 12-15 mm, cylindric-globose, lepidote, shorter than to as long as the persistent calyx.
Habitat: Forests, scrub, thickets, often near water
Distribution: India (Arunachal Pradesh), NE Burma, China (NW & W Yunnan, SE Xizang)
Altitude: 2000-3350m
Illustrations:
A very distinctive species
Type: E Upper Burma, Nwai valley, 4 vi 1904, Kingdon Ward 1628 (holo. E)
Occurs in Countries: CN, IN, MM Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: cream, pink, purple
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):41
Free-growing or rarely epiphytic shrub, 0-3-1 m. Young shoots loriform-setose, the setae persistent for at least one year. Leaves elliptic or elliptic-obovate or ± orbicular, 19-36 x 12-20 mm, obtuse at the apex, rounded to the base, upper surface glabrous except for a few setae at the base of the midrib, margins loriform-ciliate, lower surface whitish-papillose with vesicular scales sunk in pits with crenulate margins; petiole loriform-setose. Inflorescence l-2(-3)-flowered, pedicels loriform setose, shorter than the flowers, not or scarcely lepidote. Calyx lobes green, obovate, (6-)7-10 mm, sparsely lepidote outside, sparsely to densely loriform-ciliate. Corolla broadly campanulate, yellow or rarely cream, sometimes darker spotted, lepidote outside, (16-) 17-23 mm, tube 8-10 mm. Ovary lepidote. Capsule ovoid-cylindric, lepidote, 8-11 mm.
Habitat: Rock and cliff ledges or among boulders, rarely epiphytic
Distribution: India (Arunachal Pradesh), ne Burma, China (NW Yunnan, S & SE Xizang)
Altitude: 3050-4150m
Illustrations:
Type: China, NW Yunnan, Kari pass, Mekong/Yangtze Divide, 12-13000 ft, viii 1914, Forrest 18942 (holo. E). PI. 2k &
Synonymy: R. tapeinum Balfour f. & Farrer, Notes R.B.G. Edinb. 12:164 (1920). Type: NE Burma, Chimili cliffs, 12-13000 ft, 18 v 1919, Farrer 938 (holo. E)
Occurs in Countries: CN, IN, MM Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Epiphyte, Non-Tree Fl. Colour: cream, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):136
Shrub to 1m. Twigs green, rounded, rough with hairs and scales; internodes 1–3cm. Leaves in dense pseudowhorls of 8–12. Blade 12–27 x 12–18mm, broadly elliptic, oblong or obovate; apex broadly pointed, or rounded occasionally slightly retuse; margin entire, slightly recurved, often red; base rounded to tapering; covered with simple white hairs and sub-densely scaly. Scales irregularly lobed with a broad marginal flange and small impressed centre. Mid-vein slightly impressed above and broadly but shallowly raised beneath for most of its length; lateral veins obscure or 3–5 per side, slightly raised below and spreading at c.45°. Petiole 1.5–3 x 2.2–2.6mm, green, hairy and scaly, broadly but shallowly grooved on the upper side. Flower buds (see p.327) 18 x 10mm, ovoid, purplish red, surrounded by a collar of green, narrowly triangular, to subulate cataphylls; outer bracts narrowly ovate with subulate protruding tips; inner bracts broadly ovate with mucronate appressed apices, densely silvery white hairy distally on the outer sides, less densely so on the inner side. Inflorescence of 7–8 white or pale purplish-pink semi-erect to horizontal flowers in an open umbel, without scent. Pedicels c.10 x 1.25mm, densely white-hairy and with some brown scales. Calyx a low, densely white-hairy ring. Corolla occurring in two size classes: large, c.26 x 45mm with the tube c.17 x 15 x 7mm and lobes 22 x 24mm; and small, c.25 x 31mm x 29mm, tube 12 x 5 x 10mm and lobes c.16 x 15mm, with scattered brown scales outside and some simple hairs inside on the tube; lobes semi-erect to spreading, overlapping from 2⁄3 to most of their length and with some brown scales outside. Stamens clustered below the mouth of the flower; filaments 9mm, broadening and hairy in the proximal 1⁄3; anthers 3 x 1mm, brown, incurved to completely obscure the stigma when young, later straightening. Ovary 3 x 3mm, densely white hairy with semi-erect hairs; style 3mm, rough, hairy at the base otherwise glabrous; stigma 1.5–2.5mm in diameter. Fruit 16 x 8mm, the valves stiffly spreading, only slightly curving. Seeds 2mm, without tails 1.1mm, the longest tail 0.5mm.
Habitat: It is only known growing terrestrially around the summit of Mt Tambuyukon. In open shrubby vegetation amongst ultramafic rocks.
Distribution: Malaysia (Borneo), Sabah.
Altitude: 2400-2500m
Named after Dr Willem Meijer, Dutch botanist and outspoken conservationist, who found this species on the first known ascent of Mt Tambuyukon.
A very distinct species with its small, elliptic to obovate, very hairy leaves and short, pale pink to white flowers. Professor Sleumer knew of this species from a colour slide taken by Willem Meijer but he got only sterile specimens at Leiden and would not describe it from these fragments.
Type: Meijer SAN 34640, July 1961. Malaysia, Sabah, G. Tambuyukon, 2450m (SAN).
Occurs in Countries: MY Altitude Ranges: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:198
Shrubs to 2 m, often flowering precociously. Young growth lepidote and variably loriform-setose with straight or curved setae. Leaves ± deciduous, flat, mostly ± obovate, more rarely obovate-elliptic, 25-45(-65) x 14-21 (-27) mm, ± rounded at the apex, cuneate at the base, petiole loriform-setose; lower surface variably loriform-setose, usually with at least some setae on the base of the midrib and on margins, the setae straight or slightly curved; scales very unequal, dense, the larger c. 2 x the diameter of the smaller, the smaller usually rapidly becoming greyish, purple or almost black; upper surface puberulent at least along the midrib, rarely lepidote. Inflorescence 2-4-flowered, pedicels (11-) 15-22 mm, variably lepidote, usually loriform-setose, at least towards the base. Calyx usually obscurely lobed, lobes up to 2-5 mm, rarely one lobe considerably longer (up to 7 mm), lepidote, loriform-ciliate or glabrous. Corolla yellow to greenish yellow, sometimes flushed with red, 17-23 mm, tube 8-11 mm, lepidote and glabrous outside. Ovary lepidote, style sometimes puberulent at base. Capsule lepidote, cylindric, 9-11 mm.
A very variable species with a wide distribution area; four intergrading varieties can be distinguished
Occurs in Countries: CN, IN, MM, NP Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: green, red, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):154
Leaves loriform-setose over the whole upper surface
Habitat: Slopes, thickets and scrub
Distribution: N Burma, China (NW Yunnan, S & SE Xizang)
Altitude: 3050-4000m
Synonymy: R. trichocladum var. longipilosum Cowan, Notes R.B.G. Edinb. 19:186 (1936). Type: SE Tibet, Migyitun, 10-11000 ft, vii 1935, Kingdon Ward 11915 (holp. E)
Leaves without loriform setae on the upper surface. Loriform setae more widespread, present on at least some of the following: lower leaf surface, pedicels and calyx lobes, as well as on petioles and leaf margins. Calyx loriform-ciliate; pedicels usually loriform-setose over their whole length.
Habitat: Scrub, forest margins, slopes
Distribution: Nepal, NE Burma, China (NW Yunnan, S & SE Xizang)
Altitude: 2900-4400m
Very similar to var. meiinanthum, with which it overlaps in some areas, but extending further north and west. The remarkable gap in its distribution (from eastern Tibet to Nepal) is partially filled by var. longipilosu/n, but is still striking. Whether or not it represents an actual situation or lack of collections from intermediate areas at the right time of year is uncertain; but there is no doubt that the Nepal plant (one specimen, Stainton 580) is the same as that from China. The name R. viridescens has been applied to an almost completely evergreen variant, known only in cultivation. The recently described R. rubroluteum is also unknown from the wild; it is typical of var. mekongense except that the corollas are flushed with red.
Type: China, Yunnan, vallee du Mekong, a Sela entre le Mekong et Saluen, 28 vi 1895, Soulie (holo. P—n.v., iso. E)
Synonymy: R. viridescens Hutchinson, Gard. Chron. 94:116 (1933). Type: a cultivated specimen said to originate from seed of Kingdon Ward 5829 (holo. K, iso. E). R. rubroluteum Davidian, Quart. Bull. Amer. Rhodo. Soc. 29:144 (1975). Type: a cultivated specimen said to be from seed of Kingdon Ward 5489 (holo. E)
Leaves without loriform setae on the upper surface. Loriform setae more widespread, present on at least some of the following: lower leaf surface, pedicels and calyx lobes, as well as on petioles and leaf margins. Calyx glabrous; pedicels not setose, or setose only at the base.
Habitat: Forest, forest margins, scrub and slopes
Distribution: NE Burma, China (NW Yunnan, SE Xizang)
Altitude: 3350-4250m
Illustrations:
Synonymy: R. melinanthum Balfour f. & Kingdon Ward, Trans. Bot. Soc. Edinb. 27:85 (1916). Type: China, Yunnan, Ka-gwr-pw glacier valley, 12-14000 ft, vi 1913, Kingdon Ward 406 (holo. E). R. chloranthum Balfour f. & Forrest, Notes R.B.G. Edinb. 12:98 (1920). Type: China, Yunnan, Li-ti-ping, 11000 ft, vi 1917, Forrest 13900 (holo. E). R. semilunatum Balfour f. & Forrest, op. cit. 13:292 (1922). Type: China, Yunnan, Mekong/Yangtze Divide, ascent of Wei hsi pass, 10000 ft, ix 1904, Forrest 698 (holo. E)
Leaves without loriform setae on the upper surface. Loriform setae very sparse, restricted to petioles and leaf margins and sometimes at the base of the midrib beneath.
Habitat: Rocks, slopes, forest margins, rarely in swamps
Distribution: India (Arunachal Pradesh), China (NW Yunnan, S & SE Xizang)
Altitude: 3350-4250m
A taxon of sporadic occurrence throughout the area - R. mekongense, identifiable by its almost complete lack of loriform setae, and red-tinged corollas. It was described on the basis of an unnumbered Forrest specimen (holo. E), said to come from the Tali range. However, there is nothing else like it known from the Tali area, but the specimen (which was enclosed in a letter from Forrest to 1. B. Balfour) matches well with another collection made in the same year from the Kari pass, which Balfour and Forrest designated as a paratype (Forrest 13914). It is possible that the original type specimen was collected at 'Kari' rather than 'Tali'. One branch of the paratype specimen bears a few lateral inflorescences, which may indicate natural hybridisation with some member of subsection Triflora; most plants in cultivation under the name 'rubrolineatum'show the same feature, and may well derive ultimately from this collection.
Synonymy: R. rubrolineatum Balfour f. & Forrest, Notes R.B.G. Edinb. 12:160 (1920). Type: see below
Much-branched shrub to 50cm. Twigs spreading, densely leafy, densely reddish brown-scaly in the young parts, the internodes short. Leaves 24–40 x 12–17mm, opposite, elliptic, sub-sessile, the apex obtusely acuminate; base tapering, laxly reddish-brown-stellate-scaly beneath, glabrescent above. Petiole 2–4mm, reddish-brown scaly. Flowers solitary. Pedicels c.15mm, slender, densely reddish-brown-scaly. Calyx c.2.5mm in diameter, reddish-brown-scaly, very shortly 5-lobed. Corolla tubular, strongly zygomorphic, dark blood red, slightly curved and dilated to c.10mm diameter at the apex, sparsely shortly hairy outside, glabrous inside, 27mm long, lobes c.7mm in diameter, obovate-sub-circular, truncate-obtuse. Stamens c.23mm; filaments filiform, sparsely hairy; anthers 2.5mm, oblong, blackish red. Ovary oblong, slightly 5-grooved lengthwise, densely reddish-brown hairy; style filiform, shortly finely hairy, almost equalling the stamens in length; stigma globose, 5-lobed.
Distribution: Papua New Guinea, Schrader Mts, once found in mountain forest
Altitude: Around 2070m
Greek – melas – black; antherae – anthers. Alluding to the very dark colour of the anthers.
No type material is known to be preserved; this description is drawn from Sleumer’s (1966) translation of the original. This remains an imperfectly known species.
Type: Ledermann 12161. New Guinea (NE), Schrader Mts (B†, no lectotype designated).
Occurs in Countries: PG Altitude Ranges: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:91
Shrub to 5m. Twigs rounded, laxly covered with rounded or lobed, slightly elevated scales, becoming glabrescent, leaving the surface smooth; internodes 1.5–7cm. Leaves in loose pseudowhorls, 5–11 together at the 2 or 3 upper nodes. Blade 18–40 x 8–19mm, obovate; apex rounded and mostly shortly retuse; margin entire, distinctly but narrowly revolute; base narrowly tapering, laxly to sub-densely scaly on both sides initially; above the scales in depressions, the centres sub-persistent, often bleaching to white; below, slightly impressed, brown, more persistent. Scales very variable in size, sessile, circular, sub-entire, marginal flange narrow, centre thick. Mid-vein impressed above, strongly raised beneath especially in the proximal 2⁄3; lateral veins 2–5 per side, or obscure. Petiole 2–4 x 0.75–1mm, grooved above, brown-scaly. Flower buds to 7 x 3mm, green, narrowly ovate, apiculate, smooth. Outer bracts subulate, densely scaly, inner ones ovate, acuminate, apiculate, appressed white-hairy and brown scaly outside, mostly distally. Bracteoles c.3.3 x 0.5mm, filiform, slightly broadened upwards. Flowers solitary (rarely in pairs), half-hanging to vertically hanging. Pedicels 8–12 x 0.75mm, laxly hairy and scaly, or scaly only. Calyx oblique, small, obtusely 5-lobed, scaly outside, margin white ciliate. Corolla 25–30 x 12–15mm, orange or yellow; tube 20–25 x 4–6 x 6–8mm, cylindrical, straight or very slightly curved, laxly scaly outside, glabrous inside; lobes 6–7 x 4–5mm, ovate, half-spreading, only slightly overlapping at the base, minutely crenulate and/or ciliate around the margins. Stamens clustered on the lower side of the flower, exserted to c.4mm; filaments 25–29mm, linear, flat, nearly 1mm wide at the base, filiform upwards, glabrous; anthers c.1mm, sub-orbicular, dark brown. Disc glabrous. Ovary 3–4 x c.1.8mm, oblong-conical, densely scaly, gradually tapering distally; style 16–24mm, lying on the lower side of the flower, glabrous or with a few scales at the base; stigma club-shaped, green, c.1mm in diameter. Fruit 11–16 x 4–5mm, fusiform, longitudinally grooved, scaly, the valves curving back, the placentae only weakly breaking away from the base.
Habitat: Locally common to abundant, mostly epiphytic, often in limestone areas.
Distribution: Indonesia, Maluku, Buru, summit of Mt Togha, C Seram, Mt Murkele, Mt Binaia; Sulawesi, (C) Mt Roroka Timbu, (NW) Mt Sojol.
Named after the bird Meliphaga stigmatops Deningeri (a honey eater); said to be one of this bird’s favourite flowers.
Flowers Feb., July.
Type: Stresemann 374, Feb. 1912. Moluccas, Buru, summit of Mt Togha, 1800–2050m (L).
Occurs in Countries: ID Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: orange, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:51
Shrub to c.1m. Stems pale green, rounded, c.3mm in diameter, moderately densely covered in brown stellate scales. Leaves in loose pseudowhorls 3–8cm apart. Blade 40–75 x 17–30mm, narrowly obovate, occasionally elliptic; apex obtuse with a somewhat obscure, white, non-protruding, gland-like structure at the point; margin entire, flat or slightly and narrowly recurved; base tapering, often slightly decurrent. Mid-vein narrowly impressed above, distinctly prominent in the proximal ½–2⁄3 beneath, pink especially towards the base; lateral veins smooth, indistinct, 5–8 per side, the basal arising at an acute angle, the upper ones wide-spreading, all disappearing before the edge of the leaf: at first scaly with silvery or brown scales above but quickly glabrescent; below persistently brown scaly. Scales rounded to weakly lobed with darker centres which are often as broad in diameter as the flanges, distributed 1–2 diameters apart in the mature leaves. Petiole 4–7 x 2–3mm, faintly grooved above, pale green or pale pink with brown scales. Flower buds green, becoming almost white in the distal ½ just before opening, to 40 x 22mm, conical, but contracted near the base, acutely pointed, imbricate with the tips of the bracts reflexed. Bracts minutely hairy and with a few small, scattered brown scales outside and scales along the margins, inner bracts often shortly emarginate. Pedicels 18–22 x 2–3mm, green, laxly scaly but without simple hairs. Flowers 1 or 2 together, terminal, held more or less horizontally, white with a cream throat, very strongly and sweetly scented. Calyx a lobed disc, densely scaly below, less so near the perimeter. Corolla 52–60 x 102–105mm; tube 26–30 x c.15 x 17–24mm, glabrous outside but with retrorse white hairs in the proximal ½ inside; lobes c.46 x 35–46mm, spreading horizontally, overlapping to c.½ their length, with a rather irregular ‘frilled’ margin. Stamens clustered on the lower side of the flower, exserted 20–25mm from the mouth; filaments 38–43 x 0.2mm wide expanded suddenly for the basal 2.5mm to c.1.4mm wide, glabrous but densely white hairy in the basal expanded portion, white, slightly dimorphic; anthers c.7mm, brown, shortly but distinctly apiculate at the base. Disc green with dense short, white, erect hairs. Ovary c.6 x 5mm, broadly trapezoid in outline, densely silvery scaly and with sparse short patent hairs mostly towards the top; style c.50mm, cream, lying on the lower side of the corolla tube but curving upwards when the stigma becomes receptive, densely patent-hairy and sparsely scaly in the proximal 1⁄3, the scales arising on low papillae; stigma 4–7mm in diameter, white, crown-shaped, exserted up to 15mm beyond the anthers. Fruit 25 x 12mm, pale-green with a covering of dense brown scales, the outer skin only weakly separating from the valves which curve outwards on opening without twisting, the placentae separating from the central column. Seeds c.2.3mm, without tails 1mm, the longest tail 0.8mm.
Habitat: In mossy sub-montane forest. Known only from the type locality.
Distribution: Philippines, Palawan, Cleopatra Needle
Altitude: Around 1600m
Named in memory of Mary Mendum (1945–2004) who was on the expedition which collected this species: a tireless enthusiast for SE Asian botany and respected research worker.
Rhododendron mendumiae is similar to R. madulidii from Mt Mantalingajan near the southern tip of Palawan but that species has many more flowers in the inflorescence, shortly hairy stems and pedicels, and very different flower bud morphology with erect not reflexed tips to the bracts. Vegetatively, it looks very similar to R. jasminiflorum var. copelandii, but the massive flowers of this new species are totally different to the slender flowers with very small lobes of that species and the bud morphology again is also very different.
This very distinctive species is associated with section Euvireya on the basis of its short, broad, corolla tube relative to the enormous lobes and the well-spaced, stellate scales on the leaves. It is anomalous in that, from the single observation of fruit dehiscence, the outer skin remains closely attached to the valves, only weakly separating near the tips, but it clearly does not belong in the groups with adherent outer skins from the scale morphology. When this species flowered in cultivation for the first time in 2002 with a single flower, it was thought this must be an anomalous peloric form but the following year 2-flowered inflorescences were produced on several plants and it was concluded that these large flowers are normal. The seeds are unusual in having such short tails; these are characteristic of vireyas which occur in open situations on mountain peaks – R. retusum, R. adinophyllum and R. abietifolium have similar seeds with very reduced tails. Since this species was collected near the summit of Cleopatra Needle where the vegetation was dense, mossy forest, this is a surprising character. Plants have been raised from both seed and cuttings collected in the wild and from the isolation of the peak it seems virtually impossible that these are hybrids.
Given the isolation of the habitat and the very restricted area of mossy forest on the mountain, the population of this species is very small and must be vulnerable to any kind of habitat disturbance.
Type: Argent, Chavez, Cronk, Fuentes, Mendum, Middleton & Wilkie 53, 22 Jan. 1998. (Cultivated collection: 20 Sept. 2003, Acc. No. 19981815), Philippines, Palawan, Cleopatra Needle (PNH, E).
Occurs in Countries: PH Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:277
Tree, c.6m. Leaves sub-coriaceous, narrowly oblanceolate, 10-14.5 x 2.3-3.2cm, 4-4.5 x as long as broad, apex cuspidate, base cuneate, upper surface glabrous when mature, though sometimes midrib tomentose towards base, lower surface glabrous except for the tomentose midrib towards base, with minute red punctate hair bases persisting; petioles c.lcm, densely matted-tomentose, hairs dendroid. Inflorescence c.8-flowered; rhachis c. 15mm; pedicels c.20mm, densely setose-glandular. Calyx c.lmm, setose-glandular, lobes rounded. Corolla campanulate, glabrous within, reddish-purple, apparently with darker nectar pouches, c.40mm. Ovary densely hairy, with rufous setae and setose glands; style glandular to tip. Capsule not known.
Habitat: Montane forests
Distribution: China (SE Yunnan)
Altitude: Around 2300m
R. mengtszense shows some affinities with species in subsection Maculifera in the indumentum on the petioles and pedicels. The punctate hair-bases and glandular style do however suggest that it is correctly placed in subsection Irrorata.
Type: China, SE Yunnan, SE of Mengtsz, 7000ft, Henry 10275 (holo. E; iso. K).
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: red
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):292
Shrub, 2-3m; young shoots covered with +adpressed-strigose hairs. Leaves dimorphic, chartaceous; spring leaves narrowly lanceolate, 2-7.5 x 0.3-1.2cm, c.6 x as long as broad, apex acute, base cuneate, margin entire, ciliate, upper surface sparsely strigose, lower surface paler, sparsely strigose, more densely so on midrib; summer leaves 13-23 x 4-5mm, otherwise as for spring leaves; petioles c.lmm, strigose. Calyx c. 1 mm, lobes minute, strigose. Corolla funnel-campanulate, lilac-purple, c.30mm; tube c. 13mm, 5-6mm wide at base, widening above, glabrous. Stamens 5, puberulent below. Ovary densely strigose; style glabrous or strigose below. Capsule ovoid, 8-10mm long, strigose.
Distribution: China (SW Guangxi)
18.* R. longifalcatum P.X.Tan, Guihaia 2: 73, f.6 (1982). Type: China Guangxi, Shangsi Xian, Shiwandashan, 200m, 8 iii 1944, S.Q. Chen (S.H. Chun) 4664 (holo. IBSC). Map 5. Differs from R. meridionale in its apparantly thinner, oblong lanceolate leaves that are more densely tomentose below, in its calyx with crenulate lobes and in its obovate oblong corolla lobes. Known only from the type. Tan separates R. meridionale from R. longifalcatum in his key by the stamens being longer than the style.
Var. satistylum is distinguished by its strigose style base, a difference that we find unconvincing. Var. minor has a distinctive appearance on account of its small leaves and is maintained here, even though the type and only specimen seen lacks flowers.
Closely allied to R. hainanense and perhaps conspecific, but differing in the ± obsolete calyx, in the fewer (5) stamens and in the 5-6-flowered inflorescence. Most of the material cited by Tan comes from Shiwanda Shan in Guangxi Prov. or close to it. Typical R. hainanense also apparently occurs on the same mountain, and at least one specimen (Ceng, II.D. 24778) from that locality is intermediate, with the small calyx of R. meridionale, but the 3-flowered inflorescence and 7 stamens of R. hainanense. Several of Tan's records of both species from Shiwanda Shan, refer to fruiting specimens and are evidently identified on the basis of the presence or absence of a large calyx. As there is no difference in the vegetative characters, in the absence of flowers there must be some doubt as to the identity of these specimens.
Type: China, Guangxi, Fang-cheng Xian, Nasuo, 5 iv 1956, Hopu Exp. 2320 (holo. IBSC)
Occurs in Countries: CN Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: lilac
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):108
Spring leaves 50~75mm long
Illustrations:
Type: China, Guangxi, Fangcheng Xian, Shiwan-dashan, 500-630m, 27 iii 1944, S.Q. Chen (S.H. Chun) 4811 (holo. IBSC)
Synonymy: R. meridionale P.X.Tan. var. setistylum P.X.Tan, Guihaia 2: 71, t.4 (1982)
Spring leaves not more than 20mm long
Type: China, Guangxi, Kan Tung, Miu Shan, N Luchen, 900m, 18 vi 1928, R.C. Ching 6142 (holo. IBSC; iso. A, PE)
Shrub to 2 m. Young growth lepidote and filiform-acicular puberulent. Leaves oblong-elliptic to narrowly oblong-elliptic, (16—)30—40(-56) x (5-)9-25 mm, acute at apex, cuneate at the base, sparsely lepidote and puberulent along the midrib and some of the veins above, densely to moderately lepidote beneath, the scales usually brownish, broad-rimmed, and contiguous or overlapping. Inflorescence usually more than 20-flowered, with a conspicuous rachis, the pedicels puberulent and sparsely lepidote, 10-20 mm. Calyx lobes 1-2 mm, triangular or narrowly triangular, acute, lepidote and fringed with loriform hairs. Corolla funnel-campanulate, 5-8 mm, the tube 1-3 mm, white, unspotted, densely lepidote on the outside, glabrous within. Stamens 10, exceeding the corolla, filaments glabrous. Ovary lepidote, style impressed, shorter than stamens, glabrous or more rarely with a few hairs near the base. Capsule cylindric, lepidote, 5-6 mm.
Habitat: Scrub and thickets
Distribution: China (Heilongjiang, Jilin, Hebei, Hubei, Gansu, Shanxi, Shandong, Sichuan, Liaoning), Korea
Altitude: 1600-2600m
Illustrations:
A very distinct and easily recognised species, looking superficially like a very large Ledum. It is variable in scale density and corolla size, but the variation is continuous, and the two species recognised by Diels cannot be maintained.
Synonymy: R. rosthornii Diels, Bot. Jahrb. 29:509 (1900). Type: China, Szechuan, Tseku lao, Chu shin-kon, Rosthorn 2556 (n.v.). R. pritzelianum Diels, op. cit.: 510. Type: China, Szechuan, Nan chuan, Rosthorn 2145, 2146, 2162 (n.v.)
Occurs in Countries: CN Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: white
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):132
Dwarf shrub, 0.6-1.6m; young shoots whitish-tomentose; perulae persistent or deciduous. Leaves elliptic, 5.5-7.5 x 1.5-2(-3)cm, 2.5-4 x as long as broad, apex apiculate, base ± cuneate to rounded, upper surface glabrous, lower surface with a dense, felted, cinnamon to buff rosulate indumentum; petioles c.0.7cm, glabrescent. Inflorescence 3-7-flowered; rhachis c.5mm; pedicels 10-20mm, floccose-tomentose and glandular. Calyx 2-10mm, lobes fleshy to chartaceous, sparsely hairy and glandular. Corolla ± fleshy, pale rose to deep crimson, sometimes with faint flecks, 30-35mm. Ovary brown-tomentose, glandular. Capsule 10-12 x c.5mm.
Habitat: Bouldery slopes, open pine forests
Distribution: China (NW Yunnan, SE Xizang)
Altitude: 3650-4250m
The large chartaceous calyx has been the main character used for separating R. perulatum from R. microgynum. This is not however a constant feature, even on the type of R. perulatum.
Type: China, SE Xizang, Ka-gwr-pw, Mekong/Salween divide, 28°25'N, 12000ft, vii 1917, Forrest 14242 (holo. E).
Synonymy: R. perulatum Balfour f. & Forrest, ibid. 11: 106 (1919). Type: SE Xizang, Tsarong, Dokar-la, Mekong/Salween divide, 11000ft, vii 1917, Forrest 14421 (holo. E; iso. K). R. gymnocarpum [Balfour f. exj Tagg, Notes R.B.G. Edinb. 15: 315 (1927). Type: China, SE Xizang, Tsarong, Ka-gwr-pw, Mekong/ Salween divide, 28°40'N, 14000ft, vii 1918, Forrest 16687 (holo. E).
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: crimson, rose
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):395
Erect to spreading shrub to 1.2m. Twigs rounded, minutely rough with the dense covering of dark-brown overlapping scales. Leaves 5–7 together in tight pseudowhorls; 2–6cm apart. Blade 25–40 x 7–12mm, narrowly elliptic with an obtusely pointed to rounded apex; margin entire but slightly uneven, flat; base tapering; quickly glabrescent above; densely persistently scaly below, the scales partially overlapping or the gaps between scales less than the width of the smaller scales. Scales with a broad lobed and striate flange and large darker, swollen centre. Mid-vein impressed above, very prominent beneath; lateral veins 2–4 per side, wide-spreading, almost to the perpendicular, hardly distinct beneath, but moderately distinct and impressed above. Petiole 5–7 x 1.5mm, distinctly grooved above, densely dark-brown scaly. Flower buds narrowly ellipsoid, smooth, green, with brown scales only in the basal 1⁄3, imbricate. Bracts: the basal with brown scales outside, upper ones glabrous but all finely fringed with white hairs. Inflorescence of 1–4 flowers hanging vertically downwards. Pedicels 15 x 1mm, green and densely covered in brown scales. Calyx a low, brown, scaly disc. Corolla 26 x 18mm, purplish-pink, pale pink or greenish-white, without scent; tube 20 x 6 x 8mm, cylindrical, fluted and a little swollen at the base, laterally flattened, with scattered brown scales outside, glabrous inside; lobes 10 x 7mm, wide-spreading, with or without scales outside. Stamens irregularly arranged with more on the lower side of the corolla; filaments 24mm, glabrous, tapering from base to apex; anthers 2 x 1mm, pale orange-brown. Ovary 5 x 2mm, densely scaly; style 17mm, scaly in the proximal 4mm, otherwise glabrous, tapering upwards; stigma 1.5mm in diameter, green. Fruit 20–37 x 4mm, distinctly fluted and slightly curved, with the remains of the stigma curved upwards, opening lantern-like, the outer skin not peeling back. Seeds 5–6mm, without tails 0.7–0.8mm, the longest tail 3mm, distinctly wavy.
Habitat: Epiphytic in mossy forest or terrestrially on open ridges
Distribution: Malaysia (Borneo), Sarawak, Mt Api, Mt Mulu, Mt Murud and Mt Batu Lawi. Sabah, Mt Lumarku.
Altitude: 800-2000m
Greek – micro – little or small; malayanum – of Malaya. The small species related to R. malayanum.
Hybrids recorded in the wild are with R. durionifolium ssp. sabahense on Mt Lumarku and with either R. durionifolium or R. fallacinum on Mt Mulu in Sarawak.
The small leaves covered underneath in overlapping scales, alpine habit and umbels of mostly 1–2 purplish pink or greenish-white, hanging flowers which are prominently scaly outside make this species quite distinct. Rhododendron lamrialianum is probably most likely to be confused, with its similar small leaves, but the scales on the undersides of the leaves are much more widely spaced with parts of the lower epidermis visible, whereas in R. micromalayanum they are densely overlapping and completely obscure the leaf surface. Flower colour in the two species is completely different, R. lamrialianum having bicoloured orange and yellow flowers. Some forms of R. malayanum outside Borneo can have leaves as small and can grow in alpine situations but they usually then have darker maroon-coloured flowers from less imbricate flower buds which are scaly up to the top. Rhododendron micromalayanum differs anatomically from all forms of R. malayanum so far sampled in having a double palisade layer in the leaves, R. malayanum having a single palisade layer.
Type: Nooteboom & Chai 2279, 28 April 1970. Borneo, Sarawak, Kalabit Highlands, Mt Batu Lawi summit (L, SAR).
Occurs in Countries: MY Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: brown, green, orange, pink
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:123
Epiphytic or (extremely rarely) free-growing shrub to 2 m. Young growth lepidote, glabrous. Leaves mostly narrowly elliptic, rarely elliptic or tending to obovate, glabrous, undersurface papillose but not whitish, scales close, yellow, unequal, at least the smaller sunk in crenately-margined pits, and with their rims upturned. Inflorescence (4~)5—10-fIowered, rachis well developed and conspicuous, pedicels thin, flexuous, lepidote, 25-35 mm, extending to 50 mm in fruit. Calyx with well developed lobes (2—)3—5 mm, lepidote, glabrous, held ± at right angles to the floral axis or even reflexed, reflexed in fruit. Corolla broadly campanulate, yellow, 9-13 mm, tube 4-6 mm, lepidote outside, pilose within. Stamens 10, filaments pilose towards the base. Ovary lepidote. Capsule narrowly cylindric, often sickle-shaped, lepidote, 12-16 mm.
Habitat: Epiphytic, 2450-3350(-4300) m
Distribution: India (Arunachal Pradesh), Bhutan, China (NW Yunnan, S & SE Xizang), NE Burma.
A distinct species, whose affinity lies with subsection Boothia rather than with R. genes tier ianum (p. 148), with which Cowan & Davidian (Rhodo. Yearb. 3:92, 1948) relate it, as subseries Genestierianum of series Boothii. This affinity is shown in all characters but particularly in the epiphytic habit, scale type, corolla shape and seed type. The resemblances with R. genestierianum are superficial. This species also resembles R. brachyan-thum (subsect. Glauca, p. 144) in its inflorescence and R. auritum (subsect. Tephropepla, p. 128) in its reflexed calyx lobes.
Type: China, SE Tibet, Tsarong, Salween/Kiu chiang Divide, W of Si K'ia, 9-10000 ft, vi 1922, Forrest 21811 (holo. E)
Occurs in Countries: BT, CN, IN, MM Subgenus: Rhododendron Habit: Epiphyte, Non-Tree Fl. Colour: yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):134
Greek – micro – little or small; phyllum – leaf. The small-leafed rhododendron.
Type: de Kock 89, March 1911. New Guinea (S), Mt Goliath, 3200m (BO, lectotype, L, fragment).
Synonymy: R. minimifolium Wernham, Trans. Linn. Soc. London, II, Bot. 1916. 9: 98.
Subgenus: Vireya
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:143
Upright shrub, usually dwarf, 0.3-2m; young shoots covered with adpressed flattened brown hairs. Leaves monomorphic, chartaceous, elliptic to lanceolate, 1-4 x 0.5-1.5cm, 2-2.6 x as long as broad, apex obtuse to acute, mucronulate, base cuneate, margin entire, both surfaces with adpressed red-brown hairs, the lower surface paler, with a denser indumentum; petioles l-4mm, covered with brown strigose hairs. Inflorescence 3-6-flowered, with smaller axillary inflorescences below the terminal ones; pedicels 3-7mm, covered with shining chestnut-brown hairs. Calyx densely covered with brown strigose hairs; lobes lanceolate, l-2mm. Corolla funnel-cam-panulate, usually purple-rose, occasionally white flushed pink, with crimson flecks, 10-15(-22)mm; tube 6-8mm, 2-3mm wide at base, glabrous on outer surface, pubescent within. Stamens 5, longer than corolla, filaments sparsely pilose below middle. Ovary densely covered with shining chestnut-brown hairs; style glabrous. Capsule c.8 x 4mm, densely strigose.
Habitat: Open scrub
Distribution: E Burma, China (Yunnan, SW Sichuan), Thailand?
Altitude: 1800-3050m
Illustrations:
There is some doubt over the identity of the specimen from Thailand (see note under R. saxicolum).
Type: China, Yunnan, in montibus circa Tali, 2130m, Delavay (iso. K)
Synonymy: R. microphyton Franchet var. trichanthum A.L. Zhang, Acta Bot. Yunnanica 4: 249 (1982). Type: China: Yunnan, Bijiang, 28 vi 1979, AM Zhang 79-2093 (holo, KUN, n.v.)
Occurs in Countries: CN, MM, TH Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: crimson, pink, purple, white
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):43
A much-branched, erect, terrestrial shrub or small tree to 2m. Twigs rounded, glaucous-white with tiny brown scales, becoming glabrescent, 2–4mm in diameter; internodes 3.5–10cm. Leaves 3–6 together in tight pseudowhorls at the upper 1–3 nodes. Blade 40–85 x 18–33mm, elliptic; apex broadly acute to obtuse; margin narrowly revolute; base tapering; initially scaly on both sides, above the scales persisting as very small dark brown points, more persistently and sub-densely scaly beneath. Scales very varied in both size and morphology, the smallest mostly circular, pale brown and flat, the larger ones stellately lobed and dark brown and distinctly raised. Mid-vein narrow and impressed above, grooved proximally for c.10mm, beneath strongly raised almost to the apex; lateral veins 5–8 per side, spreading at c.45°, or somewhat obscure, irregular, anastomosing, slightly depressed above and raised beneath in dried leaves, reticulation indistinct. Petiole 6–10 x 1–2mm, not or hardly grooved above when fresh, densely scaly. Inner bracts spathulate with marginal scales on long stalks otherwise glabrous. Bracteoles to 22 x c.1mm, linear to linear-spathulate, glabrous, irregularly toothed at the apex. Umbels 2–6-flowered, the flowers held semi-erect. Pedicels moderately densely covered with pale brown appressed, sub-stellate scales and minutely patently hairy, 15–17 x c.2mm. Calyx obliquely disc-shaped, very shortly and obtusely 5-lobed, 4–5mm in diameter, with brown scales and minutely hairy. Corolla 45–50 x c.35mm; tube 30–35 x 6–8 x 12–14mm, sub-cylindrical, sulcate at the base, distinctly downwardly curved, laxly but obscurely sub-stellate-scaly outside and sparsely to densely hairy in the proximal ½, shortly hairy inside, the lobes 15 x 12mm, sub-circular, spreading horizontally or sometimes a little reflexed, overlapping to c.½ their length, with a few very small scales near the base outside. Stamens exserted to 10mm, clustered around the style on the upper side of the mouth of the corolla; filaments green, filiform, sub-densely hairy in the proximal ½, laxly hairy almost to the top; anthers c.3.5 x 1.3mm, pale brown, oblong, curved, the base obtuse. Disc densely hairy. Ovary c.7 x 3mm, sub-cylindric-conical, base tapering, apex tapering distally, green but densely covered with silvery, sub-patent hairs and scales; style at first with the stigma just below the anthers in the mouth of the flower, later exserted to c.10mm, hairy and scaly in the proximal 2⁄3, glabrous above; stigma globose, c.3mm in diameter.
Habitat: Open sub-alpine shrubbery by roadside
Distribution: Indonesia, New Guinea (W), Darnell ridge, Timika to Tembagapura road.
Altitude: Around 1600m
Named after Mr H.A. Miller, consultant for the Freeport Mining Company, who did so much to aid the Kew expeditions to the mining area where this species was found.
R. flavoviridi J.J.Sm. similis et ab omnibus aliis speciebus in sectione Vireya cognitis colore floris pallide viridi distincta. A R. flavoviridi J.J.Sm. staminibus in facie abaxiali (haud adaxiali) corollae deorsum (haud sursum) curvatae fasciculatis, pedicellis et pilis et squamis indutis, ovario multo longiore, foliis tenuioribus et forsan ramulis glaucis recedit.
Known only from the type collection.
This species is superficially similar to R. flavoviride J.J.Sm. as it has the same distinctive pale green flowers. However, the flowers are curved downwards not upwards and are horizontally disposed not hanging, and the stamens are clustered on the upper side of the mouth of the corolla not the lower. Other small differences are that the stems are pale glaucous, not dark green, the leaves are narrower and always with tapering bases never the rounded bases which are common in R. flavoviride, the petioles are without grooves for the greater part of their length not clearly grooved as in R. flavoviride, the pedicels and calyx are distinctly hairy, not scaly only, and the corolla often has hairs outside as well as within. The scales of this new species are also distinctive in the great variation in size and shape and their dark brown colour; the scales in R. flavoviride are more uniform and paler and mostly translucent.
Type: Argent, Johns & Utteridge 00619, 11 Nov. 2000. Indonesia, Papua, Darnell ridge, Timika to Tembagapura road, c.4°16'S 137°01'E, 1600m (BO, E, K).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Tree Fl. Colour: green
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:304
Shrub, l-2.2m. Leaves lanceolate to oblanceolate, 8.5-11 x 3-4.5cm, 2.2-2.8 x as long as broad, apex acute to apiculate, base rounded, lower surface with a bistrate indumentum, the upper layer fulvous, lanate-tomentose and often detersile by maturity, composed of ramiform hairs, the lower whitish, compacted and persistent; petioles 1.5-2.5cm, glabrescent by maturity. Inflorescence 6-10-flowered; rhachis up to 10mm; pedicels 20—25mm, tomentose with an admixture of stipitate glands. Calyx 3-6mm, sparsely tomentose and stipitate-glandular, lobes broad, rounded. Corolla funnel-campanulate, white to rose, with crimson flecks, 35-45mm. Ovary densely rufous-tomentose and stipitate-glandular; style glabrous. Capsule 18-20 x c.5mm.
Habitat: Forest margins, among scrub, on rocky slopes
Distribution: China (SW Sichuan)
Altitude: 3350-3650m
Probably allied to R. adenogynum
Type: China, SW Sichuan, mountains NE of Muli, 28°24'N, 101°6'E, 12000ft, 1922, Forrest 21417 (holo. E)
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: crimson, rose, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):341
Erect shrub or sparingly branched tree to 10m. Twigs rounded, reddish and sparingly scaly at the upper internodes, glabrescent and often greyish or often whitish below, 4–5mm in diameter; internodes 2–7cm. Leaves 5–9 together in loose pseudowhorls at the upper 1–2 nodes, often with small but well-formed reddish purple buds in the leaf axils. Blade 50–100 x 25–50mm, obovate-elliptic or elliptic; apex obtuse, rounded, or emarginate; margin entire and flat; base tapering, glabrescent above when mature, more persistently and laxly scaly beneath. Scales small, with the marginal zone irregularly lobed and the minute dark centre slightly impressed. Mid-vein broad, raised for up to 10mm above, slightly grooved for most of its length otherwise flat; slightly raised proximally below; lateral veins 8–10 per side, at an acute angle, rather high-ascending, anastomosing before the edge, smooth when fresh, slightly but distinctly impressed above and raised beneath when dry, as is the reticulation, dark green above, paler beneath. Petiole 6–18 x 2–3.5mm, red, weakly grooved above, persistently silvery scaly. Flower buds to 45 x 15mm, conical or narrowly ellipsoid, imbricate, glossy purplish-pink with pale areas, smooth, with the bract points appressed. Outer bracts ovate, inner ones ovate-oblong, obtuse, glabrous and shining outside, to 35 x 15mm. Bracteoles to 40 x 3mm, linear below, sub-spathulate at the apex, glabrous. Inflorescence an open umbel with 8–12, half-hanging flowers. Pedicels 25–32 x c.2mm, pale green, laxly and obscurely scaly, more densely scaly distally. Calyx oblique, a narrow rim or shortly obtusely 5-lobed, 3.5mm in diameter, scaly. Corolla 40–50 x 45–50mm, pure white, without scent; tube 25–30 x 6–8 x 12–15mm, very laxly scaly or glabrous outside, laxly patent hairy in the proximal ¾ of the tube inside, slightly sulcate near the base, cylindrical in the lowest ½–2⁄3 before expanding to the mouth; lobes 20–22 x 18–20mm, obovate, reflexed to a right angle, overlapping c.halfway. Stamens sub-equal, 25–30mm, clustered regularly around the mouth, exserted to c.3mm; filaments white, linear, laxly hairy in the lower 1⁄3, glabrous distally; anthers 3.5–4 x 1mm, pale brown, oblong, cell bases minutely apiculate. Disc prominent, hairy at the upper margin. Ovary sub-ovoid-cylindrical, densely silvery to yellowish-brown hairy, the hairs covering numerous, minute scales, 6–7 x 2.5mm, tapering distally; style sparsely hairy in its lower 1⁄6–1⁄3, as long as the stamens, lying on the lower side of the tube; stigma sub-globose. Fruit 30–35 x c.7mm, fusiform, slightly curved, warty, sub-densely hairy and scaly, with 5 deep longitudinal grooves. Seeds 4–5mm, without tails 0.7–0.9mm, the longest tail to 2mm.
Habitat: Mossy forest near the summit.
Distribution: Philippines, Mindanao, Mt Apo.
Altitude: 2700-2895m
Named after the island of Mindanao from where it originated.
Type: Copeland 1042, April 1903. Philippines, Mindanao, Davao, Mt Apo near summit, c.2895m (PNH†). De Vore & Hoover 73 (PNH†, paratype, A, E).
Occurs in Countries: PH Altitude Ranges: 2,000 - 3,000m Subgenus: Vireya Habit: Tree Fl. Colour: white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:280
Shrub, 1.5—2m; young shoots with a thin evanescent tomentum, eglandular. Leaves elliptic, 4-5 x 2-2.6cm, c.2 x as long as broad, apex rounded, base rounded, upper surface glabrous, lower surface covered with a dense fulvous lanate tomentum composed of fasciculate hairs; petioles 0.5-0.8cm, tomentose. Inflorescence c.5-flowered; rhachis 2-3mm; pedicels c.6mm, glabrescent. Calyx 8-15mm, fleshy, cupular, glabrous, lobes crimson, rounded. Corolla funnel-campanulate, crimson, with darker nectar pouches, 30-35mm. Ovary glabrous. Capsule not known.
Habitat: Cliffs, etc.
Altitude: Around 3700m
Only known for certain from the type. A specimen also from the Tsari Chu {Ludlow & Sherriff 1627) differs in its narrower, tubular-campanulate corolla, its minute, l-2mm calyx and in its greater stature (2.5-4.5m). From the material available, it is not possible to assess the significance of these differences.
R. miniatum is closely allied to R. sherriffii.
Type: China, S Xizang, Tsari Chu, Migyitun, 12000ft, 26 v 1936, Ludlow & Sherriff 1710 (holo. BM; iso. E)
Altitude Ranges: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: crimson
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):415
Shrub, 2(-5) m. Young shoots green or purplish, sparsely lepidote. Leaves elliptic to broadly elliptic, (10-)55-80(-110) x (18-)25-35(-50) mm, dark green with dried-out scales and puberulent along the midrib above, densely lepidote beneath with small-rimmed, brownish scales. Inflorescence dense, 5-8-flowered, pedicels lepidote. Calyx lobes 1-2 mm, lepidote and sparsely loriform-ciliate. Corolla (21 —)25—30(—35) mm, tube (9—)10— 14(-18) mm, rather sparsely lepidote on the outer surfaces of the lobes, sometimes also very sparsely pubescent, sparsely pubescent within the tube. Style glabrous or occasionally slightly lepidote at the base, smoothly curved downwards at anthesis. Capsule cylindric.
Two varieties may be distinguished
Occurs in Countries: US Subgenus: Rhododendron Habit: Non-Tree
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):91
Habitat: Scattered localities in open pinelands and dry creek banks
Distribution: USA (Florida)
Illustrations:
Type: Described from USA, Florida, sandy pine barrens
Synonymy: R. champanii A. Gray, Proc. Amer. Acad. Phila. 12:61 (1876)
Leaf apex acute or acuminate; branches usually not erect and rigid
Habitat: Woods, mountain slopes, etc.
Distribution: USA (Tennessee, N Carolina, S Carolina, Georgia, Alabama)
Illustrations:
The characters formerly used to separate R. minus and R. carolinianum have been thoroughly investigated by Duncan Sl Pullen (op. cit.), and have been shown to be extremely variable and not diagnostic.
Type: described from USA, banks of the Savannah river, Georgia.
Synonymy: R. punctatum Andrews, Bot. Rep. 1: t. 36 (1798). Type: described from a cultivated plant. R. punctatum var. 3, Ker in Andr. Bot. Reg. 1: t. 37 (1815). Type: described from a cultivated plant. R. cuthbertii Small, Torreya 2:9 (1902). Type: USA, Georgia, along the Savannah river, 1901, Cuthbert (n.v.). R. carolinianum Rehder, Rhodora 14:99 (1912). Type: numerous syntypes from USA, N Carolina, including Biltmore Herb. 4463 (E), Small & Heller 281 (E), Harbison 168 (E), 119 (n.v.)
Shrub, to 2.3m; young shoots with dense flattened adpressed reddish-brown setose hairs. Leaves monomorphic, subcoriaceous, broadly obovate to oblong, 0.7-1.1 x 0.3-0.5cm, 1.4-2.3 x as long as broad, apex shortly acuminate, base cuneate, margin revolute and minutely crenulate, upper surface setose, lower surface paler, setose on midrib and margin, otherwise glabrous; petioles c.2mm, setose. Calyx c.lmm, setose, lobes rounded. Corolla funnel-shaped, colour unknown, c.6mm; tube c.2.5mm, outer surface reddish-hairy, glabrous within. Stamens 5, long-exserted, filaments puberulent below. Ovary densely setose; style setose below. Capsule not known.
Distribution: China (Guangxi)
Altitude: 900-1120m
R. myrsinifolium is closely allied to this species and may be conspecific (q.v.)
Type: China, Guangxi, Chu-feng, N of Huchen hsien 1120m, 9 vi 1928, R.C. Ching 5860 (holo. PE)
Occurs in Countries: CN Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Tsutsusi Habit: Non-Tree
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):135
Erect, rounded, much branched shrub to 60 cm. Leaves (7-)9-17 x (4_)5_10 mm, broadly ovate or oblong-elliptic, apex obtuse or rounded, mucro obscure, base broadly cuneate, truncate or subcordate, undersurface tawny with some darker speckling, densely covered with contiguous golden scales, some with darker centres. Inflorescence 2-3-flowered, pedicels lepidote, 1-2 mm. Calyx lobes 4-7-5 x 3-4-5 mm, broadly rounded or ovate, margins ciliate and sometimes with a few scales, and with a band of scales up the centre. Corolla pale to deep purplish blue, funnel-shaped, 14-18 mm, tube 4-6 mm, pubescent inside and often also outside, rarely sparsely lepidote outside. Stamens 10, rarely fewer, slightly shorter than the corolla. Ovary lepidote, style 14-16 mm, exceeding the stamens, pubescent or glabrous towards the base. Capsule ovoid, c. 5 mm, lepidote.
Distribution: China (NW Sichuan)
Type: China, Szechuan SW, Djesi-la and Djesi-Longba, south of Tatsienlu, 4600 m, vi 1929, Rock 17726 (holo. E; iso. A, US)
Occurs in Countries: CN Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: blue
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):103
Shrub or tree to 4m. Twigs 3–4mm in diameter, rounded, whitish and densely brown-scaly, slowly becoming glabrescent; internodes 3–10cm. Leaves 3–6 together in tight pseudowhorls. Blade 50–86 x 30–45mm, broadly elliptic, elliptic or obovate; apex rounded and apiculate occasionally broadly pointed or slightly retuse; margin entire, narrowly cartilaginous, markedly revolute when dry; base cordate occasionally rounded or broadly tapering; laxly scaly and quickly glabrescent above, laxly and more persistently scaly below. Scales small (up to 0.2mm in diameter), with broad transparent margins and small to medium-sized dark centres which may become raised on circular swellings around the scale centre on older leaves. Mid-vein impressed above, prominently raised throughout its length below, where it is whitish; lateral veins 5–10 per side, slender, the basal 2–3 spreading almost at a right angle, the distal lateral veins spreading at c.45°, straight but branching and disappearing before the margin; reticulation obscure. Petiole 7–12 x 3–4mm, grooved above, deeply scaly and rugulose. Inflorescence an umbel with c.8 flowers. Pedicels 20–25 x c.0.7mm, erect, very densely brown scaly and with just a few, short, white, simple hairs. Calyx a low densely scaly disc. Corolla c.40 x 25mm, white or faintly pink; tube 25–28 x c.3 x c.4mm, densely scaly outside and shortly, patently, white-hairy inside; lobes c.13 x 10mm. Stamens with the anthers in the mouth of the corolla; filaments flattened and hairy in the proximal ¼, filiform and glabrous distally; anthers pale brown, c.3mm, sometimes apiculate at the base. Disc hairy on the upper margin. Ovary 4 x 1.75mm, scaly and shortly hairy with patent or slightly distally pointing hairs; style sparsely hairy and scaly in the basal ½, glabrous distally.
Habitat: Primary upper montane mossy forest.
Distribution: Indonesia, C Kalimantan (Borneo), Mt Raya
Altitude: Around 2000m
Named after Dr Joannes Mogea, the collector of this species and former curator of the Herbarium Bogoriense.
This species is similar to R. suaveolens and R. niveoflorum but the material so far collected is not complete and it is not possible to compare the single herbarium collection as completely as one would like. Floral measurements in particular being from dry material are not necessarily strictly comparable as shrinkage varies greatly in the drying process. It appears to have smaller inflorescences with fewer flowers in each umbel than the other two species but clearly has much longer petioles. It apparently replaces the other species of subsection Solenovireya on the isolated Bukit Raya and may well be endemic to this mountain.
Type: Mogea 3983. Indonesia, Central Kalimantan, Bukit Raya SE side, upper Katingan (Meddawai) River area, Upper Samba river, c.2,000m alt. (BO, L).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Tree Fl. Colour: brown
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:168
Shrub or small tree to 2m tall, usually non-rhizomatous; young twigs red-brown, sparsely to densely covered with unicellular hairs and multicellular eglandular hairs, occasionally with multicellular eglandular hairs, rarely glabrous. Vegetative bud scales glabrous or sparsely to densely covered with unicellular hairs, rarely also with multicellular eglandular hairs abaxially; margin unicellular ciliate. Leaf blade membranaceous, ovate or obovate to elliptic, the veins raised and prominent below (4.1-)4.9-9.5(-13.2) x (1.7-)1.8-2.9(-4.3)cm, base acute to oblique; apex acute to obtuse, often mucronate; adaxial surface sparsely to densely covered with unicellular hairs and multicellular eglandular hairs, occasionally with only multicellular eglandular hairs, or only unicellular hairs or glabrous, the midvein densely covered with unicellular hairs; abaxial surface glabrous, glaucous, or sparsely to densely covered with unicellular hairs, the midvein sparsely to densely covered with unicellular hairs and multicellular eglandular hairs, occasionally with only multicellular eglandular hairs; margin entire, ciliate with multicellular eglandular hairs; petiole 0.2-0.4(-0.6)cm long, sparsely to densely covered with unicellular hairs and multicellular eglandular hairs, rarely with only multicellular eglandular hairs. Flower bud scales chestnut brown; abaxial surface sparsely to densely covered with unicellular hairs, rarely glabrous; margin unicellular-ciliate. Flowers appearing before or with the leaves; inflorescence a shortened raceme of 3 to 13 flowers. Pedicels (0.4-)L0-2.5(-3.0)cm long, densely covered with unicellular hairs and multicellular eglandular hairs. Sepals less than 0.1-Q.3(-0.4)cm long, varying in length on the same flower; margins setose; abaxial surface sparsely to densely covered with unicellular hairs or densely covered with unicellular hairs and sparsely covered with multicellular eglandular hairs. Corolla yellow, golden-yellow, orange-yellow or yellow-orange; flame-red, orange-red or red; with spots on the upper corolla lobe; fragrance sweet, the tube shorter than the limb and broadly expanding into it; upper corolla lobe (1.5-)2.0-2.8(-3.4) x (L3-)1.7-2.9(-3.5)cm; lateral lobes (1.6-)2.1-3.4(-4.1) x (0.7-)1.3-2.2(-2.9)cm; corolla tube (1.2-)1.5-2.8(-3.0)cm long, 0.3-0.6(-1)cm wide at base; outer surface of corolla sparsely to densely covered with unicellular hairs; inner surface of corolla sparsely to densely covered with unicellular hairs, rarely glabrous. Stamens (3.3ó)3.6-5.4(-5.6)cm long, with dense terete or flattened unicellular hairs on proximal (1.1-)1.3-2.5(-2.6)cm of filament, exserted 0.0-0.4(-0.7)cm beyond throat of corolla. Style (3.0-)4.8-6.1 (-6.7)cm long, exserted (0.0-)0.2-1.3(-1.5)cm beyond throat of corolla, with dense unicellular hairs on proximal 0.0-1.8(-2.9)cm, stigma less than 0.1-0.2cm wide. Ovary 0.3-0.5(-0.6)cm long, 0.2-0.3cm wide at the base, densely covered with unicellular hairs and sparsely to densely covered with multicellular hairs on the ribs, or evenly covered with unicellular hairs, with a dense crown of unicellular hairs along the nectary. Capsules (1.3-)1.6-3.0(-3.6) x (0.5-)0.7-1.2 (-1.4)cm, sparsely to moderately covered with unicellular hairs, and sparsely covered with multicellular eglandular hairs. Seeds pale to dark chestnut brown, ovate or elliptic to fusiform, (2-)2.5-4.7(-5.5) x 0.9-2.4(-3.0)mm, body (l.l-)1.2-2.1(-2.3) x (0.3-)0.5-0.9mm; testa expanded and dorsiventrally flattened surrounding the body, the cells elongate, with tapering end-walls.
Habitat: Exposed grassy hillsides and meadows, open thickets and moors, open woods.
Distribution: China and Japan
Altitude: 0-2500m
Flowering from April to July.
Occurs in Countries: CN, JP Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Pentanthera Habit: Tree Fl. Colour: orange, red, yellow
Kron, K.A. (1993) A Revision of Rhododendron Section Pentanthera. Edinburgh Journal of Botany 50(3):276
Leaves 4.1-11.6 x 1.7-3.7cm, the abaxial surface glabrous to densely covered with unicellular hairs (0-19 per mm ). Flowers yellow to orange-red. Style, rarely glabrous, usually densely covered with unicellular hairs on proximal 2.9cm. Fruits sparsely to densely covered with unicellular hairs (5-60 per mm2) and with multicellular eglandular hairs (0-3 per mm2)
Distribution: Japan. From southern Hokkaido, south throughout Honshu, to Shikoku and Kyushu in open situations in thickets, woods, moors and hillsides, also on volcanic ash.
Altitude: 100-2100m
Illustrations:
Flowering from May to July.
Chromosome number: 2n = 26 (Sax, 1930)
Rhododendron molle is the basal member of the section and retains several plesiomorphic characters: a broad funnelform corolla, stamens included to only very slightly exserted beyond the corolla, and greenish yellow spots on the upper corolla lobe (see Phylogenetic Analysis). This species is quite variable in its leaf pubescence and in the pubescence of the abaxial surface of the floral bud scales. In general, it appears to be a coarser plant with larger flowers, fruits and seeds than any other members of the section. However, it is not larger in height. Creech (1962) stated that Japanese populations of this species vary from yellow to orange-red in Kyushu to exclusively orange-red in the northern part of Japan, or Honshu. He also noted that both colour forms occur in the same population and are not really separable into distinct entities. Plants of R. molle in China are exclusively yellow. Early collectors tended to regard plants from China and Japan as one species (R. sinense Sweet), while later authors such as Valckenier-Suringar (1904, 1908) and Wilson (1921) considered the plants from China to be a distinct species from those in Japan. These later authors used vegetative characters primarily to distinguish between the two taxa. Wilson (1921) stressed the importance of leaf characters in differentiating the Chinese and Japanese plants. He distinguished between R. molle and R. japonicum by leaf size and the presence or absence of long unicellular hairs which densely covered the abaxial surface of the leaf. In addition, the hardiness of the plant was used as a character; plants from China were less hardy than plants from Japan. Flower colour was also used as a distinguishing character. Initially only the red-orange or flame-coloured end of the spectrum of flower colour was known for the Japanese plant, further strengthening the distinction between these two geographically separated taxa. Although Wilson acknowledged that the habit and general appearance of the Japanese and Chinese plants were very similar, he considered them to be distinct species. He stated that the Chinese plants had smaller, less bristly calyces, flower stalks which lacked or had just a few bristles, stamens as long or longer than the corolla, and winter buds which were pubescent with short, very dense, nearly white hairs. But he consistently stressed the importance of the leaf characters, stating that the Chinese plants had leaves which were densely clothed on the lower surface with soft, nearly white, matted pubescence, which persisted throughout the life of the leaf. Wilson (1921) also considered the leaves of the Chinese plants to be larger and more 'decidedly5 oblong-lanceolate than the leaves of the Japanese azalea. By contrast, the Japanese plants were described by Wilson as possessing leaves which were 'decidedly'glabrous, except for appressed bristles and cilia on the veins and the margins, respectively. The winter buds on the Japanese plants were described as very slightly puberulous. Sleumer (1966) described the Chinese plants as more variable than did authors of earlier accounts. In his description Sleumer describes R. molle as having leaves which become glaucous or as having hairs which sometimes are confined to the veins in later stages [sic]. He also described more variability in the pubescence of the winter bud scales ofR. molle, from densely grey-pubescent or velutinous to sometimes glabrescent. Principal component analysis of 32 Operational Taxonomlc Units (OTUs) and 9 vegetative characters (Table 5, Fig. 15) Indicates that there is no morphological gap which correlates with geographical subdivisions. There is a tendency for plants from Japan to be glabrous more often than those from China, but evidently the only consistent difference In the pattern of variation in the Chinese and Japanese plants is the number of unicellular eglandular hairs per square millimetre on the fruits, and then the taxa may differ by only one hair per square millimetre (1-4 unicellular hairs per mm2 in R. molle subsp. molle and 5-60 unicellular hairs per mm2 in R. molle subsp. japonicum). Because there is no distinct morphological gap, but rather a series of correlated cllnes, only one species, R. molle, is recognized with two geographical subspecies.
Synonymy: Azalea japonica A. Gray, Mem. Am. Acad. n.s. 6: 400 (1859). Rhododendron japonicum (A. Gray) Valcken., Gartenflora57: 517 (1908). R. molle var. japonicum (A. Gray) Makino, Illus. Fl. Japan 252 (1956). Type: Japan, Hakodadi, in gardens, 1853-1856. C. Wright s.n. (holo. GH). Azalea mollis (Blume) var. glabrior Miquel ex Regel, Gartenflora 16: 289, pi. 536 (1867). A. sinensis var. glabrior (Miquel) Maxim., Ind. Sem. Petrop. 1870. Rhododendron glabrius (Regel) Nakai, Trees and Shrubs Japan 1:64 (1922). Type: Japan, Wiko. in montibus altioribus Kiso, Seibold s.n. or Burger s.n. (syntypes n.v.). Rhododendron japonicum (A. Gray) Valcken. f. aureum Wilson, Monogr. Azaleas 102 (1921). R. glabrius (Regel) Nakai var. aureum (Wilson) Nakai, Trees and Shrubs Japan 1: 66 (1922). Type: cultivated, Japan, Hondo, prov. Musashi, brought from Chichibu Mts, 11 v 1917, E. H. Wilson 8414 (holo. A). Rhododendron japonicum (A. Gray) Valcken. var. canescens Sugimoto, J. Geobot. 378 (1972). R. japonicum (A. Gray) Valcken. f. canescens (Sugimoto) Sugimoto, J. Geobot. 22: 52 (1975). Type: Japan, Honshu, prov. Shinano, Komoro, 1940, T. Makino s.n. (holo. MAK). Azalea sinensisLodd.,BoL Cab. 9: t. 885 (1824). Rhododendron sinense (Lodd.) Sweet, Brit. Fl. Gard. t. 290 (1826). Azalea pontica var. sinensis (Lodd.) Lindley, Edward's Bot. Reg. 15: 1.1253 (1829). Type: China [sic], probably from northern or central Japan (holo.: illus. in Bot. Cab. 9: t. 885; IDC #5312.48:1.5.). Rhododendron sinense (Lodd.) Sweet var. rosea Ito, Icones. PI. Jap. 17: t. 2 (1913). Type: Japan, Honzo Dsufu, /. Tsunemasa s.n. (holo. n.v.)
Leaves 5.9-13.2 x 2.0-4.3cm, the abaxial surface glabrous to very densely covered with unicellular hairs (0-60 hairs per mm ). Flowers yellow. Style glabrous or covered with dense unicellular hairs on proximal 0.1cm. Fruits sparsely covered with unicellular hairs (1.7-3.4 per mm ) and with multicellular eglandular hairs (0-24 per mm2 ). Chromosome number: In = 26 (Sax, 1930; Nakamura, 1931)
Habitat: Found on exposed grassy hillsides, dry meadows, brushy slopes, stoney hills with Pinus, and open pine forests.
Distribution: Widely distributed throughout the People's Republic of China, from Jiangsu province south to Guangdong and west to eastern Sichuan and Yunnan provinces.
Altitude: 0-2500m
Illustrations:
Flowering from April to June, occasionally as early as February and as late as July.
Synonymy: Azalea mollis Blume, Cat. Gewass. Buitz. 44 (1823). Type: cultivated, probably L, n.v.
Terrestrial shrub to 1m. Twigs rounded, 2–5mm in diameter; internodes laxly minutely scaly, lower ones glabrescent and corky, 6–15cm. Leaves 4–5 together in pseudowhorls with subulate cataphylls associated with them. Blade 110–160 x 15–30mm, narrowly elliptic; apex narrowly acute, caudate-acuminate; margin strongly but narrowly revolute; base narrowly tapering, glabrescent above with age, laxly scaly for some time beneath but eventually glabrescent. Scales minute, marginal zone irregularly sub-stellately lobed and quickly disappearing; centre shallowly impressed. Mid-vein narrow and impressed above except for the broad base; obtusely prominent beneath; lateral veins 10–14 per side, irregular, spreading, obscurely anastomosing near the edge, slightly impressed above and raised beneath, reticulation obscure above, dense and finely prominent beneath. Petiole 5–7 x 1–1.5mm, rugose, grooved above. Inflorescence c.3-flowered, an open umbel. Pedicels 25–30 x 0.7mm, laxly scaly, without hairs. Calyx c.3mm in diameter, disc-shaped, faintly lobed, oblique. Corolla 65–70mm, funnel-shaped, orange, suffused with red; tube c.25 x 5 x 10mm, sparsely minutely scaly outside, laxly hairy inside, markedly pouched proximally; lobes 40–45 x c.20mm, spreading, obovate-elliptic. Stamens sub-equal, exserted to 20mm; filaments linear and sub-densely to laxly hairy in the proximal 1⁄3, becoming nearly filiform and glabrous distally; anthers 5 x 1mm, elongate-oblong, slightly curved. Disc prominent, shortly greyish hairy. Ovary c.8 x 2mm, sub-cylindrical, tapering distally, densely minutely scaly and shortly hairy, the scales clearly visible between the hairs; style shortly hairy in the proximal ¼–1⁄3, hairy and scaly, or scaly only above, slender, equalling the stamens; stigma lobed.
Distribution: Indonesia, New Guinea (W), Noord R.
Named after Prof. Dr. J.W. Moll, former director of the Groningen botanic gardens.
Known only from the type collection; never cultivated.
Very reminiscent of R. englerianum with the narrowly revolute margins to the leaves and subulate cataphylls associated with the pseudowhorls.
Type: Pulle (Versteeg) 1297, 23 June 1907. New Guinea (SW), Noord R. (BO, K, L, U).
Occurs in Countries: ID Subgenus: Vireya Habit: Non-Tree Fl. Colour: orange, red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:319
Very similar to R. hemitrichotum, differing as follows: leaves densely pubescent on the undersurface which is not shining and white, corolla pale to deep pink, rather narrowly funnel-shaped, 19-30 mm, tube 12-18 mm, capsule 6-10 mm.
Habitat: Scrub, thickets, forest margins
Distribution: China (N Yunnan, SW Sichuan)
Altitude: 2800-3800m
Type: China, Yunnan, mountains in the NE of the Yangtze bend, 10-11000 ft, vi 1913, Forrest 11490 (holo. E)
Synonymy: R. mollicomum var. rockii Tagg, Notes R.B.G. Edinb. 15:114 (1926). Type: China, Yunnan, Yangtze watershed, W slope of Lichiang snow range, iv 1923, Rock 8551 (holo. E)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: pink
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):84
Small shrub, 0-3-1 m, usually epiphytic. Young growth densely lepidote. Leaves ovate-elliptic or elliptic, 30-45 x 14-22 mm, cuneate at the base, acute at the apex, slightly revolute, upper surface dark geen, usually persistently lepidote with dried-out scales, lower surface finely papillose, brownish or silvery, densely covered with close, unequal, broadly rimmed, flat scales. Inflorescence l(-2)-flowered, pedicels 2-5 mm, densely lepidote. Calyx a minute, undulately lobed rim, very densely lepidote. Corolla tubular-funnel-shaped to tubular-campanulate, the lobes scarcely spreading, 14-20 mm, tube 10-14 mm, bright yellow, drying greenish, lepidote outside. Style impressed, glabrous, elepidote, exceeding the stamens. Capsule lepidote, ± cylindric, 14-16 mm.
Habitat: Epiphytic on trees at forest margins, or on open slopes at the edges of thickets, 2450-3650 m
Distribution: NE Burma, China (NW Yunnan, SE Xizang)
Illustrations:
Type: China, Yunnan, Lupo pass, Mekong/Salween Divide, 10-11000 ft, xi 1905, Forrest 951 (holo. E)
Synonymy: R. sulfureum sensu Diels, Notes R.B.G. Edinb. 7:66 (1912) non Franchet.
Occurs in Countries: CN, MM Subgenus: Rhododendron Habit: Epiphyte, Non-Tree Fl. Colour: green, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):60
Shrub or small tree to 2m. Twigs finely scaly and minutely but densely patently hairy but quickly glabrescent; internodes 1–2cm. Leaves arranged in pseudowhorls of 2 or 3 together, or on young vigorous growth, spirally arranged. Blade 90–180 x 50–95mm, sub-ovate to broadly elliptic; apex broadly acute; margin flat and entire; base rounded to slightly cordate; upper leaf surface smooth to slightly rugose, glabrescent, lower surface laxly scaly. Scales small, with a small centre and lobed, silvery, thin flange. Mid-vein weakly raised above in the proximal 2⁄3, then becoming impressed, very strongly and broadly raised beneath throughout its length and finely striate when dry; lateral veins 7–16 per side, spreading almost at a right angle to the mid-vein, slender and hardly tapering until near the edge of the leaf, forking towards the margin, curving and anastomosing to form a weak but distinct, looping intramarginal vein and with a conspicuously raised reticulation viewed from above; beneath smooth with the lateral veins less conspicuous but still distinctly reticulate. Petiole 5–9 x 4–5mm, minutely patently hairy and scaly, almost rounded in section, somewhat flattened but not grooved above. Inflorescence an umbel of c.4 flowers. Pedicels 16–20 x 1.5mm, with a sparse to moderate covering of scales but no simple hairs. Flowers 75 x 72mm, yellow with a reddish flush; tube c.33 x 6 x 12mm, with a few sparse scales near the base outside otherwise glabrous, irregularly but densely short-hairy inside (but the hairs not in lines); lobes 45 x 35mm, slightly retuse at the apex. Stamens irregularly arranged; filaments c.34mm, densely hairy in the basal 1⁄3 becoming glabrous distally; anthers c.5 x 1.75mm. Disc apparently glabrous. Ovary 5–6 x c.2mm, sparsely scaly and covered with very short patent white hairs; style c.35 x 1mm, with a few scales in the basal 5mm, glabrous distally; stigma c.4mm in diameter. Fruit (immature) 30 x 5mm, fusiform, minutely hairy.
Habitat: Probably terrestrial in mossy forest on the summit area (1829m).
Distribution: Malaysia (Borneo), Sabah, known only from a few collections all from Mt Monkobo in the Beluran District.
Altitude: Around 1829m
Named after G. Monkobo, the mountain from which it was collected.
Given the very restricted area of the summit of Mt Monkobo this species must be regarded as a very rare point endemic with no other very obvious places for it to occur.
Most similar to R. lowii, with which this species has been confused, but differing in the indumentum of the ovary which is of much shorter, patent hairs than in that species; flower shape is also different with a much broader tube in R. lowii. The leaf venation is also very different, especially the mid-vein which is very strongly raised both above and below in R. lowii but strongly raised only below in R. monkoboense. The ovary indumentum is very similar to that of R. retivenium but the leaf shape is quite different, being much broader with rounded to cordate lamina bases. It shares with R. retivenium flower shape and size, and a similar (but not identical) pattern of venation – there is a much stronger development of a looping intramarginal vein in this species and the reticulation is much more pronounced. It differs from both R. retivenium and R. lowii in the very fine indumentum of patent simple hairs in addition to the scales on the young twigs and the lower altitude from which it is recorded.
Type: Aban SAN 95214, 15 March 1982. E Malaysia, Sabah, Beluran District, Bt Monkobo, 1829m (SAN, K, KEP, L).
Occurs in Countries: MY Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:260
Shrub or tree to 4m. Twigs 2–4mm in diameter, rounded, at first densely patently short-hairy and laxly brown scaly, bright red; internodes 0.5–10cm, branches arising in pseudowhorls. Leaves regularly spirally arranged. Blade 6–14 x 4–8mm, broadly obovate; apex rounded, sometimes slightly retuse, without a distinct terminal gland; margin flat or very slightly revolute, sub-entire but with widely spaced scales which are sometimes faintly indented; base tapering, glossy bright green above, paler and dull beneath; glabrous or sparsely scaly above, laxly scaly beneath. Scales circular or nearly so; marginal zone relatively broad, mostly about the same diameter as the central region. Mid-vein impressed above, often with a few simple hairs in the proximal area, prominent beneath especially in the proximal ½; lateral veins not visible. Petiole to 2 x 1mm, shallowly grooved, sub-densely hairy especially above and laxly brown-scaly. Flower buds to 4 x 2mm, ovoid or ellipsoid, brown. Outer bracts subulate, erect, densely scaly outside, inner ones broadly ovate, with a few scales distally outside but with numerous semi-erect hairs and densely fringed with white hairs, obtuse or slightly apiculate, with dark brown thickened apices. Flowers solitary, half-hanging or hanging. Pedicels 3–5mm, green, densely hairy with spreading hairs, or hairy and scaly or exclusively scaly. Calyx disc-shaped, densely covered with long patent hairs. Corolla scaly, but without hairs outside, 10–15mm, red or orange, sometimes with a yellow tube. Ovary exclusively scaly.
Habitat: Open forest or sub-montane shrubberies
Distribution: Indonesia, Sulawesi (C and SE).
Altitude: 2000-3000m
Named after the collector of the type specimen.
Flowers June–Nov.
Differing from R. quadrasianum in that the leaves are regularly spirally arranged, with the margins indented with scale attachments. The scales have a broad flange and relatively small centre and the pedicels are very short, only 3–5mm. A curious feature is the fact that sometimes the upper surface of the leaves is completely glabrous even when young and developing. Superficially similar to the New Guinean R. pulleanum in the leaf shape and very lax scales with up to 1mm between them. It differs from R. pulleanum in having hairy stems and the broad flanges on the scales.
Type: Monod de Froideville 120, 1937–39. Mt Mambuliling, N of Mamasa, 2700m (BO, L).
Synonymy: R. quadrasianum f. monodii Lam, Blumea 1945. 5: 576.
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Tree Fl. Colour: orange, red, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:50
Distribution: China (S Xizang) and probably adjacent parts of ne Upper Burma
Illustrations:
Kingdon-Ward describes this species as being common in the Tsangpo Gorge. Very few specimens are however available for study. No wild-collected specimen corresponding to Ward's description of number 6261 has been located; plants under this number in BM belong to R. exasperatum. It is closely allied to R. pudorosum and R. sidereum but differs from both in its larger leaves, from the former in its non-persistent perulae, and from the latter in its pink flowers.
Synonymy: R. mollyanum Cowan & Davidian, Rhododendron Camellia Yearbook 8: 72 (1953); non R. mollianum Koorders (1909). Type: a specimen cultivated at Brodick; raised from seed as Kingdon-Ward 6261a, from Pemako, S Xizang (holo. E).
Occurs in Countries: CN, MM Subgenus: Hymenanthes
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):246
Shrub or small tree, 4-8m; young shoots with a dense blackish floccose indumentum, soon becoming glabrous. Leaves lanceolate to elliptic, (7—)9—14 x 2.8-3.5cm, c.4 x as long as broad, apex acuminate, base rounded, upper surface glabrous, smooth, lower surface with lamina glabrous and midrib floccose-tomentose, hairs folioliferous; petioles 1.5-2cm, finely hirsute and glandular. Inflorescence lax, 5-12-flowered; rhachis 10-20mm; pedicels 25-40mm, with shortly stipitate glands. Calyx c.2mm, lobes broad, rounded, glandular-ciliate. Corolla widely campanulate, lacking nectar pouches, white, sometimes tinged with pink, usually with a red basal blotch and flecks, 30-50rnm. Ovary densely tomentose, also with a few stipitate glands; style tomentose at base, otherwise glabrous. Capsule c.15 x 3mm
Habitat: Forests, etc.
Distribution: Taiwan
Altitude: 2000-2200m
Allied to R. pseudochrysanthum but larger in stature and in the size of the leaves
Type: Taiwan, Randaisan, vii 1906, Mori 7041, n.v.; Anzan, in monte Morrison, x 1906, Nakahara, n.v.
Occurs in Countries: TW Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: pink, red, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):273
A shrub or small tree to 15 m high, young branches glabrous. Leaves glabrous; blade 60-170 x 20-50 mm, elliptic to narrowly elliptic, base cuneate, apex acute or acuminate, coriaceous, margins glabrous (except in juvenile or sucker leaves, adult leaves only rarely with marginal bristles; petiole 10-18 mm long. Inflorescence buds lateral, (1-) 3-5-flowered, at the ends of leafy shoots, bud scales glabrous or minutely pilose on the back, margin shortly ciliate or glandular, caducous; pedicels 15-20 mm long, glabrous. Calyx of 5 minute glabrous lobes (abnormal elongate, pectinate or ciliate lobes also occur). Corolla white, pink, violet or magenta, with a yellow blotch, glabrous, with a narrow tube 16-22 mm long, and broad, spreading lobes to 30-40mm long. Stamens 10, filaments hairy on lower part. Ovary cylindric, c.5 mm long, glabrous; style glabrous. Capsule narrowly cylindric, c.70mm long.
Distribution: China (SE Xizang, Yunnan, Guizhou, Guangxi, Hunan, Guangdong, Hainan), Taiwan, hongkong, Japan (Ryukyu Islands), India (Assam), Burma, Thailand, Laos, CAMBODIA, Vietnam, W MalaySIA (Kedah, Pahang).
Illustrations:
R. moulmainense has a very wide range within which many species ha ve been described. Some of these may prove to be sufficiently distinct, but in this presentation all forms with large funnelliform flowers, glabrous pedicels and glabrous leaves are regarded as a single species. Single-flowered inflorescences are recorded from Taiwan (but see under R. latoucheae) and in Yunnan 1-flowered forms have been segregated as R. mackenzieanum. The Yunnan plants have long corollas which distinguish them from R. latouchae of eastern China. One or both of these may prove to be distinct species. However, on the basis of collections at present available, the segregation of local variants appears to us to be premature. Similarly, as pointed out by Sleumer (1958) the use of ovary tomentum to separate R. moulmainense from R. klossii, and R. henryi from R. dunnii appears unacceptable. The length and form of the calyx lobes is variable, even in the same flower. Aberrant calyx lobes occur in R. pectinatum Hutchinson but are not sufficient for specific status.
Type: Described from a cultivated plant grown by Veitch from seed collected by l.obb in S Burma on the Gerai Mts, Moulmain at 5000 ft.
Synonymy: R. ellipticum Maxim., Bull. Acad. Sci. St. Petersb. 32:497 (1888). Type: Japan, Yayama Archipelago, 1886, Tashiro, n.v. R. westlandii Hemsley, J. Linn. Soc. Bot. 26:31 (1889). Type: Hongkong, Lantao Island, 2500 ft, Westland 87 (holo. K). R. oxyphyllum Franchet, J. Bot. (Morot) 12:264 (1898). Type: China, C Yunnan, entre Moungle et Kou ma tze, 30 iii 1895, Henry, n.v. R. siamensis Diels, Feddes Repert. 4:289 (1904). Type: Thailand, Doi Sutep, 1500m, 20 iii 1905, Hosseus 507 (iso. E). R. klossii Ridley, J. Fed. Mai. St. Mus. 4:43 (1909). Type: Malaysia, Gunong Berumbum, 6000 ft, Ridley 13589 (holo. SING). R. leucobotrys Ridley, loc. cit. (1909). Type: Malaysia, Kedah Peak (Gunong Jerai), 3-4000 ft, vi 1893, Ridley 5531 (holo. SING). R. leiopodum Hayata, Icon. PI. Formosan. 3:136 (1913). Type: Taiwan, Shichiscitansan, iv 1911, Sasaki, n.v. R. leptosanthum Hayata, op. cit.: 137 (1913). Type: Taiwan, prope Ako, 5000 ft, 1907, T. Kawakami, n.v. R. tanakai Hayata, op. cit. 4:15 (1914). Type: Taiwan, Mt Arisan, inter Karapin et Suisharyo, 3000 ft, iv 1913, Hayata & Tanaka, n.v. R. stenaulum Baulf. f. & Forest, Notes R.B.G. Edinb. 10:157 (1917). Type: China, W Yunnan, divide between the Pu-piao and Yung Chang valleys, 7-8000 ft, iv 1910, Forrest 5530 (holo. E). R. nematocalyx Balf. f. &. W.W. Sm., Notes R.B.G. Edinb. 10:124 (1917). Type: China, W Yuinnan, Hills NW of Tengyueh, 25∞ 15'N, 7000 ft, v 1912, Forrest 7673 (holo. E). R. mackenzianum Forrest, Notes R.B.G. Edinb. 12:132(1920). Type: China, W Yunnan, Shweli-Salween divide, 25∞N, 9000 ft, iv 1918, Forrest 16111 (holo. E). R. laoticum Dop, Fl. Gen. Indo-chin. 3:735 (1930). Type: Laos, environs de Nape, Delacour, n.v. R. pectinatum Hutchinson, Gard. Chron. ser. 3,101:119 (1937). Type: a plant grown from seed at Exbury of Forrest 26022, originating from Yunnan in China.
Occurs in Countries: CN, IN, JP, KH, MM, MY, TH, TW Subgenus: Azaleastrum Habit: Tree Fl. Colour: magenta, pink, yellow
Philipson, W.R. & Philipson, M.N. (1986) A Revision of Rhododendron III. Subgenera Azaleastrum, Mumeazalea, Candidastrum and Therorhodion. Notes from the Royal Botanic Garden Edinburgh 44(1):13
Shrub of 1-1.3 m, often epiphytic. Young growth loriform-setose, the setae variably deciduous. Leaves narrowly ovate to elliptic or obovate, 31-40 x 16-22 mm, rounded to cordate at the base, obtuse at the apex, pale green and elepidote above and with a few filiform-acicular hairs along the midrib, margins loriform-ciliate with variably persistent cilia, lower surface pale green or brownish with rather dense scales; petioles loriform-setose. Inflorescence 1-2-flowered, pedicels lepidote and filiform-acicular-pubescent. Calyx 5-lobed, the lobes rounded, c. 2 mm, lepidote and filiform-acicular-pubescent. Corolla openly funnel-campanulate, white, often flushed pink, usually with dark red spots on the inside of the upper part of the tube, glabrous and elepidote outside, rather densely pubescent within the tube, 30-34 mm, tube 16-18 mm. Stamens very unequal. Style exceeding stamens, glabrous or slightly pubescent towards the base. Capsule large, cylindric, tapering, 20-22 mm, densely lepidote.
Habitat: On rocks and tree trunks, or epiphytic
Distribution: China (C Sichuan)
Altitude: 2000-4000m
Illustrations:
Type: China, Thibet or., circa Moupine, alt. 4000 m, David (holo. P—n.v., iso. E)
Occurs in Countries: CN Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Epiphyte, Non-Tree Fl. Colour: pink, red, white
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):58
Shrub, l-2m; young shoots densely clothed with loosely adpressed flattened strigose hairs intermixed with softer grey-brown, sometimes glandular, pilose hairs. Leaves dimorphic, chartaceous; spring leaves ovate-lanceolate, 3.5-5 x 1.5-2cm, 2-2.5 x as long as broad, apex acute or obtuse, mucronate, base cuneate, margin entire, both surfaces clothed with adpressed reddish-grey pilose hairs, especially on midrib; summer leaves oblanceolate, 15-30 x 5-10mm, c.3 x as long as broad, otherwise as for spring leaves; petioles 3-5mm, densely clothed with spreading flattened strigose and softer pilose hairs. Inflorescence 1-3-flowered; pedicels 10-15mm, clothed with soft spreading pilose, sometimes glandular and flattened, strigose hairs. Calyx glandular-pubescent, lobes lanceolate, up to 15mm long, often slightly erose. Corolla widely funnel-shaped, white to rose-pink or red, 25-50mm; tube 12-25mm, glabrous. Stamens 10, c. as long as corolla, papillate below middle. Ovary setose; style glabrous. Capsule conic-ovoid, c.5mm long.
Type: e regno Chinensi allata', n.v.
Synonymy: Azalea mucronata Blume, Bijdr. 853 (1826)
Occurs in Countries: JP Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: red, rose, white
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):116
Flowers white (only known in cultivation)
Var. mucronatum is the widely cultivated white form of the species. It may occur in the wild as the albino form of var. ripense.
Habitat: Rocks by streams, etc.
Distribution: Japan (SW Honshu, Shikoku, NE Kyushyu)
Illustrations:
Closely allied to R. macrosepalum but differing in the smaller leaves, adpressed-hairy shoots, etc. Widely cultivated, with many distinct garden forms, of which one is represented by the type of var. mucronatum. These have almost certainly been derived from var. ripense, a native of S Japan.
Straggling open shrub to 2 m. Young growth lepidote and puberulous. Leaves completely deciduous, thin, strigose with loriform hairs on the upper surface towards the margin at least when young, the upper surface of the midrib puberulent, sparsely lepidote beneath, 40-60 X 15-30 mm. Inflorescences precocious. Pedicels very short, obscure. Calyx rim-like, lepidote. Corolla very openly funnel-shaped, 21-26 mm, tube 8-12 mm, 33-42 mm in diameter, bright mauve-pink, rarely white, pilose outside near the base, glabrous or sparsely pilose inside. Stamens 10, exserted, filaments pubescent towards the base, anthers blue. Ovary lepidote, style glabrous. Capsule lepidote.
Distribution: USSR (E Siberia, Ussuri region), China (Hubei, Shandong), MONGOLIA, Korea, Japan (Honshu, Kyushu)
Illustrations:
Synonymy: R. dauricum var. mucronulatum (Turczaninow) Maximowicz, Rhodo. Asiae Or. 44 (1870). R. mucronulatum var. albiflorum Nakai, Flora Koreana 2:76 (1911). Type: Corea, Seoul, K, Jo (n.v.). R. taquetii Leveille, Feddes Rep. 12:101 (1913). Type: Korea, Quelpaert, Hallaisan, 1700 m, vi 1911, Taquet 5788 (holo. E). R. mucronulatum var. ciliatum Nakai, Fl. Sylv. Koreana 8:35 (1919). Type: 'Hab. in Corea media et austr. nee non insula Quelpaert'. R. mucronulatum var. acuminatum Hort.
Occurs in Countries: CN, JP, MN, RU Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: mauve, white
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):113
Shrub to 1.5m. Twigs c.2mm in diameter, rounded, green or red, laxly to sub-densely scaly, older parts glabrescent; internodes 1.5–7cm. Leaves 3–6 together in tight or loose pseudowhorls. Blade 30–70 x 7–20mm, narrowly elliptic, often slightly broader in the distal ½; apex acute or shortly acuminate; margin entire and flat; base narrowly tapering, sometimes shortly obtuse, sub-densely scaly at first on both sides, glabrescent above, scaly for a longer time beneath. Scales small, irregularly lobed and with minute, dark centres, shallowly impressed. Mid-vein prominent proximally above, smooth proximally for a few millimetres and then narrowly impressed distally; lateral veins 6–8 per side, straight and ascending, indistinctly anastomosing before the margin, very slightly raised on both sides, often indistinct. Petiole 2–6 x 1–2mm, not grooved, flattened with a few scales. Flower buds to 28 x 8mm, pale green, narrowly ovoid, acutely pointed, the bracts mostly appressed, the outermost sometimes slightly spreading, glabrous or with a few marginal scales. Bracts to 22 x 7–9mm, ovate to narrowly ovate, membranous, acute, glabrous and shining. Bracteoles to 15 x 1mm, linear, glabrous. Inflorescence an open umbel with 3–6 semi-erect to half-hanging flowers. Pedicels 15–25 x c.1.25mm, sparsely scaly or glabrous. Calyx c.4mm in diameter, oblique, rim-like, obtusely angled or very shortly lobed up to 1mm. Corolla 20–25 x 25–32mm, broadly funnel-shaped, sometimes sweetly scented, whitish cream to yellow, pink or red, lobed to halfway; tube 10–12 x 5–6 x 10–12mm, straight, glabrous outside, shortly hairy inside; lobes 13–15 x 11–13mm, spreading, overlapping up to halfway, sub-circular. Stamens irregularly spreading all round the mouth or loosely clustered on the lower side, exserted to 10mm; filaments linear, densely covered with long, spreading, white hairs in the proximal ¼–1⁄3, glabrous distally; anthers 1.5–2 x 1mm, broadly oblong to obovate. Disc prominent, glabrous. Ovary c.4 x 2mm, obovoid-cylindrical, glabrous, abruptly contracted distally; style glabrous, 7–10mm on the lower side of the tube but curving upwards; stigma c.1.5mm, obconical. Fruit 18–22 x c.5mm, sub-cylindrical.
Habitat: Mostly terrestrial in open places, hillsides or pastures, also near volcanoes, sometimes epiphytic in mountain forest. Locally common.
Distribution: Indonesia, Sumatra, widespread.
Altitude: 900-2100m
Latin – multi – many; color – coloured. Alluding to the variation in the colour of the flowers.
Type: Teysmann 778. Sumatra, West Coast, Mt Singalang (U, lectotype, BO).
Synonymy: R. salicifolium (non Becc.) Blume, Fl. Jav. Pl. inéd. 1863–83. t.7 C, f.2. R. multicolor var. curtisii Hort., Garden 1884. 26: 433. R. curtisii T.Moore, Florist & Pomologist 1884. 113: t.615. Azalea multicolor (Miq.) Kuntze, Rev. Gen. Pl. 1891. 2: 387. R. javanicum (non (Blume) Benn.) Steen., Arch. Hydrobiol. 1932. Suppl. 11: 318.
Occurs in Countries: ID Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: cream, pink, red, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:194
Shrub or small tree to 3m. Twigs densely scaly initially; internodes 4–6cm. Leaves 3–6 together in tight pseudowhorls. Blade 40–95 x 25–65mm, obovate-elliptic or broadly elliptic; apex obtuse, or very shortly and abruptly obtusely acuminate; margin entire, flat or slightly revolute proximally; base broadly tapering, sometimes decurrent, scaly initially, glabrescent above with age, densely and persistently scaly beneath. Scales small, marginal zone sub-stellately lobed; centre becoming dark. Mid-vein slightly impressed above, weakly grooved in the proximal 10mm, strongly prominent beneath but tapering and flattening gradually from base to apex; lateral veins 10–14 per side, close and parallel to each other, straight proximally, obscurely anastomosing before the margin, with some other less distinct veins between them, all somewhat prominent on both sides, reticulation lax and faintly raised underneath only. Petiole 6–8 x c.1.5mm, very slightly or not grooved above, scaly, somewhat flattened. Outer bracts to 12 x 14mm, broadly ovate, inner ones spathulate, all densely scaly distally outside, and along the margins. Bracteoles filiform. Inflorescence 5–8-flowered in an open umbel, the flowers held semi-erect to horizontal or half-hanging. Pedicels 6–10 x c.1mm, densely scaly. Calyx c.2.5mm in diameter, oblique, disc-shaped, very shortly lobed. Corolla 55–75 x 20–25mm, trumpet-shaped, or trumpet-ventricose, white, sweetly scented; tube 40–55 x 3–4 x 7–8mm, straight, often ventricose, broadest at about 2/3 of the distance from the base; outside glabrous or laxly scaly, the scales denser at the bases of the lobes, inside sub-densely hairy in the proximal ½, glabrescent distally; lobes 8–15 x 6–8mm, spreading, obovate-elliptic. Stamens exserted to 8mm; filaments linear below and densely, patently, hairy in the proximal 2/3, filiform and glabrous above, unequal; anthers 2.5 x 0.9mm. Disc densely and shortly white-hairy or glabrous. Ovary 5–6 x c.1.5mm, elongate columnar, shallowly 5-ribbed, very densely covered with thick, almost circular scales, gradually tapering distally; style becoming exserted to 8mm, slender and glabrous or with a few scales at the base; stigma shortly obconical, crenulate. Fruit 30–35 x 4–5mm, elongate- fusiform, sub-densely scaly.
Habitat: Terrestrial or epiphytic, on grassy slopes or Castanopsis and Nothofagus forest
Distribution: Papua New Guinea, Eastern Highlands: Mt Michael, Mt Otto, Daulo Pass. Simbu District: Engwegl, (Upper Chimbu R. valley), Gembogl. Western Highlands: Aiyura and near Wankl village, Mt Hagen. Sepik District: Telefomin.
Altitude: 1370-2050m
Latin – multi – many; nervi – veining. Alluding to the distinct venation of the leaves.
Type: Smith NGF 1021, Oct. 1944. New Guinea, Western Highlands, Aiyura, 1830m (L, LAE).
Occurs in Countries: PG Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Tree Fl. Colour: white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:181
Spreading shrub to 10cm. Twigs 1–1.5mm in diameter, rounded, the youngest parts densely covered with stellate scales on stalks and with occasional hairs, older parts warty with the scale stalks; internodes 1–6cm. Leaves 5–7 together in well-marked pseudowhorls. Blade 6–12 x 3–8mm, narrowly to broadly elliptic, sometimes obovate; apex shortly acuminate, sub-acute to obtuse, or rounded; margin flat, entire or minutely crenulate; base tapering; laxly scaly and quickly glabrescent above, laxly and more persistently scaly below. Scales variably sized, rounded to stellate, impressed. Mid-vein impressed above and slightly raised below or obscure; lateral veins mostly obscure, sometimes with one at an acute angle. Petiole 1.5–2 x 1mm, grooved above, scaly with minute scales and occasional short hairs. Flower buds to 8 x 4mm, green becoming brown before opening, smooth with all bracts appressed. Bracts to 8 x 3.5mm, broadly ovate to broadly elliptic, covered with semi-appressed hairs outside and a few scales near the centre line distally and on the margin near the apex. Bracteoles c.8mm, filiform, with a few scales near the apex. Flowers solitary, rarely in pairs, hanging vertically. Pedicels 8–10 x 0.8mm, red, densely scaly with stalked scales and a few hairs. Calyx c.2.5mm in diameter, obliquely cup-shaped, 5-lobed, densely scaly. Corolla 25–28 x 18mm, dark red, without scent, narrowly funnel-shaped; tube 20–22 x 3–4 x 6–8mm, weakly curved, laxly silvery scaly outside, glabrous inside; lobes c.6 x 6mm, circular, overlapping to 1⁄3. Stamens loosely clustered on the lower side of the mouth, exserted to c.2mm; filaments linear, red, glabrous; anthers of two sizes, c.0.8 x 0.6mm and c.1.4 x 0.9mm. Disc with some hairs and scales at the upper margin. Ovary c.5 x 2mm, oblong-conical, longitudinally 5-grooved, densely silvery, stellate-scaly, gradually tapering distally; style c.8mm on opening, elongating to 15mm as the flower ages, with some sparse, spreading, yellowish hairs or scales at the base, elsewhere glabrous, or glabrous all over; stigma minute, c.1mm in diameter. Fruit 25 x 4mm, fusiform, curved, outer layer peeling away and the valves curling back. Seeds 6–7.5mm, without tails c.0.7mm, the longest tail 3.5mm, tails laxly crimped.
Habitat: Mossy forest
Distribution: Indonesia, New Guinea (W), Nassau Mts, W side; Mt Jaya (Carstensz); Snow Mts region, E of the Baliem Valley.
Altitude: 1750-2600m
Latin – muscus – moss; cola – inhabiting. Living amongst mosses, alluding to the habitat.
Type: Docters van Leeuwen 10907, Oct. 1926. New Guinea (N), Nassau Mts, W side, 2600m (BO, L).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:144
Small shrub, to 1.5m; young shoots covered with adpressed flattened brown hairs. Leaves monomorphic, persistent, coriaceous, elliptic to obovate, 0.6-0.8 x 0.3-0.5cm, 1.6-2 x as long as broad, apex acute, base cuneate, margin obscurely crenate, both surfaces glabrescent, lower surface paler, with a few hairs on midrib; petiole l-2mm, indumentum as for shoots. Inflorescence 2-3-flowered; pedicels c.4mm long, densely brownish-setose. Corolla campanulate, purple, c.lOmm; tube c.4mm long, 2mm wide, glabrous. Stamens 5, exserted, filaments glabrous. Ovary strigose; style setose below. Capsule not known.
Distribution: China (Guangxi)
Altitude: Around 1000m
Known only from the type. Allied to R. minutiflorum but differing in the smaller, coriaceous leaves.
Type: China, Guangxi, Fang-Cheng Xian, Nalexiang, Marxia, 1000m, 26 iv 1956, Hopu PL Exp. 2511 (holo. PE, iso. IBSC.)
Synonymy: R. caespitulum P.X.Tan, Survey Gen. Rhododendron S. China 110, f.26 (1983). Type as for R. myrsinifolium.
Occurs in Countries: CN Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: purple
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):135
Shrub to 50cm. Twigs c.1mm in diameter, sub-densely sub-stellately scaly; internodes 2–5cm. Leaves 3–5 together in pseudowhorls, or spirally arranged, close together in the upper 1⁄3 of the internodes. Blade 14–20 x 3–4mm, very narrowly ovate-elliptic; apex shortly acuminate, minutely apiculate; margin sub-crenulate with impressed scales, sub-revolute; base broadly tapering; laxly scaly on both sides initially, becoming glabrescent above, persistently scaly beneath. Scales with the marginal zone variously sub-stellately lobed; centre minute and slightly impressed. Mid-vein slightly impressed above, prominent beneath; lateral veins obscure. Petiole c.2mm, slender, scaly. Bracts to 20 x 6mm, glabrous, membranous, red-brown, shining, ovate; the upper with a 5–6mm subulate point. Inflorescence of solitary or paired flowers. Pedicels c.18mm, slender, densely stellate-scaly. Calyx c.2mm in diameter, oblique, disc-shaped, obscurely lobed. Corolla c.35mm, fleshy, red; tube c.25 x 4 x 8mm, cylindrical, slightly curved, glabrous inside and out, base lobed; lobes 8–9 x 5–6mm, erecto-patent, broadly obovate. Stamens unequal, exserted to c.2mm; filaments linear, glabrous; anthers obovate, 1–1.3mm. Disc glabrous. Ovary cylindrical-fusiform, very densely scaly, without hairs, c.6 x 2mm, gradually tapering distally; style c.14mm, slender, scaly at the base only, glabrous distally; stigma globose.
Distribution: Indonesia, New Guinea (W), Idenburg R., Bernhard Camp. Epiphytic on tall trees in mossy forest
Altitude: Around 2150m
With a resemblance to Myrsine (Myrsinaceae), a cultivated ornamental.
Known only from the type collection.
Type: Brass 12630, Feb. 1939. 18km SW of Bernard Camp, Idenberg R., 2150m (A, L, fragment).
Occurs in Countries: ID Altitude Ranges: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:225
Very similar to R. ferrugineum, differing as follows: smaller shrub, rarely exceeding 0-5 m, leaves narrowly obovate, obtuse, 14-23 x 5-8 mm, less densely lepidote beneath, obscurely crenulate, pedicels filiform-acicular pubescent as well as lepidote, calyx lobes narrowly triangular, up to 2 mm, usually fringed with scales and a few loriform hairs. Corolla pink, 15-17 mm, tube 9-10 mm, more densely pubescent and less densely lepidote outside, style shorter than to ± as long as ovary. BULGARIA, JUGOSLAVIA, ROMANIA, USSR (western European part)
Illustrations:
Vicariates with R. ferrugineum.
Type: Habitat in alpibus Transsilvaniae australis'
Synonymy: R. kotschyi Simonkai, Enum. PL Transs. 389 (1886). R. ferrugineum subsp. kotschyi (Simonkai) Hayek, Prodr. Fl. Bale. 2:17 (1928)
Subgenus: Rhododendron Habit: Non-Tree
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):111
Dwarf shrub, to 0.5m; young shoots covered with adpressed flattened brown strigose hairs. Leaves monomorphic, persistent, coriaceous, obovate to oblanceolate, 1-2.5 x 0.5-1.2cm, c.2 x aslongasbroad, apex mucronate, base cuneate, margin entire, upper surface glabrescent, lower surface with sparse adpressed strigose hairs, especially on midrib; petioles c.3mm, densely adpressed-strigose-hairy. Inflorescence 2-4-flowered; pedicels 2-3mm, pilose. Calyx minute, densely strigose. Corolla funnel-campanulate, rose, with or without darker flecks, c.30mm; tube c.lOmm, glabrous. Stamens 5, filaments glabrous. Ovary densely pilose; style glabrous. Capsule not known.
Habitat: Moist shaded cliffs
Distribution: China (Guangdong, Jiangxi)
Altitude: Around 500m
Type: China, Guangdong, Naamkwam Shan, Zengcheng Xian, 20 iv 1932, W.T. Tsang (Huang, H.D.) 20392 (holo. PE, iso. K)
Occurs in Countries: CN Altitude Ranges: 0 - 1,000m Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: rose
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):132
Leaves with lateral veins obsolete beneath; corolla with dark flecks
Since we have seen no material of var. cryptonerve we are dependent on Tan's brief description for our understanding of this taxon.
Type: China, Guangdong, Pingyuan Xian, 500m, 27 iv 1957, L. Teng 4437 (holo. IBSC, n.v.).
Leaves with conspicuous lateral veins beneath; corolla apparently without flecks
Low, prostrate, much-branched shrub; young shoots covered with adpressed flattened shining brown hairs. Leaves persistent, chartaceous, monomorphic, elliptic to elliptic-obovate, 0.5-1.2 x 0.2~lcm, 2-2.5 x as long as broad, apex acute or mucronulate, base cuneate, margin entire, upper surface with scattered pilose hairs borne on raised pustules, lower surface paler, with scattered adpressed shining brown hairs; petioles l-4mm, densely strigose. Inflorescence 2-3~flowered; pedicels 3-5mm, densely covered with flattened shining brown hairs. Calyx strigose, lobes c.2mm, ciliate. Corolla funnel-campanulate, dark-red, 20-25mm; tube villous within. Stamens 10, longer than corolla, filaments pilose in lower half. Ovary densely setose; style glabrous. Capsule not known.
Distribution: China (N Taiwan)
Illustrations:
Allied to R. serpyllifolium but differing in the number of stamens, etc.
The corollas are described in Fl. Taiwan (3: 32) as being 35mm and 40mm across. These measurements are significantly larger than those cited in the type description and those on the type specimen itself.
Type: China N Taiwan, in Monte Shichiri, (Chihsinshan), vii 1905, Nakahara 82 (holo. TI)
Occurs in Countries: CN, TW Subgenus: Tsutsusi Habit: Non-Tree
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):129
Shrub, 1-3.5m. Leaves elliptic, 8-11 X 3-4.3cm, c.2.5 X as long as broad, apex acute to apiculate, base rounded, lower surface with a bistrate indumentum, the upper layer loose and fawn, with long-rayed floccose hairs, the lower compacted; petioles c.1.5cm, glabrescent. Inflorescence 12-15-flowered; rhachis 5- 10mm; pedicels c. 15mm, sparsely pubescent. Calyx c. 1mm, glabrous, lobes rounded. Corolla funnel-campanulate, white flushed rose to pale pink, with purple flecks and sometimes also a basal blotch, 30-35mm. Ovary densely rufous-tomentose; style glabrous. Capsule not known.
Habitat: Open scrub and pine forests
Distribution: China (NW Yunnan)
Altitude: 3350-4000m
Allied to R. pomense and R. dignabile.
Type: China, W NW Yunnan, Mekong/Salween divide, 11 -12000ft, vi 1917, Forrest 14060 (holo. E; iso. K).
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: pink, purple, rose, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):363
Greek – nanos – dwarf; phyton – a plant. Originally thought to be a very small plant.
Type: Eyma 682, 17 June 1937. Indonesia, Celebes (C), Enrekang, Rantemario (L, A, BO, K).
Occurs in Countries: ID Altitude Ranges: 3,000 - 4,000m Subgenus: Vireya
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:49
Shrub to 2m. Twigs erect, slender, tips shortly patent hairy and moderately scaly, stems covered with the scars and the thick cushions of fallen leaves. Leaves densely and regularly spirally arranged. Blade 4–7 x 1.5–2.5mm, elliptic to narrowly elliptic; apex shortly tapering, obtuse to rounded; margin flat or slightly recurved, entire or crenulate by impressed scales; base tapering, laxly, silvery and sub-persistently scaly on the upper surface, finally glabrescent; persistently laxly brown-scaly beneath. Scales circular, marginal zone narrow, entire or a little wavy; centre dark brown, thick, distinctly impressed. Mid-vein narrowly impressed above, distinct, but not raised beneath; lateral veins not visible. Petiole 1.5–2 x c.0.5mm, semi-rounded, grooved above, hairy and scaly. Flower buds to 6 x 2.5mm, narrowly ovoid, dark purplish-red. Outer bracts triangular, subulate; inner ovate to elliptic with a short obtuse point, sparsely scaly outside, glabrous within and with a conspicuous fringe of white hairs on the margins. Bracteoles 4–5mm, filiform, sub-spathulate distally and densely ciliate. Inflorescence of solitary flowers, or in twos, red, cylindrical, hanging vertically. Pedicels 5–7 x 0.75mm, slender, shortly hairy and moderately scaly. Calyx minute, disc-shaped, wavy and obscurely 5-lobed, scaly outside, glabrous inside. Corolla 17–20 x c.9mm, slightly oblique, straight or slightly curved; tube 12–14 x 4–6 x 7–8mm, straight, or slightly curved, moderately covered with scales outside; lobes 3–5 x 2–4mm, half-spreading, overlapping for ½ their length, scaly outside except near the margins, also with a few hairs near the tips, glabrous inside, entire or irregularly crenulate, but not irregularly denticulate at the apex. Stamens slightly dimorphic, exserted to c.2mm, irregularly and variously arranged; filaments linear, slightly broader towards the base, glabrous; anthers 1.3–1.8mm, broadly oblong, dark purple. Disc glabrous. Ovary 2–2.8 x 1.2–1.8mm, conical-ovoid, 5-furrowed, densely scaly, gradually tapering distally; style 7–8mm, pink, glabrous or with scales for c.1mm proximally, deflexed to the lower side of the corolla; stigma c.0.9mm in diameter, shortly club-shaped hardly thicker than the style, dark purple. Fruit to 7 x 3.5mm, shortly cylindrical, deeply grooved, not becoming erect, the valves curving back, the placentae not separating. Seeds 1–1.4mm, without tails 0.7–0.9mm, the longest tail 0.2mm.
Distribution: Indonesia, Sulawesi, Latimodjong Range, Mt Rantemario, scattered plants in the open country near the summit at 3100–3300m.
Altitude: 3100-3300m
Flowers March, June, probably continuously.
Described originally as a dwarf shrub, it was in fact seen growing to nearly 2m on the open summit area of Mt Rantemario.
Distribution: Indonesia, SW Central Sulawesi, Latimodjong Range, frequent on rocks just below the western edge of the plateau of bivouac Heinrich, at 3200–3250m; known only from the type collection.
Altitude: 3200-3250m
Greek – petra – a rock or stone; philus – loving. Alluding to the rocky habitat.
Differs from the type variety by less distinctly hairy twigs, leaf blade 2.5–6 x 1.5–2.5mm, obovate-elliptic, obtuse and mostly a little retuse at the apex and shortly hairy in the lower ½. With shortly but distinctly ciliate calyx lobes, minutely hairy pedicels and sub-globose-obovoid anthers c.1mm.
Flowers June
Type: Eyma 1046, 28 June 1937. Indonesia, Celebes (C), Enrekang, Latimojong Range (L, A, BO, K).
Shrub. Twigs flattened, sub-densely scaly; internodes 7–15cm. Leaves 4 together in pseudowhorls. Blade 70–100 x 35–50mm, elliptic, apex shortly, gradually acuminate, sub-acute; margin entire, sub-revolute; base broadly tapering, glabrescent above at maturity, laxly scaly beneath. Scales small, brown, irregularly lobed; centre slightly impressed. Mid-vein slightly but distinctly impressed above, very prominent beneath for the proximal ¾, less so distally, more densely scaly than the lamina; lateral veins 6–8 per side, distant from each other, diverging at an acute angle, straight below, obscurely curved-anastomosing near the edge, somewhat raised above (but impressed in the very middle), prominent beneath, reticulation obscure. Petiole 10–15 x 1–1.5mm, grooved above, sub-densely scaly. Outer bracts to 25 x 8mm, ovate, inner ones spathulate, all hairy on both sides, otherwise not or very laxly scaly, long-ciliate. Bracteoles to 20mm, sub-filiform, glabrous below, narrowly spathulate, hairy distally. Inflorescence a c.8-flowered umbel. Pedicels 10–12mm, thick, densely sub-stellately scaly. Calyx c.2.5mm in diameter, oblique, irregularly shortly and obtusely 5-lobed, scaly. Corolla trumpet-shaped, white; tube c.45 x 3–4 x 4–5mm, straight or slightly curved, sub-densely sub-stellately scaly outside, densely, shortly and patently white hairy in the proximal 1⁄3, gradually less hairy distally inside; lobes 10–12 x 8–10mm, elliptic-obovate to obovate-spathulate, spreading, laxly scaly outside, glabrous inside. Stamens unequal, c.55mm, exserted; filaments linear and densely patently hairy proximally, less hairy and finally glabrous distally; anthers c.3 x 0.8mm, oblong, base obtuse. Disc sub-densely short-hairy. Ovary elongate-conical, densely covered with almost circular scales, c.8 x 1.5mm, tapering distally; style scaly at the very base, glabrous otherwise, equalling the corolla tube in length; stigma narrowly shortly obconical. Fruit 40–45 x c.4mm, elongate-cylindrical, curved, shortly tapering at both ends, laxly scaly.
Habitat: In hill forest dominated by Castanopsis and in open grassland
Distribution: Papua New Guinea, Sattelberg Region, Morobe District: Ogeramnang; Mt Saruwaged; Wau Salamoa track; Tukwabat village, S of Lae.
Altitude: 1770-2440m
Latin – natalis – relating to birth. ‘Gift from nr. 1 for my 64th birthday’. Presumably collected by a special field companion for Mary Clemens.
The status of this species is not clear; it would appear to be relatively rare. A collection at Kew (Frodin 2824) agrees well with the description but it is from Telefomin, a very long way to the west of all other collections.
Type: Clemens 4852, 3 Jan. 1937. New Guinea (NE), Morobe District, Ogeramnang (Satelberg region) (A, L, fragment).
Occurs in Countries: PG Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:182
Shrub to c.30cm. Twigs 0.5–1mm in diameter, very slender, stellately scaly with brown scales, when young, later glabrescent; internodes 2–8cm. Leaves in pseudowhorls, 2–4 together. Blade 20–50 x 5–20mm, narrowly to broadly elliptic; apex gradually tapering, broadly acute to obtuse; margin flat or a little revolute; base tapering; densely brown scaly on both sides when young. Scales deeply stellate, fragile; with a small centre from a minute tubercle. Mid-vein smooth above, raised below; lateral veins 5–6 per side, obscure on both sides, without reticulation. Petiole 2–4mm, slender, initially stellately scaly. Bracts to 8mm, ovate acuminate; outer ones narrowly ovate, subulate, outside densely stellately scaly, without hairs. Bracteoles c.10 x 1.5mm, almost linear, slightly broadened distally, sub-glabrous. Inflorescence 2–3-flowered, flowers half-hanging to hanging. Pedicels 5–9 x c.1mm, slender, brown-stellate-scaly, without hairs. Calyx c.3mm in diameter, obliquely saucer-shaped, hardly lobed, stellately scaly outside. Corolla 15mm, tubular, a little expanded at the lobes, slender, red or purple; tube c.10 x 2.5 x 3.5mm, glabrous on both sides, slightly 5-lobed at the base; lobes c.5 x 5mm, sub-circular. Stamens not exserted; filaments glabrous; anthers c.1mm long. Disc very shortly hairy. Ovary c.4 x 1.5mm, cylindrical, very densely brown stellate-scaly, without hairs, tapering distally; style c.6mm, scaly at the base, then distally shortly, grey-patently hairy, almost to the apex; stigma club-shaped. Fruit c.20 x 4mm, narrowly fusiform, scaly.
Habitat: Epiphytic in Castanopsis or Nothofagus dominated montane forest.
Distribution: Papua New Guinea, New Britain, Kandrian subdistrict, Mt Klangal; Pomeo subdistrict, Mt Lululua; Talsea subdistrict, Mt Talawe, Mt Tangis
Altitude: 800-1585m
Named after the island of New Britain from where it comes.
Sleumer (1973) notes the similarity of this species to R. rarum. It is distinguished as the leaves are widest in the middle, the corolla is glabrous and the anthers are much smaller.
Type: Croft & Katik NGF 15558, 15 May 1973. New Britain, Kandrian subdistrict, Mt Klangal (summit), 25 miles NNE of Gasmata, 800m (L, LAE).
Occurs in Countries: PG Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: purple, red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:91
Shrub or small tree, l-6m; young shoots sparsely floccose-tomentose, eglandular or (rarely) setose-glandular. Leaves elliptic to oblong or oblanceolate, 4-11 x 1.9—3.2cm, 1.7—5(—7) x as long as broad, apex rounded and apiculate to acuminate, base ± rounded, upper surface glabrous, lower surface usually ± glabrous, with a glaucous, strongly papillate epidermis; petioles 1-1.5cm, sparsely floccose-tomentose or glabrescent, rarely setose-glandular. Inflorescence 5—8(— i2)-flowered; rhachis c.5mm; pedicels 10-15mm, sparsely stellate-tomentose, sometimes with a few stipitate glands. Calyx 2-15mm, cupular when well-developed, often ± deciduous, lobes tomentose, sometimes also glandular, with ciliate margins. Corolla fleshy, tubular-campanulate, crimson or bright red, occasionally straw yellow, 35-45mm. Ovary densely tomentose, sometimes with a varying proportion of stipitate glands (rarely glabrous), tapering into the ± glabrous style. Capsule 20-25 x c.4mm, usually strongly curved.
Habitat: Amongst rocks and scrub, pine forests
Altitude: 2750-3350m
21*. R. bijiangenseT. L. Ming, ActaBot. Yunnanica 3: 116, t.2 (1981), see p. 000. Type: China, W Yunnan, Bijiang Xian, 2900m, 23 v 1980, Yang, C. H. 80-0083 (holo. Herb. Inst. Bot. Kunming). Shrub, elm; young shoots densely setose-glandular. Leaves narrowly lanceolate, 7-10 x 2-2.5cm, 3.5-4 x as long as broad, apex apiculate, lower surface green and epapillate, glabrous except for the glandular midrib and main lateral veins; petioles clem, densely setulose-glandular. Inflorescence c.lO-flowered; rhachis c.lOmm; pedicels 15-20mm, densely setulose-glandular. Calyx 7-8mm, glandular, lobes ± fleshy, reddish, 5-6mm, with glandular-ciliate margins. Corolla fleshy, campanulate, c.30mm, reddish-purple. Ovary densely setose-glandular, ± abruptly contracted into the glabrous style. Capsule not known. china (W Yunnan). Only known from the type. Probably allied to R. neriiflorum but differing in the setose indumentum, in the papillate, green leaf epidermis and in the ovary ± abruptly contracted into the style.
Occurs in Countries: BT, CN, IN, MM Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: crimson, red, yellow
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):408
The status of this subspecies is uncertain as the taxonomic significance of the characteristic alveoli on the lower surfaces of the leaves (caused by more prominent veins) is not known.
Synonymy: R. agetum Balfour f. & Forrest, Notes R.B.G. Edinb. 13: 29 (1920). Type: China, W Yunnan, eastern flank of the N'Maikha/Salween divide, v 1919, Forrest 17851 (holo. E; iso. K). CHINA (W Yunnan).
Distribution: China (W Yunnan, SE Xizang), NE Upper Burma
Illustrations:
Type: China, Yunnan, in monte Tsangchan, Delavay 294 (?iso. E, K)
Synonymy: R. euchaites Balfour f. & Forrest, Notes R.B.G. Edinb. 13: 43 (1920). Type: China, W Yunnan, Shweli/Salween divide, vi 1913, Forrest 12125 (holo. E; iso. K). R. phoenicodum Balfour f. & Farrer, Notes R.B.G. Edinb. 13: 285 (1922). Type: NE Upper Burma, Hpimaw Pass, 10000ft, 6 v 1919, Farrer 877 (holo. E; iso. K). R. neriiflorum Franchet subsp. euchaites (Balfour f. & Forrest) Tagg and subsp. phoenicodum (Balfour f. & Farrer) Tagg in Stevenson (ed.), The Species of Rhododendron 533 (1930).
Distribution: China (S Xizang, Mid W Yunnan), Upper Burma, NE India (Arunachal Pradesh), Bhutan
Illustrations:
A variable species with at least some geographical variation; allied to R. floccigerum (q.v.) and to R. sperabile.
Kingdon-Ward 9321, with sparsely hairy leaves, may be a hybrid of subsp. phaedropum.
Synonymy: R. phaedropum Balfour f. & Farrer, Notes R.B.G. Edinb. 13: 283 (1922). Type: NE Upper Burma, Nyitadi, 9000ft, 17 ix 1920, Farrer 1530 (holo. E; iso. K). R. floccigerum Franchet var. appropinquans Tagg & Forrest, Notes R.B.G. Edinb. 15: 312 (1927). Type: China, Mid-West Yunnan, Chienchuan/Mekong divide, 26°20'N, 99°40'E, 10000ft, vi 1923, Forrest 23291 (holo. E). R. floccigerum Franchet subsp. appropinquans (Tagg & Forrest) Chamberlain, Notes R.B.G. Edinb. 37: 333 (1979). R. tawangense Sahni & Naithani, Indian Forester 105: 685, t. (1979). Type: NE India, Arunachal Pradesh, Kameng Division, Tawang, Sahni & Naithani ser. 2: 751 (holo. DD, n.v.).
Shrub. Twigs elongate, weak, rounded, laxly foliate, densely stellately scaly. Leaves opposite. Blade 35–70 x 5–9mm, very narrowly ovate or nearly linear; apex acute; margin entire; base broadly tapering, nearly rounded; scaly on both sides initially, glabrescent above, more persistently scaly beneath. Petiole 2–3mm. Inflorescence of solitary flowers. Pedicels to 5mm, densely stellately scaly. Calyx 2.5–3mm in diameter, disc-shaped, densely stellately scaly, very shortly 5-lobed. Corolla 27–33mm, tubular, bright pink-red to purplish, zygomorphic and slightly curved; tube densely stellately scaly outside, glabrous inside; lobed to c.1⁄5, lobes sub-circular, erecto-patent. Stamens to 25mm, very slender; filaments filiform, laxly hairy; anthers c.2mm, oval. Ovary c.6mm, oblong, densely stellately scaly; style c.6mm, slender, laxly hairy; stigma spherical, 6-lobed.
Distribution: Papua New Guinea, Schrader Mts, in mountain forest, epiphytic
Altitude: Around 2070m
Latin – Nerium oleander L., the oleander (Apocynaceae); folium – leaved. The leaves being of similar shape to those of the oleander.
The type material was destroyed in Berlin and this species has still to be recollected. The description given is from Sleumer’s (1966) translation of the original diagnosis. It would be surprising if the leaves were really opposite; this presumably relates to a very poor specimen either growing weakly or having lost most of its leaves in handling. Otherwise the only good character separating this species from R. rarum is the very short pedicels. The short style would seem to be a less reliable character although emphasised by Schlechter when describing this species. It could reflect the fact that the flowers were very young when collected. Van Royen & Kores (1982) note R. rarum as being reported from the West Sepik District which if true means the distribution of this species comes very close to if not overlapping that of R. neriifolium and would cast doubt on the validity of this species.
Type: Ledermann 11777. New Guinea (E), Northern part, Sepik R. region, Mt Schrader (B†).
Occurs in Countries: PG Altitude Ranges: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: pink
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:92
Shrub to 1.5m. Twigs 1.5–2.5mm in diameter, sparsely scaly to almost glabrous; internodes 2–10cm. Leaves 3–5 together in tight pseudowhorls. Blade 56–80 x 7–14mm, narrowly elliptic to almost linear; apex acute; margin entire, slightly revolute in the proximal ½; base narrowly tapering; glabrescent above, laxly scaly beneath. Scales small, deeply, irregularly and broadly lobed in the marginal zone; centre minute, slightly or not impressed. Mid-vein slightly impressed above in the proximal ½, very slightly raised below throughout its length; lateral veins 4–6 per side, diverging at an acute angle, the whole leaf smooth with obscure reticulation when fresh, becoming more prominent when dry. Petiole 1–2 x c.2.5mm, indistinctly grooved above and with a few pale brown scales. Flower buds c.25 x 15mm, narrowly ovoid, acute. Bracts to 28 x 10mm, translucent red or pink, ovate, long-acuminate, the apex tapering to a 2–3mm long acute point, glabrous outside. Bracteoles to 15mm, subulate, glabrous. Inflorescence an irregular open umbel of 2–5 flowers which are semi-erect to half-hanging. Pedicels 10–13 x 1.5–1.6mm, laxly scaly and sparsely covered in spreading white hairs. Calyx a low ring, with sparse scales. Corolla 30–35 x 25mm, funnel-shaped, lobed to halfway, glossy orange or red; tube 16–17 x 6–8 x 11–14mm, straight, glabrous inside and out; lobes 12–15 x 10–12mm, sub-erect, strongly overlapping for most of their length, obovate-sub-spathulate. Stamens c.20mm, arranged regularly all round the mouth, not exserted; filaments linear, dilated and laxly hairy in the lower ¼, glabrous and narrower distally; anthers 4.5 x 1.25mm, elongate-oblong, each cell shortly pointed at the base. Disc prominent, glabrous. Ovary 7 x 3mm, conical, densely white-hairy and with some small brown scales; style 8mm, glabrous; stigma 1.5mm in diameter. Fruit 10 x 6mm, ovoid- cylindrical, densely hairy and scaly.
Habitat: Mostly terrestrial, rarely epiphytic, in mossy forest or open, sunny landslides, not common.
Distribution: Malaysia (Borneo), Sabah, Mt Kinabalu (Kinataki R., Mesilau R., Marai Parai Spur); Mt Lotung. The record from Bt Raja in Kalimantan (Indonesian Borneo) (Sleumer 1966) is now referable to R. exuberans.
Altitude: 1900-3050m
Latin – nervus – a nerve or vein; ulus – the diminutive; osum – abundant or marked. Alluding to the abundant development of small veins in the leaves.
It is very similar to hybrids that occur on Mt Kinabalu between R. crassifolium and R. stenophyllum but these occur at lower altitude and have longer, rounded, swollen petioles without a groove on the upper side.
Type: Clemens 33186, 19 May 1933. Borneo, North Borneo, Mt Kinabalu, 2440–3050m (BM, A, BO, E, L, NY).
Occurs in Countries: MY Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: orange, red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:263
Tall shrub with young branches minutely puberulous. Leaves glabrous except for the petiole and upper mid-rib; blade narrowly elliptic-ovate, c.45 x 16 mm, base cuneate, narrowed to an obtuse or emarginate apex, mucronate, chartaceous, lateral veins obscure; petiole about 6 mm long. Inflorescence buds lateral, 1-flowered, clustered near the ends of the leafy shoots; outer bud scales short, inner elongated (c.l2mm); pedicel 10mm long, puberulous and with glandular hairs. Calyx lobes oblong to ovate, 6-7 x 2-5-3mm, margin slightly ciliate or glabrous. Corolla magenta-rose with darker spots, glabrous on the outside, c.22 mm long, rotate with a short tube and spreading lobes. Stamens 5, filaments hairy below. Ovary subglobose, c.2-5mm high, setose and glandular, 5-loculate; style with numerous glandular hairs on its lower part. Capsule c.6 x 5 mm, verrucose.
Habitat: In scrub
Distribution: NE Burma
Altitude: 1300-3300m
This species is distinguished from all other members of section Azaleastrum by the densely glandular lower part of the style. The small, narrow, chartaceous, rather than coriaceous leaves with inconspicuous venation are also characteristic. It is a local species, occurring in the south western limits of the range of R. leptothrium. In Cox, Farrer's Last Journey (1926), p. 220, this plant is provisionally identified as R. leptothrium.
Type: Burma, Htawgaw Fort, 4000 ft, Farrer 807 (holo. E).
Synonymy: R. medoense Fang & M. Y. He var. adenostylum Fang & M. Y. He, Bull. Bot. Res. 3,1:2, f. 2 (1983). Type: NE Upper Burma, Tzi-tzo-ti, 3300m, iv 1925, Forrest 26420 (holo. PE-n.v., iso. E).
Occurs in Countries: MM Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Azaleastrum Habit: Non-Tree
Philipson, W.R. & Philipson, M.N. (1986) A Revision of Rhododendron III. Subgenera Azaleastrum, Mumeazalea, Candidastrum and Therorhodion. Notes from the Royal Botanic Garden Edinburgh 44(1):6
Small tree, c.3m. Leaves lanceolate to elliptic, 17-20 x 5.2-7.5cm, 2.6-3 x as long as broad, apex acute to apiculate, base broadly cuneate, upper surface glabrous, lower surface covered with a hght brown adpressed indumentum composed of sub-radiate hairs with long arms; petioles 3-3.5cm, glabrous or with the remains of a radiate indumentum. Inflorescence c. 15-flowered; rhachis c.lOmm; pedicels c.25mm, densely tomentose. Calyx c.5mm, densely tomentose. Capsule c.15 x 4mm, densely lanate-tomentose; style glandular, at least below.
Only known from two fruiting specimens from the same locality. Without flowers, this distinctive species cannot be referred with certainty to any subsection, though Sleumer (1958) has noted the similarity in leaf indumentum to R. traillianum var. dictyotum (subsection Taliensia).
Type: Vietnam, Nhatrang, 26 v 1922, Poilane 3679 (holo. P).
Subgenus: Hymenanthes Habit: Tree
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):428
Slender shrub to 60cm. Twigs 1–3mm in diameter, rounded, green but distinctly brown-scaly; internodes 2–7cm. Leaves 3–7 together in tight pseudowhorls, together with conspicuous, subulate, cataphylls. Blade 25–80 x 6–30mm, narrowly elliptic or very narrowly ovate; apex long-acuminate and often somewhat curved, acute; margin slightly recurved; base tapering to rounded or weakly cordate, rugose, especially when dry, moderately densely scaly on both sides initially, becoming glabrescent above, more persistently scaly beneath. Scales brown, sessile, highly variable, the largest deeply, stellately lobed, or sub-dendroid; centre small and not impressed. Mid-vein distinctly impressed above and very thick and prominent beneath; lateral veins 7–13 per side, widely spreading, slightly to strongly raised above and impressed beneath (especially when dry) so as to make the surface rugose, reticulation obscure. Petiole 2–4 x c.2mm, distinctly grooved above, densely brown-scaly. Flower buds to 20 x 7mm, narrowly ovoid, acute, pale green although prominently brown-scaly. Outer bracts subulate with the tips slightly spreading, inner ones larger, ovate-acuminate, acute, the points mostly appressed, stellate-scaly outside, and with scales along the margins, often persistently clasping the flower after it has opened. Flowers solitary or in twos, horizontal or half-hanging. Pedicels 3–5 x c.2mm, densely stellately scaly. Calyx c.2.5mm in diameter, oblique, shortly 5-lobed, scaly outside. Corolla 35–45 x 55–65mm, deep, bright yellow, saucer-shaped; tube 12–15 x 8–9 x 16–20mm, but contracted in the middle to c.7mm, white with scattered brown scales outside and deeply sulcate in the proximal ½, distally, yellow, smooth and glabrous, except for small clusters of scales at the junctions with the lobes, glabrous inside; lobes 20–30 x 17–25mm, spreading almost horizontally and overlapping ½–2⁄3, broadly obovate with rounded or emarginate apices. Stamens c.18mm; filaments slender, bent through a right angle, glabrous at the base, hairy above the angle and then glabrous distally; anthers linear-oblong, 4–5 x 1–1.5mm. Disc prominent, hairy at the upper margin. Ovary c.8 x 4mm, sub-cylindrical, with long, white, sub-patent hairs which cover scales, abruptly contracted distally; style 10–15mm, glabrous, yellow, at first deflexed downwards or to one side; stigma club-shaped, becoming deeply 5-lobed. Fruit 35–43 x 5–6mm, fusiform-cylindric, densely hairy with a persistent style up to 13mm; valves reflexing and twisting after opening. Seeds 7.5–9.5mm, without tails 0.6–0.7mm, the longest tail 4–5mm.
Habitat: Mostly epiphytic in dense humid forest, along rivers particularly near waterfalls, also recorded from ‘heath-forest’.
Distribution: Indonesia, Kalimantan. Brunei. Malaysia (Borneo), Sabah and Sarawak. Widespread throughout Borneo.
Altitude: 100-800m
Named in honour of A.W. Nieuwenhuis, Professor of Ethnology at Leiden University in the Netherlands, who made several expeditions to Borneo in the 1890s.
This very distinctive species is unlikely to be confused with any other. With its rugose leaves and broad ‘saucer-shaped’, mostly solitary yellow flowers it is unlike any other.
Type: Amdjah 122, 28 Oct. 1898. Central Borneo, Sg. Buleng (SING, lectotype A, BO, L).
Occurs in Countries: ID, MY Altitude Ranges: 0 - 1,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:204
Shrub, 3-5m; young shoots tomentose and stipitate-glandular. Leaves lanceolate to oblong, 12—17(—20) x 4-5cm, 3-3.5 x as long as broad, apex apiculate, tapering below to a rounded base, lower surface with a light reddish brown, loosely lanate unistrate indumentum composed of lanate hairs; petioles 15-30mm, floccose-tomentose and glandular. Inflorescence 8-10-flowered; rhachis 10-15mm; pedicels 20-30mm, floccose-tomentose. Calyx c.lmm, floccose-tomentose, lobes triangular. Corolla campanulate, 40-50mm, deep pink at first, later yellowish-pink, with conspicuous purple flecks. Ovary stipitate-glandular and tomentose; style glabrous. Capsule 15-20 x c.8mm.
Distribution: China (Sichuan)
The unistrate indumentum on the leaves and the glandular ovary suggest an affinity with R. bureavii and R. elegantulum though the minute calyx distinguishes the present species from both. A specimen, Chang, X. S. & Ren, Y. X. 6509 from Sichuan, differs in its narrower leaves, c.13 x 2.8cm, and in its denser indumentum on the petioles and leaf undersurfaces, but is otherwise a reasonable match with the type of R. nigroglandulosum.
Type: a specimen grown in Gothenburg flowering in 1970, originating from seed collected in China, Sichuan Prov., Kangting distr., Tapanshan, 3500m, xii 1934, H. Smith 13979 (holo. GB).
Occurs in Countries: CN Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: pink, purple, yellow
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):340
Shrub to 2m tall; bark light brown, papery and shredding, revealing polished brown stems and branches; young twigs pale to red-brown, sparsely covered with multicellular gland-headed and eglandular hairs; new foliage shoots arising from axillary buds associated with foliage leaves of the previous year's shoot (i.e. below terminal bud), and some terminal buds. Vegetative bud scales glabrous abaxially, to occasionally with a few multicellular gland-headed and/or eglandular hairs near apex, sparsely to moderately unicellular-pubescent adaxially, especially near apex, and sometimes with a few multicellular gland-headed and eglandular hairs near apex; margin fringed with unicellular hairs distally, becoming glabrous proximally; lowermost scales with apices similar to those of upper scales, not long aristate (although occasionally with rudimentary blade). Leaves deciduous, dark green adaxially, pale green abaxially, turning orange to red in autumn, alternate (with internodes becoming more closely spaced towards tip of shoot). Blade membranaceous, obovate, often broadly so, to rarely broadly elliptic, 4-18 x 1.5-8.5cm; base attenuate, with blade decurrent along basal portion of midvein; apex rarely obtuse, usually rounded to emarginate, with a short mucro; midvein strongly raised and prominent abaxially, the secondary, tertiary, and some higher order veins slightly raised abaxially, thus vein reticulum usually conspicuous; adaxial surface, including midvein, with scattered multicellular gland-headed and eglandular hairs; abaxial surface with scattered multicellular gland-headed and eglandular hairs, the lateral surfaces of midvein very sparsely to moderately fringed with straight to crisped, unicellular hairs, especially near base, or such hairs lacking, and with multicellular gland-headed and eglandular hairs, the secondary veins with scattered multicellular hairs, sometimes sparsely unicellular-pubescent near junction with midvein, especially at base of blade; margin entire to irregularly undulate with a fringe of multicellular eglandular hairs, usually with a few gland-headed hairs intermixed; petiole essentially lacking, the base abruptly expanded into a very broadened point of attachment, forming a ± triangular slight protuberance below terete portion of midvein. Flower bud scales with abaxial surface glabrous, sometimes with a few unicellular hairs or multicellular gland-headed or eglandular hairs near apex, the adaxial surface sparsely to densely covered with unicellular hairs, especially near apex, often with a few multicellular hairs near apex; margin ciliate with unicellular hairs, usually with a few glandular hairs intermixed, to unicellular-ciliate near apex and with closely associated multicellular glandular hairs proximally. Flowers appearing with or after the leaves; inflorescence an umbellate raceme of 6-15 flowers. Pedicels 8-25mm long, moderately to densely covered with multicellular gland-headed hairs. Calyx lobes lingulate to broadly ovate-triangular, 0.9-6 x 1.2-2mm; apex rounded to acute; margin fringed with multicellular gland-headed hairs; adaxial surface glabrous; abaxial surface with scattered multicellular gland-headed hairs, often sparsely unicellular-pubescent near apex. Corolla white, lacking spots, ± actinomorphic, tubular-campanulate, the tube longer than the limb and broadly expanding into it; corolla lobes all ± similar, 0.5-0.9cm long and wide; corolla tube 1-1.6mm long; outer surface of corolla glabrous; inner surface of corolla sparsely unicellular-pubescent towards base. Stamens 10, straight, variable in length, 1.4-2.2cm long, included; filaments glabrous distally, becoming densely covered with flattened unicellular hairs proximally. Ovary 3-5mm long, moderately to densely covered with multicellular gland-headed hairs; style straight, 1.2-1.8cm long, glabrous. Capsules ovoid to ellipsoid, 0.7-1.7x0.5-0.7cm, strongly grooved, moderately covered with multicellular gland-headed hairs. Seeds light yellowish brown, ellipsoid with 5 well-developed longitudinal furrows, 0.6-1 x 0.2-0.35mm; testa tightly appressed to body, with cells at each end elongated and fused to form + stellate tails 0.2-0.5mm long, the cells covering body elongate. Cotyledons lacking multicellular hairs and with venation represented only by midvein.
Habitat: Woods and thickets
Distribution: Japan (north-central Honshu)
Altitude: 1000-1850m
Illustrations:
Rhododendron nipponicum is a taxonomically isolated species. It is easily distinguished from other primitive members of subgen. Pentanthera (i.e. the species of sections Rhodora and Sciadorhodion) by its flowers with a white, unspotted, actinomorphic, tubular-campanulate corolla with the tube longer than the limb, and a straight style, which are produced with or after the leaves. In addition, its cotyledons are distinctive because they possess only a midvein (M. Philipson, 1980). The species has a distinctive bark that is papery and shredding, revealing polished brown stems and branches. Like members of sect. Rhodora, this species has tailed seeds and vegetative shoots that lack a terminal 'whorl'of leaves and arise from axillary buds associated with foliage leaves (all likely symplesiomorphies). As pointed out by Wilson (1921), the leaves of this species are most similar to those of R. schlippenbachii (of sect. Sciadorhodion), but considering the numerous differences between these two species in floral and seed characters their similarities in leaf form are likely due to convergence.
Rhododendron nipponicum may be the cladistically basal member of subgen. Pentanthera, and its placement in the monotypic sect. Viscidula, as proposed by Matsumura & Nakai (1916) and maintained by Sleumer (1949, 1980) and M. Philipson (1970, 1980), is clearly supported (see Cladistic Analysis).
Synonymy: Azalea nipponica (Matsum.) Copeland, Am. Midi. Nat. 30: 595 (1943). Type: Japan, prov. Uzen, Gassan-hen, 24 vii 1887, S. Okubo & R. Yatabe s.n. (lecto., designated here, TI).
Occurs in Countries: JP Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Pentanthera Habit: Non-Tree
Judd, W.S. & Kron, K.A. (1995) A Revision of Rhododendron VI. Subgenus Pentanthera (Sections Sciadorhodion, Rhodora and Viscidula). Edinburgh Journal of Botany 52(1):24
Erect or ascending, much branched shrub to 1-3 m. Leaves 5-11 X (2-5-)3-7 mm, ovate or elliptic, apex obtuse or rounded, mucro absent or obscure, base truncate to broadly cuneate, undersurface uniformly fawn or with scattered darker scales as well, with the scales contiguous or almost so. Inflorescence 1-2-flowered, pedicel lepidote, 0.5-1 -5 mm. Calyx (l*5-)2.5-3 mm, the lobes strap-shaped, rounded, equal or unequal, indumentum and scales variable. Corolla rosy lilac or violet-purple, funnel-shaped, 12-15 mm, tube 4-5 mm, pubescent inside. Stamens (8-)10, equalling or slightly longer than corolla, filaments pubescent towards the base or glabrous. Ovary lepidote, style exceeding the stamens, pubescent or glabrous at the base. Capsule ovoid, c. 5 mm, lepidote.
Two varieties may be distinguished
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m: 5,000m + Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: lilac
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):98
Leaf uniformly pale lepidote beneath
Habitat: Moorlands
Distribution: China (NW Sichuan)
Altitude: 3300-5000m
nitidulum
Type: China, Szechuan W, Mupin, 3300-4000 m, vi 1908, Wilson 3458 (holo. A; iso. BM, E, K)
Synonymy: R. nitidulum var. nubigenum Rehder & Wilson, op. cit.: 510. Type: China, W Szechuan, vicinity of Tachienlu, 4300-4500 m, vii 1908, Wilson 3461 (holo. A; iso. BM, E, K)
Habitat: Rocky slopes
Distribution: China (C Sichuan, Mt Omei only)
Altitude: 3200-3500m
Type: China, Szechuan, Mt Omei, 3300 m, vii-viii 1931, Wang 23448 (holo. A; iso. E)
Low, compact, much branched shrub, prostrate or attaining 60-90(-120) cm. Leaves 3.5-9(-12) x (1-5-)2-5(-6) mm, elliptic to broadly elliptic, ovate or rotund, apex obtuse, rounded or acutish, emucronulate or very shortly mucronulate, base broadly cuneate, undersurface yellowish to fawn, often with dark brown speckling, the scales contiguous to slightly discontiguous, the majority pale gold with darker scales widely but regularly spaced, rarely the dark scales as many as the paler. Inflorescence l-2(-3)-flowered, pedicels 0.5-1 -5 mm, lepidote and sometimes also pubescent. Calyx obsolete or with lobes 2-4(-4-5) mm, oblong or elongate-deltoid, lepidote and sometimes pubescent at the base, bearing pale and some dark scales on their outer surface, margin lepidote and often with some cilia. Corolla varying from rich purple through magenta and lilac to pink, broadly funnel-shaped, pubescent in the throat and often also on the outside, elepidote or occasionally lepidote, (7-)9-13(-16) mm, tube (2-5-)3-4(-6) mm. Stamens usually 10, filaments pubescent towards the base, longer or shorter than corolla. Ovary lepidote, style variable, 3-5-18 mm, usually longer than stamens, rarely shorter, glabrous or slightly pubescent at the base. Capsule rotund to ovoid, 3-5 mm, lepidote.
Three subspecies may be recognised
Occurs in Countries: BT, CN, IN, NP Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m: 5,000m + Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: lilac, magenta, pink, purple
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):105
Calyx lobes 2-4(-4-5) mm. Calyx lobes ciliate; leaf apex ± acute.
Habitat: Alpine moorland, cliffs
Distribution: China (NW & C Yunnan)
Altitude: 3100-4300m
The Philipsons record natural hybrids between the subspecies of R. nivale and various other species (1975, pp. 52, 53, 55)
Type: China, Yunnan, Chao-lioshau, Mekong/Yangtze Divide, 4260 m, vii 1924, Forrest 25707 (holo. E)
Calyx ±obsolete
Habitat: Open moorland, dry rocky slopes, swampy grassland
Distribution: China (NW Yunnan, SE Xizang, SW & NW Sichuan)
Altitude: 3200-5000m
Type: China, Yunnan, mountains of Moting, NE of the Yangtze/ Mekong watershed, vi 1923, Rock 9342 (holo. E, iso. K)
Synonymy: R. nigropunctaturn Franchet, Journ. de Bot. 5:95 (1891). Type: Thibet, entre Lhassa et Batang, 8 v 1890, Henri cVOrleans (holo. P, iso. K). R. ramosissimum Franchet, ibid. 12:64 (1898). Type: Setchuen occidental au sud de Tatsienlu, Mussot (iso. BM). R. alpicola Rehder & Wilson, PI. Wils. 1:506 (1913). Type: China, W Szechuan, N of Tachienlu, Ta-pao-shan, 4000-5000 m, vii 1908, Wilson 3465 (iso. BM, E, K). R. alpicola var. striatum Rehder & Wilson, op. cit.: 513. Type: China, W Szechuan, N of Tachienlu, Ta-pao-shan, 4300 m, 7 vii 1908, Wilson 3467a (iso. BM, E, K, US). R. violaceum Rehder & Wilson, op. cit.: 513. Type: China, W Szechuan, Wilson 3463 (holo. A; iso. E, US). R. oresbium Balfour f. & Kingdon Ward, Notes R.B.G. Edinb. 9:253 (1916). Type: China, Tibet/Yunnan frontier, Doker la, 13-15000 ft, Kingdon Ward 541 (holo. E). R. stictophyllum Balfour f., Notes R.B.G. Edinb. 11:139 (1919). Type: China, Szechuan, Principality of Batang, Yaragong, vi 1903, Soulie 3303 (holo. P, iso. E). R. vicarium Balfour f., ibid. 12:176 (1920). Type: China, W Szechuan, Tatsienlu, 27 vi 1894, Soulie 2772 (holo. P, iso. E). R. batangense Balfour f., ibid. 13:31 (1920). Type: China, W Szechuan, Principality of Batang, Yaragong, vi 1903, Soulie 3304 (holo. P, iso. E). R. oreinum Balfour f., op. cit. 13:54 (1920). Type: China, W Szechuan, Yaragong, v 1904, Soulie 3710 (holo. P). R. yaragongense Balfour f., op. cit. 13:64 (1920). Type: China, W Szechuan, Principality of Batang, Yaragong, Soulie 3709 (holo. P, iso. E)
Calyx lobes 2-4(-4-5) mm. Calyx lobes lepidote-margined; leaf apex rounded.
Habitat: Open mountainsides, screes, up to 5800 m
Distribution: Nepal, India (Sikkim), Bhutan, China (S & SE Xizang)
Type: Sikkim/Tibetan frontier, 4800-5490 m, Hooker (holo. K; iso. E, UPS, US)
Synonymy: R. paludosum Hutchinson & Kingdon Ward, Notes R.B.G. Edinb. 16:175 (1931). Type: S Tibet, Rong-chu (Tumbatse), 12000 ft, Kingdon Ward 5792 (holo. K, iso. E)
Shrub to 80cm. Twigs 3–4mm in diameter, rounded, green, finely brown scaly; internodes 3–15cm. Leaves 4–6 together in tight pseudowhorls. Blade 50–80 x 25–40mm, obovate, elliptic or broadly elliptic; apex obtuse to rounded, sometimes minutely mucronate; margin entire, flat when fresh, becoming slightly revolute when dry; base rounded to cordate; quickly glabrescent above, more densely, persistently scaly beneath. Scales brown, rounded to irregularly lobed, c.0.1mm in diameter, weakly impressed into shallow pits. Mid-vein impressed into a narrow groove above, only slightly raised beneath; lateral veins 3–5 per side, inconspicuous, reticulation obscure. Petiole 2–3 x 4–5mm, grooved above, green or with a faint reddish flush on the upper side, scaly. Flower buds (see p.327) c.40 x 20mm, green, narrowly ovate, acute, the bracts standing out from the buds at an acute angle with a ‘spiky’ appearance. Bracts to 30 x 14mm, ovate elliptic below but narrowly acuminate with channelled and inrolled upper margins; margins minutely scaly otherwise glabrous, shiny green in the central and upper parts, translucent towards the lower margins. Inflorescence 9–14 flowers in an open or one-sided umbel. Pedicels c.20 x 2mm, dark-pink, pale brown scaly and minutely covered with patent white hairs. Flowers half-hanging to semi-erect. Calyx forming a low irregular disc covered with hairs and scales. Corolla c.50 x 40mm, pure white with a faint sweet scent; tube c.40 x 8 x 5mm, distinctly narrowed upwards, glabrous outside, inside covered with moderately dense patent hairs; lobes c.19 x 20mm, circular or nearly so, overlapping for at least ½ their length and spreading at right angles or a little reflexed, glabrous. Stamens irregularly filling the mouth of the corolla tube but not exserted; filaments white, with some short white patent hairs in the proximal 5mm otherwise glabrous; anthers 2.5–3mm, pale brown, weakly apiculate at the base. Disc green, minutely hairy on the upper side. Ovary 6–7 x c.3mm, densely white scaly and with short white slightly distally directed simple hairs, gradually tapering; style scaly in the proximal ¼ and with semi-erect hairs in the proximal ½, completely glabrous distally, pink at the base, becoming white; stigma c.3mm in diameter, white, rounded, remaining within the mouth of the flower.
Habitat: Epiphytic in large trees in montane mossy forest, or terrestrial on deep peat, sometimes in ultrabasic areas
Distribution: Malaysia (Borneo), Sarawak, Fifth Div. Route from Bakelalan to Mt Murud; Mt Murut, Lawas; Mt Api, Fourth Div., summit ridge; Bario, Ulu Baram, path to Kuba’an Pungor Pwan; Secondary Peak of Batu Lawi. Sabah, Mt Lumarku, Sipitang District.
Altitude: 1300-2100m
Latin – niveus – snow white, alluding to the pure snow-white flowers of this species.
This species is superficially very similar to R. suaveolens but differs most conspicuously in the bract shape of the flower buds which in this species have subulate erect points whereas those of R. suaveolens have broad, reflexed leafy points. The pedicels are shorter, proportionately broader and with denser scales compared with the longer and more delicate pedicels of R. suaveolens which have only a very sparse covering of scales. The stigmas remain completely immersed within the corolla tube in this species, even in old flowers, whereas they become exserted when receptive in R. suaveolens although as an artefact of drying they can appear exserted in herbarium specimens of this species. The leaves are much thicker and more leathery in R. niveoflorum than in R. suaveolens, with the margin hardly showing any sign of a translucent cartilaginous edge whereas in R. suaveolens leaves held against the light show a distinct pale translucent cartilaginous margin. The distributions are at present fairly distinct except for three anomalous collections. Rhododendron suaveolens occurs along the western mountain spine of Sabah from Kinabalu along the Crocker Range with just one record from G. Mulu in Sarawak (Burtt & Woods 2140). Rhododendron niveoflorum is known from the above listed locations in northern Sarawak with the two doubtful records listed above from Sabah. The fruiting collection (Argent & Lamb 1536) from G. Lumarku near Sipitang has every appearance of being this species and would not be at all surprising given that this area contains many other plants known from northern Sarawak. The collection made by A. Lamb (SNP 0316) from the ridge north of Low’s Gulley also appears to be this species, although the damaged flowers were reported as dark pink and there are no bud scales to compare. The type collection has always had pure white flowers in cultivation as reported from the wild (Burtt & Martin 5250); however, another Burtt & Martin collection (5363) from higher up on Mt Murud is described as having flowers flushed with pink from red pedicels. Introduced into cultivation in Edinburgh in 1967 by Bill Burtt and Adam Martin, it grows slowly, its pure white, slightly scented flowers being attractive but not very freely produced on lanky gnarled stems.
Type: Burtt & Martin 5380, 27 Sept. 1967 (Cultivated specimen 19672550, collected RBGE, 11 April 2001). Sarawak, G. Murud, c.1800m (SAR, A, E, L).
Occurs in Countries: MY Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:166
Tree, up to 6m. Leaves oblanceolate to elliptic, 11.5-17 x 4-4.5cm, 2.9-3.8 x as long as broad, upper surface glabrous , lower surface with a dense ± compacted fawn dendroid indumentum; petioles 1 —1.5cm, floccose. Inflorescence 15-20-flowered, dense; rhachis c.20mm; pedicels c.lOmm, densely white- to rufous-tomentose. Calyx 1—2mm, lobes obscure. Corolla tubular-campanulate, deep magenta to deep lilac, with darker nectar pouches, 30-35mm. Ovary densely white- to fawn-tomentose. Capsule shortly cylindrical, c.20 x 8mm.
Habitat: Rocky valleys, mixed forest
Distribution: NE India (Sikkim), Bhutan
Altitude: 2900-3650m
Illustrations:
A distinctive species with no close allies.
Occurs in Countries: BT, IN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: lilac, magenta
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):332
Low shrub; young shoots ad pressed-strigose, soon glabrescent. Leaves monomorphic, deciduous, chartaceous, ovate to ovate-oblong, 0.7-1.5 x 0.4-0.6cm, 1.7-2.5 x as long as broad, apex obtuse, apiculate, base cuneate, margin entire, upper surface glabrescent; petioles l-2mm, strigose. Inflorescence 3-4-flowered; pedicels 3-4mm, densely pilose. Calyx densely pilose, lobes acute. Corolla funnel-shaped, 15mm, red, details of tube not known. Stamens 7-10, unequal, slightly exserted; filaments pubescent below. Ovary pubescent; style glabrous.
Habitat: Open grasslands
Distribution: China (N Taiwan)
Altitude: 2000-3000m
Apparently allied to R. nakaharai and R. longiperulatum but differing in the smaller corolla and slightly exserted stamens.
Type: Taiwan, Hsinchu, Sikayotasan, Fukyama 3005, n.v.
Occurs in Countries: CN, TW Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: red
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):125
Epiphytic shrub. Twigs rounded, brown, densely covered with dark brown scales. Leaves in tight pseudowhorls; up to 12cm apart. Blade 70–150 x 15–35mm, narrowly elliptic; apex acuminate with a long, slender acute apex; margin entire, narrowly recurved when dry; base tapering; glabrescent above, densely and persistently scaly below, the scales touching and slightly overlapping. Scales variable in size, brown, with broad striate flanges and large brown centres, the largest with conspicuously very dark centres. Mid-vein impressed above, prominent beneath; lateral veins 5–6 per side, distant, ascending, slightly impressed above and raised beneath, reticulation obscure. Petiole 10–14 x 2mm, densely scaly. Bracts to 10–17mm, ovate to elliptic-ovate, sub-acute, glabrous outside, ciliate on the margins. Bracteoles filiform. Inflorescence in c.12-flowered umbels, the flowers hanging. Pedicels 10–20mm, patently short-hairy, not scaly (but described only in fruit). Calyx 3mm in diameter, disc-like, obscurely and obtusely lobed with shortly ciliate lobes. Corolla 40–45mm, tubular, red; tube 35 x 6–7 x 6–7mm, cylindrical, slightly curved, glabrous outside, hairy inside along the 5 main veins; lobes 8–10 x 6–8mm, broadly obovate to nearly rounded. Stamens slightly unequal, as long as the corolla or slightly exserted; filaments filiform, densely brown-hairy in the proximal 1⁄3; anthers 3.5mm, oblong, (in the Negros specimen only 2mm). Disc glabrous. Ovary narrowly cylindrical, densely scaly; style elongated, filiform, densely scaly in the proximal ½, glabrous distally, nearly as long as the corolla; stigma conical. Fruit 4–8 x 3–4mm, cylindrical, slightly curved, densely brown-scaly. Seeds 6–7mm, without tails 1mm, the longest tail 3.5mm.
Distribution: Philippines, Mindanao, near Lake Lanao, 800m; Catanduanes, Mt Mariguidon, 270m; S Negros, Dumaguete, Cuernos Mts.
Altitude: 270-800m
Named after Mrs J.B. Norton (née Jesse Baker), 1877–1938, at the request of the collector for having largely inspired her interest in botanical work.
Doubtfully specifically distinct from R. malayanum but with larger flowers and more in the umbel than is usual in that species at least in the wild. It is also described with glabrous bracts, apart from the marginal fringe of white hairs, which if true would be another distinguishing character, but this description may have resulted from describing inner bracts if the outer were missing. The leaves are very similar to those of R. malayanum and R. apoanum. It remains a poorly known species and apparently has not recently been recollected. Sleumer (1966) noted that there were small differences between the known specimens, each from three different localities.
Type: Clemens 500, April 1906. Philippines, Mindanao, Lanao, Lake Lanao Camp Keithley (PNH†, E, fragment, L, fragment).
Synonymy: R. catanduanense Merr. in H.F.Copel., Phil. J. Sc. 1929. 40: 149, pl.2.
Occurs in Countries: PH Altitude Ranges: 0 - 1,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: brown, red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:124
Shrub to 2m. Twigs 2–5mm in diameter, scaly but early glabrescent; internodes 2–10cm. Leaves 3–5 together in tight pseudowhorls. Blade 20–40 x 15–35mm, elliptic to broadly elliptic; apex acute; margin entire, narrowly revolute; base broadly tapering, slightly decurrent; at first densely covered on both sides with flattish, pale scales, glabrescent above at maturity, laxly to sub-densely scaly beneath. Scales flat, rounded to irregularly lobed, with a broad flange and small slightly impressed centre. Mid-vein narrowly impressed above, distinctly raised beneath throughout its length; lateral veins 4–10 per side, wide-spreading, straight before curving near the margin, indistinctly anastomosing, slightly impressed above and raised beneath, reticulation obscure. Petiole 8–13 x 1–1.5mm, grooved above, scaly. Flower buds to 25 x 8mm, narrowly ovoid, the bracts standing vertically or spreading, not appressed. Outer bracts ovate with a long subulate point, inner ones elliptic, narrowly acute, scaly along the central line outside and along the margins, glabrous inside. Bracteoles to 20 x 3mm, filiform to linear, glabrous. Inflorescence of 4–8 flowers in an open umbel, curving downwards. Pedicels 6–8 x c.1mm, laxly scaly, and hairy. Calyx obliquely disc-shaped, wavy, obtusely and shortly lobed, c.4mm in diameter, densely scaly outside. Corolla 30–40 x 12–25mm, obliquely tubular, red or pink; tube 25–35 x 4–6 x 8–15mm, distinctly curved, laxly to sub-densely scaly outside, glabrous inside; lobes 8–12 x 8–14mm, broadly obovate to sub-circular, sub-erect or spreading, overlapping 1⁄3–2⁄3. Stamens tightly clustered on the upper side of the mouth, not or only weakly exserted; filaments linear, very laxly hairy in the lower ½, glabrous distally, red; anthers 2–3.5 x 1–1.5mm, obovate to broadly oblong, purple. Disc prominent, shortly hairy at the upper margin. Ovary 4–5 x c.2mm, sub-cylindrical, densely white-hairy, and densely (but obscurely) scaly, gradually tapering distally; style slender, with some sparse hairs and scales at the base, becoming exserted; stigma to c.1.5mm in diameter.
Habitat: Open places in the sub-alpine forest or in open alpine vegetation
Distribution: Indonesia, New Guinea (W), Wissel Lakes, Mt Carstensz and Oranje Mts.
Altitude: 2500-3000m
Latin – nubes – cloud; cola – dwelling. Alluding to the cloudy habitat.
Differs from R. culminicola by the narrowly subulate to acute bracts and the almost glabrous filaments. It also grows at lower altitude and tends to have more acutely pointed leaves.
Type: Kloss s.n. New Guinea (W), Mt Carstensz, 2500–3200m (BM).
Synonymy: R. nubicolum Wernham (orthographic variant). R. acrocline Sleumer, Reinwardtia 1960. 5: 158. R. hatamense (non Becc.) Sleumer, Reinwardtia 1960. 5: 153, pro parte. R. culminicolum var. nubicolum (Wernham) Sleumer, Reinwardtia 1960. 5: 221.
Occurs in Countries: ID Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: pink, red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:215
Shrub or small tree; shoots glabrous. Leaves broadly rhombic, 2-8 x 1-6.5cm, apex acute, tip blunt, upper and lower surfaces covered with long brown hairs when young, becoming glabrous on upper surface; petioles 3-10mm, densely pale brown-villous with the lower half glabrous, to densely lanate. Inflorescence 1-2-flowered; pedicels 5-I0mm, covered with brown pubescent hairs. Calyx minute. Corolla funnel-cam-panulate, 20-30mm, rose-purple, lobes c.20mm, broadly oblong. Stamens (? 5-)8-10, glabrous. Ovary densely pale brown-villous; style glabrous. Capsule 2-3mm, ovoid.
In the last ten years a number of infra-specific taxa have been published within R. nudipes mostly by Yamazaki. We have not seen material of most of these and, as the type descriptions are inadequate and non-comparative, it has not been possible to produce a key. The following treatment and synonymy follows Yamazaki without attempting to make any assessment of the validity of the taxa included.
Type: Japan, Kyushyu, Mt Higo, Prov. Asosan, Ogata (holo. TI, n.v.)
Occurs in Countries: JP Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Tsutsusi Habit: Tree Fl. Colour: rose
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):150
Type: Japan, Oziya Shi, Oziya, 100m, 3 viii 1964, cult. Tokyo, 18 v 1974, T. & F. Yamazaki (holo. TI, n.v.).
Young shoots pubescent. Leaves small, 1.5-4.5 x 1.2-3cm, apex obtuse. Capsule suberect, cylindrical.
Distribution: Japan (Kyushyu)
Altitude: Around 1100m
Type: Japan, Kyushyu, Pref. Miyazaki, Kirishimayama, Sonoura, 1100m, 27 viii 1972, TMinamidami (holo. TI, n.v.).
Leaves rhombic, 35-50 x 25-40mm, apex acute, upper and lower surfaces sparsely pilose, more densely so on midrib towards base; petioles densely lanate. Calyx c.2mm, densely villose. Stamens 10. Ovary villose; style glabrous. Capsule 10-13 x c.3mm, curved.
Habitat: Rocky mountain slopes
Distribution: Japan (SW Honshu, Shikoku)
Altitude: Around 400m
Illustrations:
Synonymy: R. lagopus Nakal, Bot. Mag. (Tokyo) 40:483 (1926); R. wadanum Makino var. lagopus (Nakai) Hara, Enum. Sperm. Jap. 1: 78 (1948); R. reticulatum D.Don var. lagopus (Nakai) Hatusima, Sci. Rep. Yokosuka City Mus. 15: 22 (1969). Syntypes: Japan, Hondo, Mt Daisen, fl. & fr., A.Kimura (holo. TI, n.v.).
Leaves rhombic, widest at the middle. Corolla red-purple. Capsule 8-10 x 4-5mm
Distribution: Japan (Honshu)
Altitude: 100-700m
Young shoots and petioles densely lanate. Leaves sub-chartaceous, large, in fruit sparsely pubescent below.
Distribution: Japan (Shikoku)
Altitude: Around 1800m
Type: Japan, Pref. Tokush-ima, Mt Tsurugisan, 1800m, 9 viii 1976, Yamazaki 1128 (holo. TI, n.v,)
Habitat: Light forest
Distribution: Japan (Honshu, Kyushyu)
Altitude: 200-1000m
Illustrations:
The Maximovicz material of R. nagasakianum seen at the BM, which may be an isotype, has corollas with at least 8 stamens, not 5 as stated by Nakai. Therefore, on the basis of this specimen, we reduce R. nagasakianum to a synonym of var. nudipes.
Synonymy: R. nagasakianum Nakai, Bot. Mag. (Tokyo) 40: 484 (1926). Type: Japan, Kyushyu, Nagasaki Prov., Hizen, Maximovicz (holo. ? LE, n.v.; iso. ? BM, Hb. Hance 13570). R. nagasakianum Nakai var. gracilescens Nakai, op. cit. 485 (1926). Type: Japan, Kyushyu, Mt Fugendake, montium Unzen, Prov. Hiaen, Anon. (holo. KYL, n.v.). R. reticulatum D.Don var. nudipes (Nakai) Hatusima, Sci. Rep. Yokosuka City Mus. 15: 23 (1969)
Capsule cylindrical, 13-20 x 4-5mm
Distribution: Japan (Shikoku)
Known only from the type
Type: Japan, Shikoku, Pref. Awa, Miyahama Sasa-toge, 14 viii 1947, C.Abe (holo.TI,n.v.)
Stiffly erect shrub to 1.5m. Twigs slender, rounded, tips densely covered with stalked scales, lower parts rough after the scales have gone. Leaves spirally arranged, more densely towards the tips. Blade 10–15 x 4–9mm, broadly obovate to nearly rounded; apex rounded, broadly obtuse or slightly retuse; margin slightly or not revolute; base broadly tapering or rounded, convex above; initially densely scaly on both sides, glabrescent above at maturity. Scales round, large, sessile, marginal zone entire or nearly so; centre thick, slightly or not impressed. Mid-vein smooth above, prominent beneath, often obscure; lateral veins 2 or 3 or obscure. Petiole 1–1.5mm, slender. Bracts to 3mm, narrowly ovate, sub-acute to obtuse, glabrous, but ciliate on the margins. Bracteoles to 4mm, linear-spathulate, shortly hairy distally. Inflorescence of solitary flowers, rarely in twos, hanging vertically. Pedicels 5–6.5mm, thick, densely scaly (the scales on very short stalks), very sparsely or not hairy. Calyx oblique, small, irregularly 5-lobed, scaly outside with triangular, obtuse, lobes, to 0.5mm. Corolla pink or dark-red, sometimes yellow at the base, tubular, slightly zygomorphic; tube c.10 x 3.5 x 3.5mm, cylindrical, straight, sparsely to sub-densely scaly outside, glabrous inside; lobes 1.2–1.8 x 1.5–2mm, erect, ovate-circular, irregularly denticulate, laxly scaly outside, in the proximal ½. Stamens included within the mouth; filaments linear, slightly dilated towards the base, glabrous; anthers 0.8–1mm. Disc glabrous. Ovary c.3mm, cylindrical, 5-ribbed, covered with brown scales, tapering distally; style 4–5mm, thick, laxly scaly in the proximal ½; stigma club-shaped, indistinctly 10-lobed. Fruit 8–13 x 2.5–3mm, fusiform, distinctly 5-ribbed.
Habitat: Terrestrial or epiphytic in sub-alpine shrubberies as part of the understory, forest margins, open mossy or grassy areas, clearings in ridge forest, or open clayey ground of old gold workings
Distribution: Indonesia, New Guinea (W). Papua New Guinea (E). Along the Main Range from Mt Doorman and the Hellwig Mts to Mt Victoria, also throughout the Huon Peninsula.
Altitude: 2000-3500m
Latin – nummatum – rich or wealthy, alluding to the leaves being rounded like coins.
This species usually has almost circular leaves with distinct scales on their undersides, although not as distinct or as far apart as in R. pulleanum.
Type: H.J. Lam 1807, 29 Oct. 1920. New Guinea (W), Doormantop, 3200m (BO, L).
Occurs in Countries: ID, PG Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:55
Shrub or small tree, 2-10 m, sometimes epiphytic. Leaves large, 170-260 x 75-130 mm, oblong-elliptic or oblong-obovate, tapered to the base and the bluntly acute or obtuse apex, upper surface rugose, elepidote, lower surface with a dense covering of very unequal scales, the smaller almost rimless or narrowly rimmed, the larger about 2 x the diameter of the smaller, broadly rimmed, the rim ascending to cup-shaped, irregular; secondary and tertiary veins forming a conspicuous reticulum all over the lower surface. Inflorescence 2-5-flowered, pedicels 20—33 mm, lepidote. Calyx conspicuous, deeply 5-lobed, the lobes narrowly oblong, obtuse, sparsely lepidote or elepidote, sometimes with a few filiform-acicular hairs. Corolla funnel-campanulate, white with a yellow blotch, mouth very oblique, (75-)100-125 mm from base to apex of the longest lobe, tube (45-)70~80 mm, sparsely lepidote outside. Stamens 10, filaments pubescent towards the base. Ovary densely lepidote, tapered into the style which is lepidote in the lower part. Capsule densely lepidote, cylindric or ovoid cylindric, 50-70 X 18-20 mm, weakly 5-ridged, much exceeding the persistent calyx.
Habitat: Cliffs, ledges, rocky slopes in open forest
Distribution: India (Arunachal Pradesh), China (NW Yunnan, SE Xizang)
Altitude: 1200-3650m
Illustrations:
R. nuttallii has a broken distribution pattern, scattered over a wide area. There is a specimen from Guizhou province (Chen feng hsien, Tsiang 4201) which is inadequate for certain identification, but which may well be R. nuttallii] this would extend the distribution considerably further eastwards.
Type: Bhutan'(i.e. India, Arunachal Pradesh, cf. Ludlow, Trans. Bot. Soc. Edinb. 41:351-363, 1972) Duphla hills at Mere Patar, on the banks of the Papoo, 4000-5000 ft, Booth (holo. K).
Synonymy: R. sinonuttallii Balfour f. & Forrest, Notes R.B.G. Edinb. 13:60 (1920). Type: China, SE Tibet, Salween/Kiu-chiang Divide, ix-x 1919, Forrest 18939 (holo. E)
Occurs in Countries: CN, IN Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Rhododendron Habit: Tree Fl. Colour: white, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):36
Shrub to 3m. Twigs 2mm in diameter, sub-densely, minutely, reddish-brown scaly; internodes 2–3cm. Leaves 3–4 in pseudowhorls at the upper 2 or 3 nodes. Blade 45–65 x 20–30mm, elliptic-obovate; apex rounded or mostly slightly retuse; margin entire; base broadly tapering, scaly initially on both sides, at maturity glabrescent above, sub-densely and persistently scaly beneath. Scales minute, with the thin marginal zone variously indented; centre a little impressed, large and of dark-brown colour typical of the section. Mid-vein narrow and impressed above, as thick as the petiole beneath at the base and very prominent, gradually less so distally; lateral veins 7–9 per side, curved and anastomosing towards the margin, minutely impressed above, somewhat raised or nearly invisible beneath, without reticulation. Petiole 6–8 x c.2mm, grooved above, densely scaly, a little flattened. Bracts 7 x 4mm, ovate-acuminate, hairy on both sides, white-ciliate round the margins. Inflorescence a 3-flowered umbel. Pedicels 14–18mm, slender, laxly scaly. Calyx 2.5mm in diameter, oblique, disc-shaped, very shortly or not lobed, scaly outside. Corolla 26–30mm, tubular, slightly curved, gradually widened to the mouth, pink, or orange-red; tube 20 x 3–4 x 6mm, laxly scaly outside, glabrous inside; lobes 7–10 x 4–5mm, obovate, sub-erect. Stamens unequal, the longer ones nearly as long as the corolla; filaments linear, glabrous; anthers 1–5 x 0.7mm. Disc glabrous. Ovary 4 x 1.5mm, elongate-conical, densely scaly, gradually tapering distally; style slender, exserted; stigma rounded. Fruit 10mm.
Habitat: Reported as common in open Leptospermum woodland
Distribution: Malaysia, Malay Peninsula, Pahang, top of Mt Benom.
Altitude: 2050-2105m
Latin – obscurus – meaning indistinct, from the fact that the author originally thought this was a hybrid.
Described as common on the summit of Mt Benom by Whitmore, who made only the second known collection of this species from the type locality. This caused Sleumer (1973) to revise his opinion of the status of this plant as a true species rather than the hybrid that he suspected it was when it was first described.
Type: Strugnell F.M.S. 22344. West Malaysia, Pahang, on top of G. Benom (KEP).
Occurs in Countries: MY Altitude Ranges: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: orange, pink
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:124
Shrub or small tree to 8(-10)m tall, usually non-rhizomatous; young twigs red-brown, rarely yellow-brown, grey or glaucous, sparsely to densely covered with unicellular hairs and multicellular gland-tipped hairs or glabrous, occasionally sparsely to densely covered with only unicellular hairs. Vegetative bud scales glabrous or sparsely covered with unicellular hairs and multicellular eglandular hairs abaxialiy; margin unicellular-ciliate or glandular. Leaf blade membranaceous, ovate or obovate to elliptic, (2.5-)3.5-8.2(-10.8) x (0.8-)1.2-2.9(-3.6)cm; base acute to obhque; apex acute to obtuse, often mucronate; adaxial surface sparsely covered with unicellular hairs and multicellular eglandular or gland-tipped hairs, with only multicellular eglandular hairs, the multicellular gland-tipped hairs, or both, or glabrous, the midvein densely covered with unicellular hairs, rarely also with multicellular gland-tipped hairs or eglandular hairs; abaxial surface glabrous, sparsely covered with unicellular hairs, multicellular gland-tipped hairs or both, rarely with multicellular eglandular and glandular hairs, midvein sparsely covered with multicellular eglandular hairs or with unicellular hairs and multicellular gland-tipped hairs, rarely with unicellular hairs and multicellular eglandular hairs or with only multicellular gland-tipped hairs; margin entire, ciMate with multicellular eglandular hairs or with multicellular eglandular and gland-tipped hairs; petiole (0.1-)0.2-0.5(-1.0)cm long, sparsely to densely covered with unicellular hairs and multicellular eglandular or gland-tipped hairs, rarely with all three types of hairs. Flower bud scales chestnut brown; abaxial surface sparsely to densely covered with unicellular hairs, rarely also with sparse multicellular eglandular or gland-tipped hairs; margin unicellular-ciliate or glandular. Flowers appearing with the leaves or after they have expanded; inflorescence a shortened raceme of 3 to 15 flowers. Pedicels (0.9-)l.l-2.0(-2.6)cm long, covered with multicellular gland-tipped hairs, occasionally with multicellular eglandular hairs. Sepals 0. l-0.4(-0.9)cm long, often varying in length on the same flower; margins glandular-fimbriate, rarely setose; abaxial surface sparsely to densely covered with unicellular hairs and multicellular gland-tipped hairs or with only multicellular gland-tipped hairs, occasionally glabrous or with unicellular hairs and multicellular eglandular hairs, rarely with only multicellular eglandular hairs. Corolla white, with a yellow blotch on the upper corolla lobe, white and pink or salmon, or pink with an orange blotch on the upper corolla lobe, rarely white with yellow lines at the throat, or with the tube white to red, fragrance sweet or mephitic, the tube longer than the Emb and gradually expanding into it; upper corolla lobe (1.3-) 1.4-2.3(-2.8) x 1.2-2.1(-2.6)cm; lateral lobes (1.5-)1.7-2.4(-2.9) x (0.7-)0.9-1.4(-1.7)cm; corolla tube (1.5-)1.8-2.6(-2.9)cm long, (0.2-)0.3-0.5(-0.6)cm wide at base; outer surface of corolla sparsely to densely covered with unicellular hairs arid multicellular gland-tipped hairs that continue up the corolla lobes, rarely also with multicellular eglandular hairs; inner surface of corolla sparsely to densely covered with unicellular hairs, occasionally glabrous. Stamens (4.0-)4.6-6.3(-7.5)cm long, with dense terete or flattened unicellular hairs on proximal (1.8-)2.1-3.3(-3.6)cm of filament, exserted (2.4-)3.0-4.2(-4.7)cm beyond throat of corolla. Style (4.1-)4.6-6.6(-8.2)cm long, exserted (2.6-)3.3-4.8(-5.3)cm beyond throat of corolla, with dense unicellular hairs on the proximal (0.2-)0.3-L0(-L3)cm; stigma 0.1-0.3cm wide. Ovary 0.2-0.4(-0.5)cm long, (0. l-)0.2-0.3(-0.4)cm wide at the base, densely covered with unicellular hairs and multicellular eglandular and gland-tipped hairs, or lacking multicellular eglandular hairs, with a dense crown of unicellular hairs along the nectary, rarely with only multicellular eglandular or gland-tipped hairs or both. Capsules (1.2-)1.3-1.8(-2.2) x (0.4-)0.5-1.0(-1.4)cm, sparsely covered with unicellular hairs and with multicellular eglandular or gland-tipped hairs. Seeds pale to dark chestnut brown, ovate or elliptic to fusiform, (1.0-)1.5-2.3(-3.0) x(0.5-)0.7-l.l(-1.5)mm,body(0.6-)0.8-1.4(-1.6)x(0.2-)0.3-0.5(-0.7)mm; testa expanded and dorsiventrally flattened, surrounding the body, the cells essentially isodiametric, with transverse end-walls
Habitat: Moist wooded slopes and canyon bottoms, along rivers and streams, shrub thickets, Darlingtonia bogs, serpentine ridges, ocean bluffs
Distribution: South-western Oregon to southern California
Altitude: 0-2700m
Illustrations:
Chromosome number: 2n = 26 (Sax, 1930; Janaki-Ammal et al., 1950)
Flowering primarily in June and July, but occasionally as early as February or as late as November, especially in southern California.
Rhododendron occidentale is most closely related to R. austrinum and R. luteum, as suggested by King (1977a, 1980). Morphologically, it shares the characters of glandular bud-scale margins and glandular foliage with R. austrinum and R. luteum, and these three species form a monophyletic group (seePhylogenetic Analysis). However, R. occidentale is much more variable than either R. austrinum or R. luteum, as some individuals may possess unicellular-ciliate bud-scale margins, or have a combination of gland-tipped and unicellular cilia. Other characters such as leaf and corolla size are continuously variable throughout the range of R. occidentale and do not show any geographic or ecological correlation. Rhododendron occidentale can be distinguished from R. luteum and R. austrinum by its white corolla. Additionally, it is separated from R. austrinum by its broader, more ovate fruits, which are usually less densely unicellular pubescent than those of R. austrinum, and distinguished from R. luteum by the seeds with shorter testa cells and transverse end-walls.
The name R. occidentale (Torr. & A. Gray) A. Gray has priority since this species was first given a name in the genus Azalea (see synonomy). Subsequent transfer of Azalea californica to Rhododendron would create a later homonym with R. californicum Hooker.
Synonymy: Azalea occidentalis Tour. & A. Gray, Pac. R. R. Rep. 4:116 (1856). Type: CaMfornia, Sonoma Co.: Laguna de Santa Rosa, 1 v 1856, Bigelow s.n. (lecto., designated here, NY; isolecto. NY). Azalea californica Torr. & A. Gray ex Durand, in J. Acad. Phil. ser. 2, 3: 94 (1855). Type: California, Nevada Co.: shady hills along Deer Creek, H. Pratten s.n. (holo. P-DU). Azalea nudiflora L. var. ciliata Kellogg, Proc. Calif. Acad. Sci. 1:60 (1855). Type: (probably destroyed). Rhododendron sonomense Greene, Pittonia 2: 172 (1891). R. occidentale (Torr. & A. Gray) A. Gray var. sonomense (Greene) Rehder, Monogr. Azaleas 127 (1921) (holo. ND-G, n.v.). Rhododendron occidentale (Ton*. & A. Gray) A. Gray var. paludosum Jepson, Man. FL PL Calif. 741 (1925). Type: California, Fortuna, 1916, Jepson s.n. (holo. n.v.).
Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Pentanthera Habit: Tree Fl. Colour: orange, pink, red, white, yellow
Kron, K.A. (1993) A Revision of Rhododendron Section Pentanthera. Edinburgh Journal of Botany 50(3):317
Small tree, c.3m; young shoots covered with glandular setae. Leaves oblanceolate, 5.5-10 x 1.3—2cm, 4-5 x as long as broad, apex cuspidate, base rounded, upper surface glabrous when mature, lower surface with a dense matted yellow-brown indumentum composed of flagellate hairs; petioles 1-1.5cm, stipitate-glandular. Inflorescence dense, 8-12-flowered; rhachis c.5mm; pedicels 5-8mm, densely stipitate-glandular. Calyx c.lmm, glandular-setulose. Corolla tubular-campanulate, apparently with depressed nectar pouches, dark red, c.35mm. Ovary densely glandular-setulose; style glabrous. Capsule not known
Habitat: Thickets
Distribution: China (Sichuan)
Altitude: 2600-3000m
A distinctive species on account of its persistent leaf indumentum; probably most closely allied to R. strigillosum.
Type: China, Sichuan, Wa-shan, 2400-3000m, vi 1908, Wilson 3425 (holo. A; iso. BM, E, K)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: red
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):269
Much-branched shrub, to 3m; young shoots densely clothed with spreading red-brown glandular hairs intermixed with scattered + spreading, flattened hairs. Leaves dimorphic, persistent, chartaceous; spring leaves ovate-lanceolate 3.5-6 x 1.8-2.5cm, 2-2.4 x as long as broad, apex acute to mucronate, base rounded to broadly cuneate, margin entire, covered with light brown long pilose hairs on both surfaces, hairs somewhat longer on midrib; summer leaves 15-20 x 8-10mm, otherwise as for spring leaves;.petioles 4-9mm, covered with spreading pilose hairs. Inflorescence 1-3-flowered; pedicels 5-10mm, covered with spreading glandular red-brown hairs. Calyx green, glandular-hairy and pilose, lobes ovate-lanceolate, c.2mm, ciliate. Corolla funnel-shaped, 25-35mm, orange-red to coral-pink; tube c.l2mm, outer surface glabrous, inner surface papillate. Stamens (8-) 10, unequal, as long as or longer than corolla, filaments papillate below middle. Ovary densely glandular-setose; style glabrous. Capsule ovoid, 8-10mm, glandular-setose.
Habitat: Sandstone cliffs etc.
Distribution: China (Taiwan)
Altitude: 0-2450m
Illustrations:
A distinctive species with no close allies.
Type: Taiwan, prope Tansoy, 1884, Oldham 212 (iso. BM, K, PE)
Synonymy: R. oldhamii Maxim, var. glandulosum Hayata in J. Coll. Sci. Imp. Univ. Tokyo 25: 153 (1908). Syntypes: Taiwan; Suizan, in montibus Morrison, 7702ft, x 1905, Nagasawa 668; 8000ft, Nagasawa 2210; 9000ft, x 1906, Nagasawa 1807; in montibus centralibus, 10000ft, xi 1906, Kawakami & Mori 1860, omnes n.v. R. ovatosepalum Yamamoto in J. Soc. Trop. Agric. 5:405 (1933). Type: Tawian, Pref. Shinchiku, iv 1918, Simada, n,v.
Occurs in Countries: CN, TW Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: orange
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):110
Shrub, c.1.2m. Twigs rounded, slender, tips densely reddish-brown-scaly; upper internodes 1.5–3cm. Leaves in tight pseudowhorls of 2–3 at the upper node only, sub-sessile. Blade 30–50 x 15–30mm, sub-ovate-elliptic; apex shortly acuminate, obtuse; margin recurved; base truncate to rounded or sub-cordate, glabrescent above at maturity, laxly scaly beneath. Scales thin, marginal zone irregularly dentate; centre slightly impressed. Mid-vein faintly impressed or nearly flat above, strongly raised beneath proximally, less so distally; lateral veins c.8 per side, straight, curved-anastomosing near the margin, prominent on both sides, lax reticulation, raised especially beneath. Petiole 1–2 x 1–1.5mm. Flowers solitary or in twos, terminal. Pedicels 28–30mm, thick, obliquely thickened below the calyx, scaly and very shortly hairy. Calyx c.2.5mm in diameter, shortly 5-lobed and wavy. Corolla broadly trumpet-shaped, pink; tube 35–37 x c.4 x 5–6mm, cylindrical, straight, laxly scaly and very laxly short-hairy outside, sub-densely hairy inside in the proximal part, less so distally, glabrous at the mouth; lobes 10–12mm in diameter, spreading, broadly obovate to nearly circular, scaly outside at the base, otherwise glabrous. Stamens slightly exserted from the throat; filaments linear, sub-densely to laxly hairy in the proximal 2/3, glabrous distally; anthers c.2.6 x 1mm, oblong, base obtuse. Disc hairy especially at the upper margin. Ovary c.7 x 2mm, elongate-conical, densely hairy and scaly, with 5 longitudinal furrows, gradually tapering distally; style c.35mm, slightly exserted, laxly hairy and very laxly scaly to the middle, glabrous distally; stigma thickly conical-globose.
Habitat: Ridge forest
Distribution: Papua New Guinea, Central District, Mt Victoria, NW of ‘The Gap’.
Altitude: Around 2895m
Greek – oligos – small; anthos – flower. The small-flowered rhododendron.
Known only from the type collection.
Type: Carr s.n., 15 Jan. 1936. New Guinea (SE), Central District, ascent to Mt Victoria, crest of the main range NW of ‘The Gap’, c.2895m (BM, SING, L, fragment).
Occurs in Countries: PG Altitude Ranges: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: pink
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:183
Shrub to 1m. Twigs semi-rounded, the tips densely brown stellate-scaly, the older parts glabrescent and rough with minute tubercles; internodes 10–20cm. Leaves laxly spiral. Blade 60–100 x 30–40mm, broadly elliptic; apex shortly acuminate, sub-acute or sub-obtuse; margin slightly wavy or revolute; base very broadly tapering to rounded; when young densely brown-scaly above and beneath, mature blades glabrescent except along the mid-vein, densely, minutely tubercled and very rough to the touch. Scales minute, deeply stellately divided, shortly dendroid, each on top of a minute pale persistent epidermal tubercle. Mid-vein thick, flattened, a little raised and impressed in the lower part above, prominent beneath; lateral veins c.10 per side, dense, irregular, straight below, anastomosing near the margin, slightly prominent on both sides, veins laxly prominently reticulate, finer reticulation obscure. Petiole c.10 x 2.5mm, flattened, at first densely scaly, rough when the scales have gone. Bracts to 45 x 20mm; middle and inner bracts spathulate, densely white hairy both in and outside. Bracteoles to 30 x 2mm, linear, very densely whitish hairy, with partly appressed hairs. Inflorescence of 7–8 flowers in an open umbel. Pedicels 8–10 x c.1.5mm, densely appressed-hairy and laxly stellately scaly, with fragile scales. Calyx c.4mm in diameter, oblique, circular, obscurely 5–6-lobed, densely hairy and scaly outside. Corolla 90–100 x 40–50mm, elongate-tubular below, expanded above, fragrant, pink at the tube, shading to white at the lobes; tube 60–70 x 4–5 x c.8mm, cylindrical, glabrous outside, densely covered with long retrorse hairs almost to the mouth inside; lobes 25–30 x 18–25mm, broadly obovate to sub-circular, glabrous. Stamens exserted to c.10mm; filaments linear and densely covered with retrorse hairs below, more laxly hairy distally, filiform and glabrous in the ultimate ¼; anthers c.6 x 1.2mm, elongate-oblong, the base obtuse. Disc white hairy. Ovary 10–12 x c.2.5mm, elongate-cylindrical, very densely stellately scaly and laxly short-hairy (the hairs mostly hidden by the scales), gradually tapering distally; style 50–60mm, thick below, very densely stellately scaly and without hairs in the proximal 30–40mm, more slender and completely glabrous distally; stigma large, globose, distinctly 5-lobed.
Habitat: A frequent epiphyte on large trees in mossy forest
Distribution: Indonesia, New Guinea (W), Bernhard Camp, Idenburg R. and Snow Mountains region E of the Baliem Valley
Altitude: 1500-1800m
Latin – opulentus – sumptuous; no doubt an impressive plant.
Type: Brass 12001, Jan. 1939. New Guinea (W), Northern part: 15km SW of Bernhard Camp, Idenberg R. (A, L).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: pink, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:92
Shrub or tree, 1.5-15 m. Leaves ± orbicular to ovate-orbicular, 7-12.5 X 5.6-7.7 cm, 1.2-1.5 x as long as broad, apex rounded to slightly retuse, base cordate, lower surface glabrous; petioles stout, 2.5-3.5 cm, glabrous. Inflorescence 10-17-flowered; rhachis up to 17 mm; pedicels 35-40 mm, slender, glabrous above, minutely glandular below. Calyx c. 0.5 mm, lobes rounded, glabrous. Corolla 7-lobed, campanulate, glabrous, rose-pink, without flecks, 35-40 mm. Stamens 14, filaments glabrous. Ovary stipitate-glandular; style glabrous. Capsule 15-20 x c. 5 mm, straight to circinnate.
Habitat: Coniferous forests, rocks, etc.
Altitude: 2500-4000m
R. orbiculare is a distinctive species with no close allies. The rejection of the name R. rotundifolium follows Rehder & Wilson (in Sargent (ed.), PL Wilsonianae 1: 540, 1913).
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: rose
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):237
Leaves ovate-orbicular, c. 1.5 x as long as broad, 12.5 cm long
Distribution: China (Guangxi)
Subsp. cardiobasis has consistently longer leaves; the differences between the two subspecies are otherwise small.
Synonymy: subsp. cardiobasis (Handel-Mazzetti) Chamberlain, Notes R.B.G. Edinb. 37: 331 (1979), sphalm. R. cardiobasis Sleumer, Notizbl. Bot. Gart. Berlin-Dahlem 12: 434 (1935), basionym. Type: S China, Guangxi, Yao Shan, Kuchen, 11 v 1929, Sin 8979 (iso. E)
Leaves orbicular, c. 1.2 x as long as broad, 7-9.5 cm long
Distribution: China (C & S Sichuan, Guangxi)
Illustrations:
A specimen, Kwangfu Exped. 636, differs from subsp. orbiculare in its glandular style but otherwise resembles it closely.
Type: China, W Sichuan, in monte Houang-chen-Thin, prope Moupine, 4000 m, Pere David, (n.v.)
Synonymy: R. rotundifolium David, J. N China Branch Asiat. Soc. 6: 216 (1873), nom. subnudum. Type assumed to be as above.
Shrub or small tree to 4m. Twigs 1.5–2.5mm in diameter, round, green, when young thinly covered in small flat scales; internodes 3–10cm. Leaves 4–6 together in tight pseudowhorls, with a few additional small ovate leaves which have very pronounced petioles for their size. Blade 32–65 x 35–60mm, broadly ovate to circular; apex obtusely pointed or rounded; margin entire, flat, with a narrow cartilaginous edge; base rounded to cordate; quickly glabrescent and smooth above, laxly to sub-densely scaly below. Scales very small, brown, sub-circular, only weakly lobed but with a pronounced central area, impressed in shallow pits. Mid-vein slightly raised but grooved proximally, becoming impressed, extending the full length of the leaf but becoming very narrow distally; beneath very slightly raised proximally but quickly becoming smooth or even slightly impressed distally; lateral veins 5–7 per side, spreading at 45°, straight or slightly curving, very slightly impressed above, indistinct below, reticulation obscure. Petiole green, 2 x 5mm, with small brown scales, weakly or not grooved above. Flower buds green, narrowly conical, the scales with subulate points. Inflorescence an open, loose, umbel of 2–6 flowers which are held horizontally or slightly hanging. Pedicels 12–17 x 2.5mm, usually conspicuously red in colour, scaly with small brown scales. Calyx a low circular or 5-angled disc. Corolla 70–80 x 70–80mm, pale-pink or white, without or just faintly scented; tube 35–50 x 7–12 x 10–18mm, pouched at the base and 5-angled in the lower ½, sparsely scaly outside and shortly hairy towards the base inside; lobes 30–40 x 22–33mm, overlapping to 1⁄5 of their length and bent back perpendicularly. Stamens in a group on the lower side of the corolla; filaments 60–65 x 0.75mm, pink, shortly hairy in the basal ½; anthers 3.5mm, brown. Ovary 8 x 3mm, purplish-red with silvery scales and very short, white hairs; style 35–56 x 2mm, shortly hairy and with a few scales in the lower ½, glabrous above; stigma pink, 5mm in diameter, circular. Fruit 30 x 6mm, splitting lengthwise from the apex. Seeds 4mm, without tails 0.8mm, the longest tail 1.6mm, crimped.
Habitat: Frequently growing as an epiphyte on large trees in mossy forest but also on the ground in suitable open vegetation on mountain ridges and rocky outcrops
Distribution: Malaysia (Borneo), Sarawak, widespread. Sabah. Brunei. Indonesia, Kalimantan (Borneo), Sulawesi (W and C).
Altitude: 800-1800m
Latin – orbiculatus – circular, referring to the often nearly circular leaves.
Rhododendron orbiculatum was first collected in 1911, probably on G. Selinguid on the Sabah/Sarawak border, by J.C. Moulton, a former curator of the Sarawak Museum and Director of the Raffles Museum and Library. The species is similar to R. edanoi, R. suaveolens and R. lambianum but all of these species have many more, smaller flowers in the umbel and longer, elliptic rather than orbicular leaves. The species has been moved from section Solenovireya (Sleumer 1966) as the corolla lobes are much longer than is usual in this group, often being almost as long as the tube.
Type: Moulton s.n. Borneo, Sarawak, Mt Batu Lawi, Upper Limbang R., c.1740m (SAR, L, fragment).
Occurs in Countries: ID, MY Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Vireya Habit: Epiphyte, Tree Fl. Colour: white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:269
Shrub. Twigs weakly angular, slender, tips sub-densely scaly, glabrescent with age. Leaves mostly 3 together in tight pseudowhorls. Blade 80–140 x 30–50mm, narrowly ovate to elliptic, broadly elliptic to slightly obovate, sometimes with slightly unequal sides; apex acuminate and acute to obtuse; margin flat; base narrowly tapering; glabrescent above when mature, laxly stellate-scaly beneath. Scales thin, irregularly dentate, flat; centre small, faintly impressed. Mid-vein slightly impressed above, prominent beneath; lateral veins 8–12 per side, dense, curved and anastomosing before the margin, obscurely impressed above, raised beneath, reticulation inconspicuous on both sides. Petiole 8–10 x 1.5mm, laxly scaly. Flower buds to 60 x 20mm, imbricate, ellipsoid, smooth. Bracts to 30 x 18mm, ovate to broadly obovate, scaly and shortly hairy outside in the distal ½ and shortly hairy in the distal ½ inside, with longer appressed hairs proximally. Bracteoles to 30mm, filiform, laxly hairy. Inflorescence compact, 8–12-flowered, the flowers erect or semi-erect. Pedicels c.2–4 x 1.5mm, scaly. Calyx c.2.5mm diameter, obtusely 5-lobed. Corolla trumpet-shaped, probably white; tube 45–60 x 3–4 x c.11mm, cylindrical, straight, practically glabrous outside, hairy almost to the mouth inside; lobes c.20 x 15mm, broadly elliptic or obovate, glabrous. Stamens exserted to 14mm, clustered on the upper side of the flower before collapsing irregularly; filaments linear and densely patently hairy in the proximal ½, gradually glabrescent distally; anthers c.4 x 1mm, oblong, base obtuse. Disc shortly hairy on the upper side. Ovary 8–10 x 1.7mm, cylindrical, densely covered with long, appressed, distally directed hairs with some scales between them, gradually tapering distally; style c.40mm, laxly covered with hairs for the proximal 2/3, glabrous distally; stigma shortly broad-obconical, indistinctly 5-lobed.
Distribution: Indonesia, New Guinea (W), Mt Carstensz.
Altitude: 1095-1495m
Greek – oreo – pertaining to mountains, alluding to the mountainous habitat.
Type: Kloss s.n. New Guinea (W), Ascent to Mt Carstensz, 1095–1495m (BM, L, fragment).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:174
Greek – oreites – a mountaineer; oreo – pertaining to mountains.
Type: Brass & Meijer Drees 9992, Sept. 1938. New Guinea (W), 7km north of Mt Wilhelminatop, 3560m (A, L).
Occurs in Countries: ID Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:57
Leaves 11–15 x 5–8mm, elliptic or ovate-elliptic. Corolla greenish-yellow.
Distribution: Indonesia, New Guinea (W), Lake Habbema; Mt Jaya, locally common in shrubberies
Greek – chloro – green, alluding to the green colour of the flowers.
Differing from the type variety only really in the colour of the flowers.
Type: Brass 10668, Oct. 1938. New Guinea (W), 6km NE of Lake Habbema (A, L).
Erect shrub to 2.5m. Twigs 1.5–2mm in diameter, rounded, densely covered with stalked scales, glabrescent and rough when the scales have gone. Leaves spiral, crowded at the ends of the new shoots. Blade 8–12 x 4–7mm, elliptic; apex gradually sub-acuminate to obtuse; margin revolute in the proximal ½, crenulate where impressed scales are attached; base broadly tapering or rounded to truncate, sub-densely persistently scaly on both sides. Scales circular, marginal zone narrow, entire or nearly so; centre large, thick, somewhat impressed. Mid-vein slightly impressed above, prominent beneath, lateral veins slightly or not visible. Petiole c.2mm, slender, scaly. Bracts to 5 x 2.5mm. Outer bracts triangular, inner ones ovate to elliptic, apiculate, scaly outside at the apex, sometimes with a few hairs, otherwise glabrous, densely long-ciliate, often persisting around the base of the pedicel. Bracteoles c.6mm, filiform, laxly hairy. Inflorescence of solitary flowers, half-hanging. Pedicels c.10mm, slender, with dense scales on very short stalks, not hairy. Calyx c.2.5mm in diameter, oblique, cup-like, shortly 5-lobed, lobes to 1mm, sub-acute or obtuse, appressed to the corolla. Corolla tubular, slightly zygomorphic, red; tube 16–17 x 3 x 6mm, densely scaly outside, glabrous inside; lobes 3–4 x 3–4mm, sub-circular, scaly outside except near the margins which may be shortly hairy outside, glabrous inside, margin crenulate or irregularly denticulate, not ciliate. Stamens as long as the corolla, slightly unequal; filaments glabrous, linear below, filiform distally; anthers c.1mm, brown, obovate-oblong. Disc glabrous. Ovary c.4 x 1.5mm, shortly ovoid-cylindrical, densely covered with very slightly stalked or sessile scales, gradually tapering distally; style slender and glabrous; stigma at first at the mouth, later distinctly exserted. Fruit 8–12 x 3.5mm, cylindrical, deeply 5-grooved, densely scaly, valves not or slightly twisted.
Habitat: Terrestrial in sub-alpine forest or forest borders, or in shrubberies, occupying patches of wet sandy or peaty soil. Common
Distribution: Indonesia, New Guinea (W), Mt Trichora (Wilhelmina).
Altitude: 2900-3650m
Shrub or small tree, 1.3-5 m. Leaves obovate-elliptic to elliptic, 6-8.5 x 2.2-4 cm, 2-3.2 x as long as broad, apex rounded, mucronate, base rounded, lower surface with persistent punctulate hair-bases, otherwise glabrous; petioles 1—2.5 cm, often glandular when young, soon glabrescent. Inflorescence 6-8-flowered; rhachis 5-8 mm; pedicels 15-20 mm, glandular or sparsely rufous-tomentose. Corolla (5-) 7-lobed, campanulate, glabrous or finely pubescent within, deep pink, 35-40 mm. Stamens 10-14, filaments glabrous or puberulent. Ovary glabrous or stipitate-glandular; style glabrous. Capsule 20-25 x c. 6 mm, curved.
Habitat: Forests, etc.
Distribution: China (NW Yunnan, Sichuan, Gansu, Shaanxi, Hubei)
Altitude: 2650-4150m
The three varieties may be parts of a geographical cline with var. oreodoxa in C Sichuan and var. shensiense restricted to Shaanxi Province. Var. fargesii is apparently the most widespread of the three taxa (see distribution map 68, p. 239). However, further studies in the field are required before this variation pattern can be confirmed.
Var. oreodoxa can only be reliably distinguished from var. fargesii by the glabrous ovary; both can have either glabrous or puberulent filaments.
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: pink
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):238
Ovary stipitate-glandular. Pedicels glandular; corolla usually 6-7-lobed
Illustrations:
Synonymy: R fargesii Franchet, J. Bot. (Morot) 9: 390 (1895). Type: China, E Sichuan, Sanken cheou, pres Ta-lin-hien, Farges 1317 (iso. E,K). R. m/Z?escms Hutchinson, Bot. Mag. 142: t. 8643 (1916). Type: a plant cultivated at Kew, from Wilson's seed, collected in 1908 (photo. E)
Ovary glabrous
Illustrations:
Type: China, Sichuan, ad Moupine, Pere David (iso. E)
Synonymy: R. haematocheilum Craib, Gard. Chron. 53: 214 (1913). Type: a cultivated specimen raised by Veitch from Wilson's seed (E). R. reginaldii Balfour f., Notes R.B.G. Edinb. 11: 114 (1914). Type: China, Gansu, valley between Siku and Satanee, over 9000ft, 2 v 1914, Farrer 63 (holo. E). R. UmprichtiiDids, Feddes Repert. 17:195 (1921). Type: China, Sichuan, Wen tchuan hsien, Pe mu schan, in jugo Tien tsching, 3400 m, v 1914, Limpricht 1406 (iso. K)
Ovary stipitate-glandular. Pedicels sparsely rufous-tomentose; corolla (?always) 5-lobed
Type: China, Shaanxi, ? Tai-pei-shan, 1955, Gaoy S. T. (s.n.) [Beijing 370117] (holo. PE)
Synonymy: R. shensiense R. C. Ching in sched. China (Shaanxi). Forests, 2300-2500m.
Shrub or small tree, 1-8 m. Young growth lepidote, usually whitish or greyish pruinose. Leaves mostly evergreen, sometimes semi-deciduous, orbicular, elliptic to oblong or obovate, apex rounded to acute, base cuneate to cordate, 21-63(-87) X 18-31 (-40) mm, upper surface usually elepidote, often slightly puberulent along the midrib, undersurface with dense but not contiguous purplish, reddish brown or greyish, opaque, narrowly rimmed scales; petiole glabrous or puberulent, the puberulence, when present, often extending to the underside of the midrib. Inflorescence l-3(-4)-flowered, pedicels (8-)15-20(-26) mm, sparsely lepidote, often greyish or whitish pruinose. Calyx reduced to a rim, rarely slightly lobed, sparsely lepidote, sometimes ciliate with filiform-acicuiar hairs. Corolla rose or rose-lavender, often with darker spots, more rarely white, (21~)25-30(-34) mm, tube (9-) 16-21 (-23) mm, elepidote and glabrous outside, pubescent within the tube. Capsule lepidote, oblong-cylindric, 11-16 mm.
Habitat: Scrub, open thickets, forests, forest margins and on rocky slopes
Distribution: China (N & NW Yunnan, S & SE Xizang, SW Sichuan)
Altitude: 2750-4250m
Illustrations:
A very common species, variable in leaf shape and flower size, but immediately identifiable by means of the leaf scales, which are unlike those of any other species. It appears to form hybrids with R. racemosum (p. 82) and R. zaleucum (p. 63) in Yunnan, with R. concinnum (p. 75) in Sichuan, and perhaps with R. cinnabarinum subsp. xanthocodon (p. 124) in Xizang
Type: China, Yunnan, W flank of Lichiang range, 11-12000 ft, vi 1910, Forrest 5873 (holo. E)
Synonymy: R. timeteum Balfour f. & Forrest, Notes R.B.G. Edinb. 12:166 (1920). Type: China, SW Szechuan, Muli mountains, valley of the Litang, 11000 ft, Forrest 16285 (holo. E). R. artosquameum Balfour f. & Forrest, ibid. 13:234 (1922). Type: SE Tibet, Tsarung, Ka gwr pu, 12000 ft, vii 1917, Forrest 14535 (holo. E). R. cardoeoides Balfour f. & Forrest, op. cit: 239 (1922). Type: China, NW Yunnan, Kari pass, 11000 ft, vi 1917, Forrest 13931 (holo. E). R. depile Balfour f. & Forrest, op. cit.: 268. Type: China, Yunnan, Bei-ma-shan, 12000 ft, vi 1917, Forrest 13992 (holo. E). R. hypotrichum Balfour f. & Forrest, op. cit.: 268. Type: SE Tibet, Tsarung, Mekong/Salween Divide, 10-11000 ft, vi 1918, Forrest 16543 (holo. E). R. phaeochlorum Balfour f. & Forrest, op. cit.: 284. Type: SE Tibet, Tsarong, Salween/Kiu-chiang Divide, viii 1919, Forrest 19200 (holo. E). R. pubigerum Balfour f. & Forrest, op. cit.: 289. Type: SE Tibet, Tsarong, Salween/Kiu-chiang Divide, vii 1919, Forrest 19206 (holo. E). R. trichopodum Balfour f. & Forrest, op. cit.: 304. Type: SE Tibet, Tsarong, Doker la, 11000 ft, xii 1917, Forrest 14347 (holo. E). R. exquisetum Hutchinson, Card. Chron. 98:98 (1932). Type: a cultivated specimen (holo. K, iso. E)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Tree Fl. Colour: rose, white
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):69
Much branched erect shrub to 1 -3 m. Leaves 8-16 x 2-5-5(-6)mm, narrowly elliptic to lanceolate, apex obtuse, shortly or obscurely mucronate, base cuneate, undersurface yellowish brown to fawn, usually with deeper brown speckling, scales contiguous or almost so, golden to yellow-brown with few to many darker scales intermixed. Inflorescence (1-) 2-4(-5)-flowered, pedicels lepidote, l*5-2(-3) mm. Calyx 0-5-1-5 mm, lepidote at base, lobes rounded to deltoid, often unequal, sometimes with a few scales on the back, margin occasionally with a few scales and cilia. Corolla pale to deep lavender blue to purple or whitish pink, funnel-shaped, 7-13-5 mm, tube 2-4-5 mm, pubescent in the throat, lobes elepidote or sparsely lepidote outside. Stamens 8-10, shorter than to equalling the corolla. Ovary lepidote, style 3-5-5 or 15-16 mm long, glabrous or sparsely lepidote. Capsule ovoid, 5 mm, lepidote.
Three varieties may be distinguished
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: blue, lavender, pink, purple
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):103
Corolla blue to purple. Style 15-16 mm.
Habitat: Thickets on alpine slopes, 3500 m
Distribution: China (N & NW Yunnan)
Type: China, Yunnan, mt. Ta-pao-shan, between Wei hsi and the Mekong, vii 1928, Rock 17135 (holo. NY; iso. A, E)
Corolla white
Known only in cultivation, and distinguished from var. orthocladum solely by its white flowers
Synonymy: R. microleucum Hutchinson, Gard. Chron. 93:334 (1933). Type: a cultivated specimen (holo. K, iso. E)
Corolla blue to purple. Style 3 -5-5 mm
Habitat: Forest margins, cliffs, thickets
Distribution: China (N Yunnan, SW Sichuan)
Altitude: 2500-4500m
Type: China, Yunnan, mountains in the NE of the Yangtze bend, 3350-3650 m, vii 1913, Forrest 10481 (holo. E; iso. A, K)
Shrub to 4 m high, young branches and petioles minutely puberulous and sometimes also with glandular hairs. Leaves glabrous except for the petiole and upper mid-rib; blade broadly ovate or ovate elliptic, 30-60 x 16-26 mm, base rounded or cuneate, apex acute or obtuse, often emarginate, mucronate; petiole 6-16 mm long. Inflorescence buds lateral, 1-flowered, clustered near the ends of the leafy shoots; outer bud scales short, inner elongate (12-14 mm long); pedicel 15-20 mm long, puberulous and with few to many glandular hairs. Calyx lobes usually broadly rounded, 4-7 x 3-4 mm, glabrous or fringed with fine cilia and/or sessile or stalked glandular hairs. Corolla pink to pale purple or white, the upper three lobes with darker spots, glabrous or the tube minutely puberulous on the outside and/or within, rotate, with a short tube and spreading lobes, 40-50 mm across. Stamens 5, filaments hairy for a variable distance above the base. Ovary subglobose, c.2-5 mm high, setose and glandular, 5-Iocular; style glabrous. Capsule broadly ovoid, c.7 x 5 mm, verrucose.
Habitat: In thickets and forests, and on open mountainsides, mostly at low altitudes, but reaching 2000 m in Hubei.
Distribution: China (Anhui, Zhejiang, Fujian, Guangdong, Jiangxi, Hubei, Sichuan, Guizhou, Guangxi), Taiwan (central mountains).
Illustrations:
R. ovatum is not uncommon over a wide range in eastern and central China, but is rare in Taiwan. Formerly, specimens from the western part of its range were distinguished as R. bachii on the basis of the glandular hairs fringing the calyx, but we agree with Clarke (1976) that this species should be merged with R. ovatum. Fringed calyx lobes are certainly more frequent in the central Chinese provinces than in the eastern, but fully or partially fringed lobes occur in coastal States among populations with mainly glabrous calyx lobes, whereas the reverse occurs in the inland States. Evidently there is a cline in this character, but even the recognition of subspecies appears unwarranted.
Occurs in Countries: CN, TW Subgenus: Azaleastrum Habit: Non-Tree Fl. Colour: purple, white
Philipson, W.R. & Philipson, M.N. (1986) A Revision of Rhododendron III. Subgenera Azaleastrum, Mumeazalea, Candidastrum and Therorhodion. Notes from the Royal Botanic Garden Edinburgh 44(1):4
Shrub. Twigs 0.5–1mm in diameter, densely brown-stellate-scaly, at first glabrescent and smooth later. Leaves laxly spirally arranged. Blade 3–7 x 2.5–4mm, ovate, shortly acuminate, sub-acute or obtuse; margin thickened, flat or slightly recurved; base broadly rounded; initially scaly on both sides, quickly glabrescent above, more persistently scaly below. Scales irregularly stellately lobed, not or only slightly impressed. Mid-vein and lateral veins obscure. Petiole 0.5–1mm, slender. Bracts to 15 x 5mm, membranous, ovate-elliptic, inner ones long subulate-acuminate, glabrous and shining. Flowers solitary. Pedicels 4–6mm, slender, densely stellate-scaly. Calyx c.2.5mm in diameter, disc-shaped, margin wavy, scaly outside. Corolla 25–27mm, slightly zygomorphic, pink, thin; tube 18–20 x c.3 x c.5mm, cylindrical, glabrous both inside and out; lobes 5–7 x 5–7mm, spreading, sub-circular. Stamens exserted to c.3mm, unequal; filaments linear, glabrous; anthers 1–1.2mm, hardly longer than broad. Disc prominent, glabrous. Ovary c.3.5 x 2mm, sub-cylindrical, densely scaly, gradually tapering distally; style c.14mm; stigma globose.
Habitat: Epiphytic in stunted, mossy forest on an exposed summit
Distribution: Indonesia, New Guinea (W), Idenburg R., Bernard Camp, c.139°E 3°30'S.
Altitude: Around 2100m
With leaves like those of Vaccinium oxycoccus (cranberry).
Type: Brass 12184, Jan. 1939. New Guinea (N), Idenburg R., 18km from Bernard camp, 2100m (A, L, fragment).
Occurs in Countries: ID Altitude Ranges: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: pink
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:146
Shrub to 2m. Twigs 4–6mm in diameter, rounded, or weakly 4-angled, with conspicuous, spherical lateral buds, laxly scaly at first, glabrescent and whitish later; internodes 3–6cm. Leaves spiral or c.3 together in loose pseudowhorls. Blade 40–80 x 25–45mm, obovate; apex obtuse or rounded, sometimes slightly emarginate; margin narrowly cartilaginous, flat, sub-serrulate-crenulate; base tapering; glabrescent above at maturity, sub-densely scaly below. Scales small, rounded, large, marginal zone variously angular or lobed; centre minute and distinctly impressed. Mid-vein narrowly impressed above, thick, flattened and obtusely prominent beneath; lateral veins 6–8 per side, lower two from near the base, the others at an angle of c.45°, all high-ascending and curved-anastomosing before the margin, slightly impressed above and raised beneath, reticulation inconspicuous. Petiole 3–6 x 2.5–3.5mm, grooved above, scaly. Bracts to 18 x 13mm, ovate, laxly scaly outside, apices obtuse or rounded; inner bracts obovate-spathulate, to 25 x 10mm. Bracteoles to 30mm, linear, glabrous. Inflorescence 3–9-flowered open umbels. Pedicels 9–16 x c.1mm, densely scaly, without hairs. Calyx c.5mm in diameter, disc-shaped, scaly outside. Corolla 45–70mm, half-hanging, tubular or narrowly funnel-shaped, greenish-yellow to light yellow; tube 30–45 x 6–10 x 10–12mm, straight, fleshy, glabrous inside and out, sulcate at the base; lobes c.15 x 15mm, sub-circular, erect to half-spreading. Stamens unequal, not exserted; filaments glabrous, linear; anthers 2.5–4 x 1.5–2.5mm, brown, broadly obovoid-cordate, distinctly narrow towards the base and ending in a small basal appendage. Disc prominent, glabrous. Ovary c.6 x 3.5–4mm, ovoid-cylindrical, densely covered with reddish-brown scales, abruptly contracted distally; style c.30mm, sub-densely scaly at the base, glabrous distally; stigma globose, shortly 5-lobed. Fruit 20–25 x 8–9mm, obliquely obovoid-cylindrical, scaly.
Habitat: In open sub-alpine forest often in limestone areas
Distribution: Papua New Guinea, Madang District, Finisterre Mts; Morobe District, Saruwaket Mts, Mt Enggan, Rawlinson Mts.
Altitude: 2135-3655m
Greek – pachy – thick; carpo – relating to the fruit. Alluding to the thick broad fruits of this species.
Van Royen & Kores (1982) note the similarity of this species to R. brassii and suggest that they may have to be united if intermediates are collected. At present R. brassii may be distinguished by its acutely, or sub-obtusely pointed, smaller leaves (up to 50 x 27mm).
Type: Clemens 41390, 18–20 May 1940. New Guinea (NE), Morobe District, Rawlinson Range, 2135–3655m (A, E, L, fragment).
Occurs in Countries: PG Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: green, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:295
Very similar to R. roseatum differing only in the narrower leaves with laxer scales on the lower surface.
Habitat: Forest margins, scrub, slopes and cliffs
Distribution: NE Burma, China (N, W, C & S Yunnan)
Altitude: 1800-4000m
A very variable species in terms of scale density, corolla size and indumentum. None of this variation is correlated, however, even though individual specimens can appear very divergent. The original description of R. pachypodum, stating that the flowers are yellow, seems to be mistaken: the type specimen has no flowers, and other very similar specimens collected by Forrest in the same area are annotated 'flowers white with yellow blotch'. The only specimen actually annotated 'flowers yellow'has no flowers.
Type: China, Yunnan, head of Hsia-kuan valley, 6000 ft, v 1913, Forrest 10008 (holo. E)
Synonymy: R. pilicalyx Hutchinson, Notes R.B.G. Edinb. 12:66 (1919). Type: Yunnan, Mengtsz, northern mountains, 8000 ft, Henry 10524 (holo, E). R. scottianum Hutchinson, op. cit.: 64. Type: China, Yunnan, head of Hsia-kuan valley, 6000 ft, v 1913, Forrest 10008 (holo. E). R. supranubium Hutchinson, op. cit.: 68. Type: China, Yunnan, E flank of the Tali range, 11-12000 ft, vi 1910, Forrest 6764 (holo. E)
Occurs in Countries: CN, MM Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):53
Shrub; young shoots tomentose, later glabrescent. Leaves oblong, 6-9 x 2.5-3.5cm, c.2.5 x as long as broad, apex acute to apiculate, base rounded, upper surface rugose to smooth, glabrous, lower surface with a whitish-brown to rufous ramiform tomentum that usually persists, occasionally only on the midrib; petioles c. 1.5cm, tomentose. Inflorescence 10-20-flowered; rhachis 10-20mm; pedicels c.25mm, glandular-pubescent. Calyx c.Imm, glandular, especially on the margins of the rounded lobes. Corolla widely campanulate, white to pale pink, with or without purple flecks, c.40mm. Ovary densely stipitate-glandular; style glabrous. Capsule c. 15 x 5mm.
Distribution: Taiwan
Hayata mentions the rugose leaves, densely tomentose beneath, and the glabrous style, as the chief characters separating this species from R. morii. Recently Patrick has introduced this species into cultivation and it is only known to me through this source. The leaves of the plants I have seen are not rugose, but have a well-developed, persistent, ramiform indumentum on the undersurface, in contrast to the folioliferous indumentum of the two preceding species, presumed to be the closest relatives of R. pachysanthum.
Type: Taiwan, in montibus centralibus, iv 1911, Mori, n.v.
Occurs in Countries: TW Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: pink, purple, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):274
Shrub to 1.5m. Twigs 3–5mm in diameter, semi-rounded, densely scaly at first, older parts often whitish; internodes 4–13cm. Leaves in loose pseudowhorls. Blade 50–90 x 25–50mm, obovate or elliptic-obovate; apex rounded, sometimes slightly retuse; margin entire, revolute proximally, otherwise flat; base broadly tapering; at first densely scaly on both sides, quickly glabrescent both above and below. Scales small, reddish, sessile and flat, fragile, marginal zone irregularly sub-stellately lobed; centre minute, hardly or not impressed. Mid-vein thick and grooved proximally above, as strong as the petiole proximally beneath; lateral veins 8–9 per side, straight, at an angle of c.45° and sub-parallel proximally, curved and joining before the margin, faintly impressed above, a little raised beneath, reticulation obscure. Petiole 10–25 x c.2mm, densely scaly initially. Immature bracts laxly scaly outside, without hairs. Bracteoles to 15mm, filiform, glabrous. Inflorescence 2–3-flowered. Pedicels 8–14 x 1.5–2mm, with dense, small brown scales and fine short hairs in the proximal ¾, distally more densely and with longer hairs. Calyx 6–7mm in diameter, an oblique rim with irregular spreading, triangular lobes, up to 4mm, hairy and scaly along the margin. Corolla 70–80mm, funnel-shaped, deeply 6–7-lobed, light orange on the tube outside, white at the lobes, fleshy; tube 25–30 x 8–9 x 20–25mm, straight, pouched at the base, glabrous outside, densely white-hairy proximally inside; lobes 45–50 x 25–35mm, obovate-spathulate, spreading. Stamens 12–14, unequal, exserted; filaments linear, proximally densely white-hairy, filiform and glabrous distally; anthers c.8 x 1–1.2mm, hinged, elongate-oblong, base obtuse. Disc prominent, densely white-hairy on the margin. Ovary 8–9 x c.4mm, thickly cylindrical, with reddish-brown stellate scales, without hairs, tapering distally; style c.40 x 1–1.5mm, glabrous; stigma rounded, 6–9mm in diameter, with 6–7 thick, sub-globular lobes.
Distribution: Indonesia, New Guinea (W), Balim R. Valley near Wiligimaan.
Altitude: Around 1800m
Greek – pachy – thick; stigma – the stigma. Alluding to the large stigma of this species.
Young secondary forest, terrestrial on stony clay.
Known only from the type collection.
Type: Versteegh BW 10464, 25 June 1961. New Guinea (C), Balim R. valley, Wiligimaan, c.1800m (L, CANB).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: orange, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:296
Shrub or small tree, l-6m; young shoots tomentose. Leaves elliptic to obovate, 9-15 x 2-4.2cm, 2.7-4.5 x as long as broad, apex ± cuspidate, base rounded, upper surface glabrous at maturity, lower surface with short folioliferous hairs on and near the midrib, otherwise glabrous; petioles 1.4-2cm, with an evanescent tomentum and occasionally a few stipitate glands. Inflorescence lax, 7-10-flowered; rhachis less than 5mm; pedicels 10-25mm, tomentose. Calyx c. 1.5mm, lobes rounded, ciliate. Corolla narrowly campanulate, with a broad base but lacking nectar pouches, white suffused with pink, with a purple basal blotch and flecks. Ovary densely tomentose, eglandular; style glabrous or glandular at base. Capsule c.20 x 4-6mm.
Habitat: Woods, open slopes, etc.
Distribution: China (Sichuan & adjacent parts of NE Yunnan)
Altitude: 2500-3600m
R. monosematum is only known for certain from the type although several plants that are assumed to be hybrids between R. strigillosum and R. pachytrichum are a fair match. It differs from R. pachytrichum only in its glandular ovary, calyx, pedicels and petioles, trivial characters in view of the obvious transition from glandular to branched hairs in R. strigillosum. Furthermore, some of the plants raised from the same batch of seed (Wilson 1521) are typical R. pachytrichum.
Probably most closely allied to R. maculiferum and R. sikangense.
Type: na, Sichuan, circa Moupine, Abbe David (iso. E)
Synonymy: R. monosematum Hutchinson, Bot. Mag. 142: t. 8675 (1916). Type: a plant grown at Kew from seed collected by Wilson in 1903 as seed no. 1521 (holo. E). Ic: Fang, PL Omeiens. t.22 (1942).
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: pink, purple, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):270
Shrub or small tree, 2-5m. Leaves sub-coriaceous, oblanceolate to oblong, 9-14 x 3-5cm, c.3 x as long as broad, apex acuminate, base rounded to cuneate, margin not undulate, upper surface glabrous when mature, lower surface usually with conspicuous veins and a papillate cuticle, with a thin, persistent or detersile stellate indumentum, red punctate hair-bases lacking; petioles 1.5-2cm, glabrous. Inflorescence 5-10-flowered; rhachis c.20mm; pedicels c. 20mm, densely dendroid-tomentose. Calyx c.2mm, tomentose, lobes rounded. Corolla campanulate, glabrous within, pale cream to pink, with purple flecks and a basal blotch, 40-55mm. Ovary densely dendroid-tomentose, with stipitate glands; style glabrous. Capsule not known.
Habitat: Under Abies, etc.
Distribution: Bhutan, ne India (Arunachal Pradesh)
Altitude: 1800-3300m
The cuticle, even in R. epapillatum, is slightly papillate and there is no correlation between the degree of the papillosity of the leaf cuticle and the leaf shape as has been suggested.
R. papillatum is accepted in preference to R. epapillatum since it is the more commonly used name for this species.
Type: Bhutan, Bela Djang Pass, 10000ft, 10 v 1915, Cooper 3885 (holo. E)
Synonymy: R. epapillatum Balfour f. & Cooper, ibid. 13: 257 (1922). Type: Bhutan, Timpu, 6000ft, 24 v 1915, Cooper 3818 (holo. E)
Occurs in Countries: BT, IN Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: cream, pink, purple
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):304
Much-branched shrub to 50cm, with fleshy roots. Twigs 1–2mm in diameter, the upper 1–2 internodes sub-densely covered with minute brown stalked scales, glabrescent and minutely warty, or a little rough to the touch after the scales have gone; internodes 2–7cm. Leaves 4–6 together in tight pseudowhorls. Blade 10–18 x 6–12mm, obovate, broadly elliptic to circular; apex rounded, sometimes slightly retuse; margin slightly revolute; base broadly tapering, more rarely rounded, glabrescent above when mature, sub-densely scaly beneath. Scales small, variously angled or sub-stellately lobed at the margin; centre dark, small and distinctly impressed. Mid-vein impressed above, obtusely prominent in the proximal ½–¾ beneath, disappearing distally; lateral veins obscure. Petiole c.2 x 0.6–1mm, somewhat flattened, scaly. Flower buds to 10 x 4mm, cylindrical-conical, imbricate, smooth. Bracts to 6 x 3mm, membranous, ovate to ovate-oblong, obtuse, glabrous outside, or minutely sub-papillose-hairy, fringed with scales initially. Bracteoles filiform, glabrous, to 6mm. Inflorescence 1–3-flowered. Pedicels 15mm, (up to 25mm in fruit), slender, erect, densely covered with shortly stalked, brown, stellate scales, almost without hairs. Calyx c.2.5mm in diameter, brown-scaly, irregularly 5-lobed, the lobes 1–1.5mm (one or two, up to 2.5mm), sub-acute, spreading or reflexed. Corolla 13–15mm, tubular, deep pink to purplish red; tube 8–10 x c.3 x c.4mm, straight, glossy, sub-densely scaly outside, glabrous inside; lobes 4–5 x 4–5mm, sub-circular, spreading. Stamens c.12mm; filaments linear, glabrous; anthers 1mm, obovoid. Disc low, glabrous. Ovary 4.5 x 1.5mm, sub-cylindrical, densely stellate-scaly, completely without hairs, with 5 deep longitudinal furrows, abruptly contracted distally; style 6–7mm, slender, scaly at the base, laxly patently hairy for the following 2mm, glabrous distally; stigma dilated, obliquely shortly obconical. Fruit (sub-mature) 18–23 x 4mm, fusiform, densely scaly, with a persistent style.
Habitat: Terrestrial in open places on moss-cushions, or epiphytic in mossy forest.
Distribution: Indonesia, New Guinea (W), Vogelkop Peninsula, Arfak, Nettoti and Tamrau Mts, possibly also in the Oranje Mts.
Altitude: 1525-2550m
Of Papua – geographical area where ‘Papuans’ or Melanesians were found, in this case the island of New Guinea.
A delicate species with small flowers.
Type: Beccari 5793A, July 1875. New Guinea (W), Vogelkop peninsula, Mt Arfak, Hatam, 1525–2135m (FI, L, fragment).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: pink, red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:230
Small tree, 5-8m; young shoots densely rufous stellate-tomentose. Leaves broadly obovate, 9-12 x 4.5-6.5cm, c.2 x as long as broad, apex acuminate, base rounded, both surfaces glabrous when mature though often with persistent stellate tomentum on midrib; petioles 1.5-2cm, densely stellate-tomentose when young, becoming less so at maturity. Inflorescence 6-12-flowered; rhachis c.20mm; pedicels 20-25mm, stipitate-glandular and with a floccose stellate tomentum. Calyx 2-5mm, lobes rounded, tomentose, glandular, especially on the margins. Corolla fleshy tubular-campanulate, red with darker lines, 30-50mm. Ovary densely tomentose, with some stipitate glands; style stipitate-glandular and floccose-tomentose. Capsule 25-30 x 6mm.
Distribution: Lower Burma
Altitude: Around 1900m
Illustrations:
A distinctive species with an isolated distribution.
Type: Burma, Moulmein, Moolee, 6000ft, Parish 1021 (holo. K).
Occurs in Countries: MM Altitude Ranges: 1,000 - 2,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: red
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):375
Dwarf shrub, 0.6-1.3m; young shoots soon glabrescent; perulae deciduous. Leaves obovate to elliptic, 4.5—8 x 2—3.5cm, c.3 x as long as broad, apex rounded, apiculate, base rounded to ± cuneate, upper surface glabrous, lower surface finely papillate, glabrous except for a few white hairs on the midrib and main veins; petioles broad, up to 0.5cm, glabrescent. Inflorescence 4-6-flowered; rhachis c.3mm; pedicels 10-20mm, glabrous. Calyx c.5mm, glabrous, lobes broad and rounded. Corolla tubular-campanulate, white or pale yellow flushed pink, with red flecks, 40-50mm. Ovary with a few scattered hairs. Capsule not known.
Habitat: Cliffs
Distribution: China (S Xizang)
Altitude: 3000-3700m
An aberrant member of subsection Neriiflora on account of the pronounced reddish flecks on the posterior corolla lobes. There are apparently several plants referred to R. faucium (subsection Thomsonia) that approach R. parmulatum but differ in their more open, less obviously tubular-campanulate corollas and in the greater number of flowers per inflorescence. These intermediates may well be of hybrid origin.
Type: China, E Xizang, Doshong La, ll-12000ft, Kingdon-Ward 5%15 (holo. E; iso. K).
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: pink, red, white, yellow
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):400
Small, weak shrub. Twigs slender, 0.6–1mm in diameter, densely covered at first with dark, brown, shortly stalked scales, minutely warty and rough to the touch; internodes 1.2–4cm. Leaves 2–4 together in pseudowhorls. Blade 6–12 x 3–8mm, broadly elliptic to sub-obovate-elliptic; apex obtuse to round; margin pale, sub-cartilaginous, entire or sub-crenulate with impressed scales; base broadly tapering or rounded, laxly to sub-densely scaly on both sides when young, glabrescent above, more persistently scaly beneath. Scales irregularly stellate, flat, slightly impressed. Mid-vein and lateral veins not visible. Petiole 1mm, slender, scaly. Bracts to 6 x 2.5mm, narrowly ovate-acuminate, distinctly sub-densely appressed-hairy, fringed initially with scales along the margin. Inflorescence of solitary or paired flowers. Pedicels 7–10mm, slender, densely covered with shortly stalked, deeply stellate-incised scales and very short slender sub-patent hairs. Calyx 2mm in diameter, disc-shaped, deeply obtusely 5-lobed, scaly outside. Corolla 10–12mm, tubular; tube c.8 x 2.5 x 3.5mm, sub-densely stellate-scaly outside, glabrous inside; lobes c.4 x 4mm, spreading, sub-circular, scaly outside in the proximal ½. Stamens exserted to c.2mm, unequal; filaments filiform, glabrous; anthers c.1mm, obovate. Disc glabrous. Ovary c.2 x 1.2mm, obconical-cylindrical, densely stellate-scaly, gradually tapering distally; style c.3.5mm, slender; stigma club-shaped-sub-globose.
Distribution: Indonesia, New Guinea (W), Wissel Lakes region: summit of Mt Mutaro (Moetaro).
Latin – parvus – little, small or puny; ulum – the diminutive. Alluding to the small, weak nature of the plant.
Known only from the type collection.
Type: Eyma 5203, 9 Sept. 1939. New Guinea (W), Wissel Lake Region, slope and summit of Moetaro (BO, L).
Occurs in Countries: ID Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:146
Shrub to 2m, with swollen roots and spreading branches. Twigs 1–2mm in diameter, laxly scaly and patently short hairy; internodes 1.5–3cm. Leaves 3–6 together in well-marked pseudowhorls at the upper 2–3 nodes. Blade 12–32 x 10–25mm, obovate to obovate-elliptic, broadly elliptic to almost circular; apex rounded, retuse, or broadly tapering, sometimes mucronate; margin entire, flat or a little recurved especially near the base, somewhat cartilaginous; base broadly tapering to the petiole, dark to medium green and a little shining above, paler and dull beneath, initially scaly on both sides, glabrescent above with age, more persistently and sub-densely scaly beneath. Scales circular or irregularly lobed, marginal zone relatively broad; centre impressed. Mid-vein impressed above in the proximal 2⁄3; broad and obtusely prominent proximally beneath, narrower and smooth or even a little impressed distally; lateral veins 3–4 per side, arising at 45° and curving upwards, smooth and mostly inconspicuous. Petiole 1–2 x 1–2mm, flat and grooved above, laxly short-hairy and scaly, sometimes hardly distinct from the blade. Flower buds to 9 x 5mm, ellipsoid to somewhat obovoid, pale brown and often flushed with pink or red. Bracts fully appressed, minutely appressed hairy outside and with a few scales near the apex, fringed with scales along the margins, outermost bracts minutely appressed hairy inside also, but the inner bracts glabrous inside. Outermost bracts triangular, passing through ovoid to the innermost which are spathulate with the marginal scales on long stalks. Bracteoles to 10mm, filiform, sparsely scaly. Inflorescence solitary or occasionally paired flowers, which are half-hanging to fully pendent. Pedicels 10–15 x c.1mm, pink, densely short-hairy and stellately scaly. Calyx c.2.5mm in diameter, obliquely cup-shaped, shortly obtusely 5-lobed, scaly and with a few simple white hairs. Corolla 20–22 x 15–19mm, broadly tubular or tubular campanulate, deep pink or red; tube 16–18 x 11–12 x 6–7mm, straight, pouched at the base and with some faint longitudinal lines, sparsely scaly and hairy outside, glabrous inside; lobes 4–5 x 8–9mm, broadly obovate, overlapping to 2⁄3, reflexed and becoming revolute. Stamens at first tightly clustered in the centre of the mouth, later spreading regularly around the perimeter; filaments pale pink, dimorphic alternately long and short, white-hairy throughout; anthers c.2 x 1mm, brown, hairy at the back. Disc low, glabrous. Ovary 3–4 x 2–2.5mm, ovoid-conical, silvery scaly and densely covered in semi-erect white hairs; style straight, 3–8mm, pale green or pink, glabrous or with a few hairs at the base; stigma green. Fruit 10–18 x c.4mm, sub-cylindrical, pink or green, hairy and scaly, shedding an outer layer and the valves then splitting and curving back, sometimes twisting, the placentae tending to break away distally in an irregular manner. Seeds 3.5mm, without tails c.1mm, the longest tail to 2mm.
Habitat: Epiphytic or terrestrial in mossy forest and on peaty soil, often common
Distribution: Malaysia (Peninsula), Main Range from Mt Kerbau to Mt Batu Puteh and also on Mt Tahan.
Altitude: 1370-2135m
Latin – pauci – few; florum – flowers. ‘With few flowers’, presumably alluding to the solitary or 2-flowered inflorescences.
Type: Wray 231, 1887. Malay Peninsula, Perak, G. Batu Puteh (CAL).
Synonymy: R. elegans Ridl., J. Linn. Soc. Bot. 1908. 38: 314. R. calocodon Ridl., J. Fed. Mal. St. Mus. 1914. 5: 38. R. pauciflorum var. calocodon (Ridl.) Sleumer, Reinwardtia 1960. 5: 156.
Occurs in Countries: MY Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: pink, red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:192
Prostrate to erect dwarf shrubs. Young growth lepidote and pubescent. Leaves obovate or obovate-elliptic, rounded to the apex, cuneate at the base, 17-26 X (6—)8—13 mm, upper surface ± persistently lepidote, margin revolute, lower surface with rather dense, unequal scales, the larger with somewhat undulate rims, c. 2 x the smaller, all golden when young, often becoming dark brown. Inflorescence 1-2-flowered, pedicels 9-18 mm in flower, up to 25 mm in fruit, lepidote. Calyx lobes oblong, rounded, 2-5-4 mm, lepidote, reddish. Corolla pink to pale purplish mauve, 24-30 mm, tube 13-18 mm, densely pilose and sparsely lepidote outside. Stamens 10, filaments pubescent towards the base. Ovary lepidote, sometimes pubescent towards the apex, style impressed, exceeding the stamens, pubescent, lepidote or glabrous at the base. Capsule lepidote, c. 9 mm.
Habitat: Cliffs and ledges
Distribution: India (Arunachal Pradesh), China (SE Xizang)
Altitude: 2900-3050m
Illustrations:
I can find no distinction, other than flower colour, between R. pemakoense from the Tsangpo gorge (corolla pink) and R. patulum from the Delei valley, some 190 km to the south east (corolla pale purplish mauve)
Type: China, S Tibet, Pemakochung, Tsangpo gorge, 21 xi 1924, 10000 ft, Kingdon Ward 6301 (holo. K, iso. E)
Synonymy: R. patulum Kingdon Ward, loc. cit. Type: Tibet/Assam frontier, Mishmi Hills, Delei valley, 30 v 1928, Kingdon Ward 8260 (holo. K, iso. E)
Occurs in Countries: CN, IN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: mauve
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):121
Straggling epiphytic shrub, 0-3-1.3 m. Indumentum whitish to beige. Leaves 34-50 x 14-25 mm, oblong-elliptic, obtuse at the apex, upper surface smooth, shining, glabrous and elepidote. Inflorescences 2-3-flowered, pedicels densely tomentose. Calyx 5-lobed, lobes oblong or oblong-obovate, long ciliate, the outer surface sparsely to densely tomentose and with a few reddish scales. Corolla white, white flushed pink, or cream, openly funnel-campanulate, ± actinomorphic, 15-22 mm, tube 7-10 mm, lepidote outside, ± glabrous within. Stamens 10, ± actinomophic, filaments pilose in the lower part. Ovary 5-locular, lepidote and densely tomentose, especially towards the apex. Style sharply deflexed, shorter than the stamens, usually with a few hairs and scales at the base. Capsule ± oblong, c. 12 mm.
Habitat: In dense forest
Distribution: Nepal, India (Sikkim), Bhutan, China (S Xizang)
Altitude: 2270-3630m
Illustrations:
Type: Sikkim Himalaya, 9000-11000 ft, Hooker (holo. K)
Occurs in Countries: BT, CN, IN, NP Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: cream, pink, white
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):27
Shrub or small tree to 4(-8)m tall; young twigs reddish brown, glabrous to sparsely covered with multicellular eglandular or gland-headed hairs; bark pale grey-brown, vertically furrowed; new foliage shoots arising from axillary buds associated with foliage leaves of terminal cluster of the previous year's shoot (i.e. just below terminal bud), and from some terminal buds. Vegetative bud scales glabrous abaxially, sparsely unicellular-pubescent adaxially; margin fringed with unicellular hairs, usually with multicellular glandular hairs intermixed, especially just below apical region; lowermost scales with apices similar to those of upper scales, not long aristate. Leaves deciduous, lustrous green adaxially, light green abaxially, often with red-tinged margins on young plants, turning orange to red in autumn, pseudo-verticillate, with (4-5(~7) leaves clustered at apex of shoot. Blade chartaceous, elliptic to obovate, 2.1-6.3 x 1.1-3.8cm; base cuneate to attenuate; apex shortly acuminate to acute or obtuse, with a short mucro; midvein moderately to strongly raised abaxially, secondary, tertiary, and higher order veins slightly raised and forming a clearly visible reticulum; adaxial surface glabrous to sparsely covered with multicellular eglandular hairs, the midvein ± densely covered with unicellular hairs, often with a few multicellular eglandular hairs; abaxial surface glabrous to very sparsely unicellular-pubescent near base of blade, the lateral surface of midvein sparsely to densely covered with long, ± straight to crisped, unicellular hairs toward base, often with scattered multicellular eglandular and gland-headed hairs, the secondary veins glabrous, to sparsely unicellular-pubescent at base of blade; margin serrulate, with fringe of long, multicellular eglandular hairs; petiole 2.5-8mm long, sparsely unicellular-pubescent adaxially and these hairs associated with very long, multicellular eglandular hairs, often also a few gland-headed hairs, the base of petiole slightly expanded at point of attachment. Flower bud scales larger, but otherwise similar to those of vegetative buds. Flowers appearing before, or rarely with, the leaves; inflorescence a reduced raceme of 1 or 2 flowers. Pedicels 6-16mm long, glabrous or moderately covered with multicellular gland-headed hairs. Calyx lobes broadly to narrowly triangular to ovate, 0.5-5 x 1.2-1.6mm; apex attenuate, acuminate, or acute, to rounded; margin entire to slightly erose, glabrous to fringed with unicellular hairs, the hairs often irregularly spaced or limited to tuft(s) at apex; adaxial surface glabrous; abaxial surface glabrous. Corolla pink to deep rose, with red-brown spots on upper three lobes or limited to upper lobe, occasionally spots lacking, fragrant, zygomorphic, rotate-campanulate, the tube much shorter than the limb and gradually expanding into it; corolla lobes all±sfmilar, 1.2-2.6 x 1.1-2.5cm; corolla tube 0.4~lcm long; outer surface of corolla glabrous; inner surface of corolla very sparsely unicellular-pubescent towards base. Stamens 10, declinate, variable in length, 0.8~-2.5cm long, included; filaments glabrous throughout to very sparsely to densely covered with flattened unicellular hairs proximally, the shorter filaments tending to be more pubescent than the longer ones. Ovary 3.5-4.5mm long, glabrous; style deciinate, 2.2-2.8cm long, glabrous. Capsules ovoid, 1.2-2x0.5-0.8cm, glabrous. Seeds shiny and dark to light chestnut-brown, angular ovoid to ellipsoid, 2-3.5 x 1-1.5mm; testa tightly appressed to body, tails lacking, the cells elongate. Cotyledons with multicellular gland-headed hairs along margin and well-developed reticulate venation.
Habitat: In deciduous and coniferous forests and thickets
Distribution: Japan (Honshu, Shikoku, Kyushu)
Altitude: 500-1700m
Illustrations:
Plants with glandular-pubescent pedicels and those with glabrous pedicels can occur together, and bloom at the same time. However, these characters do not show correlation with other morphological features or geography. Thus, the recognition of three varieties within R. pentaphyllum, as was done by Komatsu (1916), Ohwi (1965), and Yamazaki (1988), cannot be justified.
Rhododendron pentaphyllum is most closely related to R. schlippenbachii and R. quinquefolium, especially the latter; see key and discussion following descriptions of these species for distinguishing characters. The Philipsons (M. Philipson, 1980; W. Philipson, 1980) were the first to recognize the close affinity of R. pentaphyllum to R. quinquefolium, although the similarity of the two species was noted by Maximowicz (1887). Rhododendron pentaphyllum is easily distinguished from R. quinquefolium by its flowers that usually bloom before the leaves (vs. with leaves), pink (vs. white) corolla, and vegetative shoots arising from axillary buds associated with foliage leaves (see key). In addition, the leaves and petiole margins of R. pentaphyllum have a conspicuous fringe of multicellular eglandular hairs, and the bark is thin.
The species has potential as an ornamental (Wilson, 1921)
Synonymy: Azaleapentaphylla (Maxim.) Copeland, Am. Midi. Nat. 30: 595 (1943). Type: Japan, Kyushiu, prov. Osumi, summit, Mt Taka-kuma, Tashiro (holo. LE, n.v.). Rhododendron pentaphyllum Maxim, var. nikoense Komatsu, Icon. PI. Koisikav. 3: 45, t. 168 (1916). Rhododendron nikoense (Komatsu) Nakai in Nakai & Koidz., Trees and Shrubs Japan 1: 68 (1922). Type: Japan, central mountains (n.v.). Rhododendron quinquefolium Bisset & S. Moore var. roseum Rehder in Bailey, Stand. Cycl. Hort. 5: 2947 (1916). Type: n.v. Rhododendron pentaphyllum Maxim, var. shihohanum T. Yamazaki, J. Jap. Bot. 63: 312 (1988). Type: Japan, Shikoku, pref. Kochi, Agawagun Nanokawa, 21 iv 1890, K Watanabe s.n. (holo. TI, n.v.).
Occurs in Countries: JP Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Pentanthera Habit: Tree Fl. Colour: red, rose
Judd, W.S. & Kron, K.A. (1995) A Revision of Rhododendron VI. Subgenus Pentanthera (Sections Sciadorhodion, Rhodora and Viscidula). Edinburgh Journal of Botany 52(1):19
Small shrub, occasionally up to 1.8m. Twigs slender, rounded, warty with the dense covering of stalked scales in the youngest parts, later rough with these persistent scale stalks. Leaves 3–7 together in pseudowhorls. Blade 13–20 x 5–10mm, obovate to spathulate; apex rounded-obtuse, sometimes minutely retuse; margin entire, strongly recurved; base narrowly tapering; silvery scaly at first above later glabrescent, laxly to sub-densely and more persistently brown scaly beneath. Scales sparsely distributed, sessile, circular, entire or undulate with a narrow to quite broad marginal zone, and thick somewhat impressed centre, sometimes with two concentric rings and a small brown centre. Mid-vein strongly impressed above, sometimes with a few white hairs proximally in the groove, thick and prominent beneath; lateral veins 2–3 per side, spreading, slightly impressed above, and slightly raised beneath, reticulation obscure. Petiole 2–3 x 1–1.5mm, grooved above, yellow, scaly and very shortly hairy. Flower buds to 9 x 5mm, obovate with obtuse to rounded apices, smooth, the bract tips appressed. Outer bracts shortly subulate, scaly outside, glabrous inside, the inner ones to 6 x 3mm, ovate, obtuse often mucronate, scaly at the top outside, densely white-ciliate on the margins. Bracteoles to 6.5mm, filiform, glabrous except for one or two scales near the apex. Inflorescence an open umbel with 3–5 flowers per umbel (up to 7 in cultivation), the flowers held more or less horizontally. Pedicels 5–7 x 0.75mm, green, densely covered with stalked scales, without hairs. Calyx minute, shortly obtusely 5-lobed, sometimes with one or two longer, acute lobes, to 3mm, densely scaly. Corolla 8–10 x 4–7mm, white? or bright yellow; tube 5.5–6.5 x 3–3.5 x 4.5–5.5mm, straight, cylindrical, or widening slightly distally, moderately silvery or translucent-scaly outside, glabrous inside; lobes 2.2–2.5 x c.3mm, held stiffly erect, or only very slightly spreading, overlapping up to ¾, retuse, with some silvery, translucent scales outside except near the margins. Stamens irregularly clustered centrally in the mouth of the flower; filaments linear, yellow, slightly broadened towards the base, glabrous; anthers c.0.6 x 0.5mm, brown, strongly inwardly curved. Disc glabrous. Ovary conical, c.2mm, densely scaly; style 3–4mm, green, glabrous; stigma rounded. Fruit 8–11 x 3–4mm, sub-cylindrical, yellow, deeply 5-furrowed longitudinally, scaly; valves curving outwards, straight or a little twisted, placentae remaining coherent with the central column. Seeds 1.8–2.3mm, without tails 0.7–1mm, the longest tail 1mm, the tails distinctly broad and often with more than one point.
Habitat: In mossy summit forest, usually epiphytic, locally common
Distribution: Malaysia (W), Pahang, Cameron Highlands, Mt Brinchang.
Altitude: Around 1830m
Named after the state of Perak in Malaysia.
Type: Wray 1574. Malay Peninsula, Pahang, Cameron Highlands, G. B(e)rumbun (CAL).
Occurs in Countries: MY Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: white, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:40
Shrub or small tree to 5m tall, usually non-rhizomatous; young twigs red-brown, sparsely covered with multicellular eglandular hairs, occasionally also sparsely to densely covered with unicellular hairs, or glabrous, rarely sparsely covered with only unicellular hairs. Vegetative bud scales glabrous, or rarely sparsely covered with unicellular hairs abaxially; margin unicellular-ciliate. Leaf blade membranaceous, ovate or obovate to elliptic, (5.2-)5.9-8.2(-10.9) x (1.4-)1.8-2.9 (-3.4)cm wide; base acute to oblique; apex acute to obtuse, often mucronate; adaxial surface sparsely covered with multicellular eglandular hairs, or glabrous, occasionally sparsely covered with unicellular hairs and multicellular eglandular hairs, rarely sparsely covered with only unicellular hairs, the midvein sparsely to densely covered with unicellular hairs; abaxial surface glabrous or sparsely to densely covered with unicellular hairs, rarely sparsely covered with only multicellular eglandular hairs, the midvein sparsely to densely covered with unicellular hairs and multicellular eglandular hairs, occasionally only with multicellular eglandular hairs; margin entire, ciMate with multicellular eglandular hairs, these usually somewhat more conspicuous than in Rhododendron canescens where the hairs are appressed to the margin of the leaf; petiole 0.2-0.5(-0.6)cm long, sparsely to densely covered with unicellular hairs and multicellular eglandular hairs, the unicellular hairs sometimes restricted to the adaxial groove, rarely sparsely covered with only multicellular eglandular hairs. Flower bud scales chestnut brown; abaxial surface glabrous, occasionally sparsely to densely covered with unicellular hairs; margin unicel-lular-ciliate, rarely also glandular. Flowers appearing before or with the leaves; inflorescence a shortened raceme of 6 to 15 flowers. Pedicels (0.4-)0.6-1.2(-1.9)cm long, sparsely covered with unicellular hairs and sparsely to densely covered with multicellular eglandular hairs, often lacking unicellular hairs. Sepals less than 0.1-0.2(-0.4)cm long, often varying in length on the same flower; margins setose, very rarely also with multicellular gland-tipped hairs; abaxial surface sparsely to densely covered with unicellular hairs and multicellular eglandular hairs, or with only multicellular eglandular hairs, rarely with unicellular hairs and multicellular eglandular and gland-tipped hairs, glabrous, or only with unicellular hairs or multicellular gland-tipped hairs. Corolla deep pink, the tube darker pink or crimson, occasionally pink to rose pink throughout, rarely white or pale pink, fragrance sweet, the tube longer than the Emb and gradually expanding into it; upper corolla lobe (0.6-)1.0-1.4(-1.6) x (0.4-)0.7-1.2(-1.4)cm; lateral lobes (0.9-)1.2-1.8(-2.5) x (0.4-)0.5-0.9(-1.4)cm; corolla tube (1.2-) 1.3-1.8(-2.2)cm long, (0.1-)0.2-0.3(-0.5)cm wide at base; outer surface of corolla sparsely to densely covered with unicellular hairs and multicellular eglandular hairs, or multicellular gland-tipped hairs, rarely covered with all three types of hairs, or with only multicellular eglandular hairs, the multicellular hairs often continuing up the corolla lobes; inner surface of corolla sparsely to densely covered with unicellular hairs. Stamens (3.2-)4.0-5.6(-6.8)cm long, with dense terete or flattened unicellular hairs on proximal (1.4-) 1.9-2.6(-3. l)cm of filament, exserted (1.9-)2.4-3.8(-5.0)cm beyond throat of corolla. Style (2.2-)4.2-5.9(-7.2)cm long, exserted (1.6-)3.0-4.5(-5.0)cm beyond throat of corolla, with dense unicellular hairs on proximal (0.0-)0.7-2.0(-3.5)cm; stigma (less than 0.1-)0.1-0.2cm wide. Ovary (Q.2-)Q.3-0.5(-0.6)cm long, 0.1-0.2(-0.4)cm wide at the base, densely covered with multicellular eglandular hairs and unicellular hairs, rarely with multicellular gland-tipped hairs and unicellular hairs. Capsules (1.2-)1.5-2.3(-2.5) x 0.3-0.5(-0.6)cm, narrowly ovate to cylind-ric, sparsely covered with unicellular hairs and sparsely to moderately covered with multicellular eglandular hairs. Seeds pale to dark chestnut brown, ovate or elliptic to fusiform, (1.0-)1.6-2.8 (-3.6) x 0.4-1,2(-1.3)mm, body (0.6-)0.8-1.3(-1.6)mm, (0.1-)0.2-0.5(-0.6)mm; testa rather closely fitted around the body of the seed, the cells short, with transverse end-walls, or isodiametric.
Habitat: Upland woods, bluffs and stream banks, ridge-tops, sandy open woods.
Distribution: USA: Vermont, Massachusetts and New York, south and west to western Tennessee and east to the northern Atlantic Coastal Plain, south to South Carolina. Outlying populations in Tuscaloosa, Shelby and Clarke counties, Alabama and as far south as Clay and Dougherty counties, Georgia.
Altitude: 100-1000m
The name R. periclymenoides is the correct one for this species. The commonly used R. nudiflorum is incorrect because the name was superfluous when published (see also Shinners, 1962 and Wilbur, 1976). The epithet 'luteum' cannot be used since C. K. Schneider's transfer to Rhododendron is a later homonym of R. luteum Sweet (see synonymy).
This species most closely resembles R. canescens, from which it can be distinguished by its more glabrous leaves and bud scales and by the more gradually expanding corolla tube (see R. canescens for more detailed discussion). In addition, R. periclymenoides usually has corolla tubes that are covered with multicellular eglandular hairs. However, glandular corolla tubes do occur scattered throughout the geographic range of this species. In most cases, the glandular corolla tube is probably not the result of hybridization with R. canescens, since glandular forms of R. periclymenoides occur in populations which are isolated geographically from R. canescens (see Appendix for citation of putative R. canescens x R. periclymenoides hybrid).
Flowering from March to June.
Chromosome number: In = 26 (Janaki-Ammal et al., 1950; Li, 1957)
Synonymy: Azalea periclymenoides Michaux, Fl. Bor.-Amer. 1: 150 (1803). A. periclymena Persoon, Synop. Plant. 1: 213 (1805). A. nudiflora (L.) var. periclymenoides (Michx.) Heynhold, Nomen. Bot. 1:108 (1840). Type: inNew Jersey. A. Michauxs.n. (lecto., designated here, P-MICHX; IDC #6411,36:11.2). Azalea lutea L., Sp. PL ed. 1, 1: 150 (1753). Rhododendron luteum (L.) C. K. Schneider, Handb. Laubholsk. 2: 500 (1911), non R. luteum Sweet, Hort. Brit. ed. 2, 343 (1830). Type: 215.2 K[alm], (lecto. LINN; IDC 118:111.2). Azalea nudiflora L., Sp. PL ed. 2,1: 214 (1762), nom. illeg. Rhododendron nudiflorum (L.) Torr., FL N. Middle United States 1: 424 (1824), nom. illeg. Type: as for A. lutea L. Rhododendron periclymenoides (Michx.) Shinners f. eglandulosum Seymour, FL New England 429 (1969). Type: as for A lutea L. Azalea nudiflora L. var. alba Aiton, Hort. Kew. 1: 203 (1789). A. periclymenoides Michx. var. alba Pursh, FL Am. Septentr. 1: 152 (1814). Rhododendron nudiflorum (L.) Torr. var. album (Pursh) C. Mohr, PL Life Ala. 653 (1901). Rhododendron nudiflorum f. album Rehder, Monogr. Azaleas 137 (1921). Type: n.v. Azalea nudiflora L. var. carnea Aiton, Hort. Kew. 1:203 (1789). A. periclymenoides (Michx.) var. carnea Pursh, FL Am. Septentr. 1: 152 (1814). Type: n.v. Azalea nudiflora L. var. papilionacea Aiton, Hort. Kew. 1: 203 (1789). A. periclymenoides (Michx.) var. papilionacea (Aiton) Pursh, FL Am. Septentr. 1: 152 (1814). Rhododendron nudiflorum (L.) Torr. var. papilionaceum (Aiton) Zabel, in Beissner, Schelle & Zabel, Handb. Laubholsk. 380 (1903). Type: n.v. Azalea nudiflora L. var.partita Aiton, Hort. Kew. 1:202 (1789). A. periclymenoides (Michx.) var. partita (Aiton) Pursh, FL Am. Septentr. 1: 152 (1814). Type: n.v. Azalea nudiflora L. var. rutilans Aiton, Hort. Kew. 1: 203 (1789). A. periclymenoides (Michx.) var. rutilans (Aiton) Pursh, FL Am. Septentr. 1: 152 (1814). Type: n.v. Azalea periclymenoides Michaux var. polyandra Pursh, Fl. Am. Septentr. 1: 152 (1814). Rhododendron nudiflorum (L.) Torr. vm.polyandrum (Pursh) G. Don, Gen. Syst. 3: 847 (1834). Azalea nudiflora var. polyandra (Pursh) DC, Prodr. 7: 717 (1839). Type: n.v. Azalea nudiflora var. rosea Hoffmannsegg, Verz. der Pflanz. Kult. 3rd sap. 23 (1826). Type: n.v. Azalea nudiflora var. calycosa Wood, Class Book Bot. 490 (1872). Type: n.v. Azalea nudiflora L. var. glandifera Porter, Bull. Torrey Bot. Club 27: 508 (1900). Rhododendron nudiflorum (L.) Ton*, var. glandiferum (Porter) Rehder, Monogr. Azaleas 138 (1921). R. nudiflorum (L.) Torr. f. glandiferum (Porter) Fern., Rhodora43:619 (1941). Azalea periclymenoides f. glandifera (Porter) Uttal, in Sida 3: 169 (1988). Type: (Syntypes probably at PH, n.v.).
Occurs in Countries: US Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Pentanthera Habit: Tree Fl. Colour: crimson, pink, rose, white
Kron, K.A. (1993) A Revision of Rhododendron Section Pentanthera. Edinburgh Journal of Botany 50(3):319
Shrub. Twigs c.4mm in diameter, rounded, red-brown, glabrous; the one known (upper) internode 10cm. Leaves 4 in a pseudowhorl. Blade 85–135 x 40–55mm, ovate to elliptic-ovate, gradually acuminate towards the sub-acute apex; margin a little revolute; base rounded to slightly cordate, or unequal, glabrescent above; sub-densely scaly beneath. Scales minute, irregularly sub-stellately lobed in the marginal zone; centre darker, slightly impressed. Mid-vein thick, striate lengthwise, a continuation of the thick petiole, obtusely and very prominent in the proximal part above, broad and flat beneath; lateral veins 12–15 per side, at an angle of nearly 90°, parallel, obscurely arching inwards before the margin, slightly impressed above, hardly raised beneath, reticulation lax, obscure on both sides. Petiole 4–6 x c.3mm, slightly flattened and grooved above, initially scaly. Inflorescence 9-flowered. Pedicels 20–27mm, strong, laxly or very laxly scaly, more densely so just below the calyx, not hairy. Calyx 4–5mm in diameter, disc-shaped, obscurely lobed or crenate, thick, glabrous. Corolla 25–27mm, funnel-shaped; tube 10–13 x c.5 x c.10mm, glabrous outside, densely shortly grey-hairy for the proximal 2⁄3 inside; lobes 13–15 x 10–13mm, elliptic-obovate. Stamens sub-equal, nearly as long as the corolla; filaments linear and densely sub-patently white-hairy in the proximal ½, filiform and glabrous distally; anthers 3.5 x 1.3mm, broad-oblong. Disc prominent, glabrous. Ovary 5–6 x c.2mm, sub-cylindrical, glabrous, tapering distally; style columnar, glabrous, c.6mm; stigma knob-like.
Habitat: Probably epiphytic
Distribution: Indonesia, Sumatra, West Coast, Kerintji.
Altitude: Around 1000m
Latin – perplexus – confused, intricate or obscure, alluding to the uncertain nature of this species.
Known only from the type collection.
Similar to the Bornean R. crassifolium differing chiefly in the petiole length which is not the good distinction implied by Sleumer (1966), since subsequent field work in Borneo has shown R. crassifolium can have a petiole almost as short. Further collections are needed to clarify the position of this species which could possibly be a hybrid with R. sessilifolium as one of the parents.
Type: Ultée 108, no date. Sumatra, W coast, Kerintji, c.1000m (BO).
Occurs in Countries: ID Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:251
Very similar to R. dendrocharis but the shoots more persistently loriform-setose, and the corolla white, less densely hairy within.
Habitat: Rocks and slopes
Distribution: China. (C Sichuan)
Altitude: 1800-2300m
The three species (R. moupinense, R. dendrocharis and R. petrocharis) are all very similar, and are all found in one relatively small area. It is likely that population studies would suggest a rather different treatment, probably recognising only one species. One specimen (Wang 22890) from Ma-pien-hsien, appears intermediate between moupinense and either dendrocharis or petrocharis, having vegetative features of the latter two and at least one large flower (c. 30 mm) with an elongated, exserted style and very unequal stamens; an undissected flower on the sheet is considerably smaller (22 mm), and the style is not clearly exserted. It is impossible to tell the colour of the flowers in this specimen. A further specimen from Guizhou, Fan ching shan, Lao shan near Ching huang tung, 2200 m, 1931, Steward, Chiao & Cheo 492, is very similar to R. moupinense, but has a less open flower and the style is lepidote for some distance above the base: this may be another related species, geographically separated from the rest of the subsection, but the one specimen available is poor and not fit for description.
Type: China, Sze'tschwan, Wen tschuan hsien, in valle Scha pe infra Tschin wei, in rupibus, 1800 m, 26 iv 1914, Limpricht (fragment E)
Occurs in Countries: CN Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Rhododendron Habit: Non-Tree
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):59
Shrub, c.1m. Twigs c.2mm in diameter, slender, densely dark brown stellate-scaly at first, glabrescent and rough later; internodes 3–8cm. Leaves 3–4 together in pseudowhorls or more loosely crowded in tight spirals. Blade 40–100 x 25–55mm, elliptic or mostly obovate-elliptic; apex rounded, obtuse often apiculate; margin entire, slightly revolute; base broadly tapering or rounded; initially covered with a dense, dark reddish brown covering, of stellate scales on both sides, becoming smooth above but remaining scaly for a longer time beneath, ultimately glabrescent there also, but remaining distinctly rough to the touch. Scales small, deeply divided, sub-sessile but each on top of a minute epidermal tubercle, very fragile. Mid-vein slightly impressed above, thick and prominent beneath; lateral veins 5–7 per side, straight below, irregularly curved-ascending and anastomosing in the upper part, faintly prominent when young, a little impressed above in fully mature leaves, prominent beneath, reticulation dense and conspicuous, visible on both sides. Petiole 5–8 x 1–1.5mm, not or only weakly and obscurely grooved, densely brown, stellately scaly. Flower buds to 25 x 13mm, ovoid to ovoid-cylindrical, acutely to obtusely pointed, smooth with all the bracts tightly appressed, predominantly green and glabrous except for the marginal fringes of brown stellate scales. Bracts to 15 x 8mm, ovate to obovate-spathulate, the basal triangular and brown scaly outside, upper ones obtuse, glabrous except for the marginal scales. Bracteoles to 15 x 1mm, linear-spathulate, sub-glabrous. Inflorescence of 2–5 flowers in one-sided umbels, hanging to half-hanging. Pedicels 14–25 x c.2mm, densely stellately scaly (sometimes apparently with hairs as the scales can be very pale), green. Calyx c.3mm in diameter, reduced to an almost circular disc, which may be irregularly dentate, densely stellate-scaly. Corolla tubular below, expanded distally, zygomorphic, pink to deep red, or cream; tube 30–40 x 5–8 x 10–16mm, curved, brown scaly outside, shortly patently white hairy inside; lobes 16 x 13mm, scaly outside except near the margins, gradually reflexed so that the tips are almost perpendicular, overlapping c.halfway. Stamens exserted to c.20mm, clustered together on the upper side of the flower, slightly unequal; filaments dark red, sparsely to densely, patently hairy in the proximal 1⁄3–½; anthers 2.5–3 x c.1mm, purple, oblong. Disc densely white-hairy at the upper margin. Ovary 5–7 x 2–3mm, cylindrical, densely and exclusively pale brown-stellate-scaly, tapering distally; style on the upper side of the corolla tube, pale brown-stellately scaly and sometimes very laxly hairy at least in its proximal ½, often to nearly the top, glabrous near the tip; stigma broadly obconical-globose, dark purple, at first below the mouth of the flower, becoming exserted, often beyond the anthers.
Habitat: Epiphytic or terrestrial on ridges (including limestone ridges)
Distribution: Papua New Guinea, West Sepik District, above Telefomin; Western Highlands, Nondugl; Southern Highlands; Enga Province; Simbu (Chimbu) District; Eastern Highlands District, Goroka region; Central District, Mt Musgrave. Indonesia, New Guinea (W), recorded from around Wamena.
Altitude: 2135-2560m
Greek – phaios – dark or dusky; chiton – a tunic. Alluding to the dense brown covering of scales.
The species is still not clearly distinguishable from R. beyerinckianum although as understood here R. phaeochitum has larger flatter leaves as well as hairy filaments and disc.
Type: MacGregor s.n., 1889. New Guinea, SE, Milne Bay District, Mt Musgrave (MEL, L, fragment).
Occurs in Countries: ID, PG Altitude Ranges: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: brown, cream, pink, purple, red, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:93
Shrub to 4m. Twigs slender, the tips with a dense brown covering of stellate scales; internodes 2–10cm. Leaves 4–6 together in pseudowhorls. Blade 30–80 x 20–40mm, elliptic to obovate-broadly elliptic; apex obtuse or sub-acuminate; margin slightly revolute at the very edge; base tapering; covered with fragile brown stellate scales initially, early glabrescent with age above, less so below especially on the veins. Scales dendroid, with a deeply stellately divided marginal zone, depressed towards the minute centre, which is prolonged downwards into a very slender stem, which rests on a distinct epidermal tubercle. Mid-vein narrowly impressed above, thickly prominent proximally below, less so distally; lateral veins 6–9 per side, irregular, curved-anastomosing before the margin, very slightly impressed or often obscure above, hardly prominent beneath. Petiole 8–14 x 1.5–2mm, densely scaly initially. Flower buds sub-globose, 10–15mm in diameter. Bracts to 12mm, thin, the outer ones ovate, densely stellate-scaly at the midline outside and with a fragile scaly fringe; inner ones sub-spathulate, glabrous. Bracteoles c.10 x 1–1.5mm, sub-spathulate-linear, glabrous. Inflorescence of 2–4-flowered open umbels. Pedicels c.10mm, slender, densely stellately scaly. Calyx c.2.5mm in diameter, obliquely rimmed, minutely 5-lobed, scaly outside. Corolla 30–40mm, tubular, curved, expanded at the lobes, zygomorphic, pale to deep red; tube 15–20 x 3 x 5mm, glossy and densely covered with golden scales outside, laxly hairy inside; lobes c.10 x 8mm, sub-spathulate-obovate. Stamens slightly exserted; filaments linear, densely to laxly hairy in the proximal ¾, glabrous distally; anthers c.2 x 1mm, obovate-oblong, dark purple to almost black, the base obtuse. Disc prominently hairy only on the upper margin. Ovary 5 x 2.5mm, sub-cylindrical, densely covered with brown stellate scales and paler, appressed hairs, tapering distally; style c.12mm, slightly hairy at the base, glabrous distally; stigma club-shaped. Fruit 20–25 x 4–5mm, fusiform, densely scaly and hairy.
Habitat: In understory of Nothofagus forest
Distribution: Indonesia, New Guinea (W), Vogelkop Peninsula, Tamrau, Nettoti and Arfak Mts. Common in the Arfak Mountains around the Anggi Lakes
Altitude: 1800-2550m
Greek – phaeo – dusky; christum – like christi. A phaeovireya with similarities to R. christi.
A natural hybrid of R. phaeochristum apparently with R. culminicola var. angiense was found once in the Arfak Mts near Lake Anggi Gita at 1900m. In general appearance, the stellate scales and in the flowers it displays characters of R. phaeochristum, but in the wider, more obovate and blunt leaves, with a less dense covering of stellate scales and no trace of epidermal tubercles, it has the characters of R. culminicola var. angiense.
Type: Sleumer & Vink 4465, 26 Jan. 1962. New Guinea, (NW), Anggi Gigi Lake (L, A, CANB, G, K, LAE, UC).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:94
Shrub, 1.2-4.5m. Leaves elliptic to ovate-oblong, 4-14.5 x 1-6.5cm, 1.7—3(—4) x as long as broad, apex acute to apiculate, base rounded to cordate, lower surface with a dense compacted or felted, sometimes agglutinated, brown indumentum composed of radiate to sub-ramiform hairs; petioles 1.5-2cm, floccose. Inflorescence 8-15-flowered; rhachis 10-15mm; pedicels 10—25mm, glabrescent. Calyx c. 1mm, usually glabrous. Corolla funnel-campanulate, white flushed pink, with crimson flecks, 20-50mm. Ovary glabrous or with a few papillate hairs, especially at apex; style glabrous. Capsule 13-20 x c.7mm.
Habitat: Open forests, stony pasture
Distribution: China (S Xizang, NW Yunnan, SW & C Sichuan)
Altitude: 3350-4200m
Var. levistratum in particular is also closely allied to both R. alutaceum (q.v.) and R. traillianum.
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: crimson, pink, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):350
Leaves 4-9cm, indumentum felted or agglutinated, sometimes splitting; corolla 20- 35mm. Indumentum agglutinated, sometimes splitting.
Closely resembling some forms of R. aganniphum but with a darker indumentum than var. aganniphum and a less patchy indumentum than var. flavorufum.
Synonymy: R. agglutinatum Balfour f. & Forrest, Notes R.B.G. Edinb. 12: 88 (1920). Type: China, SW Sichuan, mountains around Muli, 12-13000ft, vi 1918, Forrest 16319 (holo. E). R. lophophorum Balfour f. & Forrest, ibid. 11: 95 (1919). Type: China, NW Yunnan, mountains around Atuntze, vi 1917, Forrest 13971 (holo. E; iso. K). R. syncollum Balfour f. & Forrest, ibid. 11: 142 (1919). Type: China, NW Yunnan, mountains N of Atuntze, vi 1917, Forrest 14035 (holo. E). R. dumulosum Balfour f. & Forrest, ibid. 13: 41 (1920). Type: China, NW Yunnan, Mekong/Salween divide, 13000ft, vi 1917, Forrest 14088 (holo. E).
Leaves 4-9cm, indumentum felted or agglutinated, sometimes splitting; corolla 20- 35mm. Indumentum felted, not agglutinated, continuous.
The type of R. dryophyllum is closer to var. phaeochrysum than to var. levistratum. However, most of the remaining material, including most cultivated specimens, that have been assigned to R. dryophyllum, should be referred to var. levistratum.
Intermediates between R. phaeochrysum and both R. agganiphum and R. przewlaskii occur in N & C Sichuan; these probably come from introgressed populations.
Synonymy: R. levistratum Balfour f. & Forrest, Notes R.B.G. Edinb. 11: 88 (1919). Type: China, NW Yunnan, mountains of Atuntze, vi 1917, Forrest 14026 (holo. E; iso. K). R. dichropeplum Balfour f. & Forrest, ibid. 13: 40 (1920). Type: China, NW Yunnan, in the NE of the Yangtze Bend, 12000ft, vii 1913, Forrest 10612 (holo. E; iso. K). R. theiophyllum Balfour f. & Forrest, ibid. 13: 61 (1920). Type: China, SW Sichuan, Muli Mountains, vii 1918, Forrest 16836 (holo. E; iso. K). R. aiolopeplum Balfour f. & Forrest, ibid. 13: 262 (1922). Type: China, W NW Yunnan, E of Chungtien, 12000ft, vii 1918, Forrest 16467 (holo. E; iso. K). R. helvolum Balfour f. & Forrest, ibid. 13: 262 (1922). Type: China, W Yunnan, Mountains of Chungtien, 12-13000ft, vii 1918, Forrest 17784 (holo. E; iso. K). R. intortum Balfour f. & Forrest, ibid. 13: 269 (1922). Type: China, NW Yunnan, Mekong/Salween divide, v 1918, Forrest 16303 (holo. E; iso. K). R. sigillatum Balfour f. & Forrest, ibid. 13: 294 (1922). Type: China, NW Yunnan, Mekong/Salween divide, 12000ft, vii 1917, Forrest 14145 (holo. E; iso. K). R. vicinum Balfour f. & Forrest, ibid. 13: 305 (1922). Type: China, NW Yunnan, Bei-ma-shan, 12-13000ft, vi 1917, Forrest 14024, (holo. E; iso. K). R. dryophyllum sensu Cowan & Davidian, Rhododendron & Camellia Yearbook 10: 136 (1955) pro max. parte, excl. typ.
Leaves 8-14.5cm, indumentum felted, not splitting; corolla 32-50mm.
Illustrations:
Var. phaeochrysum intergrades with both vars. agglutinatum and levistratum. R. cupressens was differentiated on account of its pale leaf indumentum. It seems likely that introgressive hybridisation is taking place between R. phaeochrysum and R. aganniphum which may account for this pale indumentum.
Type: China, E NW Yunnan, mountains in the NW of the Yangtze Bend, 11 —12000ft, vii 1913, Forrest 10547 (holo. E; iso. K)
Synonymy: R. dryophyllum Balfour f. & Forrest, Notes R.B.G. Edinb. 11: 38 (1919). Type: China, NW Yunnan, Mekong/Salween divide, 11000ft, vii 1917, Forrest 14107 (holo. E; iso. K). R. cupressensNitzeXwis, ActaHortiGothob. 26: 117 (1963). Type: a plant cultivated in Gothenburg, fromTapanshan, Kangtingdistr. in Sichuan, 3 x 1934, H. Smith 13977 (holo. GB).
Shrub to 1m. Twigs 2–3mm in diameter, rounded, the tips stellate-scaly, later densely minutely warty and rough to the touch after the scales have gone; internodes 3–6cm. Leaves 3–4 together in pseudowhorls. Blade 50–80 x 30–50mm, broadly elliptic or ovate-elliptic; apex shortly tapering, obtuse; margin shortly revolute; base very broadly tapering to nearly rounded; stellate-scaly initially on both sides. Scales small, fragile, dendroid, each on top of a persistent epidermal tubercle, quickly becoming glabrescent but rough with the tubercles on both sides especially beneath. Mid-vein as thick as the petiole, above prominent and grooved along the midline in its proximal 2⁄3, impressed distally; lateral veins 6–8 per side, irregular, straight below, obscurely curved-anastomosing before the margin, very slightly impressed above, prominent beneath. Petiole 10–15 x c.2mm, grooved above, densely scaly. Inflorescence of 2–3 flowers. Pedicels 15–20 x c.1mm, densely brown-stellate-scaly. Calyx 5–6mm in diameter, disc-shaped, densely scaly, without hairs, with 5 distinct, irregular, elongate-triangular sub-acute teeth, which are white-ciliate and spreading to 2–4mm. Corolla 55–60mm, zygomorphic, tubular below, gradually widened upwards, red; tube c.50 x 6 x 15mm, curved, densely brown stellate-scaly outside, with white long retrorse hairs inside; lobes 15–20 x 12–15mm, broadly spathulate to sub-circular, scaly outside except near the margins, glabrous inside. Stamens unequal; filaments 45–55mm, linear, wider and densely patently hairy proximally, narrower and glabrescent to glabrous distally; anthers 5–5.5 x c.2mm, brown, broadly oblong. Disc glabrous. Ovary c.7 x 3mm, obconical-cylindrical, densely covered with sub-appressed, yellowish, stiff hairs which cover the scales, abruptly contracted distally; style thick, densely hairy and laxly scaly below, more laxly patently hairy but more densely scaly distally, glabrous at the upper 5mm below the globose stigma.
Habitat: Epiphytic in mossy forest
Distribution: Indonesia, New Guinea (W), Bernhard Camp, Idenburg R., c.139°E 3°30'S one collection
Altitude: Around 2150m
Greek – phae – dark; opsis – aspect. An allusion to its dark appearance.
Not reported since the original collection and never cultivated.
Type: Brass L.J. 12658, Feb. 1939. New Guinea (W), Northern part, 18km SW of Bernhard Camp, Idenburg R. (A, L).
Occurs in Countries: ID Altitude Ranges: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:94
Distribution: China (S Xizang)
Only known from the type. Closely allied to R. beanianum but with a very different leaf indumentum.
Type: China, Xizang, Dri La, Zayul, 1933, Kingdon-Ward 11040 (holo. BM)
Synonymy: R. beanianum Cowan var. compactum Cowan, Notes R.B.G. Edinb. 21: 148 (1953), type as above. Straggling shrub, 1.5—2.5m; young shoots tomentose. Leaves ovate to elliptic, 6-11 x 2.7-5.2cm, c.2.2 x as long as broad, apex rounded, apiculate, base rounded, upper surface glabrous when mature, rugulose, lower surface with a bistrate indumentum, the upper layer thick, fulvous and dendroid-tomentose, the lower white and adpressed; petioles l-2cm, tomentose. Inflorescence 6—8-flowered; rhachis c.5mm; pedicels 12-15mm, tomentose. Calyx 3-6mm, irregular, glabrous. Corolla fleshy, tubular-campanulate, crimson, with darker nectar pouches, 28—36mm. Ovary densely tomentose. Capsule 14—18 x c.4.5mm.
Occurs in Countries: CN Subgenus: Hymenanthes
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):387
Shrub or small tree, 4-8m. Leaves coriaceous, lanceolate to oblanceolate, 8-13.5 X 3-4.2cm, (2.5-)3.2-3.5 x as long as broad, apex rounded and apiculate to acute, upper surface glabrous, lower surface with a white compacted indumentum embedded in a surface film; petioles 1.5-2cm, glabrescent when mature. Inflorescence 8-20-flowered; rhachis 10—20mm; pedicels 30-40mm, floccose. Calyx 1—2mm, floccose, lobes minute. Corolla funnel-campanulate, pinkish to pale purple, 28-35mm. Ovary densely rufous-tomentose, eglandular; style glabrous. Capsule 15-30 x 3-4mm, curved.
Habitat: Forests, mountain slopes
Distribution: China (C Sichuan)
Altitude: 2000-2750m
Illustrations:
Closely allied to R. argyrophyllum but distinguished by the more intensely coloured corollas and the rufous-tomentose, eglandular ovary. Apart from subsp. nankingense, R. argyrophyllum generally has smaller leaves. However, a single specimen, McLaren AH 371, is intermediate, with the rufous-tomentose ovary of R. pingianum but small leaves more reminiscent of R. argyrophyllum subsp. argyrophyllum.
Type: China, Sichuan, Ma-pien-hsien, 2500m, 24-25 v 1930, Fang 432, fl. (holo. SZ; iso. E).
Occurs in Countries: CN Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: pink, purple
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):326
Shrub or tree, 2-8 m. Leaves thick, broadly elliptic, 7-11 x 5-7 cm, 1.4-1.7 x as long as broad, apex rounded, mucronate, base rounded, lower surface with minute punctulate hair-bases when mature, otherwise glabrous; petioles broad, up to 10 mm, winged, glabrous. Inflorescence c. 12-flowered; rhachis up to 45 mm; pedicels 20-25 mm, glabrous. Calyx c. 1 mm, with minute glabrous rounded lobes. Corolla 7-lobed, open-campanulate, entirely glabrous, pinkish-red, lacking markings, 35-45 mm. Stamens 14, filaments puberulent below. Ovary and entire style stipitate-glandular. Capsule not known.
Habitat: In thickets
Distribution: China (SE Sichuan, Guangxi)
Altitude: 1800-2100m
A distinctive species on account of its characteristic leaves and winged petioles; without close allies
Type: China, SE Sichuan, Nan ch'uan, Ken ao p'ing, Bock von Rosthorn 658 (photo. E).
Occurs in Countries: CN Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: pink
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):236
Shrub or tree to 6m. Twigs 5–7mm in diameter, rounded, tips laxly stellate-scaly; internodes 9–16cm. Leaves 5–7 together in tight pseudowhorls. Blade 65–140 x 40–90mm, elliptic or obovate-elliptic; apex rounded or obtuse; margin entire, flat; base slightly but distinctly cordate, glabrescent above at maturity, laxly scaly beneath. Scales stellate, the thin marginal zone quickly disappearing; centre small, slightly impressed, finally minutely impressed-spotted beneath. Mid-vein broad proximally, gradually narrowed upwards, impressed for the whole length above, thick and obtusely prominent beneath, 2–3mm wide at the base; lateral veins c.8 per side, irregular, spreading, divided and anastomosing before the margin, impressed above, prominent beneath, veins and veinlets forming an impressed lax reticulation above, which is weakly raised or obscure beneath. Petiole 2–6 x 2–3mm, flattened, glabrous. Outer bracts to 20 x 10mm, ovate, inner ones oblong-spathulate, obtuse, outside densely, coarsely hairy, inside more laxly hairy. Bracteoles c.20 x 2mm, linear-spathulate, densely short-hairy at the outside middle line. Inflorescence an 8–20-flowered open umbel, flowers horizontal to half-hanging. Pedicels c.20 x 1mm, densely scaly and very shortly hairy. Calyx c.4mm in diameter, disc-shaped, slightly oblique, sub-glabrous outside, shortly sub-acutely 5-lobed, or occasionally with irregular 2–9 x c.1mm long teeth, which are glabrous or very shortly hairy. Corolla 80–90 x 40–50mm, white, long-tubular below, expanded upwards, initially laxly scaly outside, the scales fragile and falling quickly, laxly hairy inside the tube, white or cream, suffused with pink distally or dark pink, scented; tube 55–70 x 4–5 x 7–9mm, straight; lobes c.20mm, obovate-spathulate. Stamens slightly longer than the corolla tube, unequal; filaments linear, in the lower ¾, sub-densely to more laxly hairy, distally glabrous; anthers 4.5–5 x 1–1.2mm, elongate-oblong, base obtuse, a little curved. Disc prominent, glabrous. Ovary c.8 x 2–2.5mm, elongate-cylindrical, gradually tapering distally, densely yellowish-hairy, laxly scaly although the scales are usually obscured by the hairs; style nearly as long as the corolla tube, for the proximal 10mm, sub-densely to laxly hairy and scaly (the scales clearly visible among the hairs), glabrous distally; stigma conical-globose. Fruit 50–80 x 7–8mm, elongate-fusiform, densely hairy and scaly.
Habitat: Terrestrial on margins of mossy forest-grassland, on ridge shrubberies and river banks, locally common.
Distribution: Papua New Guinea, Western, Eastern and Southern Highlands; Mts Hagen, Kerigomna, Wilhelm, Otto, Wamtakin, Giluwe and Kubor.
Altitude: 2680-3260m
Greek – pleio – more than usual; anthum – flower. Alluding to the many-flowered inflorescence.
Type: Robins 362, 9 July 1957. New Guinea (C), Western Highlands, Mt Hagen, c.3050m (CANB, L, LAE).
Occurs in Countries: PG Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Tree Fl. Colour: cream, pink, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:184
Shrub, 0.6-4 m. Young growth lepidote, not pruinose, puberulent. Leaves evergreen or subdeciduous, sometimes entirely deciduous, 35-60 (-73) x 13-23 mm, narrowly elliptic, acute at apex, cuneate at base, ± elepidote above, lepidote beneath with flat, yellow or brown scales 3-5 x their own diameter apart; petiole and lower surface pale green, not pruinose. Inflorescence loose, pedicels lepidote and sometimes puberulent, (8-)10-18 mm. Calyx minute, disc-like or undulate, sometimes ciliate. Corolla white, white flushed pink or lilac, often with yellow or red spots, (23-)25-32 mm, ± elepidote outside. Capsule 11-18 mm.
Habitat: Forest and forest margins, thickets, rarely on cliffs and in meadows, 2000-4500 m
Distribution: China (N & NW Yunnan, SW & NW Sichuan)
Very similar to R. yunnanense with which it vicariates to the north, but lacking the bristles on leaf margin and petiole. Also similar to R. rigidum from which it differs in its denser scales, puberulent petiole and midrib, and the absence of pruinose bloom.
Type: China, Yunnan, Salween/Mekong Divide, 10500 ft, 1918, Forrest 16357 (holo. E)
Synonymy: R. hormophorum Hort., pro parte.
Occurs in Countries: CN Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: lilac, pink, red, white, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):68
Shrub, 0.6—3m; young shoots densely stipitate-glandular. Leaves oblong to obovate, 8-15 x 3.2-5.2cm,2-3 x as long as broad, apex rounded, apiculate, base cuneate, glabrous above, with a thick continuous or patchy rufous dendroid tomentum beneath; petioles l-2cm, stout, stipitate-glandular and tomentose when young. Inflorescence dense, 10(—20)-flowered; rhachis c.5mm; pedicels 7— 18mm, stipitate-glandular. Calyx 5— 10mm, lobes irregular, glandular-ciliate, otherwise glabrous. Corolla fleshy, tubular-campanulate, light to deep crimson, 40—50mm. Ovary densely stipitate-glandular. Capsule 20-25 x 7—9mm.
Habitat: Thickets, open rocky slopes
Distribution: NE India (Arunachal Pradesh), China (S Xizang, NW Yunnan)
Altitude: 3650-4600m
4*. R. x hemigymim (Tagg & Forrest) Chamberlain, Notes R.B.G. Edinb. 37: 333 (1979)- R. pocophorum x R. eclecteum. Syn: R. chaetomallum Balfour f. & Forrest var. hemigynum Tagg & Forrest, Notes R.B.G. Edinb. 16: 189 (1931). Type: China, SE Xizang, Tsarong, Salween/Kiu-chiang divide, NW of Si-chi-to, 12000ft, vi 1922, Forrest 21728 (holo. E). Shrub, l-2m; young shoots sparsely stipitate- to setose-glandular. Leaves obovate ('jargonelle-shaped') to elliptic, 8.5-12 x 3-5cm, 2-2.8 x as long as broad, apex rounded, apiculate, base broadly cuneate, upper surface glabrous when mature, lower surface with a thin discontinuous floccose-tomentose indumentum; petioles 0.7-1.5cm, broad, sparsely setose. Inflorescence c.6-flowered; rhachis less than 5mm; pedicels 10- 15mm, setose-glandular. Calyx (5-)15mm, irregular to cupular, lobes ciliate, otherwise glabrous. Corolla fleshy, tubular-campanulate, crimson to magenta-rose, 45-52mm. Ovary rufous-tomentose to stipitate-glandular. Capsule not known. china (SE Xizang), ne upper burma. Open rocky slopes, mixed scrub, 3350-4400m. Intermediate between R. eclecteum and R. pocophorum, with the leaf shape and broad petioles of the former species and the setose- to stipitate-glandular young shoots and petioles and a leaf indumentum more typical of the latter. Both species occur at the localities from which the hybrid has been collected.
Occurs in Countries: CN, IN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: crimson
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):387
Leaves with a patchy discontinuous indumentum beneath.
Closely allied to R. coelicum (q.v.). Two plants, are intermediate between R. pocophorum and R. catacosmum and may be hybrids. Three plants, Forrest 25590 & 25786 and TA: 17014, occurring in an area to the south of the range of R. pocophorum (see map 122), apparently differ in their loose, 4—6-flowered inflorescence, but are otherwise closer to R. pocophorum than they are to R. coelicum, with which they are sympatric. The status of these three plants remains uncertain.
Synonymy: R. hemidartum [Balfour f. ex] Tagg, Notes R.B.G. Edinb. 15:314 (1927). Type: China, E Xizang, Tsarong, Salween/Kiu-chiang divide, 28°24'N, 98°24'E, 13-14000ft, viii 1921, Forrest20028 (holo. E)
Leaves with a continuous indumentum beneath.
Type: China, E Xizang, Tsarong, Salween/Kiu-chiang divide, NW of Si-chi-to, 12000ft, vi 1922, Forrest 21713 (holo. E)
Small, procumbent shrublet. Leaf-bud scales persistent. Leaves elliptic to obovate, c. 10 x 4-5 mm, upper surface elepidote but beset with whitish loriform setae, undersurface brown with dense scales borne in 2-3 tiers, those of the lowermost tier golden, paler than the others. Inflorescence 2-4-flowered, pedicels very short, lepidote. Calyx lobes obovate, 5-6 mm, elepidote and glabrous outside, margins densely loriform-ciliate, inner surface densely puberulent. Corolla white to pink, glabrous and elepidote outside, tube 8 mm, lobes 5 mm, mouth of the tube densely pilose within. Stamens 6. Ovary densely lepidote. Capsule unknown
Habitat: Rocky places
Distribution: Bhutan
Altitude: 4250-4700m
Known only from the type and one other collection (Ludlow & Sherriff 3428)
Type: Bhutan, Tang Chu, Ritang, 14-15000 ft, Ludlow & Sherriff 3216 (holo. E)
Occurs in Countries: BT Altitude Ranges: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: pink
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):161
Tree or shrub to 7m. Twigs 5–8mm in diameter, rounded, at first with a thick covering of reddish-brown stellate scales, quickly glabrescent; internodes 5–11cm. Leaves 5–7 together in well-marked pseudowhorls additionally with several very reduced leaves. Blade 70–150 x 40–90mm, elliptic or broadly elliptic; apex gradually broadly tapering or sub-acuminate, the extreme tip obtuse; margin entire and flat; base broadly tapering to rounded, or shortly cordate, sometimes ‘pinched’ into a vertical undulation; when young, densely scaly, at first the scales white but they quickly turn brown before falling off; becoming glabrescent above and often beneath also. Scales sub-dendroid, narrowly stellately divided to the minute centre, fragile, leaving no pits. Mid-vein c.2mm wide proximally, gradually narrower and slightly impressed distally; lateral veins 9–11 per side, slightly curved, often deeply forked, anastomosing before the margin, faintly though even distinctly impressed above, hardly raised or inconspicuous beneath, reticulation obscure. Petiole 20–40 x 4–5mm, grooved above, green but densely brown scaly. Flower buds to 16 x 15mm, spherical, or top-shaped, smooth with all except the outermost bracts fully appressed, green or pale brown. Outermost bracts subulate, densely brown scaly, other bracts with only a few scales outside, fringed with long-stalked brown scales along the margins, glabrous inside, sub-circular, rounded at the apex but often splitting to become emarginate. Bracteoles c.20mm, linear to filiform, glabrous. Inflorescence of 25–30 horizontal to semi-erect flowers in a full umbel. Pedicels 60–80 x 1.5–2mm, orange-red, scaly. Flowers brilliant pink, or orange with a yellow centre, very strongly scented. Calyx 4–5mm in diameter, oblique, circular, sometimes shortly and obtusely 5-lobed. Corolla 30–35 x 40–48mm; tube 18–20 x 5–7 x 13–20mm, funnel-shaped, strongly angled and slightly grooved proximally, with transparent scales outside and irregular hairs in the proximal ½ inside; lobes 18–20 x 15–18mm, broadly obovate-spathulate, slightly retuse, with scales in the central part outside, overlapping to c.½, spreading horizontally. Stamens irregularly arranged in two groups on either side of the flower; filaments 25mm, sub-densely to laxly hairy in the proximal 1⁄3, glabrous distally, yellow at the base, passing through pink to red distally; anthers 2.7–3 x c.1.2mm, pale-brown. Disc deeply lobed, hairy between the glabrous lobes. Ovary 5–6 x 3–4mm, green, with distally pointing hairs which cover scales; style green and hairy in the proximal 2⁄3, glabrous and pinkish-brown distally, c.12mm; stigma pinkish-brown, c.2mm in diameter. Fruit 21–28 x 7–9mm, fusiform, opening by strong valves, which curve back after the outer coat has peeled off. Seeds 3mm, without tails 1mm, the longest tail 1mm.
Habitat: Occurring in dense mossy forest, hanging from cliffs and on ridges
Distribution: Malaysia (Borneo), Sabah, Mt Trus Madi, Mt Kinabalu: Mesilau East R. Basin, Meligan Range. Sarawak, possibly from Mt Murud and Mt Mulu although there is some doubt about the identity of plants from these mountains.
Altitude: 1300-2300m
Greek – poly – many; anthos – flowered. The many-flowered rhododendron.
This species is easily known by its dark-brown, scaly covering on long-petioled, smooth leaves and bright pinkish-orange, strongly scented flowers. It is probably most closely related to R. verticillatum from Sarawak and West Kalimantan but it has a much shorter corolla tube, only about ½ as long as in that species, and never has simple hairs on the petioles as R. verticillatum probably always has. The original collection of this species from G. Trus Madi was a terrestrial tree almost 7m high, growing on a ridge, but subsequent collections demonstrate it is often on cliffs or epiphytic and not necessarily so large. There are no records of any wild hybrids.
Type: Collenette 644, 7 Jan. 1961. North Borneo, Mt Trus Madi, Crest of main ridge, 2135–2285m (K, L).
Occurs in Countries: MY Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:275
Erect shrub to 1-2 m. Leaves (4-)8-18(-20) X (2-)3-6(-8) mm, narrowly elliptic to elliptic, acute or obtuse, very shortly or obscurely mucronate, base cuneate, undersurface greyish with brown stippling, or more uniformly reddish brown, the scales discontiguous or contiguous in groups. Inflorescence up to 5-flowered, pedicels lepidote, 0.5-3 mm. Calyx obsolete to 2-5 mm, lobes sometimes unequal, deltoid to rounded, lepidote, margins ciliate and/or lepidote. Corolla lavender to rich purple-blue, rarely white, broadly funnel-shaped, pubescent inside and occasionally outside as well, elepidote, 7-5-13 mm, tube 2-5-5 mm. Stamens 10, .filaments pubescent towards the base. Ovary lepidote, style exceeding stamens, glabrous or rarely with a few hairs at the base. Capsule oblong, up to 6 mm, lepidote.
Habitat: Forest margins, open slopes, cliffs
Distribution: China (N, NW, W & C Yunnan)
Altitude: 3000-4300m
The Philipsons (1975, p. 43) report natural hybrids with R. nivale subsp. australe and other species.
Type: China, Yunnan, paturages et rochers au Koua-lou-po (Hoking), 3000 m, Delavay 267 bis (holo. P; iso. A, E)
Synonymy: R. scintillans Balfour f. & W. W. Smith, Notes R.B.G. Edinb. 9:217 (1916). Type: China, Yunnan, summit of Lankong/Hochin pass, 11000 ft, v 1913, Forrest 10014 (holo. E). R. compactum Hutchinson, Gard. Chron. 91:326 (1932). Type: a cultivated specimen (holo. K)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: purple, white
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):102
Shrub or small tree, 1-6 m. Young growth densely lepidote. Leaves narrowly elliptic to very narrowly elliptic, 50-100 X 15-30 mm, cuneate at base, acute to somewhat rounded at apex, upper surface dark green, lepidote or elepidote, glabrous, lower surface very densely covered with large, flat, overlapping, flaky scales, dark brown or yellowish brown. Inflorescences 3-4-flowered, pedicels lepidote, 9-15 mm. Calyx minute, undulate, lepidote, rarely filiform-acicular-ciliate. Corolla purple, 25-31 mm, tube 10-15 mm, lepidote outside. Stamens 10, filaments pubescent towards the base. Ovary lepidote, somewhat pubescent at apex. Style glabrous. Capsule narrowly cylindric, c. 15 mm.
Habitat: Woods and thickets
Distribution: China (NW & SW Sichuan)
Altitude: 2000-3000m
Illustrations:
A very distinct species. In specimens collected in the wild the scales on the leaf undersurfaces appear to fray out at the edges into cobwebby material; this is consistent on all the specimens, and does not appear to be due to fungal infection. It is not found on cultivated material, and its significance is obscure.
Type: Thibet or., circa Mupin, alt. 2000 m, David (holo. P—n.v., iso. E)
Synonymy: R. harrovianum Hemsley, Gard. Chron. 47:4 (1910). Type: a cultivated specimen (holo. K)
Occurs in Countries: CN Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Rhododendron Habit: Tree
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):76
Shrub, 0.6-1.2m. Leaves oblong-oval, 8.5-10 X 3.5-4.7cm, 2-2.5 x as long as broad, apex apiculate, base rounded, lower surface with a thin unistrate compacted brown indumentum; petioles 1.5-2cm, floccose. Inflorescence c.5-flowered; rhachis short; pedicels 13-25mm, densely tomentose. Calyx c.l2mm, glabrous, lobes unequal, with ciliate margins. Corolla pink, c.38mm. Ovary densely tomentose. Capsule not known.
Habitat: Only known from the type.
Distribution: China (SE Xizang)
The leaf indumentum suggests an affinity with R. nakotiltum and R. dignabile but the present species may be distinguished from both by its large calyx.
Type: China, SEXizang, PomeProv., aboveShowaDzong, 11000ft, 18 vi 1947, Ludlow, Sherriff & Elliot 13177 (holo. BM).
Occurs in Countries: CN Subgenus: Hymenanthes Habit: Non-Tree
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):363
Shrub, 2-5(-8)m; young shoots glabrous. Leaves oblanceolate to broadly elliptic, 6-18 x 2.4-5.5cm, 1.8-5 x as long as broad, apex acute to acuminate, base ± rounded to cuneate, upper and lower surfaces glabrous when mature; petioles l-2cm, glabrous or with a few stipitate glands and a sparse floccose tomentum. Inflorescence 8-20-flowered; rhachis 10-50mm, glabrous or more rarely velutinous to ± lanate; pedicels 30-35mm, glabrous or stipitate-glandular. Calyx l-2mm, glabrous, lobes shallowly triangular. Corolla campanulate, lilac-pink to purple, usually with greenish-yellow flecks, 35-50mm. Ovary and style glabrous. Capsule 15-25 x 3-4mm.
Habitat: Forests, Rhododendron thickets
Distribution: SPAIN, PORTUGAL, BULGARIA, N TURKEY, USSR (W Caucasia), LEBANON.
Altitude: 0-1800m
Illustrations:
Specimens with a velutinous rhachis, the character used to distinguish the European subsp. baeticum from subsp. ponticum (in which the rhachis is usually glabrous), occur sporadically, even in E Turkey & Caucasia. There is therefore no justification in maintaining the two taxa at any rank. Similarly, the differences used to distinguish var. brachycarpum from var. ponticum are considered to be too trivial to justify the maintenance of that taxon.
R. adansonii Pepin is probably synonymous with R. ponticum though the plate that accompanies the type description is too poor to be certain.
9*. R. x sochadzeae Char & Davlianidze, Zam. Sist. Geogr. Rast. 27: 84 (1967)- R. ponticum x R. caucasicum. Type: USSR, Georgia megrelia jugi Okhaczkus in declivio orientale, locus 'Patara Djakona', 11 vii 1964, Sochadze & Davlianidze (holo. TBI, n.v.). Intermediate between the two parents, differing from R. ponticum in its white to pale pink corolla and usually pubescent ovary, and from R. caucasicum in its longer (5-17cm), glabrous leaves. Forests, open slopes, 1700-2400m. This hybrid occurs wherever the ranges of the two species overlap.
Type: a Tournefort specimen from the Orient, n.v.
Synonymy: R. lancifotium Moench, Meth. 45 (1794), nomen illegit. R. speciosum Salisbury, Prodr. 287 (1796), nomen illegit. R. parviflorum Dumont de Courset, Bot. Cult. ed. 2,1: 253 (1811). No type designated. R. algarvense Page, Prodr. Southampt. Gard. 38 (1817), nomen nudum. R. baeticum Boissier & Reuter in Boissier, Diagn. Ser. 2,3: 118 (1856). Type: Spain, in montibus Baeticae australibus circa Algeciras et Tarife, Boissier & Reuter, n.v. ?R. adansonii Pepin, Ann. Fl. Pomone 304, t. (1859). R. ponticum L. var. brachycarpum Boissier, Fl. Or. 3: 972 (1875). Syntypes: Lebanon, Labillardiere; inter Zachle et Beckfaya, Boissier, in monte Sanin, Ehrhardt; in valle Hamama, Mart., n.v. R. ponticum L. subsp. baeticum (Boissier & Reuter) Handel-Mazzetti, Ann. Naturhist. Mus. Wien 23: 53 (1909).
Occurs in Countries: BG, ES, LB, PT, RU, TR Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: green, lilac, purple
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):313
Shrub or small tree, l-4.5m; young shoots glandular at first, soon giabrescent. Leaves obovate to elliptic, 3.7-5.5 x 1.6-2.2cm, c.2.5 x as long as broad, apex rounded, apiculate, base rounded, upper and lower surfaces glabrous, lower epidermis epapillate though with minute mammillae, usually with a few glands; petioles 0.5—0.8cm, glabrous. Inflorescence c.6-flowered; rhachis 2-5mm; pedicels 5-10mm, glabrous. Calyx 5-10mm, irregular, reddish, glabrous. Corolla campanulate, probably with nectar pouches, deep crimson, sometimes with darker flecks and/or basal blotches, 30-35mm. Ovary and style glabrous. Capsule not known.
Habitat: Rhododendron and bamboo thickets
Distribution: China (S Xizang)
Altitude: Around 3700m
This species has some affinities with R. cerasinum, especially in the leaf shape and texture, but in its corolla it appears to be closer to R. thomsonii.
Type: China, S Xizang, Chayul Chu, Lung, 12000ft, 29 iv 1936, Ludlow & Sherriff1391 (holo. BM; iso. A, E)
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: crimson
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):419
Shrub to 1m. Twigs 1.5–2.5mm in diameter, very laxly covered with appressed scales, quickly glabrescent; internodes 4–9cm. Leaves 3–6 together in pseudowhorls. Blade 65–110 x 29–46mm, obovate- to elliptic; apex shortly acuminate or obtuse; margin narrowly revolute; base acutely tapering, glabrescent but densely blackish punctate above when mature, laxly appressed-scaly beneath. Scales minute, marginal zone narrow, irregularly lobed; centre slightly impressed, becoming glabrescent beneath also. Mid-vein flat, slightly, or not raised above, obtuse and much more prominent proximally beneath; lateral veins 7–9 per side, narrow and sub-parallel, curved-ascending and obscurely anastomosing along the margin, slightly raised on both sides, reticulation obscure. Petiole 7–9 x c.2mm, grooved above, rounded, scaly. Inflorescence 5–6-flowered. Pedicels c.15mm, thick, densely scaly, without hairs. Calyx c.4mm in diameter, obliquely disc-shaped, crenulate or obtusely lobed, scaly outside. Corolla c.40mm, funnel-shaped, red; tube c.20 x 4 x 6–8mm, sulcate at the base, sparsely, sub-stellately scaly outside, finely hairy in the proximal ½ inside; lobes 18–20 x 14–16mm, obovate-spathulate, often retuse, spreading. Stamens exserted; filaments linear, laxly hairy in the proximal ½, glabrous distally; anthers c.4 x 1mm, oblong, base obtuse. Disc low, glabrous. Ovary c.5 x 2mm, sub-cylindrical, tapering distally, finely shortly hairy, and sub-densely covered with minute, sub-entire scales; style 17–20mm, glabrous; stigma thick, globose.
Habitat: Epiphytic
Distribution: Indonesia, Sulawesi (SE), Mengkoka Mts, Mt Porema.
Altitude: Around 1400m
Of Porema, the place where this species was collected.
Known only from the type collection.
Type: Kjellberg 2627, 24 Oct. 1929. Celebes (SE), B. Porema (in the north part of the Mengkoka Mts), 1400m (S, BO, L, fragment).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:289
Weak, erect, 1- to few-stemmed shrub to 50cm. Twigs 1–2mm in diameter, young ones purplish, laxly scaly; internodes 3–9cm. Leaves 4–6 together in loose pseudowhorls. Blade 30–50 x 15–23mm, obovate to elongate-obovate; apex rounded, to obtuse, sometimes a little emarginate; margin slightly revolute and sub-crenulate with impressed scales; base tapering; immature ones sub-densely or laxly scaly on both sides, mature ones shining, early glabrescent above, more slowly so beneath. Scales small, flat, marginal zone angular or stellately lobed; centre small and impressed. Mid-vein slightly grooved proximally, flat distally above, as thick as the petiole at the base, gradually decreasing distally beneath; lateral veins 3–4 per side, obscure, without visible reticulation. Petiole 6–10 x c.1mm, winged in the upper part by the decurrent blade, nearly rounded below. Flower buds c.20 x 8mm, oblong. Bracts to 12 x 7mm, ovate, distinctly keeled; inner ones obovate to spathulate, all shining and laxly scaly outside, fringed with deciduous scales. Inflorescence 2-flowered. Pedicels c.10mm, slender, sub-densely sub-stellately scaly. Calyx c.2mm in diameter, oblique, wavy. Corolla c.23mm, sub-campanulate-tubular, zygomorphic, hanging, waxy, reddish-purple, shiny, glabrous; tube 15–18 x c.3 x c.6mm, straight, distinctly 5-pouched near the base; lobes 6–8 x 6–8mm, erect, broadly obovate-spathulate. Stamens exserted to c.4mm; filaments linear, glabrous; anthers c.2 x 1.5mm, sub- obovate-elliptic, the base obtuse. Disc prominent, glabrous. Ovary 2.5 x 1.2mm, sub-cylindrical, tapering distally; style 7–8mm, slender, glabrous; stigma club-shaped.
Habitat: Terrestrial in Nothofagus forest at 2320m, and Libocedrus forest at 3500m.
Distribution: Indonesia, New Guinea (W), Arfak Mts: Mt Sarumont near Iray, Anggi Gigi Lake, and near Lake Habbema. Known only from the type collection and one other.
Altitude: 2320-3500m
Greek – porphyra – the purple dye obtained from a marine gastropod; anthes – flowers. Alluding to the flower colour.
Type: Sleumer & Vink 4452, 26 Jan. 1962. W New Guinea, Arfak Mts, Mt Saru-mot, near Iray, Anggi Gigi Lake (L, A).
Occurs in Countries: ID Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:224
Tree, c.5m. Leaves oblong to obovate, 7-9 x 3.5-4cm, c.2 x as long as broad, apex obtuse, mucronate, base rounded, upper surface glabrous, lower surface presumed to be pubescent below at first though soon giabrescent, with a dense spongy indumentum of branched hairs overlying the midrib below; petioles 2—2.5cm, densely tomentose. Inflorescence 7—8-flowered; pedicels c.l8mm, rufous-pilose. Calyx c.lmm, hirsute. Corolla open-campanulate, probably white, c.30mm. Ovary densely rufous-tomentose.
Tagg, in Stevenson (ed.), The Species of Rhododendron 840 (1930), suggests an affinity with R. rufum (subsection Taliensia). Without seeing any material, I hesitate to confirm this suggestion.
Type: N China, in Prov. Kansu orientali, in valle ubi pagus Tschagon, 10 vii 1895, Potanin, n.v.
Subgenus: Hymenanthes Habit: Tree Fl. Colour: white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):428
Shrub or small tree, 3-10m. Leaves oblong-obovate to oblanceolate, (14-)20-30(-40) x 5.2-12cm, 2.2-2.8(-3.6) x as long as broad, apex rounded, base cuneate, upper surface glabrous, lower surface with a silvery compacted and agglutinated indumentum; petioles l-2cm, strongly flattened and winged, sparsely tomentose to glabrescent. Inflorescence 12-20-flowered; rhachis up to 25mm; pedicels 30-40mm, sparsely floccose-tomentose. Calyx l-2mm, tomentose. Corolla 7-8-lobed, obliquely campanulate, pale yellow or white flushed with pink, to pink with crimson flecks and a basal blotch, 35—50mm. Stamens c. 16. Ovary covered with a dense buff tomentum. Capsule 30-40 x 6-10mm, usually curved.
Habitat: Pine and mixed forest
Distribution: China (SE Xizang, NW Yunnan)
Altitude: 3350-4250m
Illustrations:
The differences in flower colour used by Tagg to separate R. coryphaeum from R. praestans are of little significance, especially since flower colours of the respective types are not known.
Type: China, Yunnan, Kari Pass, Mekong/Yangtse divide, 13000ft, viii 1914, Forrest 13023 (holo. E)
Synonymy: R. coryphaeum Balfour f. & Forrest, Notes R.B.G. Edinb. 12: 100 (1920). Type: China, W NW Yunnan, Mekong/Salween divide, 11-12000ft, vi 1918, Forrest 16561 (holo. E). R. semnum Balfour f. & Forrest, ibid. 13: 59 (1920). Type: China, W NW Yunnan, Mekong/Salween divide, vi 1917, Forrest 14233 (holo. E; iso. BM)
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: crimson, pink, white, yellow
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):247
Shrub. Leaves obovate-elliptic, 6-8 x 2.5-3.2 cm, c.2.5 x as long as broad, apex rounded, mucronate, base rounded, lower surface glabrous; petioles c. 1.5cm, at first with a floccose dendroid indumentum, soon glabrous. Inflorescence c. 7-flowered; rhachis 5 — 10mm; pedicels c. 10mm, glabrous. Calyx 1—2mm, glabrous. Corolla 5-lobed, open-campanulate, with nectar pouches, entirely glabrous, white flushed pink to pale pink, with purple flecks, 30-40mm. Stamens 10, filaments glabrous. Ovary and style glabrous. Capsule not known.
Distribution: China (W Hubei)
Clearly, on account of its nectar pouches and floccose petioles, an aberrant member of subsection Fortunea. Possibly a hybrid of R. oreodoxa: more wild-collected material is required before the status of this species can be confirmed.
Type: a plant cultivated at Kew, raised from seed collected by Wilson as Veitch 1800 (E).
Occurs in Countries: CN Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: pink, purple, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):240
Shrub to 2m. Twigs green, rounded, at first covered in small pale brown or transparent scales but quickly glabrescent. Lateral buds often distinct, reddish, triangular and pointed. Leaves in distinct pseudowhorls of 4–6 large and a few small ones. Blade 50–72 x 18–32mm, ovate or elliptic; apex rounded or retuse; margin entire but broadly revolute; base tapering; dark green, quickly glabrescent and shiny above, sparsely scaly, paler and dull beneath. Scales lobed, to stellate, brown. Mid-vein impressed above, strongly raised below throughout its length; lateral veins 3 or 4 per side, spreading at c.80°, often rather obscure. Petiole 2–6 x 3–4mm, weakly grooved, finely scaly, minutely hairy on the upper side, often purplish-red. Flower buds 14 x 8mm, broadly ellipsoid, smooth, green to dark red, minutely hairy outside and with a few pale brown scales. Bracts broadly ovate with rounded apices which often split so as to become emarginate, the margins densely scaly, inside glabrous. Bracteoles filiform, grooved, with a few scales distally especially on the margins. Inflorescence a 3–7-flowered umbel, the flowers hanging vertically downwards. Pedicels 20–37 x c.1.25mm, with patent white hairs and a few scales, green or red. Calyx a low circular or weakly angular disc, densely scaly and with a few simple hairs. Corolla 50–80 x 27–30mm, pink or pinkish-violet, without scent; tube 40–60 x 7–8 x 10–12mm, slightly curved and strongly fluted proximally; lobes 21–22 x 10–12mm, sub-erect on opening and overlapping ½–2⁄3, later spreading and not overlapping. Stamens distributed around the lower side of the mouth of the flower; filaments 60mm, glabrous to the base or hairy in the proximal 1⁄3, mostly white, becoming pink distally; anthers 2.5 x 1mm, exserted to c.12mm, pale brown with an outwardly curved point at the end of each cell. Ovary 12 x 3.5mm, green, with spreading hairs and some scales; style 50mm, green, white or flushed pink, glabrous; stigma circular, c.2mm in diameter. Fruit 30–32 x 5–6mm, hairy and scaly, on opening the valves curving back to a wide angle and the placentae separating from the central column. Seeds 3.2mm, without tails 1mm, the longest tail 1.2mm.
Habitat: Montane forest, mostly epiphytic.
Distribution: Malaysia (Borneo), Sabah, Mt Kinabalu, Mt Alab, along the Crocker Range to near Tenom.
Altitude: 1100-1800m
Latin – praetervisus – overlooked, from the fact that specimens of this species had accumulated in herbaria under R. longiflorum.
Type: Lajangah SAN 44622, 22 Oct. 1965. Borneo, Sabah, Mt Kinabalu, W trail (L, SAN).
Occurs in Countries: MY Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: pink
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:268
Shrub. Leaves elliptic-oblanceolate, 10-18 x 2.5-6 cm, 3-4 x as long as broad, apex acuminate, base broadly cuneate, lower surface entirely glabrous; petioles 1-1.5 cm, glabrous. Inflorescence c. 10-flowered; rhachis c. 10 mm; pedicels 1-1.5 cm, glabrous. Calyx 1-2 mm, glabrous. Corolla 5-lobed, campanulate, glabrous outside, puberulent within towards base, white, sometimes suffused with pink, with flecks and a conspicuous purple blotch, 50-60 mm. Stamens 10, filaments puberulent below. Ovary and style glabrous; stigma capitate. Capsule c. 30 x 12 mm, broadly cylindrical.
Distribution: China (SE Sichuan, Hubei)
Closely allied to and hybridising in the wild with R. sutchuenense
Type: China, W Hubei, iii & ix 1900, Wilson 17 (E, K); 1908, Wilson 507 [error for Wilson 509?]; S Patung, Henry 5285 (K)
Occurs in Countries: CN Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: pink, purple, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):127
Shrub to 2m. Twigs c.1.5mm in diameter, rounded, slender, few-branched, at first very densely covered with brown, stellate scales, glabrescent below; internodes 2–6cm. Leaves 3–6 together in pseudowhorls. Blade 50–100 x 4–7mm, linear, sub-sessile, straight; apex gradually tapering, sub-acute; margin very slightly or not revolute; base shortly tapering; initially scaly on both sides, silvery, early glabrescent and rough above, brown and more persistent beneath. Scales with the marginal zone stellately divided, dendroid, with a small centre, each on top of a minute epidermal persistent tubercle. Mid-vein strongly impressed above, prominent beneath, lateral veins not visible. Petiole 3–4 x 2mm, not or only very slightly grooved in the distal part, densely scaly. Flower buds to 15 x 6mm, narrowly ovoid with the points of the bracts erect or slightly spreading. Bracts to 15 x 6mm; the outer ovate, subulate-acuminate, stellate-scaly outside mainly at the apex and fringed with stalked scales. Bracteoles 10–15mm, linear, laxly scaly. Flowers solitary or mostly in twos, rarely 3 or 4, hanging. Pedicels 9–12 x c.1mm, very slender, densely scaly. Calyx c.2mm in diameter, cup-shaped, glabrescent outside, with obscure teeth. Corolla 25–27 x c.12mm, zygomorphic, membranous, pale purple, without scent, glabrous in and outside (see note below); tube 15–18 x 5 x 6mm, cylindrical, curved; lobes 6–8 x 5–7mm, spreading, obovate-spathulate to sub-circular. Stamens 25–28mm; filaments linear below, filiform distally, glabrous; anthers 1.5 x 1mm, broadly oblong. Disc finely shortly hairy on the upper margin. Ovary c.3–4 x 1–2mm, elongate-conical, very densely brown-stellate-scaly, gradually tapering distally; style 15–20mm, scaly in the proximal ½–1⁄3, sometimes with a few short hairs in the middle, glabrous distally; stigma shortly obconical. Fruit 22 x 3mm, fusiform, densely brown scaly.
Habitat: Epiphytic or terrestrial on poor clayey soil, disturbed roadside shrubberies
Distribution: Indonesia, New Guinea (W), Hellwig Mts; Orion Mts; Star Mts, Sibil R. Valley; Mt Jaya.
Altitude: 900-1300m
Named after Sir David Prain, 1857–1954, one time superintendent of the Calcutta Botanic Garden, professor of botany at the medical college in Calcutta and president of the Linnean Society of London.
Type: Versteeg 1661, 25 Aug. 1907. New Guinea, SW Noord River, on top of ‘Resi’ ridge, 900m (BO, K, L, U).
Occurs in Countries: ID Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:95
Shrub or tree, 2.5-9m. Leaves oblanceolate to elliptic, 13.5-15 x 5.5-6.2 cm, c.2.5 x as long as broad, apex ± rounded, apiculate, base rounded to tapering, upper surface glabrous, ± rugulose, lower surface with a bistrate indumentum, the lower layer adpressed, the upper buff, composed of strongly fimbriate, cup-shaped hairs; petioles 1.5-2cm, glabrous, terete. Inflorescence 10—20-flowered; rhachis c.20mm; pedicels 25—30mm, lanate-floccose. Calyx minute, densely tomentose. Corolla 6-7-lobed, obliquely ventricose-campanulate, white with a purple basal blotch, 35-45mm. Stamens (10-)12-14. Ovary densely tomentose. Capsule not known.
Habitat: Scrub
Distribution: NE Upper Burma
Altitude: Around 3350m
R. preptum is closely allied to and possibly a hybrid of R. rex subsp. arizelum but differs in its narrower leaves and paler indumentum
Type: NE Upper Burma, N'Maikha/Salween divide, 11000ft, v 1919, Forrest 18034 (holo.E).
Occurs in Countries: MM Altitude Ranges: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: purple, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):257
Small shrub to l(-l-5) m. Leaf-bud scales quickly deciduous. Leaves narrowly elliptic or oblong-narrowly elliptic, more rarely elliptic, 11-30 (-35) x 5-10(—14) mm, tapered or ± rounded to the base, tapered or rounded to the apex, dark, glossy green, lepidote or elepidote above, beneath pale brown to brown with dense, overlapping scales arranged in 2-3 tiers, the tiers often very clearly distinguished, scales of the lowermost tier golden yellow, paler than those of the upper tiers; margins ciliate with loriform setae or eciliate. Inflorescence dense, several-flowered, pedicels short, lepidote or elepidote, pubescent or glabrous. Calyx lobes oblong, often acute, (2.5-)3-5(-6) mm, usually lepidote outside, margins variably lepidote and/or loriform-ciliate, inner surface variably puberulent. Corolla white, rarely flushed pink or entirely pink, often yellowish orange towards the base of the tube, tube 6-10(-12) mm, lobes (3-)3-5-5(-6) mm, tube usually glabrous outside, more rarely sparsely pilose or somewhat lepidote, densely pilose inside at the throat. Stamens 5(-6). Capsule lepidote, c. 4-5 mm.
Habitat: Cliffs and ledges, stony or rocky slopes, rarely on forest margins
Distribution: China (N & NW Yunnan, S & SE Xizang, SW Sichuan)
Altitude: 3350-4600m
Illustrations:
A very variable species, particularly with regard to leaf and corolla indumentum and scaling; the following variants, with the names that have been applied to some of them, are found: (a) Leaves and corolla glabrous (R. tsarongense, gymno- miscum, clivicolum, primuliflorum sensu stricto). (b) Leaves ciliate, corolla glabrous (R. acraium, cremno- philum). (c) Leaves glabrous, corolla pilose. (d) Leaves ciliate, corolla pilose (R. cephalanthoides). (e) Leaves ciliate, corolla lepidote (R. lepidanthum). (f) Leaves glabrous, corolla lepidote. These variants are not geographically distinguished, and none of them appears to be of any taxonomic significance. Some of the variants with pilose corollas approach R. kongboense (p. 163); distinctive characters are given under that species. There is also a specimen from Gansu (Kansu, Farrer 88) which seems most likely to belong to R. primuliflorum, in spite of the wide geographical gap between it and the rest of the species. It was described as R. praeclarum Balfour f. & Farrer (Notes R.B.G. Edinb. 9:261, 1916), but the material is inadequate for its recognition as a separate species.
Type: Thibet, inter Lhassa et Batang, 10 v 1890, Bonvalot & Prince Henri d'Orleans (iso. E)
Synonymy: R. acraium Balfour f. & W. W. Smith, Notes R.B.G„ Edinb. 9:209 (1916). Type: China, Yunnan, mountains of Chungtien plateau, 12-13000 ft, vii 1913, Forrest 10652 (holo. E). R. cephalanthoides Balfour f. & W. W. Smith, op. cit.: 216. Type: China, Yunnan, E flank of the Likiang Range, 11-11500 ft, v 1906, Forrest 2182 (holo. E). R. clivicolum Balfour f. & W. W. Smith, op. cit.: 221. Type: China, Yunnan, mountains in the NE of the Yangtze bend, 11-12000 ft, vii 1913, Forrest 10585 (holo. E). R. cremnophilum Balfour f. & W. W. Smith, op. cit.: 223. Type: China, Yunnan, mountains of the Chungtien plateau, 13000 ft, vii 1914, Forrest 12631 (holo. E). R. gymnomiscum Balfour f. & Kingdon Ward, Notes R.B.G. Edinb. 9:230 (1916). Type: China, Tibeto-Yunnan frontier, Ka-gwr-pw glacier, 14000 ft, vi 1913, Kingdon Ward 505 (holo. E). R. lepidanthum Balfour f. & W. W. Smith, op. cit.: 245. Type: China, Yunnan, Lichiang range, 11-14000 ft, v 1913, Forrest 10034 (holo. E). R. tsarongense Balfour f. & Forrest, Notes R.B.G. Edinb. 11:150 (1919). Type: China, SE Tibet, Tsarong, on Ka gwr po, 14000 ft, Forrest 14334 (holo. E). R. primuliflorum var. cephalanthoides (Balfour f. & W. W. Smith) Cowan & Davidian, Rhodo. Yearbook 2:79 (1947). R. primuliflorum var. lepidanthum (Balfour f. & W. W. Smith) Cowan & Davidian, loc. cit.
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: orange, pink, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):165
Shrub, 2-6m. Leaves oblong to ovate-lanceolate, 6-12 X 1.8-5cm, (2-) 2.7-3.6 x as long as broad, apex ± acute, base rounded to cordate, lower surface with a white to fawn bistrate indumentum, the upper layer ramiform, spongy, lanate-tomentose, the lower ± compacted; petioles l-2cm, tomentose at first, usually soon glabrescent. Inflorescence 10-20-flowered; rhachis 5-10mm; pedicels 15-20mm, glabrous, slender. Calyx c.lmm, lobes rounded, glandular-ciliate. Corolla campanulate, white to pink, with purple flecks, 25-37mm. Ovary and style glabrous. Capsule narrowly cylindrical.
Habitat: Open forests, among deciduous shrubs, etc.
Distribution: China (E Xizang)
Altitude: 2900-3950m
Illustrations:
Some of the ovaries of the type of R. principis have a few scattered hairs, whereas they are totally glabrous in the remaining material, including the type of R. vellereum. This is the only difference between the two taxa; the latter is therefore not maintained here. The following specimens are intermediate between R. aganniphum and R. principis: Ludlow, Sherriff & Elliot 15002, 15016.
Synonymy: R. vellereum Hutchinson in Stevenson (ed.), The Species of Rhododendron 688 (1930). Described from the Tsangpo Valley in SE Xizang-based on a specimen from Lang Dzong, Kingdon- Ward 5640 (holo. K).
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: pink, purple, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):357
Shrub or small tree to 3m tall, usually non-rhizomatous; young twigs red-brown, densely covered with unicellular hairs or sparsely to densely covered with multicellular eglandular hairs, rarely with multicellular gland-tipped hairs. Vegetative bud scales densely covered with unicellular hairs, rarely very sparsely covered with unicellular hairs abaxially; margin unicellular-ciliate, rarely ciliate above and glandular below. Leaf blade membranaceous, ovate or obovate to elliptic, (3.9-)5.0-7.3(-8.7) x (1.2-)1.8-3.0(-3.7)cm; base acute to oblique; apex acute to obtuse, often mucronate; adaxial surface sparsely covered with unicellular hairs or sparsely to densely covered with multicellular eglandular hairs, rarely glabrous, the midvein densely covered with unicellular hairs; abaxial surface sparsely to densely covered with unicellular hairs, rarely with scattered multicellular eglandular hairs, or densely covered with unicellular hairs and multicellular eglandular hairs, or glabrous, the midvein densely covered with unicellular and multicellular eglandular hairs, rarely with unicellular hairs and multicellular gland-tipped hairs; margin entire, ciliate with multicellular eglandular hairs; petiole (0.2-)0.3-0.5(-0.7)cm long, densely covered with unicellular hairs and sparsely to densely covered with multicellular eglandular hairs, rarely with unicellular hairs and multicellular gland-tipped hairs or glabrous. Flower bud scales chestnut brown; abaxial surface densely covered with unicellular hairs, very rarely glabrous; margin unicellular-ciliate. Flowers appearing before or with the leaves; inflorescence a shortened raceme of 4 to 13 flowers. Pedicels (0.7-)1.0-1.6(-2.6)cm long, sparsely to densely covered with unicellular hairs and multicellular eglandular and gland-tipped hairs, or with unicellular and multicellular gland-tipped hairs, rarely with unicellular hairs and multicellular eglandular hairs. Sepals less than 0.1-0.2(-0.3)cm long, often varying in length on the same flower; margins glandular-fimbriate or with both glandular and eglandular multicellular hairs, rarely only setose; abaxial surface sparsely to densely covered with unicellular hairs and multicellular gland-tipped hairs, rarely with unicellular hairs and multicellular eglandular hairs, or with only unicellular hairs or glabrous. Corolla deep- to rose-pink, rarely white, fragrance spicy, the tube longer than the limb and gradually expanding into it; upper corolla lobe (1.0-)l.l-1.6(-2.0) x (0.6-)0.8-1.2(-1.5)cm; lateral lobes (1.2-)1.4-2.0(-2.3) x (0.5-)0.6-0.9(-l.l)cm; corolla tube l.l-1.5(-1.9)cm long, (0, l-)0.2-0.3 (-0.4)cm wide at base; outer surface of corolla densely covered with unicellular hairs and multicellular gland-tipped hairs, the gland-tipped hairs continuing up the corolla lobes, rarely also with multicellular eglandular hairs; inner surface of corolla densely covered with unicellular hairs. Stamens (3.2-)3.6-4.7(-5.3)cm long, with dense terete or flattened unicellular hairs on proximal 1.2-2.4(-3.1)cm of filament, exserted (1.4-)2.0-2.8(-3.5)cm beyond throat of corolla. Style (3.2-)3.9-5.2(-5.7)cm long, exserted (2.0-)2.5-3.5(-4.3)cm beyond throat of corolla, with dense unicellular hairs on the proximal (0.0-)0.6-1.7(-2.4)cm; stigma less than 0.1-0.2cm wide. Ovary 0.2-0.4(-0.5)cm long, 0.1-0.2(-0.3)cm wide at the base, densely covered with unicellular hairs and multicellular gland-tipped hairs, occasionally also with multicellular eglandular hairs, rarely with unicellular hairs and multicellular eglandular hairs, often glabrous towards apex. Capsules (1.2-)1.3-2.0(-2.8)cm x (0.3-)0.4-0.5(-0.6)cm, ovate, narrowly ovate to cylindric, sparsely covered with unicellular hairs and sparsely to moderately covered with multicellular gland-tipped hairs. Seeds pale to dark chestnut brown, ovate or elliptic to fusiform, (1.8ó)2.3ó 3.2(-3.5) x (0.4-)0.6-l.l(-1.4)mm, body 1.0-1.4(-1.6)mm x (0.2-)0.3-0.6(-0.8)mm; testa expanded and dorsiventrally flattened, surrounding the body, the cells elongate, with tapering end-walls (Fig. 11). Chromosome number: In = 26 (Sax, 1930; JanaM-Ammal et al., 1950; Li, 1957). See Elustration in Galle, 1985 (photo).
Habitat: Bluffs and stream banks, open wooded slopes, acid bogs
Distribution: USA: New Hampshire and Vermont south to Ashe Co., North Carolina, and to eastern Kentucky; Union Co., Illinois and south-eastern Missouri, south to Arkansas and eastern Oklahoma. Isolated populations occur in Transylvania Co., North Carolina and Cherokee Co., Alabama, and western Tennessee to Arkansas and eastern Oklahoma
Altitude: 150-1500m
Flowering from March to June
Rhododendron prinophyllum is unique in the section because of its strongly disjunct distribution. Plants in the western part of the range often have longer corolla tubes than those in the eastern portion of the range. However, longer corolla tubes are also found scattered throughout the eastern populations and shorter corolla tubes are also found in the western populations. Since there is no morphological gap in the pattern of variation of the plants in the two portions of the geographic range, no subspecies are recognized.
Rhododendron prinophyllum is similar morphologically toR. periclymenoides and R. canescens. It is sympatric with R. periclymenoides, but essentially geographically isolated from R. canescens. Rhododendron prinophyllum can be distinguished from both R. periclymenoides and R. canescens by its broader, more gradually expanded corolla tube, and its usually consistently glandular sepal margins, pedicel and ovary. It can also be distinguished from most individuals of R. periclymenoides by the densely pubescent abaxial leaf surface, and the densely glandular corolla tube vs. the usually eglandular condition in R. periclymenoides. It differs from R. canescens by its longer pedicels and less densely pubescent, more glandular fruits. The conspicuously ciliate margins of the leaves also distinguishes R. prinophyllum from R. canescens.
The distinctiveness of R. prinophyllum can also be seen in the results of principal component analysis of fruit and mature leaf characters (see Table 5, Fig. 38). Pedicel length, number of multicellular gland-tipped hairs on the fruit, and the ratio of seed length to seed body length were the factors with the heaviest weight in the first component. Rhododendron prinophyllum has longer pedicels than either of the other two species, although there is some overlap in the range of variation, especially between R. prinophyllum and R. canescens. The best character for distinguishing fruiting specimens of R. prinophyllum from R. canescens or R. periclymenoides is the presence of multicellular gland-tipped hairs on the fruit in R. prinophyllum. In addition, the testa of the seeds in R. prinophyllum is more greatly expanded beyond the body of the seed than in either R. canescens or R. periclymenoides.
While R. prinophyllum is clearly a distinct morphological entity, in New England it has often in the past been identified asR. canescens (Day, 1899; Porter, 1899b; Blanchard, 1902; Haberer, 1905; Knowlton, 1919; Knowlton & Deane, 1922). These plants differ from R. canescens in the conspicuously ciliate leaf margins and the shorter, more gradually expanded corolla tube. Rhododendron prinophyllum usually also has longer pedicels than R. canescens.
The name R. prinophyllum is the correct name for this species. It has priority over R. canescens Porter, since Porter's name is a later homonym of R. canescens (Michx.) Sweet. The name R. roseum (Loisel.) Rehder is illegitimate because it was superfluous when published (see Shinners, 1962; Wilbur, 1976; Kron, 1989).
Synonymy: Rhododendron canescens Porter, Bull. Torrey Bot. Club. 16: 220 (1889), non R. canescens (Michx.) Sweet, Hort. Brit. ed. 2,343 (1830). Azalea prinophylla Small, N. Am. Fl. 29:42 (1914), nomen novum. Type: Pennsylvania, Monroe Co.: Pocono Summit. 22 v & 4 ix 1889, T. C. Porter s.n. (lecto., designated here, 22 v 1889, NY; isolecto. NY). Rhododendron roseum (Lois.) Rehder f. plenum Rehder, Contr. Gray Herb. 165: 10 (1947). Type: cultivated. Garden of R. H. P. Jacobus, originally found wild in the neighbouring woods. 23 vii 1935, R. H. P. Jacobus s.n. (holo. A). Rhododendron roseum (Lois.) Rehder f. albidum Steyerm., Rhodora 62: 131 (1960). Type: Missouri, Ste. Genevieve Co.: sandy pine-oak woods east of Chimney Rocks, along River Aux Vases, 5 mi E of Pickle. 24 v 1933, Steyermark 8522 (holo. MO; iso. MINN, MO)
Occurs in Countries: US Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Pentanthera Habit: Tree Fl. Colour: rose, white
Kron, K.A. (1993) A Revision of Rhododendron Section Pentanthera. Edinburgh Journal of Botany 50(3):323
Erect, few-branched shrub to 2m. Twigs 4–6mm in diameter, purplish, obtusely angular, the tips very densely and persistently scaly; internodes 3–10cm. Leaves 8–12 together in pseudowhorls, erect, or a little spreading, (the uppermost whorl concealing the inflorescence or infructescence). Blade 60–105 x 20–50mm, sub-spathulate- obovate or obovate-elliptic; apex broadly tapering to almost rounded, margin entire, slightly convex; base tapering and somewhat decurrent, young leaves covered by scales on both sides, becoming glabrescent above, very densely and sub-persistently scaly beneath. Scales sub-equal, overlapping, brown to reddish-brown and shining; marginal zone thin and wide, irregularly sub-stellately angular; centre small and impressed, leaving dark pits when the scales have gone. Mid-vein narrowly impressed above, thick and obtusely prominent beneath; lateral veins 7–9 per side, the lower ones acutely spreading, the upper ones spreading at a wide angle to the mid-vein, obscurely arching inwards before the margin, faintly impressed above, a little prominent or obscure beneath, without reticulation. Petiole 15–20 x c.3mm, flattened and grooved above, very densely scaly. Bracts to 40 x 20mm, numerous, thin, purplish, persistent for a long time; outer ones elongate-triangular to ovate-acuminate and scaly outside; inner ones elongate-elliptic to spathulate. Inflorescence a 4–10-flowered umbel. Pedicels 25–32 x c.1mm, densely scaly. Calyx c.5mm in diameter, slightly oblique, saucer-shaped, shortly 5-lobed. Corolla (only known in a withered state on young fruit) tubular below, expanded at the lobes, apparently slightly zygomorphic and red when fresh, c.30mm long, scaly at the base of the tube outside, otherwise glabrous; tube c.20 x 4–5mm; lobes c.5 x 5mm, obovate. Stamens c.27mm, with linear filaments, narrower upwards, glabrous; anthers c.3.5 x 1.5mm, sub-obovate-elliptic, the base obtuse. Disc prominent, glabrous. Ovary in a developed state (or young fruit) very densely covered with reddish stellate scales, tapering distally; style 20–25mm, scaly at the base, glabrous distally; stigma 2–2.5mm in diameter, sub-peltate. Fruit 20–25 x 6–8mm, thick-fusiform, with 5 thick ribs, densely scaly.
Habitat: Terrestrial in dense sub-mossy forest, on a steep slope below the summit
Distribution: Indonesia, New Guinea (W), Arfak Mts on Mt Gwamongga, Anggi Gigi Lake, known only from the imperfect type collection.
Altitude: Around 2550m
Latin – prolificus – bearing progeny, possibly due to its being largely described in fruit.
Type: Sleumer & Vink 4372, 21 Jan. 1962. W New Guinea, Arfak Mts, Mt Gwamongga near Sujrerei, Anggi Gigi Lake (L, A, CANB, K, LAE, UC).
Occurs in Countries: ID Altitude Ranges: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:136
Creeping shrub, 0.15—0.6m; perulae persistent. Leaves elliptic, (4-)6—7.5 x 1.8-2.8cm, 2.7—3.5 x as long as broad, apex acuminate, base cuneate, lower surface with a dense greyish to fawn bistrate indumentum, the upper layer loosely ramiform, lanate-tomentose, the lower compacted; petioles clem, glabrescent. Inflorescence 6-10-flowered; rhachis less than 5mm; pedicels 10- 15mm, glabrous. Calyx 1 -2mm, glabrous or occasionally sparsely floccose. Corolla funnel-campanulate, white or pale yellow to pink, with purple flecks, 35-45mm. Ovary and style glabrous. Capsule c.10 x 4mm.
Habitat: Rocky pastures
Altitude: 3650-4400m
A distinctive species with no close allies.
Type: China, W Yunnan, Chienchuan/Mekong divide, 26°30'N, 99°40'E, 13-14000ft, vi 1923, Forrest23315 (holo. E)
Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: pink, purple, white, yellow
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):358
Spreading shrub to 2.5m. Twigs c.2mm in diameter, slender, the youngest parts densely scaly; internodes 2–8cm. Leaves 4–5 together in pseudowhorls. Blade 30–50 x 16–30mm, elliptic; apex broadly sub-acuminate, or sometimes obtusely apiculate; margin entire, narrowly revolute; base broadly tapering, sub-densely scaly initially, glabrescent above with age, persistently scaly beneath. Scales small, round, marginal zone narrow; centre thick, yellowish, slightly impressed. Mid-vein narrowly impressed above, as thick as the petiole and very prominent in the proximal part beneath; lateral veins 4–6 per side, spreading, straight, faintly impressed above, very slightly raised beneath, or commonly obscure on both sides, without visible reticulation. Petiole 4–6 x c.1mm, grooved above. Bracts to 10 x 8mm, membranous, glabrous outside, fringed with scales towards the apices; outer ones ovate, apiculate or obtuse; inner ones obovate-elliptic to elliptic. Bracteoles to 8 x 1mm, linear sub-spathulate, glabrous. Inflorescence of 5–10 flowers. Pedicels 5–10mm, slender, sub-densely scaly. Calyx c.2.5mm in diameter, obliquely disc-shaped, shortly and irregularly 5-lobed. Corolla trumpet-shaped, pure white or greenish white, or pale pink at the tube and white at the lobes; tube c.25 x 2.5–3 x 2–2.5mm, straight or slightly curved, parallel sided except slightly expanded at the extreme base, densely scaly outside; inside with short retrorse hairs in the proximal 1⁄3, glabrous distally; lobes 5–6 x c.3mm, sub-spathulate, becoming reflexed in older flowers. Stamens exserted to c.15mm from the corolla tube when the flowers are young and the style is still included in the corolla tube, erect, and recurved with the upper part of the filaments as the flowers age, when the style becomes greatly exserted; filaments almost filiform, white, laxly or more densely hairy in the proximal ¼; anthers 1.8 x 0.5mm, oblong, the base obtuse. Disc slightly prominent, sparsely erect-hairy on the upper margin only. Ovary c.5 x 1.5mm, cylindrical, sub-densely sub-appressed, short-hairy and scaly, tapering distally; style slender, scaly almost to the top and sparsely hairy in the proximal 10mm; stigma sub-globose, very shortly 5-lobed. Fruit (immature) 25–30 x 2.5–3mm, narrowly fusiform, reddish, sparsely scaly and hairy, deeply 5-furrowed lengthwise.
Habitat: In shrubberies on poor, impervious white clay, common.
Distribution: Indonesia, New Guinea (W), Sibil River Valley.
Altitude: Around 1260m
Greek – pro – in front of; andro – male. An allusion to the distinctively exserted anthers.
Type: Kalkman 4284, 15 June 1959. Orion Mts, Sibil River Valley, 1260m (L).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: green, pink, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:65
Dwarf shrub, 0.15-lm. Leaves elliptic, 2-4 x 0.7-lcm, 3-4 x as long as broad, apex cucullate, base cuneate, margin strongly recurved, lower surface with a dense bistrate indumentum, the upper layer brown to rufous, bleaching with age, ramiform, loosely lanate-tomentose, the lower radiate, compacted; petioles up to c.0.5cm, densely tomentose. Inflorescence 5 -10-flowered; rhachis c.5mm; pedicels c.lOmm, densely rufous-tomentose. Calyx c.0.5mm, glabrous. Corolla campanulate, white to pale cream, flushed rose, with purple flecks, 25-35mm. Ovary rufous-tomentose, eglandular. Capsule 6-7 x 6mm, globose.
Habitat: Open rocky pasture
Distribution: China (SE Xizang, NW Yunnan, SW Sichuan)
Altitude: 3650-4550m
Closely allied to R. roxieanum, especially var. cucullatum, but there is seldom any confusion as there is almost no overlap. Also closely allied to R. comisteum.
Type: China, Yunnan, Mekong/Salween divide, 28°12'N, 12-13000ft, ix 1915, Forrest 13348 (holo. E; iso. K).
Synonymy: R. lampropeplum Balfour f. & Forrest, Notes R.B.G. Edinb. 13: 272 (1922). Type: China, SW Sichuan, Muli Mts, 28°18'N, 12-14000ft, vi 1918, Forrest 16509 (holo. E; iso. K)
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: cream, purple, rose, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):346
Tree, 6-30m. Leaves (12-)20-37 x (4-)8.8-16cm, 2.2-3 x as long as broad, apex rounded, retuse or minutely apiculate, base ± rounded, upper surface glabrous, lower surface glabrous in juvenile state though sometimes developing a buff, continuous, adpressed tomentum, at least along a marginal band as the plant matures; petioles 2—3cm, terete, glabrous. Inflorescence up to c. 25-flowered; rhachis 20-30mm, stout; pedicels .20-25mm, densely reddish brown tomentose. Calyx c. 2mm, tomentose, lobes broadly triangular. Corolla 8-lobed, funnel-campanulate, rose, sometimes whitish at base, with a dark basal blotch and nectar pouches, sometimes also with a few flecks, 50-75mm. Stamens 16. Ovary densely rufous-tomentose. Capsule 40-50 x c. 15mm.
Habitat: Mixed woodlands
Distribution: China (W Yunnan), NE Upper Burma.
The leaves of young specimens of var. giganteum are ± glabrous beneath and only develop the typical, continuous indumentum as the plants reach maturity. Var. protistum may represent an arrested juvenile phase though typical var. giganteum does appear to be restricted to relatively low altitudes at the southern end of the range of the species while the high level plants from NW Yunnan are the more extreme examples of var. protistum.
R. protistum is closely allied to R. magnificum (q.v.)
Occurs in Countries: CN, MM Subgenus: Hymenanthes Habit: Tree Fl. Colour: rose
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):248
Mature plants with a continuous indumentum on leaf underside
Illustrations:
Synonymy: R. giganteum [Forrest ex] Tagg, Notes R.B.G. Edinb. 15: 106 (1926). Type: China, W Yunnan, eastern flank of the N'Maikha/Salween divide, 9-10000ft, m 1921, Forrest 19335 (holo. E)
Indumentum of lower leaf surface of mature plants sparse and discontinuous or denser along a marginal band with the centre sparse
Type: China, W NW Yunnan, Mekong/Salween divide 13000ft, v 1918, Forrest 16351 (holo. E)
Synonymy: R. giganteum Tagg var. seminudum Tagg & Forrest, Notes R.B.G. Edinb. 15: 108 (1926). Type: China, W Yunnan, eastern flank of the N'Maikha divide, 9000ft, Forrest 19338 (holo. E).
Shrub to 1 m, with shredding, brownish bark. Leaves obovate or narrowly obovate, rounded to the apex and base, 30-42 x 14-25 mm, dark green and ± elepidote above, densely lepidote beneath, the smaller scales almost contiguous, pale yellow, clouded or milky. Inflorescence 4-6-flowered, pedicels lepidote, 20-30 mm, rachis obvious, 4-8 mm, lepidote, glabrous. Calyx lobes 3-5-5 mm, rounded at the apex, lepidote at the base and on the margin. Corolla campanulate, 10-13 mm, tube 5-8 mm, dull crimson to plum purple, elepidote outside. Stamens with filaments pubescent over most of their length. Capsule ovoid, 4-6 mm.
Habitat: Sheltered slopes and thickets
Distribution: India (Arunachal Pradesh), NE Burma
Altitude: 3050-3950m
A distinct species, more closely related to R. brachyanthum than to R. charitopes
Type: NE Burma, Seinghku Wang, 11000 ft, vii 1926, Kingdon Ward 7045 (holo. K, iso. E)
Synonymy: R. tsangpoense var. pruniflorum (Hutchinson) Cowan & Davidian, Rhodo. Yearbook 3:90 (1948). R. sordidum Hutchinson, Rhodo. Soc. Notes 3:286 (1932). Type: Assam, Kingdon Ward 8415 (iso. E)
Occurs in Countries: IN, MM Altitude Ranges: 3,000 - 4,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: crimson, plum, purple
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):143
Shrub or small tree to 5m tall, usually non-rhizomatous; young twigs reddish brown, glabrous. Vegetative bud scales glabrous abaxially; margin unicellular-ciliate. Leaf blade membranaceous, ovate or obovate to elliptic, (5.4-)6.1-11.3(-15.2) x (2.5-)2.8-3.9(-4.2)cm; base acute to oblique; apex acute to obtuse, often mucronate; adaxial surface glabrous, occasionally with a few unicellular hairs scattered on the midvein; abaxial surface essentially glabrous, except for the presence of multicellular eglandular hairs on the midvein and/or secondary veins; margin entire, ciliate with multicellular eglandular hairs; petiole (0.1-)0.4-0.8(-1.0)cm long. Flower bud scales chestnut brown; abaxial surface glabrous; margin ciliate with unicellular hairs. Flowers appearing after die leaves have fully expanded; inflorescence a shortened raceme of 4 to 7 flowers. Pedicels 0.5-0.9(-1.2)cm long, sparsely to densely covered with multicellular eglandular hairs, or sometimes glabrous. Sepals less than 0. l-O.3(-0.4)cm long, often varying in length on the same flower; margins setose with multicellular eglandular hairs; abaxial surface glabrous to sparsely covered with unicellular hairs, sometimes also with multicellular eglandular hairs. Corolla coral-orange or salmon to deep red, with an indistinct darker red blotch on upper lobe, fragrance lacking, the tube longer than the Emb and abruptly expanding into it; upper corolla lobe (1.1-)1.2-1.7(-1.9) x l.0-1.4(-1.7)cm; lateral lobes (1.4-)1.5-2.0(-2.1) x (0.5-)0.7-1.0cm; corolla tube 2.4-2.8 (-3. l)cm long, 0. l-0.4(-0.5)cm wide at base; outer surface of corolla glabrous to sparsely covered with unicellular hairs, sometimes also sparsely covered with multicellular gland-tipped hairs that continue up the corolla lobes; inner surface of corolla sparsely to densely covered with unicellular hairs. Stamens (6.4-)6.6-7.6(-8.4)cm long, with dense terete or flattened unicellular hairs on proximal (2.4-)2.7-3.6(-3.7)cm of filament, exserted (3.8-)4.1-5.1(-5.8)cm beyond throat of corolla. Style (6.5-)7.1-8.6(-8.8)cm long, exserted (4.4-)5.0-6.5(-6.6)cm beyond throat of corolla, glabrous; stigma 0.1-0.3cm wide. Ovary (0.2-)0.3-0.4cm long, 0.1-0.2(-0.3)cm wide at the base, densely covered with multicellular eglandular hairs and with a few unicellular hairs. Capsules 1.7-2.1(-2.2) x 0.5-0.7cm, ovate-cylindric, sparsely covered with multicellular eglandular hairs. Seeds pale to dark chestnut brown, ovate or elliptic to fusiform, (1.7-)1.8-2.9(-3.2) x 0.71-1.2(-1.3)mm, body 1.0-1.3(-1.4)mm x (0.3-)0.4-0.7mm; testa expanded and dorsiventrally flattened, surrounding the body, the cells both elongate and short, scattered throughout the testa, with transverse end-walls.
Habitat: Wooded ravines along streams in mixed pine-hardwoods.
Distribution: USA: Central Georgia-Alabama line.
Altitude: 90-200m
Illustrations:
Chromosome number: In = 26 (Janaki-Ammal et al., 1950; Li, 1957)
Flowering from June to August
Rhododendron prunifolium has the most restricted distribution of any of the species in the section. It is most closely related to R.flammeum, R. cumberlandense and R. calendulaceum, but falls outside the geographical range of all of these species. It can be distinguished from the other red-flowered species by its nearly glabrous and more gradually expanded corolla tube, and by the indistinct nature of the floral blotch. Likei?. cumherlandense, R. prunifolium flowers after the leaves have expanded, but it can be distinguished from the former by its unicellular-ciliate bud-scale margins.
Synonymy: Azaleaprunifolia Small, Fl. S.E. U.S. ed. 2. 1356,1375 (1913). Type: Georgia, Randolph Co.: along branch at northern base of bluff about 2 miles north-west of Cuthbert, 21 vii 1903, R. M. Harper 1897 (holo. NY; iso. A, F, GH, MO).
Occurs in Countries: US Altitude Ranges: 0 - 1,000m Subgenus: Pentanthera Habit: Tree Fl. Colour: red
Kron, K.A. (1993) A Revision of Rhododendron Section Pentanthera. Edinburgh Journal of Botany 50(3):327
Shrub, l-2.7m. Leaves broadly elliptic, (4.5-)6-10 x 2-4.5cm, 1.8-3 x as long as broad, apex apiculate, base rounded, lower surface with a compacted, ± agglutinated, unistrate, whitish to pale brown indumentum of long-rayed hairs, or sometimes glabrescent; petioles c.lcm, glabrous, usually yellowish in herbarium specimens. Inflorescence 10- 15-flowered; rhachis 10-15mm; pedicels 15-20mm, glabrous. Calyx c.0.5mm, glabrous. Corolla campanulate, white to pale pink, with purple flecks, 25-35mm. Ovary and style glabrous. Capsule c.20 x 5mm.
Habitat: Mountain ridges, spruce forest
Distribution: China (Qinghai, Gansu, N & C Sichuan)
Altitude: 3050-4250m
R. przewalskii shares a compacted, often agglutinated leaf indumentum with R. phaeochyrsum and apparently intergrades with that species in Sichuan. The leaves of R. dabanshanense are described as being entirely glabrous which is uncommon in R. przewalskii, though, when they are glabrous the leaf undersurface and the petioles tend to be yellowish-green, a feature that is particularly mentioned in the type description of R. dabanshanense. In that species the corollas are described, possibly erroneously, as being 12mm long, about half the size of those of R. przewalskii.
Synonymy: R. kialense Franchet, J. Bot.(Morot) 9: 392 (1895). Type: China, Sichuan, aux environs de Ta-tsien-lou, Soulie 763 (iso. E). R. dabanshanense Fang & Wang, Acta Bot. Sin. 20: 358 (1978). Type: China, Qinghai, Lo Tu (Daban Shan), 2600-3200m, Chao 7212 (holo. Qinghai Biological Research Inst., n.v.)
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: pink, purple, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):360
Erect shrub to 1m. Twigs rounded, at first, laxly covered with minute pale scales, later glabrescent; internodes 3–10cm. Leaves in well-marked pseudowhorls. Blade 25–55 x 14–28mm, elliptic; apex broadly tapering, then often almost rounded and very shortly apiculate; margin entire, narrowly revolute; base broadly tapering or rounded, initially scaly on both sides, gradually glabrescent above, sub-densely scaly beneath. Scales pale reddish-brown, minute, marginal zone variously lobed; centre impressed. Mid-vein impressed above, thick and prominent beneath proximally, less prominent distally; lateral veins 5–6 per side, irregular, straight proximally, obscurely anastomosing, slightly impressed above, slightly or not raised beneath. Petiole 2–4mm, thick, flat. Bracts to 10 x 5mm, ovate to ovate-elliptic or sub-spathulate, membranous, scaly outside, or quickly glabrescent, margin fringed with scales or very shortly irregularly toothed. Bracteoles to 10mm, linear, laxly scaly. Inflorescence a 7–9-flowered open umbel. Pedicels 25–30 x c.1.5mm, densely covered with thick, lobed scales. Calyx c.3mm in diameter, oblique, irregularly 5-toothed to 1mm, but sometimes up to 3mm, elongate-triangular and acute. Corolla 30–33mm, funnel-shaped, sub-oblique, white or pale yellow, thin; tube 18–20 x 3–4 x 4–5mm, cylindrical, densely covered with thick, sub-circular, lobed scales outside, with white spreading hairs in the lower ½ of the corolla tube inside; lobes 10–12 x 7–8mm, spreading, obovate-spathulate, shallowly retuse. Stamens exserted to c.5mm, unequal; filaments linear and densely patently hairy proximally, more slender and glabrous distally; anthers c.2.5mm, oblong. Disc glabrous below, shortly yellowish hairy on the upper margin. Ovary c.5 x 2mm, sub-cylindrical, densely covered with scales and white, forwardly directed hairs, gradually tapering distally; style slender, laxly patently hairy and scaly in the lower 1⁄3–½, glabrous distally, as long as or slightly longer than the stamens; stigma thick, rounded.
Distribution: Indonesia, New Guinea (W), Balim R. Valley, at 2100m, terrestrial amongst bracken in unfertile sandy soil.
Altitude: Around 2100m
Greek – psammos – sand; genos – child. Alluding to the sandy habitat.
Known only from the type collection although a similar collection, differing in the more scaly style although similarly hairy, was found in the Lake Habbema region, on sandy soil in a forest opening.
Type: Brass 11759, Dec. 1938. New Guinea (NW), Balim R., 2100m (A, L, fragment).
Occurs in Countries: ID Altitude Ranges: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: white, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:222
Low erect shrub to 60cm. Twigs short, stiff, 1.5–2mm in diameter, densely short-hairy and caducously scaly; internodes 2–4cm. Leaves crowded in the distal part of the upper 1–2 internodes, or in loose pseudowhorls of 4–9 leaves. Blade 10–25 x 7–14mm, elliptic to broadly elliptic; apex obtuse, often minutely apiculate; margin distinctly cartilaginous and minutely crenulate; base broadly tapering to rounded, above moderately densely and sub-persistently scaly, beneath laxly and persistently scaly. Scales brown, flat, angular or sub-stellately lobed; centre small and impressed. Mid-vein narrow, flat above, slightly prominent and purplish beneath; lateral veins 5–7 per side, the lower 2–3 pairs from or from somewhat above the base, the other higher from the mid-vein, all straight below, curved distally sometimes obscure and obscurely anastomosing, faintly impressed above, a little raised beneath, reticulation obscure. Petiole 2–4 x 1–1.5mm, grooved above, purplish-red, slightly flattened. Flower buds 13–24 x 6–10mm, green. Bracts ovate-oblong to broadly-oblong-sub-spathulate, apiculate or mucronate, rigidly membranous, purplish and shiny when dry, glabrous outside, margin caducously scaly. Inflorescence a 3–4-flowered open umbel. Flowers half-hanging, without scent. Pedicels densely sub-stellately scaly and shortly hairy, 15–20mm x c.1.5mm, elongating up to 35mm in fruit. Calyx c.3mm in diameter, membranous, disc-shaped, margin wavy and reflexed, very shortly obtusely 5-lobed. Corolla 28–35 x 20–34mm, deep pink; tube 21–26 x 6–9 x 10–11mm, straight, cylindrical but flaring in the upper 3–4mm, completely glabrous outside, sparsely hairy in the basal ½ inside; lobes 10–14 x 10–14mm, obovate, reflexed to the perpendicular, overlapping c.halfway. Stamens clustered centrally just inside the mouth; filaments linear, sparsely hairy in the basal 1⁄3, glabrous distally; anthers c.2 x 1mm, broadly oblong-elliptic. Disc glabrous. Ovary ovoid-conical, densely covered with distally directed white hairs which cover scales, abruptly contracted distally; style 8–10mm, slender, glabrous, except for some hairs at the base; stigma globose, deeply 5-lobed. Fruit 10–12 x c.6mm, erect, purple where exposed and with persistent white hairs. Seeds 1.6–1.8mm, without tails 0.5mm, the longest tail 0.7mm.
Habitat: Growing amongst moss in open areas near the summit and hybridising with possibly R. celebicum although that species occurred much lower on the mountain in the forest. The hybrids were characterised by having longer leaves which lack the crenulations on the margin and longer flowers.
Distribution: Indonesia, C Sulawesi, Latimodjong Range on Mt Rantemario
Altitude: Around 3300m
Latin – pseudo – false; buxifolium – a rhododendron from Kinabalu in E Malaysia, alluding to the similarity in form.
Type: Eyma 866, 20 June 1937. Indonesia, Sulawesi, Enrekang, Rantmario, 3300m (BO, L).
Occurs in Countries: ID Altitude Ranges: 3,000 - 4,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: pink
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:214
Low shrub, 0.5-3m; young shoots covered with a rufous to grey floccose tomentum. Leaves ovate to elliptic, (3-)4-8 x (1.5-)2.3-5cm, 2-3 x as long as broad, apex acuminate, base rounded, upper surface glabrous when mature, lower surface with a floccose indumentum when young, lamina at maturity with scattered hair remains, midrib with a persistent grey tomentum composed of folioliferous hairs intermixed with stipitate glands; petioles 0.5-2cm, densely grey-tomentose, also with stipitate glands. Inflorescence lax, 5-10-flowered; rhachis c.5mm; pedicels 25-30mm, sparsely stipitate-glandular. Calyx c.2mm, glandular-ciliate, lobes rounded. Corolla campanulate, pink, with deeper lines outside and crimson flecks within, 30-40mm. Ovary densely stipitate-glandular; style glabrous. Capsule c. 10 x 4mm.
Habitat: Gravelly slopes, etc.
Distribution: Taiwan
Altitude: Around 4000m
Illustrations:
Allied to R. morii but distinguished by the small stature, small leaves, etc. If the syntypes are properly labelled then this species has a surprisingly wide altitudinal range. Wilson describes it as being dominant on mountain tops.
R. nankotaisanense Hayata, Icon. PI. Formosan. 9:66 (1920). Type: Taiwan, Nankotaisan, iv 1917, Sasaki 51 (iso. A). Said to differ from R. morii in its completely glabrous ovary and shorter (c.20rnm) pedicels. The very poor type specimen suggests a closer affinity with R. pseudochrysanihum and differs from the type description in its smaller leaves, c.6 x 2.7cm, and larger corollas up toe.32mm. More material is required before the relationship of this taxon with R. morii and R. pseudochrysanthum can be determined.
Type: Taiwan, Mt Morrison, 13000ft, xi 1906, Kawakami & Mori 2144, 2240, n.v.; Nasto, Mushazan, 6000ft, viii 1906, Kawakami & Mori 1144, n.v.
Occurs in Countries: TW Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: crimson, pink
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):273
Erect shrub, 0-6-2 m. Young growth loriform-setose, the setae usually quickly deciduous. Leaves narrowly elliptic to narrowly obovate, tapered to the base, acute at the apex, 40-60(-80) x 16-27 mm, lower surface brownish but with rather lax scales. Inflorescence l(-2)-flowered, pedicels lepidote. Calyx variably lobed or almost disc-like, not usually persistently loriform-ciliate. Corolla white or faintly flushed pink, (50~)55-65(-70) mm, tube 25-35 mm, pubescent towards the base, laxly lepidote over most of the surface. Capsule lepidote, oblong-cylindric, up to 20 mm.
Habitat: Rocks, cliffs, thickets, and on trees
Distribution: China (NW & W Yunnan), ne Burma.
Altitude: 2400-3050m
This species is represented by many gatherings and is usually easily identifiable by its 1-flowered inflorescences and small leaves. The material put together here has been variously identified as R. ciliicalyx, scottianum, ciliipes (a paratype!), dendricola, notatum and supranubium. It approaches most closely to Hutchinson's concept of R. supranubium (as judged by determinations made by him), but the type of this is different (identified here with R. pachypodum, see p. 53) and so the new name is necessary.
Type: China, Yunnan, eastern flank of the N'Maikha/Salween Divide, v 1929, Forrest 17900 (holo. E)
Occurs in Countries: CN, MM Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: pink
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):50
Shrub. Twigs 2–3mm in diameter, rounded, upper ones densely scaly and laxly hairy; internodes 3–6cm. Leaves 3–4 together in pseudowhorls. Blade 80–120 x 30–55mm, broadly elliptic to elliptic-oblong, with somewhat unequal sides; apex obtuse to rounded, often minutely retuse; margin sub-revolute; base broadly tapering to nearly rounded; glabrescent above except for some hairs at the base, laxly scaly beneath. Scales small, deeply sub-stellate-dentate, flat; centre red-brown, small, slightly impressed. Mid-vein distinctly impressed above, thick and prominent beneath proximally, less so distally; lateral veins 6–8 per side, well spaced, straight below, curved-anastomosing before the margin, slightly impressed above, a little prominent beneath, reticulation indistinct. Petiole 6–13 x 2–4mm, glabrous or with some hairs, rough, grooved above. Bracts to 13 x 10mm, ovate, glabrous, irregularly shortly sub-serrate. Bracteoles c.10mm, linear, laxly hairy. Inflorescence 7–10-flowered. Pedicels 20–30mm, densely covered with patent greyish hairs, very laxly scaly. Calyx c.2mm in diameter, disc-shaped, inconspicuous. Corolla trumpet-shaped, pale red-violet when fresh; tube c.35 x 3–4 x 3–4mm, cylindrical, base inflated and 5-lobed, hardly or not widened towards the mouth, densely covered all over with soft greyish hairs outside, also inside in the proximal ½; lobes 10–12 x 5–7mm, obovate-rounded, spreading, densely hairy outside except near the margin, glabrous inside. Stamens unequal, as long as the corolla; filaments linear, flattened, densely whitish hairy to the proximal 1⁄3, glabrous distally; anthers 2.5 x 0.8mm, oblong, base obtuse. Disc with a few scattered hairs. Ovary 4–6 x 1.5–2mm, cylindrical, 5-ribbed, densely covered with sub-patent hairs, tapering distally; style slender, c.2/3 of the length of the corolla, laxly covered with spreading hairs in the proximal 1⁄3; stigma narrowly obconical.
Habitat: In ridge forest, on humus-rich peaty soil
Distribution: Indonesia, Kalimantan, summit of Mt Kemul.
Altitude: 1800-1850m
Greek – pseudo – false; trichanthus – with hairy flower. Named originally for the hairy flowers but since this turned out to be a name that had been used before was prefixed with ‘false’.
Known only from the type collection and never cultivated.
Type: Endert 444, 21 Oct. 1925. Borneo, Central East, W Kutei, Mt Kemul, 1800m (L, BO).
Synonymy: R. trichanthum Sleumer, Reinwardtia 1960. 5: 127, non Rehder, J. Arn. Arb. 1945. 26: 480.
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:168
Shrub. Twigs slender, rounded, c.2mm in diameter, the tips densely brown-stellate-scaly when young, quickly becoming glabrescent and smooth; internodes c.6.5cm. Leaves sub-opposite or 3 together in a pseudowhorl. Blade 35–45 x 13–22mm, elliptic; apex shortly sub-acutely acuminate and apiculate; margin slightly revolute; base tapering into the petiole; stellately scaly on both sides initially. Scales minute, dendroid, each on top of minute epidermal tubercle, quickly glabrescent above, less so beneath, but finally glabrescent and rough on both sides. Mid-vein a little impressed above and raised beneath, the lateral veins inconspicuous. Petiole 5–6 x c.1mm, densely scaly. Inflorescence a 3-flowered umbel. Pedicels 12–15 x c.0.5mm, slender, very densely stellately scaly. Calyx c.2mm in diameter, minute, oblique, in the form of a short cup, sub-entire. Corolla 35–38mm, tubular below, dilated upwards, slightly zygomorphic, red; tube c.25 x 4–5 x c.8mm, pouched at the base, completely glabrous on both sides; lobes 10–12 x 8–10mm, spreading, broadly obovate-spathulate. Stamens c.30mm, slightly unequal; filaments narrowly linear, glabrous; anthers c.2.2 x 1mm, obovate-oblong, very shortly appendaged at the base. Disc prominent, glabrous. Ovary c.4 x 2mm, sub-ovoid-cylindrical, very densely stellately scaly, and abruptly tapering distally; style 25mm, stellately scaly at the base, otherwise entirely glabrous; stigma sub-globose.
Habitat: On the ridge
Distribution: Indonesia, SW Central Sulawesi, Latimodjong Range, Pintealón, spur of Mt Pokapindjang
Altitude: 2400-2600m
Greek – psilos – bare; anthos – flower. Presumably alluding to the completely glabrous corolla.
Not yet recollected since the original find.
Type: Eyma 516, 15 June 1937. Indonesia, Sulawesi, Enrekang, Pintealón, spur of Mt Pokapindjang, ridge (BO).
Occurs in Countries: ID Altitude Ranges: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:73
Small shrub, to 1 *3 m. Young shoots lepidote and with an indumentum of filiform-acicular hairs. Leaves very narrowly elliptic to very narrowly lanceolate, strongly revolute, 18-24 x 3-6 mm, with a dimorphic indumentum above of persistent, short, filiform-acicular hairs and longer, flexuous loriform setae which are ultimately deciduous; lower surface lepidote and with an indumentum of filiform-acicular hairs. Inflorescences 2-3-flowered. Calyx rim-like, fringed with long, loriform setae. Corolla funnel-shaped, 6-11 mm, the tube 3-5 mm, rose pink, glabrous and elepidote outside, puberulent inside the tube. Stamens 8-10, filaments pubescent towards the base. Ovary lepidote and pilose. Capsule lepidote and pilose, 5-6 mm.
Habitat: Open rocky places, scrub
Distribution: China (N Yunnan, SW Sichuan)
Altitude: 2800-3000m
Illustrations:
Type: China, SW Szechuan, Muli mountains, 10000 ft, viii 1918, Forrest 16812 (holo. E)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: pink, rose
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):84
Shrub, c.3m; young shoots densely rufous-tomentose. Leaves elliptic to lanceolate, 9.5-12 x 3.3-4cm,c.3 x as long as broad, apex acuminate, base ± rounded, lower surface with a floccose brown to rufous ramiform indumentum persisting only near the midrib by maturity; petioles c.2cm, pubescent. Inflorescence c.5-flowered; rhachis c.5mm; pedicels c.20mm, densely and minutely rufous-glandular. Calyx 5-6mm, glandular and tomentose, with broad rounded lobes. Corolla campanulate, white flushed pink, 30-35mm. Ovary densely brown-tomentose; style glabrous. Capsule not known.
Distribution: China (NE Yunnan)
The distinctive leaf indumentum suggests that this species may be allied to R. detersile
Type: China, NE Yunnan, Lu-quan Xian, Wumeng Shan, 26 v 1952, Mao, P. I. 1014 (holo. Hb. Inst. Bot. Kunming)
Occurs in Countries: CN Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: pink, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):337
Shrub to 1.2m; branches slender, spreading. Twigs 1–2mm in diameter, rounded, densely sub-stellately scaly and sparsely patently hairy; internodes 1–6cm. Leaves 3–12 together in pseudowhorls at the upper 2–3 nodes. Blade 20–40 x 6–12mm, spathulate to broadly elliptic, usually broadest in the upper ½; apex obtuse to rounded sometimes minutely emarginate; margin slightly revolute when living, more so when dry; base gradually tapering, scaly on both sides initially, glabrous above at maturity, sub-densely and more persistently scaly beneath. Scales flat, pale-brown, with the marginal zone relatively narrow, irregularly and shallowly lobed; centres small, and impressed. Mid-vein impressed above, strongly prominent in the proximal ½ beneath; lateral veins not visible. Petiole 1–2.5 x 1–2mm, weakly grooved above, flattened, densely scaly, not clearly distinct from the leaf base. Flower buds ovoid, to 8 x 6mm, the bracts completely appressed, shiny green when young, becoming purplish-red. Bracts to 7 x 5mm, sub-circular-ovate; outer ones obtuse, rough outside; inner ones sub-acuminate, glabrous and shiny outside; margins fringed with scales. Bracteoles c.8mm, linear-sub-spathulate, glabrous. Inflorescence of 1–4 flowers, horizontal to half-hanging. Pedicels 10–15 x c.1mm, densely scaly and minutely hairy. Calyx c.3mm in diameter, oblique, shortly cup-shaped, shortly 5-lobed. Corolla 13–16 x 16–27mm, open-campanulate, lobed to halfway or slightly more, fleshy, deep red, and sometimes with a musky scent; tube 7–10 x 5–8 x 10–12mm, laxly or sub-densely sub-stellately scaly outside, glabrous inside, straight; lobes 8–10 x 6–8mm, broadly obovate-sub-spathulate, half-spreading, not overlapping in the fully open state, scaly except near the margins. Stamens equally distributed regularly all round the mouth of the flower, sometimes with a small gap on the lower side, slightly alternately unequal, exserted to c.5mm; filaments linear, patently hairy proximally for 1–2mm, glabrous distally; anthers broadly oblong, 2mm. Disc prominent, glabrous. Ovary c.3.5 x 2.5mm, ovoid, densely covered with long, spreading, white, hairs which cover the scales, abruptly contracted distally; style 5–8mm, glabrous; stigma sub-globose, green. Fruit 15–20 x 6mm, narrowly elliptic, persistently sub-densely long-hairy, laxly scaly, the valves twisting after opening. Seeds 3.5–4.5mm, without tails 0.7–0.8mm, the longest tail c.2mm, irregularly crimped.
Habitat: Mostly epiphytic in rain forest, mossy forest or secondary forest, sometimes epiphytic in swampy habitats.
Distribution: Indonesia, Sumatra, East and West Coast.
Altitude: 1200-2560m
Latin – pubens – downy or hairy; gemma – a seed. Alluding to the tails on the seeds.
Type: Docters van Leeuwen 7747, 4 Feb. 1924. Indonesia, Sumatra, East Coast, Upper Petani Valley, Lan Debuk-dubuk marsh (BO, L).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:193
Tree to 4m. Twigs 5–7mm in diameter, angular to rounded, densely brown-scaly, early glabrescent; internodes 12cm or more, with conspicuous rounded lateral buds. Leaves laxly spirally arranged. Blade 50–90 x 30–55mm, broadly elliptic to nearly rounded or obovate-elliptic; apex shortly (5mm) acuminate or apiculate or blunt; margin entire or obscurely crenulate, slightly revolute; base broadly tapering, truncate or rounded, sometimes a little decurrent; glabrescent and impressed-punctate above when mature in dry specimens, very densely, to overlapping, reddish-brown-scaly beneath, irregularly scattered over the surface a few much larger scales. Scales rounded, lobed or stellate, with broad pale brown marginal flanges and small dark brown impressed centres. Mid-vein thick and prominent near the base, gradually flattened and sometimes grooved above, flat or weakly raised beneath; lateral veins 5–6 per side, steeply ascending and only slightly prominent above and below, the larger ones narrowly grooved above, laxly reticulate, veinlets almost obscure above, more visible beneath. Petiole 5–8 x 3–4mm, flattened without a groove when fresh, initially scaly. Flower buds c.20 x 15mm, broadly ovoid. Bracts to 13mm; outer bracts sub-circular, inner ones broadly spathulate, obtuse with silky hairs on both sides and scaly outside. Bracteoles c.10 x 2mm, linear-spathulate, densely long-hairy. Inflorescence an 8–15-flowered umbel. Pedicels 20–25 x c.0.8mm, densely scaly, without hairs. Calyx c.4mm in diameter, disc-shaped, thick-membranous, wavy and indistinctly lobed at the margin, densely scaly outside, fringed by scales which project beyond the margin. Corolla c.40 x 30mm, pink; tube 22–25 x 4–6 x 7–8mm, straight, cylindrical but flaring just below the lobes, laxly to very laxly scaly outside, glabrous inside; lobes 11–14 x 10–12mm, broadly obovate to nearly rounded, often slightly retuse. Stamens somewhat longer than the corolla tube, unequal; filaments linear below, filiform distally, glabrous; anthers c.2.5mm, broadly sub-obovate-oblong. Disc thick, glabrous. Ovary c.5 x 3mm, obconical, very densely covered with sub-patent, short yellowish hairs which cover scales, shortly contracted distally; style c.20–25mm, hairy and scaly at the base, glabrous otherwise, thick; stigma weakly lobed. Fruit 25–30 x c.6mm, sub-cylindrical, the apex acuminate, the base tapering, slightly thicker in the upper 1⁄3, densely hairy and scaly.
Habitat: In low forest and open sub-alpine shrubberies
Distribution: Indonesia, Sulawesi, Latimodjong Range: Mt Pokapindjang and its spur to Tinabang.
Altitude: 2500-3000m
Latin – pudor – modest or shameful, alluding to the colour of the corolla being like a blush.
Type: Eyma 646, 16 June 1937. Celebes, Enrekang, between Pokapindjang and Tinábang (L, BO, K).
Occurs in Countries: ID Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:133
Tree, 6-15m; perulae persistent on the apical shoots. Leaves oblanceolate, 14-20 x 5-7cm, 2.8-3.2 x as long as broad, apex ± acute, apiculate, base rounded, upper surface glabrous, lower surface with a thin whitish compacted and agglutinated indumentum; petioles terete, 2-3cm, whitish-tomentose. Inflorescence 15-25-flowered; rhachis up to 25mm; pedicels 15-30mm, sparsely hairy. Calyx c. 1mm, sparsely hairy. Corolla 6-8-lobed, ventricose-campanulate, rose-pink with a dark basal blotch, 30-35mm. Stamens c. 16. Ovary whitish-tomentose. Capsule not seen.
Habitat: Mixed forests
Distribution: China (S Xizang)
Altitude: 3600-3800m
A distinctive species on account of its persistent perulae, a feature that is retained in cultivation.
Type: China, Xizang, Chayul Chu, Lung, 12500ft, 29 iv 1936, Ludlow & Sherriff 1386 (holo. BM; iso E)
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: rose
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):247
Small loosely branched shrub, elm, with short slender branches; young shoots clothed with grey flattened hairs, becoming ± glabrescent when older. Leaves deciduous; spring leaves oblong-elliptic 2-2.5 x 0.6-0.8(-l)cm, 2.5-3.2 x as long as broad, apex acute-apiculate, base cuneate, margins entire, ciliate, upper surface with lamina glabrescent, indumentum ± persistent on midrib and lateral veins, lower surface ± densely brownish-sericeous, indumentum more dense on midrib; petioles densely villose. Inflorescence 1-2-flowered; pedicels c.lOmm, pilose. Calyx 5-6mm, sericeous-pilose. Corolla funnel-campanulate, 25-30mm, purplish red; tube 15mm, glabrous. Stamens 10, filaments minutely pilose below. Ovary densely sericeous-pilose; style glabrous. Capsule unknown.
Distribution: China (N Guangxi)
Altitude: Around 970m
Illustrations:
Known only from the type. Closely allied to R. simsii but generally more densely hairy.
Type: China, Guangxi, Lungsheng Hsien, Pingshui Hsiang Hungtan, 970m, 12 vi 1955, Kwangfu Exp. 536 (holo. SZ)
Occurs in Countries: CN Altitude Ranges: 0 - 1,000m Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: red
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):110
Named after A.A. Pulle, eminent Dutch botanist who collected in New Guinea.
Type: Römer 1198, Nov. 1909. New Guinea (W), Hellwig Mts, Mt Agathodaemon, 2000–2500m (BO, lectotype, L, fragment).
Synonymy: R. minimifolium Wernham, Trans. Linn. Soc. London, II, Bot. 9: 98, 1916, pro parte.
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:54
Leaves 6–10 x 4–6mm. Corolla 17–20mm. Pedicels densely scaly and entirely without hairs, otherwise as var. pulleanum.
Habitat: Common on open sandy ridges and in alpine shrub vegetation
Distribution: Indonesia, New Guinea (W), near Lake Habbema; Mt Antares.
Altitude: 2300-3400m
Latin – maiusculus – somewhat greater, alluding to the larger leaves and flower.
Differing from the type variety in the larger leaves and corolla. This variety was said by Sleumer (1966) to approach R. hameliiflorum in many respects. It differs, however, in its non-scaly bracts.
Type: Brass 10834, Oct. 1938. New Guinea (W), 20km N of Lake Habbema, 2300m (A, L, fragment).
Shrub to 2m. Twigs rounded, covered with stalked scales when young, older parts glabrescent though still rough with scale stalks. Leaves densely spirally arranged. Blade 4–9 x 2.5–5mm, elliptic or elliptic-obovate; apex obtuse or sub-acute; margin revolute, the whole blade convex when dry; base tapering, deep green above, paler beneath, glabrescent above, very laxly scaly beneath. Scales large, reddish-brown, sessile, circular; marginal zone narrow, entire or nearly so; centre thick, slightly or not impressed. Mid-vein obscure above, slightly prominent beneath, lateral veins not visible above, faintly so beneath. Petiole 1–1.5mm, slender. Bracts to 7 x 4mm, ovate to sub-acute, glabrous except for the ciliate margins. Bracteoles 5–7mm, linear to narrowly spathulate, very shortly hairy. Inflorescence of solitary flowers, rarely pairs. Pedicels 5–15mm, very slender, densely scaly and finely patently hairy. Calyx oblique, scaly, irregularly lobed, 3 lobes shortly triangular to 1mm, 2 others larger to 3mm, spreading. Corolla 13–20mm, red; tube 10–12 x 3–4 x 5–6mm, cylindrical, straight, densely scaly outside, glabrous inside; lobes 2–4 x 2–2.5mm, erect, obovate-elliptic. Stamens not or slightly exserted; filaments linear, filiform, glabrous; anthers c.1mm, oblong-obovate, truncate. Disc glabrous. Ovary c.3 x 1mm, ovoid-conical, tapering distally, entirely covered with scales; style to 10mm, scaly at the base, otherwise glabrous; stigma club-shaped, moderately thickened, indistinctly 10-lobed.
Habitat: Terrestrial or epiphytic, in mossy forest, or in dense low scrub on exposed summits or in open moss-covered Vaccinium forest
Distribution: Indonesia, New Guinea (W), Nassau Mts, Mt Jaya, Mt Doorman, Hellwig Mts and Mt Goliath.
Altitude: 1420-3450m
Distinctive in the relatively large, well-spaced scales on the small leaves.
Creeping shrublet to 10 cm. Young growth lepidote and puberulent. Leaves elliptic to broadly elliptic, acute to rounded at the apex, cuneate at the base, 9-19 x 4-5-12 mm, upper surface dark green, ± elepidote, margins revolute, lower surface pale greyish green with distant, small, ± equal, golden scales. Inflorescence 1-3-flowered, pedicels 10-20 mm in flower, ultimately 38-60 mm and rigid and erect in fruit. Calyx reddish, deeply lobed, the lobes ovate-oblong or oblong, 2-3-5 mm, lepidote. Corolla 11-21 mm, tube 7-14 mm, mouth slightly oblique, pink or purple, densely pilose all over the surface, scales few, mostly on the lobes. Stamens 10, filaments pubescent towards the base. Ovary densely lepidote, style impressed, straight, somewhat clavate, shorter than the stamens. Capsule 7-10 mm, lepidote.
Habitat: Open places on slopes, rocks and banks
Distribution: Nepal, India (Sikkim, Arunachal Pradesh), Bhutan, NE Burma, China (S & SE Xizang)
Altitude: 3500-4250m
Illustrations:
Type: Sikkim Himalaya, about the Semu and T'hlonok rivers, Hooker (holo. K)
Occurs in Countries: BT, CN, IN, MM, NP Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: pink, purple
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):120
Robust shrub. Leaves oblong-lanceolate to oblong, 6-9 x 2.5-3.5cm, c.2.5 x as long as broad, base cuneate, margin revolute, upper surface glabrous and shining, lower surface glabrous; petioles 1-1.2cm, puberulent when young. Inflorescence 10-12-flowered; pedicels slender, 10-16mm, densely villous-tomentose. Calyx c.lmm, lobes sparsely pubescent. Corolla campanulate, 25-30mm. Ovary sparsely white-villous; style glabrous. Capsule not known.
As Rehder & Wilson suggest, R. purdomii is probably allied to R. przewalskii (subsection Taliensia) but it differs in its sparsely hairy ovaries, etc. It is only known for certain from the type collection, which is poorly dried, though four specimens from Shaanxi, Licent 2750 & 2845 and two collected by the Rev. Hugh are a fair match.
Two further entities have been collected in Shaanxi. The first, represented by Purdom 3 and three Hugh specimens, has an agglutinated, compacted leaf indumentum (as is usual in R. przewalskii) and a capsule up to 30mm long (longer than in that species). The second, represented by a Hugh specimen from Ha Hsien, differs in its persistently stiffly hairy capsule and in the more pronounced hairs on the pedicels. The leaves are apparently glabrous at maturity. Further flowering material is required before the status and affinities of these two entities, at present only known from fruiting material, and of R. purdomii itself can be confirmed.
Type: China, Shaanxi, Tai-pei-shan, 1910, Purdom 4 (holo. A; iso. K).
Subgenus: Hymenanthes Habit: Non-Tree
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):429
Shrub to 50cm. Twigs 1–1.5mm in diameter, sub-densely covered with orange-brown stellate scales; internodes 1.8–5.5cm. Leaves 3–6 together in pseudowhorls with several subulate cataphylls along the internodes. Blade 27–60 x 4–7(sometimes up to 11)mm, linear-elliptic; apex obtuse or broadly acute; margin flat; base tapering; scaly on both sides when young, glabrescent above with age, laxly persistently scaly beneath. Scales with the marginal zone irregularly, often obtusely, lobed, flat, pale; centre weakly or not impressed. Mid-vein impressed above, strongly obtusely prominent beneath; lateral veins obscure. Petiole 2–5mm, scaly. Inflorescence 2–4-flowered. Pedicels 12–15mm, slender, sub-densely orange-brown, stellately scaly. Calyx c.2.5mm in diameter, disc-shaped, oblique, scaly, very shortly obtusely 5-lobed. Corolla 27–32mm, tubular, somewhat zygomorphic, reddish-purple or pale pink, laxly sub-stellately scaly or glabrous outside, glabrous inside; tube 17–22 x c.4 x 6–7mm, sub-cylindrical, base pouched; lobes 7–9 x 5–6mm, half-spreading, broadly-obovate. Stamens unequal, the longest exserted to c.3mm; filaments linear, glabrous; anthers c.1.5mm, obovoid. Disc prominent, glabrous. Ovary c.4 x 1.6mm, fusiform, tapering both proximally and distally, densely scaly; style slender, glabrous, as long as the stamens; stigma sub-oblique, globose, purple.
Habitat: Epiphytic on tall trees in mossy forest.
Distribution: Indonesia, New Guinea (W), Perameles and Schrader Mts, and Idenberg R., near Bernhard Camp.
Altitude: 1100-2150m
Latin – purpureo – purple; florum – flower. Alluding to the flower colour.
Type: Pulle 563, 5 Dec. 1912. New Guinea (W), Perameles Mts, 1100m (BO, L).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: pink, red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:225
Dwarf spreading shrub to 50cm. Twigs 1–1.5mm in diameter, densely covered with sessile and shortly stalked brown scales, older parts warty. Leaves densely spirally arranged at the ends of the twigs. Blade 4–10 x 2–5mm, ovate-elliptic; apex shortly acuminate, sub-acute, often with a paler apiculus; margin distinctly crenulate at least in the distal ½, flat, cartilaginous and paler than the lamina; base tapering or almost rounded, laxly scaly on both sides initially, becoming glabrescent above, more persistently scaly beneath. Scales irregularly stellate, flat, not or slightly impressed. Mid-vein slightly impressed above, raised beneath, often obscure; lateral veins obscure. Petiole 1–2mm. Flower buds 10–12 x c.5mm, ovoid. Bracts to 12 x 6mm, membranous, ovate-acuminate, shortly subulate or apiculate, outer scaly outside, inner ones completely glabrous. Bracteoles to 8mm, linear. Inflorescence a solitary flower or up to 3 together hanging from an erect pedicel. Pedicels 6–20mm, densely covered with stalked stellate scales (without hairs). Calyx 2–3mm in diameter, disc-shaped, shortly sub-acutely 5-lobed, densely scaly. Corolla 15–23mm, tubular to sub-campanulate, slightly oblique, red, turning to orange with age; tube 10–16 x 3–4 x 5–6mm, laxly scaly proximally, or mostly glabrous outside, glabrous inside; lobes 5–9 x 5–9mm, semi-erect or spreading, obovate to sub-circular, slightly retuse. Stamens unequal, ½ as long as the corolla; filaments linear, glabrous; anthers c.1.2mm, sub-orbicular, black. Disc glabrous. Ovary 3–4 x c.2mm, ovoid-conical, abruptly contracted distally, densely stellate-scaly; style 2–4mm, columnar, glabrous; stigma globose, 5-lobed.
Habitat: Growing in alpine grassland, margins of sub-alpine forest, on exposed sandstone, in shallow sandy soil or on peaty soil at the base of rocks. Locally common.
Distribution: Indonesia, New Guinea (W), Main Range from Mt Carstensz, where it is said to be frequent, to the Oranje Mts.
Altitude: 3200-3900m
Latin – pusillus – very small, alluding to the habit of the plant.
Type: Versteeg (Pulle) 2499, 17 Feb. 1913. New Guinea (W), Oranje Mts Meer-bivouk, 3600m (BO, K, L, U).
Synonymy: R. candidapiculatum Wernham, Trans. Linn. Soc. London, II, Bot. 1916. 9: 96.
Occurs in Countries: ID Altitude Ranges: 3,000 - 4,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: orange, red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:119
Slender shrub. Twigs c.1mm in diameter, rounded, laxly to sub-densely covered with flat appressed scales, without hairs, older parts glabrescent and smooth; internodes 2–6cm. Leaves 5–7 together in pseudowhorls. Blade 25–45 x 5–12mm, narrowly elliptic; apex rounded or obtuse; margin narrowly but distinctly revolute; base tapering and slightly decurrent, when young, sub-densely scaly on both sides; at maturity glabrescent and blackish spotted; minutely rugose above; sub-densely persistently scaly beneath. Scales irregularly crenate, lobed in the marginal brown zone; centre darker and slightly impressed. Mid-vein markedly impressed above, thick and very prominent beneath; lateral veins inconspicuous. Petiole 2–4 x c.1mm, flattened, densely scaly. Bracts to 8 x 4mm, ovate-elliptic, membranous, glabrous outside, shiny, margin with fragile scales. Bracteoles c.6mm, linear-filiform, glabrous. Flowers solitary or in twos. Pedicels 10–15mm, slender, densely stellate-scaly, without hairs. Calyx c.2.5mm in diameter, disc-shaped, oblique, obscurely sub-acutely 5-lobed, densely scaly outside. Corolla 15–18mm, campanulate, thin, red, 5-lobed halfway; tube 6–9 x c.4 x 15–20mm, sub-densely to laxly scaly outside, glabrous inside; lobes 6–8 x 6–8mm, broadly obovate-spathulate, slightly spreading. Stamens exserted to c.5mm, unequal; filaments linear, slightly dilated at the base, becoming filiform distally, glabrous; anthers c.1.8 x 1mm, ellipsoid. Disc prominent, glabrous. Ovary c.3 x 1.5mm, ovoid-conical, densely stellate-scaly, abruptly contracted distally; style c.8mm, slender, glabrous; stigma obconical, deeply 5-lobed.
Habitat: On a ridge in forest
Distribution: Indonesia, N Sumatra, Gajo Lands, Mt Goh Lembuh.
Altitude: Around 1850m
Greek – pyrros – flame coloured; phorein – to have. Alluding to the colour of the flowers which were described on the label as ‘fire red’.
Known only from the type collection.
Type: Steenis 9192, 23 Feb. 1937. Sumatra, Atjeh, from summit G. Lembuh to camp ‘Halfweg’, 1850m (BO, L).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:195
Named after J.F. Quadras, a Spanish friend and associate of Vidal who collected in the Philippines.
Type: Vidal 819. Philippines, Luzon, Albay, Mt Mayon, 1330–2000m (K).
Occurs in Countries: PH Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Tree Fl. Colour: orange, red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:51
Small tree or shrub. Leaves 15–28 x 5–10mm, broadly and shortly obovate. Corolla 10–16mm, sub-campanulate broadening distally, scaly and at least laxly hairy outside. Pedicels hairy and scaly. Ovary with scales only.
Habitat: Dense moss forest on summits, sometimes epiphytic
Distribution: Philippines, Mindanao, Leyte, Negros, S Luzon.
Altitude: 1600-2440m
Named after Davao, the province from which this was first collected.
Type: Williams 2543. Philippines, Mindanao, Davao, Mt Apo, 2440m (PNH†, GH, K, NY, US).
Synonymy: R. quadrasianum f. davaoense H.F.Copel., Phil. J. Sc. 1929. 40: 143, t.1, f.9, 10. R. quadrasianum f. negrosense H.F.Copel., Phil. J. Sc. 1929. 40: 142, t.1, f.6.
Small tree or shrub. Leaves narrowly obovate, 8–11 x 2–4mm. Corolla tubular below, sub-campanulate distally, c.10mm, hairy and scaly outside. Pedicels hairy, almost without scales. Ovary with scales only.
Habitat: Open exposed ridges
Distribution: Philippines, Luzon, Mt Tapulao, Mt Pinatubo, Mt Sisipatan and Mt Paraga.
Altitude: 1800-2400m
Latin – intermedius – between or intermediate, alluding to its intermediate characters.
Type: Curran & Merritt F.B. 8063. Luzon, Zambales, Mt Tapulao (PNH†, US).
Shrub or small tree to 7m. Leaves obovate to spathulate. Blade 13–25 x 5–10mm. Petiole 2–4mm. Corolla strictly cylindrical, red, 20–25 x 12–13mm; tube 16–20 x c.4 x c.5mm, laxly hairy and scaly outside; lobes c.5 x 4mm. Anthers 0.7mm. Pedicels c.8 x 0.75mm, hairy and scaly. Ovary 4 x 2mm, scaly only.
Distribution: Philippines, Mindanao, Camiguin. Mossy forest, sometimes epiphytic
Altitude: 1000-1600m
Named after the mountain on which the type was collected.
Type: Hutchinson 4705, May 1906. Mt Malindang, Misamis province, Mindanao (PNH†, BO, K, NY, US).
Synonymy: R. malindangense Merr., Phil. J. Sc. (Bot.) 1908. 3: 256, 381.
Mostly a small tree. Leaves obovate, 11–20 x 4–8mm. Corolla to 17 x 15mm, tubular, shortly hairy and scaly outside, the lobes half-spreading. Pedicels hairy without, or with just a few, scales. Ovary scaly, without hairs.
Distribution: Philippines, Luzon, Mindoro. Mossy forest
Altitude: 1200-2500m
Named after the mountain from which it was described.
Type: Merrill 3215. Luzon, Bataan, Mt Mariveles (PNH†, BO, K, NY, US).
Shrub or small tree to 3m. Twigs rounded, slender, younger parts densely patently short hairy and laxly to sub-densely brown scaly; internodes 0.5–10cm. Leaves 4–8 in lax pseudowhorls. Blade 15–30 x 7–13mm, obovate, more rarely elliptic, sub-sessile; apex broadly obtuse or rounded, sometimes slightly retuse, terminal gland small and on the undersurface within the margin; margin revolute; base tapering, dark green and shiny above, paler and dull beneath; laxly silvery scaly initially above, gradually glabrescent, the pits of the scales remaining, sub-densely scaly beneath often with short hairs proximally especially when young. Scales small, circular or nearly so; marginal zone narrow, entire to crenulate; centre thick, brown, distinctly impressed. Mid-vein impressed above, prominent beneath especially in the proximal ½; lateral veins 2–4 per side, curved-ascending and anastomosing, minutely depressed above, slightly raised beneath, often inconspicuous. Petiole very short, to 1.5mm (the blade being decurrent nearly to the base), shallowly grooved, sub-densely brown-scaly and shortly white hairy. Flower buds c.10 x 6mm, ovoid or ellipsoid. Outer bracts ovate to sub-circular, inner ones broadly obovate-spathulate, obtuse or minutely apiculate, with a few scales distally outside and densely appressed hairy outside in the exposed areas, glabrous inside, shortly ciliate on the margins. Bracteoles to 6mm, filiform, glabrous, or with a few scales and hairs. Inflorescence of solitary flowers or in twos, rarely 3 or 4 in an umbel, half-hanging to hanging. Pedicels 10–15mm, slender, densely, shortly, patently hairy, laxly to sub-densely scaly. Calyx small, disc-shaped, 5-lobed, scaly and hairy; lobes c.0.5mm, broad-ovate and obtuse. Corolla 12–18 x 13–15mm, red, tubular, slightly oblique and dilated distally; tube 10–13 x 5–6 x 7–8mm, sub-densely scaly and with some scattered hairs at the very base outside (but not hairy all over the tube), glabrous inside; lobes 5–6 x 5–6mm, somewhat irregular, broadly elliptic-obovate or sub-circular, finely irregularly denticulate or entire at the apex, semi-erect to spreading, overlapping to c.½. Stamens loosely clustered on the lower side of the mouth, exserted to c.4mm; filaments linear, glabrous; anthers c.1mm, sub-globose. Disc glabrous. Ovary c.2 x 1.5mm, obliquely cylindrical, gradually tapering distally, grooved, densely scaly; style c.8mm, glabrous; stigma rounded, irregularly lobed. Fruit 10–15 x 2.5–3.5mm, obliquely cylindrical, densely brown-scaly. Seeds c.2mm including the narrow tail at both ends.
Habitat: Terrestrial, or rarely epiphytic. On rocky open slopes. Aabundant
Distribution: Philippines, Luzon, Albay Province, Mayon Volcano, Mindoro, Mt Isarog.
Altitude: 1330-2100m
Flowers and fruits. May–June, Sept.
Sleumer (1966) notes that ‘This is the “typical” form, i.e. the first one described of this variable species, collected again and again on Mayon Volcano, but not found elsewhere [see above]. Within the general aspect of R. quadrasianum s.lat., this is a homogeneous, glabrescent, big leaved form’. Sleumer reduced the number of infraspecific taxa that Copeland (1929) recognised. It is still not a very satisfactory treatment and needs much more field work to really understand the patterns of variation on the different mountains and islands in the Philippines. Certainly the variants seem less well differentiated than the discovireyas in New Guinea, and it was impossible to include R. quadrasianum in the key to Discovireya for West Malesia because of the complex morphological variation. This account largely follows Sleumer but the non-Philippine elements are excluded (see R. cuneifolium, R. borneense and R. monodii).
Shrub to 2m, or rarely a tree to 6m. Leaves 10–22 x 3–6mm, narrowly elongate-obovate. Flower buds hairy and scaly outside. Corolla 10–16 x 9–11mm, elongate-campanulate, red to orange; tube straight, narrowly funnel-shaped, scaly and at least laxly hairy outside. Pedicels hairy and densely scaly. Ovary scaly, without hairs.
Distribution: Philippines, Mindoro, Biliran, Luzon, Negros. Mossy oak (Castanopsis) forest, also in open secondary areas; locally common
Altitude: 1300-2400m
Latin – Rosmarinus officinalis L. – the herb ‘rosemary’ (Lamiales); folium – leaf. Alluding to the resemblance of the leaves to those of rosemary.
This variety has been in cultivation since at least 1980 from an unknown source. It has neat foliage and small, freely produced pink flowers; sometimes a pink tube with orange lobes.
Type: Vidal 1530, Bontoc (K, A, FI).
Shrub or small tree to 6(-8)m tall; young twigs dark to reddish brown, glabrous; bark grey-brown, corky, fissured into irregular ± longitudinally elongated plates; new foliage shoots arising from axillary buds associated with the lowest scaly leaves of the present year's shoots (i.e. within the terminal bud), and from some terminal buds. Vegetative bud scales glabrous abaxially, sparsely unicellular-pubescent adaxially; margin fringed with unicellular hairs, with multicellular glandular hairs intermixed, especially just below apical region; lowermost scales with long aristate apices or rudimentary blades. Leaves deciduous, dark green adaxially, pale green abaxially, often tinged with reddish purple along margin, turning red in autumn, pseudo-verticillate, with (3-) 5 leaves clustered at apex of shoot. Blade membranaceous, broadly rhombic-elliptic to obovate, 1-5.8 x0.6-3.6cm; base cuneate to attenuate; apex acute to rounded, occasionally slightly emarginate, with a short mucro; midvein and secondary veins slightly to moderately raised and visible abaxially; adaxial surface sparsely covered with straight to curled unicellular hairs to glabrous, sometimes also with scattered multicellular eglandular hairs, especially near midvein or margin, the midvein ± densely covered with flattened, + straight to curled unicellular hairs, sometimes with scattered multicellular gland-headed hairs and/or eglandular hairs; abaxial surface glabrous to moderately unicellular-pubescent, especially at base of blade, the midvein or its lateral surfaces sparsely to densely covered with long, straight to crisped, unicellular hairs, especially towards base, or such hairs lacking, often with scattered multicellular gland-headed hairs and eglandular hairs, the secondary veins glabrous to sparsely unicellular-pubescent, especially at base of blade; margin entire, with fringe of unicellular hairs, often with multicellular eglandular hairs intermixed; petiole l-5mm long, very sparsely to densely covered with unicellular hairs, sometimes with a few multicellular gland-headed and/or eglandular hairs, the base of petiole slightly expanded at point of attachment. Flower bud scales larger, but otherwise similar to those of vegetative buds. Flowers appearing with the leaves; inflorescence a reduced raceme of 1 to 3 flowers. Pedicels 6-30mm long, glabrous to moderately covered with multicellular gland-headed or eglandular hairs. Calyx lobes narrowly triangular, 0.8-3 x 0.5-1.5mm; apex acute or acuminate to rounded; margin usually fringed with multicellular gland-headed and/or eglandular hairs, occasionally these very sparse and margin essentially glabrous, sometimes with unicellular hairs; adaxial surface glabrous; abaxial surface glabrous, rarely with a few multicellular gland-headed hairs at extreme base. Corolla white, with greenish spots on upper three lobes, slightly zygo-morphic, broadly rotate-funnelform, the tube shorter than the limb and gradually expanding into it; corolla lobes ± all similar, 1-2 x 0.8-1.7cm; corolla tube 0.7-1.2cm long; outer surface of corolla glabrous; inner surface of corolla sparsely unicellular-pubescent towards base. Stamens 10, declinate, variable in length, 0.9-2.2cm long, included; filaments glabrous distally, becoming densely covered with flattened unicellular hairs proximally. Ovary 2-3.5mm long, densely covered with unicellular hairs to nearly glabrous, with unicellular hairs limited to apex; style declinate, 1.3-2.5cm long, glabrous distally, often sparsely covered with unicellular hairs on proximal portion. Capsules ovoid to±cylindric, often curved, 0.9-1.6x0.4-0.6cm, glabrous to sparsely unicellular-pubescent, especially at apex. Seeds light brown, angular-ovoid to ellipsoid, 2.5-3 x0.7-lmm; testa tightly appressed to body, tails lacking, the cells elongate. Cotyledons with multicellular gland-headed hairs along margin and well-developed reticulate venation.
Habitat: In deciduous or coniferous forests and thickets
Distribution: Japan (Honshu, Shikoku)
Altitude: 300-1700m
Rhododendron quinquefolium is probably closely related to R pentaphyllum since, in addition to the characters of the section, the two species share few-flowered inflorescences, c.l-6cm long and more or less 5-whorled leaves at shoot apices, a lack of gland-headed hairs along the leaf margins, and glabrous or nearly glabrous fruits. Their phenetic similarity is such that they have occasionally been confused (see Rehder, 1916) and misidentified specimens are common. However, the two are easily distinguished because R. quinquefolium usually blooms with the leaves (vs. before the leaves in R. pentaphyllum) and has white (vs. pink) corollas. The vegetative shoots of R. quinquefolium arise from axillary buds within the terminal floral bud, whereas those of R. pentaphyllum are associated with foliage leaves below the terminal bud (see key). In addition, the leaves and petiole margins of this species lack the conspicuous eglandular fringe so characteristic of R. pentaphyllum. Rhododendron quinquefolium also has a distinctive corky bark.
The difference in position of the vegetative buds led Wilson (1921) to place Rhododendron quinquefolium and R. pentaphyllum in two different sections (i.e. sect. Tsutsusi and sect. Rhodora), a placement followed by Sleumer (1949, 1980). However, Wilson (1921: 87) noted that Tn habit of growth, arrangement and shape of leaves and in the shape of the flowers it superficially resembles R. pentaphyllum Maxim.'. The similarity between these two species was also recognized by Maximowicz (1887). It is our opinion that these similarities are more than superficial; they are likely synapomorphic and indicative of a close relationship.
This horticulturally important species (Wilson, 1921) has been illustrated by Komatsu (1912) and Makino (1956).
Synonymy: Azalea quinquefolia (Bisset & S. Moore) Olmsted, Coville, & Kelsey, Stand. PI. Names 27 (1923). Type: Japan, Honshu, Nikko, 23 v 1876, Bisset 233 (lecto., designated here, E). Rhododendron quinquefolium Bisset & S. Moore f. speciosum N. Yonezawa, J. Phytogeogr. Taxon. 35(2): 101 (1987). Type: Japan, Honshu, pref. Shiga, Mt Hira, c.l020m, 24 v 1987, N. Yonezawa s.n. (nolo., KANA #121504, n.v.).
Occurs in Countries: JP Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Pentanthera Habit: Tree Fl. Colour: green
Judd, W.S. & Kron, K.A. (1995) A Revision of Rhododendron VI. Subgenus Pentanthera (Sections Sciadorhodion, Rhodora and Viscidula). Edinburgh Journal of Botany 52(1):16
Variably sized shrub, 0.2-3 m. Young shoots lepidote and glabrous or puberulous with fine filiform-acicuiar hairs. Leaves broadly obovate to oblong-elliptic, 15-50 x 7-30 mm, upper surface glabrous except for a few filiform-acicular hairs along the midrib, glabrous beneath, shining white-papillose, densely lepidote with almost rimless scales. Inflorescences 2-3-flowered, pedicels lepidote and glabrous or puberulent, up to 15 mm. Calyx rim-like, densely lepidote, glabrous. Corolla openly funnel-shaped, 7-17 mm; tube 3.5-8.5 mm, white to pale or deep pink, somewhat puberulous within. Filaments sparsely puberulous towards the base. Ovary densely lepidote, glabrous, style glabrous and elepidote. Capsule lepidote, 7-10 mm.
Habitat: Thickets, forest margins, scrub and rocky slopes, (800-)2750-4300 m
Distribution: China (N, NW, W & C Yunnan, SW Sichuan)
Illustrations:
An extremely variable species in terms of size, leaf size and shape, and corolla size and colour. Three variants may be recognised: a) smallish plants (up to 0.6 m), with large, broad, rounded leaves, short pedicels and corollas 14-17 mm; b) taller plants, up to 3 m, with smaller, relatively longer, more acute leaves, longer pedicels and corollas 9-14 mm; and c) very small, intricately branched plants with small, rounded leaves, short pedicels and corollas 7-9 mm. These three types intergrade considerably, and often all occur in the same general area. Therefore they cannot be given formal recognition.
Type: China, Yunnan, in monte He-chan supra Lankong, 3000 m, Delavay 299 (holo. P—n.v., iso. E)
Synonymy: R. motsouense Leveilie, Feddes Rep. 13:148 (1913). Type: China, Yunnan, montagnes aux environs de Mo-tsou (fleuve bleu), 800 m, Maire (holo. E). R. iochanense Leveilie, nora. nud.
Occurs in Countries: CN Subgenus: Rhododendron Habit: Non-Tree
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):80
Small shrub to 1 m. Leaf-bud scales deciduous. Leaves obovate-lanceolate or ovate, revolute, 10-18 x 3-6 mm, broadly tapering at the base, tapering or rounded to the acute or obtuse apex, lepidote and loriform-setose on the upper surface and margin, densely lepidote and loriform-setose beneath. Inflorescence 8-10-flowered, pedicels lepidote and loriform-setose. Calyx lobes 1-2 mm, lepidote outside, margins loriform-setose, glabrous within. Corolla purplish white, 8-10 mm, lepidote outside, pilose within the tube and at the mouth. Stamens 5. Ovary lepidote. Capsule unknown
Distribution: China (NW Sichuan)
Apparently only known from the type collection. From the description, it seems similar to R. trichostomum but is distinguished by the presence of loriform-setae on the leaves and pedicels and by the lepidote corolla tube.
Type: China, Szechuan, SW of Kangtinghsien (formerly Tatsienlu), 3040 m, 19 v 1930, Cheng 921 (holo. CHENGDU—n.v.)
Occurs in Countries: CN Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: white
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):169
Latin – radians – spreading or radiating out from a common centre, alluding to the arrangement of the flowers.
Type: Rachmat 885, Nov. 1913. Indonesia, Celebes, Central part, G. Sinadji (BO, K, L).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Fl. Colour: pink, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:169
Scales more deeply stellate-incised at the marginal zone, sub-dendroid, each on top of a more distinct minute epidermal elevation than in var. radians. Outer bracts obtuse, long hairy at the apex or practically glabrous, somewhat shining. Style hairy and scaly almost to the top.
Habitat: In low forest, on volcanic grit or sandy soil.
Distribution: Indonesia, Sulawesi, (NE) Minahasa area on several volcanoes, (W) Mt Sojol.
Altitude: 1500-1700m
Named after the Minahasa region where it was first found.
Sleumer (1966) notes: ‘The corolla of the type specimen from Mt Soputan is given as white and very fragrant by the collector, and other collections from that region also seem to have had white corollas, as far as this can be concluded from the dried material. Only Koorders says, that his specimen, also collected on Mt Soputan, has dark red corollas, but no corollas are preserved in his herbarium. Boesveld, the collector of the type specimen of var. minahasae, says on the label, that he has found “a similar Rhododendron on Mt Klabat with red corollas” but I have seen no material from there which would agree with that. It remains open whether var. minahasae has always white flowers, or if, possibly, both white- and red-flowered forms exist together’. No recent collections have had red flowers so that red-flowered forms seem highly doubtful. A recent collection from Mt Sojol in west Sulawesi may represent a new taxon. It agrees in most respects with the description of var. minahasae but it has rounded scales which are if anything slightly impressed into the leaf surface rather than raised. It could be more closely allied with var. pubitubum although it has simple hairs on the outside of the corolla tube near the base. Further collections are needed to understand the variation properly.
Type: Boesveld 6. Celebes, Menado: Tondano, Soputan Volcano, 1500–1700m (BO, L).
Synonymy: R. verticillatum (non Low) Koord., Minah. 1898. 514.
Differing in the corolla tube being densely hairy throughout its length and with the lobes hairy outside along the middle line.
Habitat: In open places, peaty soil or granite
Distribution: Indonesia, Sulawesi (C), Masamba District, Tomadu-Singkalong and Limbung.
Altitude: 1700-2000m
Latin – pubi – softly hairy; tubus – a tube. Alluding to the tubular, hairy flowers.
The isotype of var. radians in Leiden actually has hairs on the outside of the corolla tube near the base, and plants collected on Mt Sojol have hairs up to halfway up the outside of the corolla tube. Thus the main distinction between R. radians and R. pubitubum is not satisfactory and R. pubitubum is reduced to varietal status. The plants with hairs up to halfway up the corollas are in cultivation; the fully hairy form is not as far as is known being cultivated.
Type: Eyma 1441, 30 July 1937. Celebes (C), Masamba, Tomadu-Singkálong, 2000m (L, BO).
Synonymy: R. pubitubum Sleumer, Reinwardtia 1960. 5: 126.
Shrub. Twigs rounded, tips laxly hairy and scaly; internodes 3–12cm. Leaves 5–12 in tight pseudowhorls. Blade 25–55 x 12–25mm, ovate to elliptic, sub-sessile; apex shortly obtusely pointed, sometimes almost rounded; margin entire, narrowly but distinctly revolute; base broadly tapering to cordate, glabrescent above sparsely scaly beneath. Scales deeply dentate, each on top of a minute epidermal tubercle, with a persistent dark centre. Mid-vein impressed above, prominent beneath; lateral veins 6–8 per side, distinctly anastomosing, slightly impressed above and prominent beneath in the oldest leaves, often obscure, reticulation inconspicuous. Petiole c.1–2 x 1–2mm, weakly grooved, laxly scaly and shortly hairy. Outer bracts to 10 x 8mm, ovate-acuminate, acute; inner ones spathulate, obtuse, laxly silky-hairy on both sides. Bracteoles to 15 x 0.5mm, linear, patently hairy. Inflorescence an open umbel of 7–20, horizontally or half-hanging flowers. Pedicels 7–13mm, thick, densely shortly patently hairy, not scaly, often pink. Calyx small, oblique; margin wavy and shortly 5-lobed. Corolla 50–75 x 25–30mm, white or very lightly flushed with pink at the lobes; tube 55–72 x 5–6 x 4–5mm, straight, cylindrical, laxly to very laxly scaly and without hairs outside, or with just a few at the base, sub-densely to laxly short-hairy proximally to ¾ inside, glabrous distally; lobes spreading, broadly obovate-spathulate, laxly scaly outside, glabrous inside, 10–13 x 7–9mm. Stamens becoming exserted to c.10mm; filaments linear, laxly patent hairy for ¾ of their length, filiform and glabrous apically; anthers obovate-oblong, base obtuse, c.1.8 x 1mm. Disc glabrous at base, hairy on the upper margin. Ovary 5 x 1.8mm, sub-cylindrical, densely patently hairy and silvery scaly, the scales often hidden by the hairs, abruptly narrowed distally; style laxly patently hairy in the proximal 5/6 and with some scales in the proximal part; stigma rounded, c.2mm in diameter, when young, near the mouth of the flower and slightly towards the lower side, becoming exserted to c.10mm.
Distribution: Indonesia, Sulawesi (C), Mt Sinadji.
Shrub or tree, 1.5-12m. Leaves coriaceous, oblanceolate to elliptic, 8.5-14 x 3-4.5cm, 2.8-3.5 x as long as broad, apex acute to acuminate, base cuneate, margin not strongly undulate, upper surface glabrous when mature, lower surface glabrous or with vestiges of a brown indumentum, with red punctate hair-bases overlying the veins; petioles 1-1.5cm, floccose. Inflorescence dense, 15-20-flowered; rhachis c.5mm; pedicels c. 5mm, glabrous or (rarely) stipitate-glandular. Calyx c.2mm, glabrous, lobes broad, rounded. Corolla tubular-campanulate, scarlet to deep crimson, with prominent nectar pouches, flecks lacking, 35-40mm. Ovary glabrous or with a few rufous hairs (? rarely densely tomentose and glandular); style glabrous. Capsule not known.
Habitat: Mixed forests
Distribution: China (SE Xizang), ?Bhutan
Altitude: 2100-2700m
A specimen from W Bhutan, Ludlow, Sherriff & Hicks 16009, closely resembles the type of R. ramsdenianum but differs in its densely tomentose ovary. Despite the obvious similarites, this plant may be a hybrid of R. kendrickii, especially as it was collected well outside the restricted area from which R. ramsdenianum is otherwise known.
R. ramsdenianum is closely allied to R. kendrickii, and is possibly conspecific, but may be distinguished from the latter by its broader leaves.
Type: China, SE Xizang, Tsangpo Gorge, 7000-8000ft, 19 x 1924, Kingdon-Ward 6284 (K, cult. Ramsden, cult. E)
Occurs in Countries: BT, CN Altitude Ranges: 2,000 - 3,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: crimson, scarlet
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):302
Shrub to 2.5m. Twigs c.2mm in diameter, rounded, sub-densely covered with fragile, brown, stellate scales, initially becoming glabrescent but then covered with numerous minute tubercles and rough to the touch, the older parts often whitish; internodes 4–10cm. Leaves 3–5 together in pseudowhorls. Blade 40–75 x 25–50mm, broadly elliptic, to nearly rounded; apex broadly tapering, obtuse or rounded; margin entire, slightly or not revolute; base broadly tapering or rounded; brown-scaly on both sides initially, the scales fragile, small, irregularly stellately divided, dendroid, each on a minute epidermal tubercle, very early glabrescent, the surface smooth above, finally glabrescent also beneath, but permanently rough with the numerous minute tubercles. Mid-vein raised and grooved above proximally, becoming very narrow and impressed distally, thick and obtusely prominent beneath; lateral veins 5–8 per side, rising at an acute angle, straight below, less conspicuous towards the margin, minutely impressed in fully mature leaves above, not or only slightly raised beneath, reticulation indistinct. Petiole 6–15 x c.2mm, rounded, scaly. Flower buds to 28 x 18mm, ovate, smooth, the apex broadly acute. Bracts 10–15 x 7–10mm; outer bracts ovate, obtuse, scaly in the middle outside, otherwise shortly papillate-hairy; inner ones to 30 x 15mm, elliptic to spathulate, densely and long-hairy on both sides. Bracteoles to 25 x c.1mm, linear, laxly hairy. Inflorescence a 5–8-flowered open umbel. Pedicels 5–12 x c.1mm, densely brown-stellate-scaly, sub-densely or laxly hairy at least below the calyx. Calyx 2–3mm in diameter, oblique, disc-shaped, small, scaly and shortly hairy outside, ciliate, very shortly 5-lobed. Corolla 40–50mm, narrowly funnel-shaped, regular, white or pink; tube c.35–40 x 3–4 x 6–8mm, very sparsely stellately scaly or glabrous outside, densely covered with long retrorse hairs inside, straight, gradually widened towards the mouth; lobes 12–18 x 7–12mm, irregular, obovate-spathulate. Stamens exserted to 6–9mm; filaments linear, long hairy below, glabrous and filiform distally; anthers 3.5–4 x c.1mm, elongate-oblong, the base with two minute points. Disc low, hairy. Ovary 6–8 x 2.5–3mm, cylindrical, gradually tapering distally, densely covered with appressed, stiff, yellow, hairs which cover the scales; style nearly as long as the stamens, thick proximally, densely patently hairy and laxly scaly in the proximal ¾, becoming less densely hairy and finally glabrous distally; stigma globose.
Distribution: Indonesia, New Guinea (W), Wissel Lakes region.
Altitude: 1750-2300m
Named after the collector, who was stationed in the Dutch East Indies for many years.
In primary or secondary forest, on steep slopes. Terrestrial on peaty or clayey soil or stony clay, derived from limestone or sandstone, locally common.
A tentative hybrid with R. rosendahlii is recorded by Sleumer in the Leiden herbarium.
Type: F.W. Rappard 898, 27 Oct. 1955. New Guinea (W), Enarotali, Wissel Lake (L).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: pink, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:96
Shrub to 4m. Twigs 4–5mm in diameter, rounded, internodes laxly to densely scaly, becoming glabrescent, smooth; internodes 4–11cm. Leaves 3–7 in loose pseudowhorls. Blade 50–90 x 20–35mm, elliptic, rarely slightly obovate-elliptic; apex shortly acuminate, acute or broadly acute; margin entire, flat or weakly and narrowly revolute; base narrowly to broadly tapering; densely scaly on both sides at first, glabrescent above when mature but minutely blackish punctate where the scales have been, laxly to sub-densely and persistently scaly beneath. Scales small, marginal zone irregularly sub-stellately lobed, disintegrating with age; centres dark, large, minutely but visibly impressed. Mid-vein slightly raised above in the proximal ½, often grooved in this part also, smooth or a little impressed distally; beneath shallowly raised in the proximal ½–¾, smooth distally; lateral veins 6–10 per side, wide-spreading, smooth or very slightly raised above, smooth and often obscure beneath, reticulation obscure. Petiole 7–18 x 3–4mm, smooth or grooved distally, scaly. Bracts to 25 x 12mm, membranous, glabrous, outer ones ovate, sub-obtuse, inner ones ovate-elliptic, slightly keeled. Bracteoles c.20 x 1.5mm, linear below, sub-spathulate distally, glabrous. Inflorescence a full or semi-open umbel of 6–12 flowers held semi-erect to horizontal. Pedicels 15–20 x c.1mm, laxly to sub-densely scaly. Calyx c.4mm in diameter, oblique, rim-like, wavy. Corolla 20–25 x 35–40mm, broadly funnel-shaped, orange, often darker at the base of the tube, or yellow, sometimes scented; tube 12–20 x 8–9 x 16–18mm, base slightly 5-lobed, laxly scaly or glabrous outside, glabrous inside; lobes 13–19 x 12–17mm, obovate-sub-circular, reflexing to the perpendicular, overlapping c.halfway. Stamens exserted to c.10mm, spreading all round the flower, unequal; filaments linear, glabrous; anthers 2–3 x 1.3mm, obtuse at the base. Disc prominent, glabrous. Ovary 4–6 x 2–2.5mm, sub-cylindric-conical, mostly glabrous from the beginning, rarely laxly scaly at first, becoming glabrous during the flowering, abruptly contracted distally; style 12–18mm, slender; stigma 2–3mm in diameter, lobes distinct. Fruit 25–30 x 5–7mm, fusiform, often slightly curved, glabrous.
Habitat: In sub-alpine shrubberies, and open volcanic areas, mostly terrestrial, rarely epiphytic.
Distribution: Indonesia, Sumatra, Gajo Lands; East Coast; West Coast, Mt Kaba.
Altitude: 1000-2500m
Latin – rari – rare or seldom; Greek – lepidotum – covered with small scales. Presumably because the scales easily fall off so that the leaves are glabrescent. Not especially apt.
Sleumer (1966) noted that ‘R. rarilepidotum is closely related to R. robinsonii from the Malay Peninsula and mainly differs by its smaller, generally red to dark red corollas’. Recent field work has established that yellow corollas often occur and in some populations, such as those on Mt Kaba, they may predominate. For differences with R. robinsonii see under that species.
Type: Lörzing 8166, 19 Jan. 1921. Sumatra, east coast, G. Sinmabung, 2000–2470m (BO, A, K, L).
Occurs in Countries: ID Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: orange, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:243
Slender much-branched shrub to 1.5m. Twigs 1–2mm in diameter, rounded, tips densely brown-scaly, older parts glabrescent, somewhat rough; internodes 2–10cm. Leaves 2–5 together in pseudowhorls, often very different in size in the same whorl, with some very reduced leaves between them. Blade 25–60 x 6–15mm, narrowly elliptic to narrowly ovate-elliptic, usually broadest in the proximal 1⁄3; apex gradually long-acuminate, acute but often with the extreme point obtuse or rounded; margin entire or weakly and irregularly sinuate, flat when fresh or slightly revolute especially near the base when dry; base rounded or broadly tapering; with sparse silvery scales above and sparse brown scales below, quickly glabrescent above, more persistently scaly beneath but eventually also glabrescent there, old leaves a little rough to the touch on both sides. Scales deeply stellately divided, dendroid, each on top of a minute, persistent, epidermal tubercle. Mid-vein impressed above and prominent beneath; lateral veins obscure. Petiole 2–4 x 0.75–1mm, slender, minutely grooved above and densely scaly. Flower buds to 12 x 7mm, ovoid, acute. Bracts to 10 x 6mm; outer bracts with spreading tips or these sometimes incurved, subulate, densely scaly outside; inner bracts broadly ovate, abruptly subulate, densely brown scaly outside in a broad stripe which expands distally, all bracts marginally scaly and glabrous inside. Bracteoles to 10mm, linear to filiform, scaly in the distal ½. Inflorescence of solitary or paired flowers, rarely more in the wild, although the close proximity of flower buds can give the appearance of 3–4-flowered umbels. Flowers hanging or half-hanging. Pedicels 7–10 x c.1mm, densely stellately scaly. Calyx c.2mm in diameter, small, disc-like, not or very shortly obtusely lobed, scaly. Corolla 25–35 x 20–25mm, pink to dark red, distinctly zygomorphic; tube 20–28 x 4–6 x 8–9mm, curved, densely stellately scaly and without hairs outside, glabrous or very laxly hairy inside; lobes 8–12 x 8–13mm, broadly obovate to sub-circular. Stamens clustered on the upper side of the corolla, slightly unequal, exserted to c.7mm; filaments narrowly linear, pink to red, glabrous proximally, laxly patently hairy in the middle, glabrous distally; anthers c.2 x 1mm, oblong, brown to purplish-black. Disc glabrous or scaly on the upper margin. Ovary c.6 x 2–2.5mm, sub-cylindrical, densely stellately scaly, gradually tapering distally; style held on the upper side of the tube, pink, scaly in the proximal 1–2mm and with semi-appressed distally pointing hairs to within 1–2mm of the apex; stigma remaining well short of the mouth of the flower even when receptive, club-shaped, purple. Fruit 30–40 x 4–5mm, narrowly oblong, the valves curving back and often twisting, the placentae breaking away from the base of the column and curving outwards. Seeds c.4mm including the tails.
Habitat: Primarily an epiphytic species of the lower moss forest, it was reported as common, growing terrestrially on road cuts by van Royen & Kores (1982).
Distribution: Papua New Guinea, widespread along the Central and Bismarck Ranges: Western, Southern and Eastern Highlands, West Sepik District.
Altitude: 1585-3350m
Latin – rarum – rare. According to Hunt (1971) named for ‘its sparsely branched and loosely leafy habit, not as might be supposed because it is uncommon’.
It has not been possible to check a record from the West Sepik District which is outside the main area of distribution of this species and overlaps with the very similar R. stelligerum. It is possible that this is a misidentification.
Type: Schlechter 18719, Nov. 1908. New Guinea (E), Central part, Bismarck Mts (B†, P, L, fragment).
Occurs in Countries: PG Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: pink, red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:96
Dwarf shrub, 1-1.5m; young shoots glandular-setose. Leaves coriaceous, lanceolate to oblanceolate, 3-7 x l-2cm, 3-3.5 x as long as broad, apex blunt, base cuneate, margins not ciliate, strongly inrolled, upper surface rough when mature from the bases of glandular setuiae; lower surface with a dense cinnamon tomentum composed of ramiform hairs; petioles 1 —1.5cm, setulose. Inflorescence 4-7-flowered; rhachis minute; pedicels c.l5mm, glandular-setulose. Calyx8-10mm, glandular, lobes rounded. Corolla campanulate, white flushed pink to rose, lacking a basal blotch though with crimson spots, c.30mm. Ovary densely glandular-setulose; style glabrous. Capsule not known.
Distribution: NE Upper Burma (only known from the type)
Illustrations:
R. recurvoides is clearly a member of subsection Glischra, close to R. crinigerum, as its strongly setulose indumentum indicates. I have recently confirmed from cultivated material that the flowers are compatible with its inclusion in subsection Glischra and not with subsection Taliensia where it was originally placed.
Type: NE Upper Burma, Seingku Wang, in the valley of the Di Chu, 11000ft, 25 vii 1927, Kingdon-Ward1184 (holo. K; iso. E).
Occurs in Countries: MM Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: crimson, pink, rose, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):288
Dwarf deciduous shrublet, c. 10cm high, young shoots glandular hairy. Leafy shoots from separate buds below the inflorescences; leaves with a short petiole; blade spathulate or oblanceolate, 5-15x3-6 mm, base obtuse, margin glandular ciliate, reticulation of veins prominent. Inflorescence buds terminal, opening to produce a 1-3-flowered raceme, the peduncle bearing leafy bracts, the peduncle, rhachis and bracts glandular hairy. Calyx lobes narrowly oblong, obtuse, c.5 x 1-2mm, glandular hairy and finely pubescent. Corolla rose-purple, ±rotate, glabrous, c.l5mm long, tube 7-8 mm long, lobes 5, broadly oblong, the division between the lower pair deeper. Stamens 10, filaments hairy below. Ovary ovoid, c.6 mm long, pubescent, 5-locular; style 5 mm long, curved, pubescent on the lower half. Capsule ovoid, c.6 mm long.
Distribution: USSR (E Siberia), China (Manchuria), Korea
We have seen no specimens of this little-known plant. Our description is based on that of Maximovicz.
Type: USSR, E Siberia, nr Jablonnoi Chrebet, Redowski, n.v.
Occurs in Countries: CN, RU Subgenus: Therorhodion Habit: Non-Tree
Philipson, W.R. & Philipson, M.N. (1986) A Revision of Rhododendron III. Subgenera Azaleastrum, Mumeazalea, Candidastrum and Therorhodion. Notes from the Royal Botanic Garden Edinburgh 44(1):20
Shrub, c.50cm. Twigs 1.5–3mm in diameter, scaly at first, older parts glabrescent; internodes 3–4cm. Leaves 4–6 spirally arranged in the upper 1⁄3 of the upper internodes, 2 or 3 of these leaves closer together in a loose pseudowhorl. Blade 35–70 x 15–35mm, elliptic or mostly elliptic- or obovate; apex shortly acuminate, sub-acute or obtuse, sometimes rounded; margin entire, slightly revolute; base tapering; quickly glabrescent above, sub-persistently and sub-densely scaly beneath. Scales small, marginal zone irregularly lobed; centre distinctly impressed, blackish with age. Mid-vein impressed above, strongly raised beneath; lateral veins 4–5 per side, spreading, obscurely anastomosing, slightly impressed above, mostly obscure beneath, reticulation obscure. Petiole 4–8 x 1–2.5mm, grooved above, semi-rounded, scaly. Flower buds to 14 x 6mm, ellipsoid to ovoid, acutely pointed, slightly flattened, smooth, glabrous except for the marginal fringing scales and some scales on one or two of the smallest outer bracts outside. Bracts to 10 x 6mm, membranous, outer ones ovate-apiculate or subulate, inner ones ovate or obovate and obtuse, glabrous outside, margin with fragile scales. Bracteoles to 12mm, linear, sub-spathulate apically. Inflorescence 3–8-flowered in an open umbel, the flowers hanging or half-hanging, bicoloured yellow and orange, without scent. Pedicels c.20 x 1mm, laxly to sub-densely sub-stellately scaly. Calyx c.3mm in diameter, obliquely disc-shaped, very shortly lobed, scaly outside. Corolla 30–40 x 25–39mm, narrowly funnel-shaped, laxly scaly outside, glabrous or practically so inside; tube 17–27 x 4–9 x 6–15mm, cylindrical, straight, base somewhat pouched, mostly yellow but variably flushed with orange in the distal ½; lobes 10–17 x 8–16mm, semi-erect to spreading, obovate, not, or only very slightly, overlapping near the base, orange with a distinctive, translucent line from the throat to near the apex. Stamens as long as the corolla tube, not exserted, dimorphic, irregularly grouped on the upper or lower sides of the mouth; filaments linear, hairy for 2 or 3mm proximally, glabrous distally; anthers oblong, c.2mm. Disc prominent, glabrous. Ovary 5–9 x c.2mm, sub-cylindrical, densely covered with very short, sub-patent grey hairs and some fragile scales; style with some hairs at the base, as long as the stamens, lying on the upper or lower side of the corolla tube when young; stigma circular. Fruit 12–20 x 5–6mm, cylindrical, sub-densely short-hairy, without scales.
Habitat: Epiphytic in Casuarina forest and summit vegetation, terrestrial on stony ground, on the slopes and crater edge.
Distribution: Indonesia, Lesser Sunda Is., Flores: Mts Geli Mutu (Kelimutu), Mandaswai and Mt Desu.
Altitude: 1500-2300m
Named after Mrs Ilse Rensch-Maier who collected the original specimen.
Type: Rensch 1495, (1498), 16 July 1927. Flores, Mt Geli Mutu, 1500–1700m (B†, BO, L, fragment).
Synonymy: R. renkkchianum Sleumer, Reinwardtia 1960. 5: 220 (orthographic error).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: orange, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:254
Shrub or small tree, l-8m; young shoots soon glabrous. Leaves rhombic-ovate, 3-6 x 1.5-4cm, apex acute, upper surface at first covered with short hairs, soon becoming glabrous, lower surface with short brown hairs, mainly on midrib and veins; petioles 2-5mm, covered with brown bristle-like hairs. Inflorescence l-2(-3)-flowered, flowers appearing before the leaves; pedicels 5-8mm covered with adpressed brown hairs, glandular, Calyx minute, ciliate, villous, glandular. Corolla funnel-campanulate, rose-purple, rarely white, 25-30mm, lobes 15mm, oblong. Stamens 10, unequal, filaments glabrous. Ovary villous; style glabrous (? occasionally pubescent below). Capsule 10mm, curved.
Habitat: Forest hillsides
Distribution: Japan (S Honshu, Shikoku, Kyushyu)
Altitude: 400-700m
Illustrations:
R. reticulatum apparently hybridizes with R. tashiroi (q.v.).
Yamazaki distinguishes var. bifolium on its two large leaves and one smaller leaf per whorl. This is a feature that occurs occasionally, sometimes along with normal whorls with three equal-sized leaves, on the same plant.
The rare white-flowered form of R. reticulatum has been called R. rhombicum var. albiflorum Makino (R. sakawanum Makino). A form with more densely hairy leaves, possibly approaching R. nudipes var. lagopus, has been referred to R. ciliatum of Nakai.
Type: A plant cultivated by Mr Knight in 1834 (n.v.)
Synonymy: R. rhombicumMiq., Ann. Mus. Lugduno-Batavum2: 164(1865). Type: A specimen collected by Buerger, n.v. R. rhombicum Miq. var. albiflorum Makino, Bot. Mag. (Toyko) 18: 66(1904). Type: Fl. white; Prov.Zyodaizi-yama in Sakawa spont., iv 1885, T. Makino. R. sakawanum Makino, J. Jap. Bot. 3:11 (1926). Type: as for R. rhombicum var. albiflorum Makino. R. reticulatum D. Don var. bifolium Yamazaki, J. Jap. Bot. 62: 288 (1987). Type: Japan, Shikoku, Tokoshima Pref., Oshima, Mugisho, K. Abe 35670 (holo. TI, n.v.). R. reticulatum D, Don var. parvifolium Yamazaki, J. Jap. Bot. 59: 209 (1984). Type; Japan, Shikoku, Pref. Kohchi, Takaoka- gun, Hidaka-mura, Nishikiyama, 21 x 1942, Yashinaga 24 (holo. TI, n.v.)
Occurs in Countries: JP Altitude Ranges: 0 - 1,000m Subgenus: Tsutsusi Habit: Tree Fl. Colour: rose, white
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):148
Shrub or small tree to 6m. Twigs 3–5mm in diameter, rounded, smooth, green or reddish, covered in flat brown scales; internodes 3–12cm. Leaves spirally arranged or weakly arranged in very loose pseudowhorls. Blade 110–160 x 30–50mm, narrowly elliptic; apex acutely pointed; margin entire and flat but strongly rolled back in young expanding leaves; base tapering, often shortly truncate, glabrescent and indistinctly dark punctate above, laxly and persistently scaly beneath. Scales minute, shallowly lobed to sub-circular with a broad marginal zone and small centre, weakly impressed. Mid-vein slightly raised above proximally but then becoming slightly impressed, raised below throughout its length; lateral veins numerous, slender, smooth or slightly raised in dried specimens, reticulation obscure when fresh, dense, fine, but prominent on both sides when dry. Petiole 10–20 x 4–5mm, not grooved, green or red, scaly. Flower buds ovoid, to 30 x 15mm. Outer bracts to 30 x 12mm, ovate, inner ones broadly ovate-oblong, innermost spathulate, obtuse, membranous, all glabrous apart from sparse marginal scales. Bracteoles c.20 x 1mm, linear, glabrous. Inflorescence 4–7-flowered in an open umbel, the flowers held horizontally. Pedicels 22–32 x 2mm, red or green, sparsely scaly, not hairy. Calyx 4–5mm in diameter, obliquely disc-shaped, the margin wavy and indistinctly 5-lobed, glabrous. Corolla 30–64 x 35–75mm, clear yellow or yellow flushed with orange, usually strongly and sweetly scented; tube 14–34 x 8 x 20mm, funnel-shaped, straight, with a few scattered scales outside, densely short-hairy inside proximally; lobes 20–37 x 21–36mm, broadly obovate to sub-circular, half-spreading, overlapping up to ¾. Stamens loosely and irregularly arranged on the lower side of the flower, sometimes in two groups on each side, exserted up to 10mm; filaments c.35mm, hairy in the lower 1⁄3; anthers 4–5 x 1mm, yellow or purple, curved, minutely apiculate. Disc thick and prominent, glabrous, or occasionally shortly hairy at the upper margin. Ovary 8–10 x 2–3mm, cylindrical, tapering gradually distally, appearing glabrous, but laxly finely and very shortly hairy and with some sparse scales; style 20–25mm, glabrous or slightly (and minutely) hairy at the very base; stigma c.5mm in diameter, yellow or turning red with age. Fruit 52 x 9mm, cylindrical but tapering at each end. Seeds 5mm, without tails 1mm, the longest tail 2mm.
Habitat: Usually growing terrestrially in shaded moist valleys often in the ultrabasic zone on Mt Kinabalu.
Distribution: Malaysia (Borneo), Sabah, Mt Kinabalu and Mt Alab (Crocker Range).
Altitude: 2000-2700m
Latin – rete – network; venium – veins. Alluding to the distinct reticulation on the leaves.
Rhododendron retivenium hybridises with R. lowii at the zone of overlap on Kinabalu at c.2600m, the hybrids having intermediate leaf size between those of the parents. A hybrid with R. crassifolium has also been recorded. This species is closely related to the R. javanicum complex but is easily distinguished from these when with young expanding leaves as the distinctive rolling is quite different to the flat-expanding leaves of that complex. The minutely hairy ovary and usually strongly and sweetly scented flowers are other distinguishing characteristics. It is similar in some respects to R. monkoboense but has much narrower leaves with tapering bases.
Type: Clemens 35017, 22 Feb. 1933. North Borneo, Mt Kinabalu, Upper Kinataki R., S Ridge, 2135m (L, A, BM, BO, E, NY).
Occurs in Countries: MY Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Tree Fl. Colour: orange, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:274
Shrub to 2m. Twigs slender, c.2mm in diameter, sub-densely scaly, early glabrescent; internodes 1–4cm. Leaves c.3 together in pseudowhorls. Blade 40–65 x 25–42mm, elliptic; apex broadly tapering to rounded; margin narrowly revolute; base broadly obtusely tapering to rounded, sub-densely scaly initially on both sides, early glabrescent above, more persistently scaly beneath, smooth to the touch. Scales sub-dendroid, each on top of a minute epidermal tubercle, small, marginal zone deeply stellate-incised; centre minute, deepened and elongated into a shorter or longer foot. Mid-vein above very narrowly impressed; beneath as wide as the petiole and strongly raised proximally, gradually narrowed and less prominent upwards, longitudinally striate; lateral veins c.5 per side, spreading, straight, weakly or not impressed above, slightly raised beneath, without reticulation. Petiole 6–10 x 1–1.5mm. Flower buds 23 x 8mm, elongate-ovoid. Outer bracts 4mm, inner ones gradually larger, up to 15mm, sub-densely covered with sessile scales in the upper outer part, fringed with scales. Bracteoles linear, to 10mm. Inflorescence c.6-flowered, glabrous in all outer parts. Pedicels 5–8mm, slender, finely short-hairy. Calyx c.2.5mm in diameter, oblique, disc-shaped, irregularly 5-lobed, lobes broadly triangular, sub-acute, fringed with long whitish hairs, becoming reflexed. Corolla trumpet-shaped, white; tube 20–23 x 3 x 3mm, sub-densely covered with retrorse white hairs almost to the mouth inside; lobes 8–10 x 3–4mm, narrow-spathulate, horizontally spreading. Stamens very unequal, up to 35mm, the shortest hardly exserted, the longest strongly exserted from the mouth; filaments filiform, densely covered with white retrorse hairs almost to the top; anthers narrowly oblong, c.3 x 0.7mm, cells sub-apiculate at base. Disc glabrous at the very base, hairy above. Ovary 5–6 x c.1.5mm, elongate-cylindric, densely covered with appressed, forwardly directed hairs and scales (which are almost hidden by the hairs), gradually narrowed distally; style slender, a little longer than the corolla tube, densely hairy proximally, more laxly so and more distinctly scaly upwards, finally glabrous; stigma globose, 5-lobed.
Habitat: Epiphytic shrub
Distribution: Papua New Guinea, Morobe District, range above Markham Point near Lae.
Altitude: 600-900m
Latin – retro – backwards; pilus – hair. Alluding to the backwardly pointing hairs in the corolla tube.
Type: Henty NGF 11906, 16 Feb. 1960. New Guinea (NE), Morobe District, above Markham Point near Lae, 900m (L, LAE).
Occurs in Countries: PG Altitude Ranges: 0 - 1,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:183
Shrub or small tree to 7m, erect or more rarely prostrate. Twigs rounded, younger parts red, at first densely covered with stalked round scales, which fall early, the persistent stalks making the twigs rough; internodes 2–6cm. Leaves 4–7 together in pseudowhorls at the upper nodes. Blade 20–60 x 10–20mm, obovate to broadly elliptic; apex distinctly retuse more rarely rounded; margin flat or distinctly recurved, entire; base tapering, dark green and shining above, paler to almost whitish green and dull beneath, laxly to sub-densely scaly on both sides initially, quickly glabrescent above but persistently scaly beneath. Scales disc-like, variable in size, marginal zone narrow and entire, the centre large and thick, distinctly impressed. Mid-vein impressed above, strongly raised beneath; lateral veins 4–7 per side, the lower ones ascending, distal ones irregularly spreading, all slightly impressed above in fully mature leaves, often only faintly visible when fresh, obscure beneath. Petiole 1–5 x 1.5–2mm, thick, grooved above, scaly and becoming rugose, often minutely hairy above. Flower buds to 14 x 9mm, ellipsoid or narrowly ellipsoid, pink, both terminal and lateral, smooth, the bracts fully appressed. Bracts to 13 x 8mm, outer subulate to ovate-acuminate, inner gradually increasing in size and broadly ovate to spathulate, shortly acute, scaly and densely appressed hairy outside, glabrous inside, all densely and long white-ciliate on the margins. Bracteoles to 8mm, linear to filiform, slightly expanded at the apex and hairy in the upper part. Inflorescence a 4–10-flowered open umbel; flowers often semi-erect on opening, becoming half-hanging to hanging. Pedicels 12–20 x c.1mm, densely patently hairy, scaly only near the apex. Calyx c.4mm in diameter, oblique, shortly 5-lobed, densely scaly outside, the lobes c.1mm, long ciliate. Corolla 22–35 x 13–15mm, narrowly funnel-shaped to tubular, red to orange-red; tube 12–28 x 4–6 x 7–8mm, straight, the base slightly dilated in the form of a ring, laxly to densely yellow-scaly and shortly white patent hairy outside, glabrous inside; lobes 4–6 x 3–6mm, erect to half-spreading, broadly elliptic to sub-circular, hairy and scaly outside except near the margins. Stamens alternately slightly dimorphic, exserted to 6–8mm, loosely spreading around the mouth or more tightly clustered on the lower side; filaments linear, widened below, glabrous; anthers c.1.5 x 1mm, broadly oblong, truncate at the top. Disc glabrous. Ovary 3–4 x c.2mm, conical, 5-angular or grooved, densely scaly, not hairy at all; style filiform, scaly at the base only, otherwise glabrous; stigma globose, shortly 5-lobed at the mouth of the flower when it opens, becoming exserted on the lower side of the flower to 8mm. Fruit 10–18 x 5–6mm, erect, oblong-fusiform; valves recurving to about horizontal, the placentae remaining coherent to the central column at first, eventually breaking away at the base and slightly spreading.
Habitat: Mostly terrestrial in sub-alpine mossy forests or shrubberies, in soil rich in humus and the moss-cushions of old fallen trees, but also on sandy, stony or rocky ground, often near craters and solfataras, where it occurs as very low, creeping, small-leafed, exposed forms. The root system extends near the surface of the ground and the stems root adventitiously; locally common
Distribution: Indonesia, Sumatra, Java especially W Java; in C Java known only from Mt Prahu (Dieng) and Mt Merapi; in E Java from Mt Ardjuno.
Altitude: 1350-3400m
Named from the distinctively retuse leaves.
Flowering throughout the year; the flowers are recorded as visited by small honey birds (Aethopyga) and bumble bees.
Rhododendron x epilosum (J.J.Sm.) Argent comb. nov. Basionym: R. retusum var. epilosum J.J.Sm., Bull. Jard. Bot. Buit. III, 1935. 13: 446. Type: Bünnemeijer 5732, 16 Nov. 1918. Indonesia, Sumatra, West coast, Padang Highlands, G. Gombak (BO, A, K, L, SING). Corolla tubular-campanulate, c.4mm long, scaly but not hairy outside. Indonesia, C Sumatra, Padang Highlands, Mt Gombak, in low forest at 2330m. Considered to be a hybrid with R. sumatranum.
Type: Blume Java s.n., sine loc. (L, U).
Synonymy: Vireya retusa Blume, Bijdr. 1826. 856. Azalea retusa (Blume) Kuntze, Rev. Gen. Pl. 1891. 2: 386.
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Tree Fl. Colour: orange, red, white, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:43
Leaves 15–25 x 7–14mm. The style laxly patently hairy at the base or in the proximal ½.
Habitat: On forested slopes
Distribution: Indonesia, N Sumatra, Atjeh: Goh Lembuh, Putjuk Angasan, Bur ni Tèlong,
Altitude: 1350-2700m
Greek – tricho – hairy; stylum – the style. Alluding to the hairy style in this variety.
Type: van Steenis 9169, 23 Feb. 1937. Indonesia, Sumatra, Atjeh, Gajo Lands, top of G. Lembuh (L, A, BO, K, SING).
Low shrub to 40cm. Twigs c.1.5mm in diameter, rounded, the tips densely stellate-scaly and rough; internodes 1–4cm. Leaves 4–6 together in pseudowhorls at the upper 2–3 nodes. Blade 10–14 x 4–7mm, narrowly ovate; apex shortly acuminate, sub-acute; margin very strongly revolute, often to the mid-vein when dry; base truncate-rounded; densely brown-scaly on both sides, initially early glabrescent and rough above, scaly for longer beneath. Scales irregularly and deeply stellately divided, the minute centre extended downwards into a stem-like foot, each scale on top of a thick persistent epidermal tubercle. Mid-vein very slightly impressed above, obscure beneath as are the lateral veins. Petiole 0.5–1mm, thick and scaly. Bracts to 10 x 5mm, ovate-subulate, outer scaly outside; inner ones narrowly ovate-acuminate, with fragile, marginal scales, whose bases give a ciliate appearance to the margin when the scales have gone, glabrous otherwise, on both sides. Bracteoles c.10mm, filiform, laxly long-hairy and scaly. Inflorescence of solitary or paired flowers. Pedicels 12–20 x c.1mm, very densely brown-stellate-scaly. Calyx 3–4mm in diameter, obliquely disc-shaped, densely brown-stellate-scaly, the lobes obtuse, c.1mm. Corolla 15–22mm, tubular-funnel-shaped, bright pink; tube 9–14 x 3–4 x 5–6mm, densely stellately scaly outside, glabrous inside; lobes sub-spathulate-circular, wrinkled, 7–9mm in diameter, laxly scaly outside from the base to the middle, otherwise glabrous. Stamens unequal, hardly exserted from the mouth; filaments linear, slightly dilated above the base, glabrous; anthers c.1.3mm, oblong-elliptic. Disc low, glabrous. Ovary c.5 x 3mm, ovoid-conical, densely stellately scaly, the apex obtuse or abrupt distally; style c.1.5 x 0.4–0.5mm, columnar, glabrous; stigma thick-obconical, slightly 5-lobed. Fruit c.8 x 4mm, ovoid-ellipsoid, densely stellate-scaly, the style persistent and the stigma distinctly 5-lobed.
Habitat: Restricted to crevices and sandy niches on sterile limestone slopes.
Distribution: Indonesia, New Guinea (W), Lake Habbema.
Altitude: Around 3225m
Latin – revolutus – rolled back, alluding to the strongly revolute margins to the leaves.
Known only from the type collection
Type: Brass 9528, Aug. 1938. New Guinea (W), Lake Habbema (L, A).
Occurs in Countries: ID Altitude Ranges: 3,000 - 4,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: pink
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:97
Large shrub or small tree, 2.5-12m. Leaves obovate to oblanceolate (8—)12—37 x 5.5-13.5cm, 1.5-3.8 x as long as broad, apex rounded to ± acute, base cordate to cuneate, upper surface giabrescent, ± smooth to rugulose, lower surface with a dense fawn to rufous indumentum composed of slightly to strongly fimbriate cup-shaped hairs; petioles 2-3cm, terete, with a dense pale tomentum. Inflorescence 12—20-flowered; rhachis 15—20mm; pedicels 15-30mm, sparsely brownish-tomentose. Calyx l-2mm, ± tomentose. Corolla fleshy, 7-8-lobed, obliquely campanulate to ± regular-campanulate, white or pale yellow to pink, with a crimson basal blotch and flecks, 30-45mm. Stamens 14-16. Ovary densely brown-tomentose. Capsule 25-35 x 6-9mm, curved
A complex and variable species, with many intermediates between the subspecies that cannot be definitely placed. While the variation trends between subsp. rex and subsp. fictolacteum are best expressed as a geographical cline, the intergradation between subsp. fictolacteum and subsp. arizelum is more likely to be due to local hybridisation. R. rex is closely allied to R. preptum and R. coriaceum (q.v.).
Occurs in Countries: CN, MM Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: crimson, pink, white, yellow
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):255
Leaves 1.5-3.8 x as long as broad; indumentum brown to rufous, composed of narrower, moderately to strongly fimbriate cup-shaped hairs; corolla white or pink to yellow. Corolla pale yellow; leaves 1.5-2.1(-2.5) x as long as broad, cup-shaped hairs narrow, strongly fimbriate.
Habitat: Rhododendron thickets, open conifer forests
Distribution: China (W Yunnan) & adjacent NE Burma
Altitude: 3000-4000m
The following specimens may belong to either subsp. fictolacteum or to subsp. arizelum or may be intermediate between them: Forrest 20366, 20381, 20820, 20821, 21861a, 25959; Rock 11640, 11642, 22038, 16, 25, 5, 97, 102, 170; Kingdon-Ward5877', 6818, 8163, 13146; Yu 20257, 20744, 20971.
Synonymy: R. arizelum Balfour f. & Forrest, Notes R.B.G. Edinb. 12: 90 (1920). Type: China, Yunnan, Shweli/Salween divide, 1T-12000ft, 1917, Forrest 15857 (holo. E).
Leaves 1.5-3.8 x as long as broad; indumentum brown to rufous, composed of narrower, moderately to strongly fimbriate cup-shaped hairs; corolla white or pink to yellow. Corolla white flushed pink; leaves (2-)2.5-3.8 X as long as broad, cup-shaped hairs moderately fimbriate.
Habitat: Conifer forests, Rhododendron thickets
Distribution: China(W Yunnan, SE Xizang), NE Burma
Altitude: 3000-4000m
A number of specimens intermediate between subsp. fictolacteum and subsp. arizelum have been collected where the ranges of the two overlap. Plants with yellow flowers and narrow leaves are as follows: Forrest 21861, 21862, 21866,22770,22772,22784; Rock 10129,11159,22108,22229,22611. Plants with white to pink flowers and broad leaves are as follows: Farrer 1549; Forrest 21869, 22788; Rock 10119, 22024, 22110, 22597,22600, 22601, 22604,22617. The type of R. arizelum var. rubicosum Cowan & Davidian (in Rhododendron & Camellia Yearbook 8: 79, 1953), Rock 11207, also belongs to this category.
Synonymy: R. fictolacteum Balfour f., Trans. Bot. Soc. Edinb. 27: 97 (1916). R. lacteum Franchet var. macrophyllum Franchet, Bull. Soc. Bot. France 34: 280 (1887). Type: China, Yunnan, Yen-tze-hay, 3200m, 31 v 1886, Delavay 2214 (iso. E,K). Ic.: Rhododendron Yearbook 4: f. 36 (1948); Cox, P., The Larger Species of Rhododendrons t. 4 (1979).
Leaves 2.4-3.1 x as long as broad, indumentum fawn, composed of only slightly fimbriate, broadly cup-shaped hairs; corolla white flushed pink
Habitat: Conifer forests
Distribution: China (S Sichuan & adjacent NE Yunnan)
Altitude: Around 3500m
Illustrations:
Subsp. rex apparently intergrades with subsp. fictolacteum where the ranges of the two taxa meet. The variation pattern may be expressed as a cline, with the more extreme forms of subsp. rex in the east, intergrading with subsp. fictolacteum in the west.
Type: China, NE Yunnan, Mont Io-chan (Yao shan), 3200m, v 1911, Maire (holo. E)
Shrub to c.80cm. Stems green, rounded, c.3mm in diameter, moderately densely covered in brown stellate scales. Leaves in close pseudowhorls 1–2cm apart, consisting mostly of 6–7 leaves. Blade 50–80 x 15–30mm, elliptic to slightly obovate; apex acute to broadly acute, sometimes shortly acuminate or apiculate; margin entire, flat, narrowly cartilaginous; base broadly tapering; with sparse silvery, sub-circular scales at first above but quickly glabrescent; below moderately brown scaly. Scales rounded or weakly lobed, slightly impressed; centres small, 1–3 diameters apart in the mature leaves. Mid-vein narrowly impressed above although slightly prominent just above the petiole where it is also faintly grooved; beneath broadly raised for c.¾ of the length proximally; lateral veins 6–10 per side, smooth, spreading broadly but then curving upwards to link with the vein above before the margin, distinct above but obscure below. Petiole 6–10 x 1.5–2mm, not grooved above, pale green with brown stellate scales. Flower buds to 40 x 20mm, ovoid, green, acutely pointed with a gradual transition from foliage leaves to bracts, these transitional forms having a smaller but distinct foliar blade with broad translucent decurrent margins instead of a petiole; inner bracts narrowly ovate to subulate with spreading points. Bracts glabrous or with a few, scattered scales outside and along the margins but no simple hairs. Pedicels 9–15 x 1–2mm, orange, moderately scaly but without simple hairs. Inflorescence of 6–10 flowers in a complete umbel. Flowers 32–40 x 30–40mm, held erect or semi-erect, bright orange with a red star in the throat, the points extended as lines along the lobes, without scent. Calyx a low scaly disc. Corolla tube c.15 x 6 x 13mm, glabrous outside, white hairy in the proximal ½ inside; lobes 15–30 x 12–22mm, semi-erect, overlapping ½–¾ of their length, rounded or weakly emarginate at the apex. Stamens regularly arranged around the mouth of the flower, exserted to c.5mm, distinctly dimorphic; filaments pale orange, with long white hairs in the proximal 1⁄3, glabrous distally; anthers c.3 x 1.5mm, dark purple. Disc green, almost glabrous but with a few short hairs on the upper margin. Ovary c.6.5 x 3mm, ellipsoid, silvery-scaly and densely white hairy; style c.14 x 0.8mm, orange, at first lying on the lower side of the corolla tube, rising to a central position as the flower ages, glabrous; stigma c.3mm in diameter, purplish-red, hardly expanded from the style. Fruit sub-cylindrical, tapering distally to the style, grooved longitudinally in the proximal 2⁄3, 20–25 x c.6mm, the calyx slightly accrescent; on splitting the outer layer peeling back irregularly, the valves spreading to c.45°, the placentae remaining adherent to the central column. Seeds c.3.7mm, without tails c.0.8mm, the longest tail 1.5mm.
Habitat: Mossy forest.
Distribution: Philippines, Palawan, Cleopatra Needle
Altitude: Around 1600m
Named in memory of Eston Reynoso, who was a wonderful companion on several expeditions and made a considerable contribution to Philippine botany working for the National Museum, Manila.
Similar in some respects to R. leytense but differing not only in the colour of the flowers, which is yellow in R. leytense, but also in the non-hairy pedicels. This species also has more flowers in the inflorescence than R. leytense. A unique feature, at least amongst the Philippine rhododendrons, is the gradual transition from foliage leaves to bracts, the intermediates having broad sheathing bases and a smaller blade.
Rhododendron reynosoi is very distinct with its bright vibrant orange flowers in a tight, erect umbel; this alone distinguishes it from all other Philippine species as those with several-flowered umbels either have very differently sized flowers or have a totally different disposition. It is much smaller leaved than R. javanicum ssp. schadenbergii as conceived by Sleumer (1966).
Type: Argent, Chavez, Fuentes, Cronk, Mendum, Middleton & Wilkie 44A, 22 Jan. 1998, 1600m. (Cultivated collection: 29 Aug. 2002, Acc. No. 19981806), Philippines, Palawan, Cleopatra Needle, just below summit. Moss forest (PNH, E).
Occurs in Countries: PH Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:281
Shrub. Twigs 5–7mm in diameter, rounded or obtusely angular at the upper internodes, tips very early glabrescent and rough; internodes 4–13cm. Leaves spirally arranged and densely aggregated together in the upper 1⁄3 of the upper 3–4 internodes, or 3–5 together in pseudowhorls. Blade 30–75 x 16–50mm, broadly elliptic; apex broadly tapering, obtuse, sometimes apiculate; margin revolute in dry specimens; base slightly cordate, brown stellate-scaly on both sides when young, fragile and quickly falling above, more slowly beneath, eventually glabrescent on both sides but remaining rough to the touch. Scales minute, sub-sessile, each on top of a paler permanent epidermal tubercle. Mid-vein above: impressed proximally, flat in its distal part above; beneath very prominent proximally, less so apically; lateral veins 8–10 per side, spreading, faintly raised on both sides, disappearing towards the margin, often inconspicuous beneath. Petiole 2–4 x 1.5–2.5mm. Bracts to 15 x 8mm, membranous, ovate-elliptic to obovate, obtuse, the outer ones scaly outside, the inner ones glabrous. Bracteoles to 15mm, linear, glabrous. Inflorescence a 3–8-flowered open umbel. Pedicels c.20 x 1mm, densely brown-stellate-scaly. Calyx disc-shaped, reflexed, densely scaly outside, the lobes sub-obtuse, 1–1.5mm, not ciliate. Corolla 45–55mm, tubular, somewhat curved and zygomorphic, pink; tube 33–40 x 5–6 x 9–10mm, sub-densely stellate-scaly outside, laxly hairy inside; lobes 10–15 x 10–13mm, spreading, broadly obovate. Stamens c.10mm, unequal, exserted from the tube; filaments linear below, sub-densely hairy at the base, laxly so in the middle, glabrous and filiform distally; anthers 3–3.5 x 1.3mm, obovate-oblong, obtuse at the base. Disc glabrous below, hairy at the upper margin. Ovary 6–8 x c.3mm, ovoid-conical, densely hairy and stellately scaly, abruptly contracted distally; style densely patently hairy and laxly scaly in the proximal ½, glabrous distally, as long as the stamens or slightly exceeding them; stigma thick, oblique, globose, distinctly 5-lobed.
Habitat: Common in more open mossy thickets on peat ridges, associated with R. haematophthalmum.
Distribution: Indonesia, New Guinea (W), Lake Habbema
Altitude: Around 3225m
Greek – rhodo – rose or rosy-red; chrom – colour. Alluding to the colour of the flowers.
Apparently not recollected since the original collection.
Type: Brass 9572, Aug. 1938. New Guinea (W), Lake Habbema (A, L, fragment).
Occurs in Countries: ID Altitude Ranges: 3,000 - 4,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: pink
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:98
Shrub to 4m. Twigs c.2mm in diameter, laxly scaly when young, internodes c.3–10cm. Leaves 4–6 together in tight pseudowhorls. Blade 30–70 x 20–60mm, broadly elliptic to broadly obovate-elliptic, sub-sessile; apex shortly and broadly tapering, obtuse, to almost rounded; margin flat; base deeply cordate, glabrescent with age above, laxly scaly beneath. Scales flat, small, marginal zone thin, wide, variously lobed; centre small, slightly impressed. Mid-vein narrowly impressed above, base as wide as the petiole, decreasing distally, grooved up to c.1⁄3 the length of the leaf, broadly prominent beneath in the proximal ½ but not strongly raised; lateral veins and reticulation smooth but distinct below, raised and very distinct above. Petiole 0–1 x 2–3mm, grooved, scaly. Bracteoles almost filiform. Pedicels c.15mm, thick, sub-densely or laxly stellate-scaly, without hairs. Inflorescence an open 4–7-flowered umbel. Calyx 2.5–3mm in diameter, very obliquely disc-shaped, indistinctly 5-lobed, scaly outside. Corolla 93 x 50mm, trumpet-ventricose, usually a little curved, pink at the base of the tube, fading to the white lobes, scented; tube 60–82 x 4–6 x 9–10mm, (up to 13mm in the widest part just above the middle), laxly scaly outside, with dense patent or retrorse hairs proximally inside, becoming more laxly so distally; lobes 15–21 x 15–22mm, perpendicularly spreading, obovate to sub-circular, overlapping 1⁄3–½. Stamens exserted to 12mm, from the mouth, irregularly clustered on the lower side of the flower, dimorphic; filaments white, linear and sub-densely hairy proximally, narrower and more laxly sub-patently hairy distally, glabrous in the upper ¼; anthers 3.5–4 x c.1mm, white or cream, narrowly oblong, base obtuse. Disc hairy on the upper margin. Ovary 7–8 x c.2mm, sub-cylindrical, densely appressed-hairy and scaly, tapering distally; style lying on the lower side of the corolla, slender, densely or more laxly hairy and laxly scaly in the proximal 2⁄3, then exclusively sparsely scaly for 3–4mm and glabrous distally; stigma thick-rounded, shortly 5-lobed, green becoming exserted to 18mm. Fruit fusiform, c.35–50 x 5mm.
Habitat: On the edge of stunted, mossy forest, sometimes on very steep banks. Locally abundant.
Distribution: Papua New Guinea, Milne Bay District: Mt Aniata, Mt Donana. Also on Mt Dayman, (Maneau Range), Mt Suckling and Mt Paga.
Altitude: 2290-2750m
Greek – rhodo – rose (red colour); leuco – indicating paleness. Alluding to the pale pink flowers.
This species is very distinct with its sub-sessile, obtuse leaves with very distinctly raised reticulation. Its beautiful pink-flushed flowers give a magnificent display, at irregular intervals but often in October or November, in Edinburgh. The plants in cultivation are not so powerfully scented as some of the other species in this section but this is certainly well worth growing from a horticultural point of view. Sleumer (1961) suggested that R. tuba might be a natural hybrid between R. rhodoleucum and R. carringtoniae. This has not satisfactorily been resolved. Rhododendron tuba certainly shows strong similarities especially to R. rhodoleucum. The tapering leaf base and longer petiole will separate R. tuba from this species.
Type: Cruttwell 1084, 9 July 1959. New Guinea (SE), Milne Bay District, Maneau Range, Mt Aniata, c.2750m (L).
Occurs in Countries: PG Altitude Ranges: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: green, pink, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:186
Shrub. Twigs 4–5mm in diameter, rounded, laxly sub-stellately scaly when young, quickly glabrescent and often whitish when older; internodes 13–15cm. Leaves mostly 5 in pseudowhorls with some reduced ones on the internodes. Blade 90–160 x 20–45mm, narrowly ovate, sometimes with slightly unequal sides; apex long-acuminate, acute; margin entire, flat or minutely and narrowly revolute; base broadly tapering, glabrescent above, laxly scaly beneath. Scales small, flat, mostly shortly lobed in the marginal zone; centre minute, hardly impressed. Mid-vein broadened above and slightly raised proximally, narrowed and impressed distally, beneath thick and obtusely prominent proximally; lateral veins c.8 per side, at an acute angle, high-ascending, indistinctly anastomosing, slightly depressed above, hardly raised beneath. Petiole 15–20 x 2–3mm, laxly scaly, semi-rounded. Bracts to 40 x 20mm. Outer bracts broadly ovate-elliptic, densely and very shortly coarsely hairy outside, glabrous inside. Bracteoles c.20 x 1mm, linear, laxly hairy towards the apex. Inflorescence an 8–9-flowered open umbel. Pedicels 15–20 x c.1mm, laxly scaly, not hairy, pink. Calyx c.4mm in diameter, disc-shaped, wavy, hardly lobed, scaly outside. Corolla 65–70mm, tubular, lobed in the upper 1⁄3, white, scented; tube 40–50 x c.5 x c.8mm, straight, lobed at the base, glabrous outside or with very sparse fragile scales, sub-densely hairy inside; lobes 20–25 x 15–20mm, spreading, sub-circular. Stamens sub-equal, exserted to 10mm; filaments linear hairy in the lower 2⁄3, filiform and glabrous distally; anthers 4–5 x 1.3mm, oblong. Disc glabrous. Ovary c.10 x 2.5mm, cylindrical, yellowish hairy and minutely scaly, gradually narrowed distally; style nearly as long as the corolla tube, yellowish hairy in the lower ¾, without scales, glabrous below the rounded stigma. Fruit (sub-mature) 50–70 x 7–8mm, cylindrical, tapering at the base, mostly curved, shortly yellowish hairy and minutely scaly, with a persistent hairy style.
Habitat: Apparently terrestrial
Distribution: Indonesia, Sulawesi, Latimodjong Range, Pokapindjang, Luwuk, in Latimodjong.
Altitude: 2800-3000m
Greek – rhodo – rose or red; podus – footed or based. Alluding to the pink pedicels.
Type: Eyma 643, 16 June 1937. Indonesia, Celebes (C), Enrekang, Pokapindjang-Tinábang (BO, L).
Occurs in Countries: ID Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: white, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:288
Shrub. Twigs slender, c.2mm in diameter, tips densely scaly; internodes 1–4cm. Leaves 3–4 together in pseudowhorls at the upper nodes. Blade 30–50 x 15–26mm, elliptic or sub-obovate-elliptic; apex broadly tapering and blunt, or almost rounded, sometimes slightly retuse; distinctly revolute at the margin; base broadly tapering, glabrescent with age above, sub-densely scaly beneath. Scales small, marginal zone sub-stellately lobed; centre minute, deeply impressed. Mid-vein very narrowly impressed above, as thick as the petiole and strongly prominent below, gradually decreasing distally beneath; lateral veins c.3 per side, a little raised beneath only, or often inconspicuous, without visible reticulation. Petiole 4–6 x 1mm, grooved above, slightly flattened, scaly. Bracteoles linear, c.10mm. Inflorescence 3-flowered. Pedicels 17–21 x c.0.8mm, sub-densely scaly, minutely patently hairy. Calyx c.2.5mm in diameter, sub-obliquely disc-shaped, very shortly and irregularly 5-lobed, scaly outside. Corolla trumpet-shaped, apparently red; tube 30–35 x 3–4 x 5–7mm, straight, sub-densely sub-stellately scaly outside, laxly hairy proximally inside; lobes 10–12 x c.8mm, obovate, spreading, scaly outside proximally. Stamens equalling or slightly exserted from the mouth of the corolla; filaments narrowly linear, patently laxly hairy in the proximal ½, glabrous distally; anthers 2.5 x 1mm, narrowly oblong, base obtuse. Disc glabrous. Ovary c.6 x 1.7mm, sub-cylindrical, densely covered with scales, which touch or even overlap each other (and possibly hide some short hairs), gradually tapering distally; style slender, as long as the corolla, scaly in the proximal 1⁄3 and laxly patently short-hairy in the proximal 2/3, glabrous distally; stigma globose, shortly 5-lobed.
Distribution: Indonesia, New Guinea (W), Swart R. Valley (c.138°15'E 3°30'S).
Altitude: 1600-2000m
Greek – rhodo – rose (the colour); salpinx – a war trumpet. Alluding to the rose-coloured corolla tube.
Known only from the type collection. This species should possibly not be included in Solenovireya on account of flower colour and the large corolla lobes in relation to the tube. Further specimens are badly needed to establish its proper identity.
Type: Bergman 815, 19 April 1958. New Guinea, Northern Part, Swart R. valley, Kadubaka, 1600–2000m (S, L, fragment).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:150
Shrub to 60cm; branches spreading. Twigs 1–1.5mm in diameter, rounded, densely covered with sub-stellate, shortly stalked scales at first, becoming glabrescent and distinctly warty and rough to the touch; internodes 2–6cm. Leaves 4–5 together in pseudowhorls. Blade 20–35 x 10–21mm, elliptic or obovate-elliptic, rarely broadly obovate; apex broadly tapering, or rarely almost rounded, the extreme tip apiculate with a short, thickened gland; margin slightly revolute; base tapering; scaly on both sides, at first, becoming glabrescent above, persistently, sub-densely scaly beneath. Scales angular or obtusely lobed in the narrow marginal zone; centre large, thick, impressed, becoming blackish. Mid-vein slightly impressed above in its proximal part, raised beneath; lateral veins sub-inconspicuous. Petiole 1–5mm, flattened, scaly. Bracts to 12 x 5mm, ovate-acuminate, apiculate subulate, membranous, scaly at the tips outside, glabrous elsewhere, margin with fragile scales. Bracteoles c.8mm, filiform, glabrous. Flowers solitary. Pedicels c.10mm, slender, very densely reddish-brown-stellate-scaly, not hairy at all. Calyx c.2.5mm in diameter, oblique, disc-shaped, scaly outside, very shortly obtusely 5-lobed. Corolla 23–27mm, tubular, fleshy, white with a pink mouth; tube c.20 x 6–7 x 7–9mm, cylindrical, slightly curved, sub-densely sub-stellate-scaly outside, glabrous inside; lobes 6–7 x 6–7mm, broadly obovate or sub-circular, glabrous. Stamens reaching just below the mouth; filaments flattened and linear, glabrous; anthers 2.5 x 1mm, sub-obovate-oblong, cells often contracted at the base into a short apiculus. Disc prominent, shortly hairy at the upper margin, glabrous elsewhere. Ovary c.5 x 2mm, sub-cylindrical, densely, very shortly greyish hairy and sub-stellately scaly, gradually tapering distally; style slender, patently hairy in the proximal ½, glabrous distally, equalling the corolla in length; stigma club-shaped. Fruit (immature) 20 x 3mm, fusiform, densely shortly hairy and laxly scaly.
Habitat: Epiphytic in mossy forest and forest margins
Distribution: Papua New Guinea, Mt Saruwaged and Rawlinson Range.
Altitude: 1525-3655m
Greek – rhodo – rose or rosy-red; stoma – mouth. The flowers originally described as white with a pink mouth.
Type: Clemens 9922, 28 Feb. 1939. New Guinea (NE), Morobe District, Mt Saruwaged, upper Camp, 2745–3265m (A, L).
Occurs in Countries: PG Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: pink, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:220
Shrub, 2-3m; young shoots spreading-stipitate-glandular, sticky. Leaves persistent, coriaceous dimorphic; spring leaves lanceolate-elliptic, 5.5-7.5 x 2.3-3cm, c.2.5 x as long as broad, apex acuminate, base cuneate, margin revolute, upper surface sparsely strigose, especially on midrib, lower surface setose; summer leaves 18-30 x 8-10mm, otherwise as for spring leaves; petioles 4-8mm, spreading-setose; Inflorescence I0-14-flowered; pedicels 13-15mm, strigose, sticky. Calyx minute, strigose, lobes triangular-lanceolate. Corolla rotate-campanulate, c.25mm, rose-red with purple flecks; tube c.10 x 8mm, glabrous. Stamens 5, filaments sparsely puberulent in lower half. Ovary strigose; style puberulent below. Capsule ovoid, c.7 x 5-6mm, strigose.
Habitat: Rocky places in upland woodlands
Distribution: China (Guangdong, Hunan, Jiangxi)
Altitude: Around 800m
Closely allied to both R. yaoshanicum and R.jinxiuense but differing from both in its broader corolla tube, etc.
Type: Guangdong, Rhuyuan Xian, Ching-Si-Tung, in silvis montis saxis, 7 vi 1933, X.P. Gao (S.P. Ko) 52804 (holo. IBSC, iso. PE)
Synonymy: R. lingiiChun in Ching, Icon. Corm. Sin. 3:151, f.4256 (1974)ó Chinese description only. Type as for R. rhuyuenense.
Occurs in Countries: CN Altitude Ranges: 0 - 1,000m Subgenus: Tsutsusi Habit: Non-Tree
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):99
Shrub, 1-10 m. Young growth sparsely lepidote, usually with pruinose-glaucous bloom. Leaves 29-65 x 13-25 mm, hard, elliptic to narrowly elliptic, acute at apex, cuneate at base, elepidote above, beneath sparsely lepidote with very distant (c. 5-8 x their own diameter apart), narrowly rimmed, golden or brown scales; petiole and upper part of midrib usually pruinose-glaucous, rarely sparsely puberulent. Inflorescence loose, pedicels lepidote, (8-)10~17 mm. Calyx minute, disc-like or undulate, sparsely lepidote, usually glabrous. Corolla white to rose pink or lilac, unspotted or spotted with red, (21-)24-27(-30) mm, ± elepidote outside. Capsule 10-16 mm.
Habitat: Scrub, thickets and forest, sometimes on rocky slopes
Distribution: China (N & NW Yunnan, SW Sichuan)
Altitude: 2000-3350m
Very similar to R. pleistanthum. Some specimens are more or less intermediate between the two; the type of R. caeruleum is, to some extent at least, one of these. R. bodinieri Franchet, Journ. de Bot. 12:257, 1898 (type: China, Yunnan, mont de Ma Kay avant le ville Se tschong hsien, Bodinier 1519, holo. P—n.v., iso. E) is a curious plant with the individual scales and inflorescence like siderophyllum but the scales themselves are very distant, as in R. rigidum. It may be a natural hybrid of these two.
Type: China, Yunnan, dans le gorge du Lan kien ho pres Mo so yn (Lankong), 2200 m, 26 iv 1884, Delavay 837 (holo. P—n.v., iso. E)
Synonymy: R. racemosum var. rigidum (Franchet) Rehnelt, Gartenflora 57:561, t. 1577 (1908). R. caeruleum Leveille, Feddes Rep. 12:284 (1913). Type: China, Yunnan, mont de Mo tsou, v 1912, Maire (holo. E). R. rarosquameum Balfour f., Notes R.B.G. Edinb. 10:137 (1917). Type: China, Yunnan, Io chan, 3200 m, Maire (holo. E). R. sycnanthum Balfour f. & W. W. Smith, op. cit.: 162. Type: China, Yunnan, E flank of Tali range, 10-11000 ft, v 1910, Forrest 6771 (holo. E). R. hesperium Balfour f. & Forrest, Notes R.B.G. Edinb. 13:263 (1922). Type: China, Yunnan, Tali range, W flank, 10000 ft, vi 1917, Forrest 15576 (holo. E). R, eriandrum [Leveille ex] Hutchinson, The Species of Rhododendron, 798 (1930). Type: none designated.
Occurs in Countries: CN Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: lilac, pink, red, rose
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):69
Named after the first collector, S.D. Ripley, an American ornithologist who spent some time in SE Asia.
Type: Ripley & Ulmer 40, 17 April 1939. Sumatra, Atjeh, Mt Losir, 2500m (PH, A).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:196
Leaves elliptic-obovate, 23–35 x 7–12mm, with a distinct apical gland. Corolla red. Differing from the type as the style has a ring of short patent hairs at its very base.
Habitat: In ridge shrubbery
Distribution: Indonesia, N Sumatra, Gajo Lands, (Mt Kemiri).
Altitude: Around 2800m
Greek – basi – base; trichum – hair. Alluding to the hairs at the base of the style.
Sleumer in the original publication noted that this was possibly a hybrid of R. ripleyi with R. pubigermen. The matter has not been resolved.
Type: Steenis 9570, 6 March 1937. Sumatra, Atjeh, G. Kemiri, E slope, 2800m (BO, L, fragment).
Leaves as in var. ripleyi but up to 60 x 23mm. Flowers red. Differs in its glabrous disc, sparsely to very sparsely hairy filaments and darker scales.
Habitat: In ridge shrubbery, locally common.
Distribution: Indonesia, N Sumatra, Gajo Lands.
Altitude: 1850-3000m
Greek – crypto – hidden; gonē – generative organ. Somewhat obscure, the male and female organs are hidden within the flower.
Sleumer in his original description says: ‘The dark chestnut scales suggest a hybrid of R. ripleyi with R. malayanum; they are very dense in the youngest, not yet fully developed leaves, touching each other as in R. malayanum’. A recent collection from Mt Kaba matches the description of this variety and was growing with R. malayanum but it is still not certain that this is a hybrid.
Type: Steenis 9167, 23 Feb. 1937. Sumatra, Atjeh, Gajo and Alas Lands, summit Mt Lembuh to camp ‘Halfweg’, 1850–3000m (BO, L).
Shrub to 2.5m. Twigs 1–2mm in diameter, at first sub-densely covered with flat scales, later glabrescent; internodes 2–5cm. Leaves 4–8 together in loose pseudowhorls, mostly with 1–2 leaves a little lower than the others. Blade 20–35 x 7–18mm, broadly elliptic to elliptic-obovate; apex obtuse, or apiculate with a protruding gland; margin finely crenulate with impressed scales and distinctly recurved; base broadly to narrowly tapering; densely scaly initially on both sides, glabrescent above with age, persistently (especially distally) scaly beneath. Scales small, of a light colour, the thin narrow marginal zone irregularly crenate or lobed; centre darker, strongly impressed, leaving a black pit in old leaves. Mid-vein slightly impressed above, somewhat prominent or smooth beneath; lateral veins 4–5 per side, spreading, impressed above, inconspicuous beneath, or inconspicuous on both sides. Petiole 2–5 x 1–2mm, flat, scaly. Bracts to 10 x 5mm, ovate-elliptic, shortly acuminate, membranous, glabrous outside, shortly fringed with scales, often persistent at the base of the pedicels. Bracteoles to 10mm, linear, glabrous. Inflorescence 1–2-flowered, (rarely up to 4). Pedicels 10–20mm, densely appressed, sub-stellately scaly, without hairs. Calyx c.3.5mm in diameter, shortly cup-shaped, margin obtusely shallowly 5-lobed, scaly outside. Corolla 25–30mm, funnel-shaped-campanulate, red; tube c.15 x 4 x 10mm, laxly sub-stellately scaly outside, glabrous inside; lobes 8–13 x 6–10mm, spreading, spathulate-obovate to sub-circular. Stamens exserted to c.5mm, unequal; filaments linear, densely covered with long, white, sub-patent hairs for c.2mm proximally, glabrous distally; anthers c.2 x 1mm, broadly oblong, the base of each cell somewhat lobed. Disc prominent, shortly hairy on the upper margin only. Ovary c.3.5 x 2mm, ovoid-conical, abruptly contracted distally, densely stellate-scaly, without hairs; style 8–17mm, slender, quite glabrous; stigma globose, deeply 5-lobed.
Habitat: In mossy forest.
Distribution: Indonesia, N Sumatra, Gajo Lands, (Mt Losir).
Not recently recollected and never cultivated.
Small tree, 3.5-16m. Leaves elliptic to oblanceolate, 9.5-17 x 3.2-5.2cm, 2.7—3.3 X as long as broad, apex acute to shortly acuminate, upper surface glabrous, lower surface with a thin compacted white indumentum embedded in a surface film; petioles 1.5-2cm, ± glabrous. Inflorescence lax, 4-10-flowered; rhachis 3-5mm; pedicels 5 —10mm, with a thin white indumentum, eglandular. Calyx l-2mm, with a thin white mealy indumentum, lobes triangular. Corolla campanulate, purplish to violet, with darker nectar pouches, 40-50mm. Ovary densely grey-felted-tomentose; style glabrous. Capsule c.25 x 10mm.
Habitat: Open rocky slopes
Distribution: China (Sichuan, ? Guizhou)
Altitude: Around 1850m
Illustrations:
The only species in subsection Argyrophylla with corollas with nectar pouches and in this respect intermediate between this subsection and subsection Arborea.
Type: China, Sichuan, Mt Omei, vi 1904, Wilson 5139 (holo. A; iso. E, K, Hb. Inst. Bot. Guangzhou).
Occurs in Countries: CN Altitude Ranges: 1,000 - 2,000m Subgenus: Hymenanthes Habit: Tree
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):328
Shrub, c, 1 m; young shoots covered with spreading, long and eglandular, and short and gland-tipped, ferrugineous hairs that become fuscous. Leaves dimorphic, chartaceous; spring leaves ovate-lanceolate, 4-9 x 1.5-5cm, 1.8-2.3 x as long as broad, apex acuminate to mucronate, base rounded, margin entire, upper surface sparsely pubescent at first, lower surface loosely hirsute and viscid when young; summer leaves 10-30 x 5-10mm, otherwise as for spring leaves; petioles 4-I3mm, with long eglanduiar and short and glandular, ferrugineous hairs. Inflorescence many-flowered; pedicels c.lOmm, pubescence as for petioles. Calyx c.4-5mm, lobes narrowly lanceolate, ciliate. Corolla tubular-campanulate, purplish-red, 22-25mm; tube c. 10mm, outer surface glabrous, inner surface puberulent. Stamens 5, puberulent below middle. Ovary rufous-setose, style hairy at base. Capsule c. 10mm long.
Habitat: Open woodland, ravines
Distribution: China (E Sichuan, Guizhou, Guangxi, Hunan, Fujian)
Altitude: 400-900m
Type: China, Guizhou, inter oppidum Duyun et vicum Lopusse, 750-900m, vii 1917, Handel-Mazzetti 10696 (holo. W, n.v., iso. E, fragm.)
Occurs in Countries: CN Altitude Ranges: 0 - 1,000m Subgenus: Tsutsusi Habit: Non-Tree
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):102
Shrub to 2.5m. Twigs 4–6mm in diameter, round, green, laxly scaly; internodes 4–10cm. Leaves 3–5 together in loose pseudowhorls. Blade 80–160 x 35–60mm, elliptic; apex shortly acuminate, narrowly to broadly acute, rarely obtuse; margin entire, flat or weakly revolute; base narrowly tapering, sometimes a little decurrent; minutely silvery scaly above at first, the scales leaving small impressed pits, laxly to sub-densely and more persistently scaly beneath. Scales irregularly lobed in the marginal zone; centre dark, shallowly impressed. Mid-vein strongly raised above proximally, gradually tapering distally becoming smooth or even slightly impressed in the distal ½, beneath broadly and shallowly raised; lateral veins 8–10 per side, curved-spreading and obscurely interarching at some distance from the margin, slightly prominent on both sides or obscure, reticulation obscure, or faintly visible beneath only. Petiole 10–25 x 3–4mm, without a groove, laxly, minutely scaly. Flower buds to 35 x 20mm, ovoid, acuminate. Bracts to 25 x 13mm, outer bracts ovate-acuminate, sub-acute, initially laxly scaly outside, but quickly glabrescent, inner ones ovate-elliptic, obtuse, glabrous. Bracteoles to 20 x 2mm, linear proximally, sub-spathulate distally, glabrous. Inflorescence 5–12-flowered, a complete or slightly open umbel. Pedicels 20–45 x c.1mm, laxly scaly, glabrescent. Calyx 3–4mm in diameter, oblique, disc-shaped or rim-like, obscurely lobed or wavy, with a few scales outside. Corolla 30–35 x 30–35mm, funnel-shaped, yellow often flushed with orange or red; tube c.15 x 5–6 x 10–15mm, pouched at the base, glabrous inside and out; lobes 13–18 x 10–15mm, spreading, broadly elliptic-obovate. Stamens 20–25mm, exserted to c.10mm, unequal, irregularly arranged around the flower; filaments linear, glabrous; anthers 3–3.5 x 1–1.3mm, oblong, a little curved, base obtuse. Disc prominent, glabrous. Ovary 5–6 x 2–2.5mm, ovoid-conical, initially with some fragile sub-stellate scales, or glabrous, often minutely warty, abruptly contracted distally; style 10–15mm, slender, glabrous; stigma 2–3mm in diameter, knob-like, thickly 5-lobed. Fruit c.30 x 6mm, fusiform, somewhat oblique and curved, glabrous.
Habitat: Epiphytic on tall trees, especially those overhanging rivers, also terrestrial on rocks by streams, occasionally on wooded hillsides or swamps, locally common.
Distribution: Malaysia (Peninsula), Main Range from Perak to Selangor, and in the Taiping Hills.
Altitude: 1035-1830m
Named after Herbert C. Robinson, one time director of the Malay States Museums.
Rhododendron robinsonii is superficially similar to R. javanicum, differing only in the completely glabrous filaments. Sleumer comments on its similarity to R. rarilepidotum, considering it different mostly on flower colour. This difference does not work as R. rarilepidotum often has yellow flowers. In cultivation R. rarilepidotum has much smaller, more conspicuously scaly leaves, and the petioles are usually at least weakly grooved above. Rhododendron robinsonii never has grooved petioles in the fresh state.
Type: Ridley 13588, Dec. 1900. Malay Peninsula, G. Berumbun, 1035–1535m (SING, BM, K).
Occurs in Countries: MY Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: orange, red, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:242
Shrub from 1-4 m. Young branches sparsely loriform-setose, the setae quickly deciduous. Leaves ± obovate, tapered to the base, abruptly acute at the apex, 70-120 x 35-60 mm, the lower surface brownish with lax to rather dense scales. Inflorescence (2-)3-5-flowered. Calyx obscurely lobed, loriform-ciliate. Corolla white or white flushed pink, with a yellow blotch at the base, (50-)55-75 mm, tube (28-)30~40 mm, pubescent at the base outside, the whole surface laxly lepidote. Capsule lepidote, c. 20 mm.
Habitat: Forests, hillsides, scrub
Distribution: China (W & SW Yunnan)
Altitude: 1800-2750m
R. roseatum vicariates with R. pachypodum, being restricted to the Shweli/Salween Divide, whereas R, pachypodum occurs to the east and north. The distinctions between the two are slight, but the geographical separation corresponds well with the morphological one.
Type: China, W Yunnan, Shweli/Salween Divide, 8000-9000 ft, v 1913, Forrest 11866 (holo. E)
Synonymy: R. lasiopodum Hutchinson, op. cit.: 58. Type: China, Yunnan, Shweli/Salween Divide, 8000-9000 ft, v 1913, Forrest 9919 (holo. E)
Occurs in Countries: CN Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: pink, white, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):51
Shrub to 3m. Twigs 1.5–2.5mm in diameter, rounded, often glaucous, sparsely scaly. Leaves 3–7 together in tight pseudowhorls. Blade 17–85 x 10–29mm, elliptic to ovate; apex tapering to broadly rounded; margin flat to slightly recurved; base shallowly cordate to broadly tapering. Scales remotely spaced on both sides, flat, thin with a broad lobed margin and small central area. Mid-vein impressed above, slightly raised below; lateral veins 4–7 per side curving upwards towards the margin, raised both above and below, reticulation obscure above, below slightly raised, the leaf surface often furrowed. Petiole 2–7mm, with sub-persistent scales. Bracts to 14 x 2mm, with scaly margins, the outer ovate, c.5 x 5mm, the apex mucronate, the internal bracts sub-linear, apex rounded. Inflorescence of 5–8, half-hanging flowers in an open umbel. Pedicels 8–15 x 0.4–0.9mm, covered with scales and simple hairs. Calyx c.1.8mm in diameter, obliquely disc-shaped, weakly 5-lobed, with scales and hairs outside, inside glabrous. Corolla pink, tubular, expanded distally but contracted shortly below the mouth; tube 53–78 x 4.3–8.2 x 3.5–7.5mm, curved, outside sparsely scaly, inside covered with short hairs especially proximally; lobes 7.5–10.5mm, spreading, apex rounded to weakly retuse. Stamens clustered together; filaments 65–76mm, densely covered with white hairs in the proximal ½; anthers 2.6–3.5mm, exserted to c.10mm. Disc covered with hairs. Ovary 7–9.5mm, densely scaly; style 58–82mm, scaly becoming laxly so upwards; stigma 1–1.4mm wide, becoming exserted.
Habitat: Terrestrial shrub in open sub-alpine woodland or shrubberies, occasionally epiphytic.
Distribution: Indonesia, New Guinea (W), above Tembagapura near Mt Jaya (Carstensz) and also in the vicinity of Mt Trichora (Wilhelmina).
Altitude: 2100-2700m
Latin – rosei – red coloured; florum – flower. Alluding to the prominent pink flush on the flowers.
Type: Raynal 17672, 11 May 1973. Irian Jaya, S spur of Mt Carstensz, Tembagapura (P, L).
Occurs in Countries: ID Altitude Ranges: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:175
Erect shrub, c.1.5m. Twigs 1.5–2mm in diameter, laxly sub-stellately scaly when young; internodes 1.5–10cm. Leaves 3–6 together in tight pseudowhorls, often with 1–2 much smaller leaves. Blade 50–105 x 25–50mm, ovate to ovate-elliptic; apex often long-acuminate, acute, obtuse, sometimes almost rounded and minutely emarginate; margin entire, narrowly revolute; base rounded to slightly cordate, glabrescent above, laxly to sub-densely scaly beneath. Scales variable in size; margin sub-stellately lobed, transparent and fragile; centre minute, impressed. Mid-vein narrowly impressed above, strongly raised beneath; lateral veins 6–8 per side, wide-spreading, curved-anastomosing before the margin, slightly raised above and beneath or almost inconspicuous, reticulation obscure. Petiole 1–4 x 1.5–2mm, grooved above. Flower buds to 27 x 17mm, minutely but densely hairy outside and laxly scaly. Bracts to 20 x 10mm, ovate, shortly acuminate, to obtuse, often splitting to appear emarginate, laxly scaly and minutely hairy outside, inner bracts obtuse, elliptic to sub-circular, densely hairy, not scaly. Bracteoles to 15 x 1mm, filiform below, sub-spathulate distally, densely hairy. Inflorescence an open umbel of 3–6 half-hanging to hanging, dark red flowers, without scent. Pedicels 25–38 x c.1mm, densely sub-patently hairy and very laxly or not scaly. Calyx c.3mm in diameter, disc-shaped, shortly obtusely angled, shortly hairy outside. Corolla 40–45 x 25–30mm, tubular-funnel-shaped; tube 25–35 x 5–6 x 12–14mm, slightly oblique, sparsely sub-stellately scaly outside, glabrous inside; lobes 10–12 x 8–10mm, broadly spathulate or sub-circular. Stamens arranged on lower side of the mouth, unequal, exserted to c.8mm; filaments linear, glabrous. Disc hairy especially at the upper margin. Ovary 6–7 x c.2.5mm, sub-cylindrical, tapering distally, densely patently hairy, the hairs hiding minute scales; style patently white-hairy proximally becoming less densely so and glabrous for the distal 2–4mm; stigma thick rounded. Fruit 40–48 x 5–6mm, fusiform, the outer layer peeling irregularly, the valves spreading widely and twisting when dry, the placentae irregularly breaking away from the base. Seeds 5–7mm, without tails 0.7–0.8mm, the longest tail c.4mm, the tails slender and wavy.
Habitat: Terrestrial, in peaty swamps and on cliffs, epiphytic in sub-alpine shrubberies
Distribution: Indonesia, New Guinea (W), Wissel Lakes region, Valentin Mts, and Mt Jaya (Carstensz).
Altitude: 1380-2600m
Named after the collector, M. Rosendahl, who collected for the Forest Service at Hollandia (now Jayapura).
Type: Rosendahl BW 3254, 9 Sept. 1955. New Guinea (W), Wissel Lake, Ulida, c.1800m (L).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:308
Large shrub or small tree, 5-6m. Leaves obovate-oblanceolate, 26.5-28(-36) x 10-14cm, 2.3-2.8 x as long as broad, apex rounded, base cuneate, upper surface glabrous when mature, lacking strongly impressed veins, lower surface with a bistrate indumentum, the lower layer white, ± compacted, the upper agglutinated, patchy, often reddish-brown, composed of strongly fimbriate cup-shaped hairs; petioles c. 1.5cm, flattened and with marked wings. Inflorescence 12-17-flowered; rhachis c.20mm; pedicels c.30mm, tomentose. Calyx c.lmm, tomentose. Corolla 8-lobed, obliquely campanulate, pale yellow with a purple basal blotch, 35—45mm. Stamens 16. Ovary densely tomentose. Capsule c.25 x 10mm, curved.
Habitat: Mixed forests
Distribution: China (NW Yunnan, around Weixi)
Altitude: 3700-4000m
An unsatisfactory species, possibly of hybrid origin. A series of specimens (Forrest 29299; Rock 16956, 16957, 17128, 17129, 18391, 18432, 167) with a rust-red leaf indumentum that is not strongly agglutinated, but with the typical winged petioles, occurs in the field with R. rothschildii. While these plants are clearly closely allied, their exact status awaits proper field studies.
Type: China, Yunnan, 1931, Forrest 30528 (holo. E).
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: purple, yellow
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):252
Shrub to c.1m. Twigs at first laxly covered with brown scales but these quickly falling to leave the surface minutely warty and often longitudinally grooved, without simple hairs. Leaves crowded into tight pseudowhorls of 3–7 full-sized leaves and several much smaller ones. Blade 25–50 x 15–30mm, elliptic to obovate; apex broadly obtuse to rounded, sometimes slightly retuse; margin recurved, strongly so when dry, often cartilaginous although this is obscured by the curved edges; base tapering, slightly decurrent; dark shining green above, much paler green beneath; laxly to sub-densely scaly on both sides when young, glabrescent above, persistently scaly beneath. Scales round to irregularly shallowly lobed, small, flat, dark brown. Mid-vein impressed above, raised below; lateral veins 3–5 per side, distinctly impressed above, smooth below, becoming slightly raised after drying. Petiole 5–12 x 2–2.5mm, grooved above, scaly. Flower buds to 18 x 10mm, green and shiny, sometimes flushed with red, with pale brown reflexed tips to the bracts. Outermost bracts subulate from a broad triangular to ovate base, becoming larger inwards and concave-ovate with acutely pointed and channelled tips, finally broadly spathulate; membranous, glabrous outside except for a few scales near the tips and a fringe of scales along the margins; minutely hairy inside. Bracteoles to 22 x 2mm, filiform, broadening slightly upwards and often with a forked tip, glabrous or occasionally with a few hairs. Inflorescence an open umbel of 2–6 flowers, held horizontally to semi-erect. Pedicels 16–21 x c.2mm, green, moderately to densely scaly with pale brown scales, without simple hairs. Calyx 4mm in diameter, irregularly lobed, up to 1.5mm. Corolla 22–28 x 45–57mm, white, without scent; tube 11–13 x 6–7 x 10–13mm, funnel-shaped, minutely brown scaly outside and with a few white hairs near the base especially in the shallow grooves, with irregular white hairs inside; lobes 24–28 x 22–25mm, minutely and obscurely brown scaly proximally to about halfway up the lobe outside, lobes overlapping 1⁄3–2⁄3, widely spreading to almost 90°. Stamens arranged in a regular cluster in the mouth of the flower, weakly dimorphic with only the anthers exceeding the corolla tube, expanding slightly back against the corolla as the flower ages; filaments 12–13mm, white, patent hairy in the proximal 1⁄3–½; anthers c.2.5 x 1mm, brown. Disc green, 10-lobed, with erect hairs on the upper side and on the outer rim of the lobes. Ovary c.4 x 3mm, green, densely silvery scaly and moderately white hairy; style green at the base, white above, patently white-hairy for up to 1.5mm proximally, otherwise completely glabrous; stigma c.2mm in diameter, pale yellow, slightly lobed. Fruit 8–12 x 5–7mm, shortly cylindrical, deep purplish red, densely hairy and covered in dark brown scales, the valves gaping to c.45°, not twisting. Seeds 1.5–2.2mm; without tails 0.5–0.8mm, the longest tail 0.6–0.7mm.
Habitat: Growing amongst ultramafic boulders in open sub-montane forest
Distribution: Philippines, Romblon Province, Sibuyan Island, Mt Guiting Guiting, Camp 3 above Magdiwang, on ridge leading to Mayos Peak.
Altitude: Around 1300m
Named after Dr John Rouse, of Melbourne, for his outstanding contribution to our knowledge of vireya rhododendrons.
This species is related to R. vidalii but is distinct in that the young stems lack simple hairs and are warty with scale stalks when the scales have gone. It also has larger, darker green leaves and much larger flowers, with the corolla lobes 24–27mm (up to 13mm in R. vidalii).
Type: Argent 19902332, Aug. 1989. Philippines, Sibuyan Is., Mt Giting Giting, Camp 3 above Magdiwang, on ridge leading to Mayos Peak, 1300m (PNH, E).
Occurs in Countries: PH Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: brown, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:208
Shrub, sometimes dwarf, 0.15-2.5(-4)m. Leaves linear to elliptic, 5-12 x 0.6-4cm, 2.2-15 x as long as broad, apex acute to cucullate, base cuneate to + rounded, lower surface with a thick bistrate indumentum, the upper layer rufous, ramiform, lanate-tomentose, loose, the lower radiate, compacted; petioles 0.4-l(-1.5)cm, rufous-tomentose to glabrescent. Inflorescence 6-15-flowered; rhachis c.lOmm; pedicels 8—15(-20)mm, tomentose and glandular. Calyx 0.5—2mm, tomentose and glandular. Corolla funnel-campanulate, white or (rarely) pale yellow, sometimes flushed with pink, with purple flecks, 20—40mm. Ovary densely rufous-tomentose and glandular. Capsule 10—15 x 3—5mm
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: pink, purple, white, yellow
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):344
Habitat: Rocky pastures, forest margins
Altitude: 3350-4250m
Var. cucullatum is intermediate between var. roxieanum and R. proteoides and is almost certainly of hybrid origin. There is a complete gradation in the leaf length/breadth ratio from the extreme forms of var. roxieanum to the extreme forms of var. cucullatum. Therefore an arbitrary dividing line has been selected so that the largest proportion of the specimens seen can be assigned to a variety. Var. cucullatum tends to have a loose indumentum which apparently partially bleaches at maturity (as in R. proteoides), while var. roxieanum has a more compact indumentum that does not bleach. Neither is, however, completely consistent in its indumentum type.
Synonymy: R. cucullatum Handel-Mazzetti, Akad. Wiss. WienMath. -Naturwiss. Kl., Anz. no. 4-5 (1921). Type: China, Sichuan, in monte Lose-schan, regione frigidi, 3900-4520m, 16 iv 1914, Handel-Mazzetti 1416, n.v. R. coccinopeplum Balfour f. & Forrest, Notes R.B.G. Edinb. 13: 248 (1922). Type: China, SW Sichuan, Muli Mts, 12000ft, vi 1918, Forrest 16379 (holo. E;iso. K). R. porphyroblastum Balfour f. & Forrest, ibid. 13: 287 (1922). Type: China, SW Sichuan, Muli Mts, 28°12'N, 13-14000ft, vi 1918, Forrest 16469 (holo. E; iso. K).
Habitat: Pine forests, alpine meadows, stony slopes
Distribution: China (SE Xizang, NW Yunnan, SW Sichuan)
Illustrations:
A specimen with almost glabrous leaves, Forrest 25539, is almost certainly referable to var. roxieanum. This feature is sometimes seen in cultivated plants that maintain the ability to revert to the usual dense leaf indumentum, probably depending on weather conditions.
Intermediates between var. roxieanum and var. cucullatum occur frequently in the wild. The distinction in the more extreme forms with short, extremely narrow leaves (var. oreonastes) is not maintained here as at least part of the type collection of var. roxieanum matches the type of var. oreonastes.
Type: China, NE of the Yangtze Bend, 27°45'N, 11-12000ft, vii 1913, Forrest 10540 (holo. E; iso. K)
Synonymy: R. recurvum Balfour f. & Forrest, Notes R.B.G. Edinb. 11: 113 (1919). Type as above. R. recurvum Balfour f. & Forrest var. oreonastes Balfour f. & Forrest, ibid. 11: 113 (1915). Type: China, NW Yunnan, Kari Pass, Mekong/ Yangtze divide, 27°40'N, 14000ft, viii 1914, Forrest 13005 (holo. E; iso. BM). R. aishropeplum Balfour f. & Forrest, ibid. 13: 229 (1922). Type: China, W NW Yunnan, Mekong/Salween divide, 28°22'N, 12-13000ft, vi 1917, Forrest 14061 (holo. E; iso. K). R. poecilodermum Balfour f. & Forrest, ibid. 13:285 (1922). Type: China, SE Xizang, Tsarong, Mekong/Salween divide, on Ka-gwr-pw, 28°25'N, 12000ft, vii 1917, Forrest 14452 (holo. E; iso. K)
Shrub, c.2.5m; young shoots with a dense lanate tomentum; perulae persistent. Leaves linear, 6.5-7.5 x 1.3-1.8cm, 4-5 X as long as broad, apex acuminate, base cuneate, lower surface covered with a bistrate indumentum, the upper layer thick, lanate-tomentose, composed of brown ramiform hairs, the lower layer compacted and whitish; petioles c.0.5cm, densely lanate-tomentose. Inflorescence 12-16-flowered; rhachis minute; pedicels c.7mm, densely tomentose. Calyx c.lmm, densely tomentose, also stipitate-glandular, lobes rounded. Corolla ? funnel-campanulate, deep pink, with flecks, c.30mm. Ovary with a dense rufous indumentum intermixed with a few glands; style glandular in the lower half. Capsule not known.
Distribution: China (E Sichuan) Only known from the type locality.
Apparently allied to R. roxieanum but differing in the more intensely coloured flowers and in the glandular style.
Type: China, E Sichuan, Wu Shan, Chao Yang Ping, Liang Feng village, 2150m, 3 v 1958, Yang, K. H. 57932 (holo. PE)
Occurs in Countries: CN Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: pink
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):347
Erect branching tree to 5m. Twigs 3–5mm in diameter, rounded, densely stellately scaly, glabrescent on older parts; internodes 3–8cm. Leaves 4–5 together in pseudowhorls. Blade 40–100 x 25–40mm, broadly elliptic, or slightly obovate; apex shortly acuminate, apiculate; margin flat or slightly revolute; base broadly tapering or rounded to slightly sub-cordate, immature ones densely brown-scaly with fragile scales and early glabrescent, leaving the leaves rough with the persistent tubercles above; covered for a longer time beneath with a nearly woolly scaly covering but later leaving the undersurface also rough. Scales large, narrowly stellately divided to form dendroid, stellate hairs, each on top of an epidermal tubercle. Mid-vein flat or minutely impressed above, as wide as the petiole and very prominent proximally, gradually less so distally beneath; lateral veins 4–8 per side, at an acute angle, straight below, curved and anastomosing before the margin, forming a lax network with the veins, with indistinct reticulation above but very distinctly so below. Petiole 10–17 x 1.5–2mm, grooved above, densely scaly. Bracts 15–22 x 8–10mm; the outer bracts ovate, sub-obtuse; the inner ones spathulate, both densely hairy on both sides, or minutely hairy or even glabrous. Bracteoles 10–15 x 1–2mm, linear to very narrowly spathulate, laxly to densely patently hairy. Inflorescence a 3–8-flowered, open umbel, the flowers horizontal to half-hanging. Pedicels 8–15 x 1–2mm, densely brown, stellately scaly, but without hairs except immediately below the calyx. Calyx deeply divided into irregular triangular lobes, to 2mm, densely, shortly-hairy and scaly outside and often with a longer fringe of hairs. Corolla 40–65 x 30–40mm, tubular, zygomorphic, bright red; tube 30–45 x 6–8 x 10–15mm, very laxly scaly or glabrous outside, with patent or retrorse hairs inside, straight below, curved and gradually dilated upwards; lobes 12–20 x 10–16mm, semi-erect or spreading, irregular, the upper two much larger than the lower three, obovate-spathulate, sometimes nearly circular. Stamens exserted to 8mm, unequal, irregularly arranged all round the mouth; the filaments red, linear and densely patently hairy proximally below, gradually less so distally becoming completely glabrous for 6–10mm; anthers 2–5 x 1–1.25mm, elongate-oblong, the base obtuse. Disc glabrous at least at the base. Ovary 8–10 x 2.5–3mm, elongate-cylindrical, gradually tapering distally, very densely hairy in the lowest 1mm (which may be the upper margin of the disc), elsewhere densely brown-scaly and hairy with the scales more numerous than the hairs and clearly visible; style as long or a little longer than the corolla tube, laxly hairy and sparsely scaly in the lower 1⁄3–2⁄3, glabrous distally; stigma thickly conical-sub-globose. Fruit 30–35 x c.6mm, fusiform, densely brown hairy and scaly. Seeds filiform, 3–4mm, with a very narrow tail at both ends.
Habitat: In forests, usually as part of the understory in closed canopy stands of moss forests or more rarely along the margins of alpine grasslands, said to be common at the Murray Pass (Wharton Range).
Distribution: Papua New Guinea, Wharton and Owen Stanley Ranges, Mt Piora, Mt Victoria, Mt Amorwange, Mt Scratchley.
Altitude: 2050-3100m
Latin – rubellus – reddish, alluding to the flower colour.
Type: Brass 4517, 6 Sept. 1933. New Guinea (E), Central District, Murray Pass, Wharton Range (L, A, BM, BO).
Occurs in Countries: PG Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Tree Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:98
Shrubs or small trees up to 10 m, or more in cultivation. Young growth lepidote, purplish. Leaves narrowly elliptic to elliptic or almost lanceolate, (40-)60-l 15 x (12-)20-45 mm," cuneate at base, acute to acuminate at apex, glabrous and ± elepidote above, very densely lepidote with overlapping or contiguous unequal scales beneath (the larger scales usually darker than the smaller, distributed all over the surface or restricted to the area adjacent to the midrib only), the surface pale or dark brown due to the density of the scales. Inflorescence up to 10-flowered, pedicels lepidote. Calyx very small, usually rim-like, sometimes undulate, sparsely lepidote, glabrous. Corolla openly funnel-shaped, (15-)20-30(-38) mm, tube (ll-)15-20(-23) mm, pink, mauve-pink, or rarely white flushed pink, glabrous but lepidote outside, pilose within the tube. Stamens 10, filaments sparsely pubescent towards the base. Ovary densely lepidote. Style glabrous, longer than the longest stamens at anthesis, declinate. Capsule lepidote, cylindric, 11-16 mm.
Habitat: Thickets and open forest
Distribution: China (N, NW, W & C Yunnan, SW Sichuan, SE Xizang), NE Burma
Altitude: 2500-3500m
Illustrations:
A widely distributed and variable species; the variation is largely uncorrected, however, and the distinction of separate species or infra-specific taxa is not possible.
Type: China, Yunnan, in dumetis ad pedem montis Tsang chan supra Tali, 2500 m, Delavay 2060 (holo. P—n.v., iso. E)
Synonymy: R. leclerei Leveilie, Feddes Rep. 12:284 (1913). Type: China, Yunnan, haut plateau de Ta-hai-tse, 3200 m, v 1912, Maire (holo. E). R. catapastum Balfour f. & Forrest, Notes R.B.G. Edinb. 13:36 (1920). Type: China, W Yunnan, Yung peh mountains, vii 1918, Forrest 16597 (holo. E). R. desquamatum Balfour f. & Forrest, op. cit.: 40. Type: China, W Yunnan, Shweli/Salween Divide, Jang-tzow-shan, v 1919, Forrest 15761 (holo. E). R. stenoplastum Balfour f. & Forrest, op. cit.: 60. Type: China, W Yunnan, Shweli/Salween Divide, v 1919, Forrest 17920 (holo. E). R. leprosum Balfour f., nom. nud. R. squarrosum Balfour f., nom. nud.
Occurs in Countries: CN, MM Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Rhododendron Habit: Tree Fl. Colour: mauve, pink, white
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):90
Low shrub to 20cm. Twigs 0.75–1.5mm in diameter, covered with shortly stalked stellate scales and with very short white hairs, warty in the older glabrescent parts; internodes 1–4cm. Leaves 4–7 together in tight pseudowhorls, with fragile cataphylls along the internodes. Blade 5–10 x 2–6mm, elliptic to ovate; apex broadly acute to obtuse; margin flat and entire; base broadly tapering to rounded, initially scaly on both sides, glabrous above at maturity, laxly but more persistently scaly beneath. Scales brown, flat rounded to sub-stellately lobed and slightly impressed, with small centres. Mid-vein impressed in the proximal 1⁄3 above, smooth and indistinct beneath; lateral veins not visible. Petiole 1–2 x c.0.5mm, not grooved above, densely brown-scaly and with very short white hairs. Flower buds to 6 x 3mm, narrowly ovoid with an acute apex, pale brown or pink, laxly scaly outside, the bract tips slightly spreading. Bracts narrowly ovate-acuminate, laxly scaly outside and along the margins. Bracteoles 4–5mm, linear. Pedicels 7–12 x c.1mm, slender, densely covered with dendroid-stellate scales and sparse white hairs. Flowers solitary or occasionally paired, held horizontally or half-hanging. Calyx obliquely cup-shaped, shortly obtusely 5-lobed, c.2mm in diameter, densely scaly. Corolla 15–20 x 25–35mm, broadly campanulate, red or pink; tube 10–12 x 7–8 x 9–10mm, laxly to moderately densely transparently scaly outside, glabrous inside; lobes 13–15 x 10–13mm, elliptic, spreading to reflexed, overlapping to c.¼. Stamens distinctly dimorphic, regularly arranged all round the mouth, the longest exserted to 1.5mm or all slightly included within the mouth; filaments 8 and 6.5mm, pink, linear, glabrous; anthers 0.7–1.2 x 0.4–0.6mm, oblong, dark-purplish-brown. Disc densely hairy along the upper margin. Ovary c.3 x 2mm, broadly sub-ovoid-cylindrical, gradually contracted distally, densely covered with short, patent hairs, less densely with scales between the hairs; style 4–4.5 x 1.5mm, sparsely hairy at the base or to 2⁄3 and sparsely scaly near the base; stigma c.2mm in diameter, green or red, globose. Fruit 12–15 x c.2mm, fusiform, pink, shortly hairy and scaly. Seeds 3–4mm including the tails.
Habitat: In alpine shrubberies and upper montane forest, epiphytic or at the base of trees.
Distribution: Indonesia, New Guinea (W), Mt Carstensz, Kemarong Valley. Papua New Guinea, Star Mts, Upper Ambun Valley, Kubor Mts, Minj–Nona Divide, Mt Hagen, Gumine, Mt Wilhelm, Mt Otto, Mt Piora, Sarawaket Mts, Busu–Tamunac area, Mt Amungwiwa, Bulldog Road, Mt Ne, Mt Giluwe, Mt Bosavi, Wharton Mts, Murray Pass, Mt Victoria and the Owen Stanley Mts.
Altitude: 2600-3400m
Latin – rubineus – ruby red; florus – flower. The ruby-red flowered rhododendron.
Type: Pullen 227, 28 July 1957. Papua New Guinea, W Highlands District: upper Minj River valley on the Minj–Nona divide (CANB).
Synonymy: R. anagalliflorum auct. non Wernham, Sleumer, Reinwardtia 1960. 5: 136. R. rubiniflorum Craven in van Royen & Kores, The Alpine Flora of New Guinea 1982. 3: 1606 (orthographic error).
Occurs in Countries: ID, PG Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: pink, red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:148
Shrub to 70cm. Twigs 1.5–2mm in diameter, laxly sub-stellately scaly when young, glabrescent and smooth later, or possibly warty; internodes 2–7cm. Leaves 3–5 together in pseudowhorls, with one or two inserted lower than the rest. Blade 20–38 x 10–16mm, elliptic to elliptic-oblong; apex shortly acuminate, sub-acute or obtuse, often apiculate with a protruding terminal gland; margin narrowly cartilaginous, entire, wavy or sub-crenulate, not or very weakly revolute; base broadly to narrowly tapering, sometimes truncate or rounded, minutely rugose above in old dry leaves, with scale remains or glabrescent, laxly and more persistently scaly beneath. Scales with the thin marginal zone irregularly sub-stellately lobed; centre slightly impressed. Mid-vein impressed above, obtusely prominent beneath; lateral veins inconspicuous. Petiole 3–7 x 1–1.5mm, a little flattened, scaly. Flower buds to 20 x 14mm, the bracts standing erect away from the bud. Bracts 10–22 x 4–9mm, ovate-acuminate, tapering to a short acumen or subulate, red, membranous, glossy, glabrous, initially with scales along the margin. Bracteoles c.6mm, filiform. Inflorescence of 2–5 flowers in an open umbel, the flowers hanging vertically. Pedicels 13–20 x c.1mm, densely reddish-stellate-scaly and densely papillose. Calyx c.3mm in diameter, obliquely disc-shaped, obscurely and bluntly 5-lobed, scaly outside. Corolla 20–26mm, tubular, sub-oblique, red or pale orange-pink, thin; tube 16–20 x c.5 x 7–8mm, straight or slightly curved, pouched at the base, laxly to sub-densely stellately scaly outside, glabrous inside; lobes 5–6 x 5–6mm, half-spreading, broadly obovate or sub-circular, slightly retuse. Stamens exserted to c.4mm, unequal; filaments linear, glabrous; anthers c.2mm, broadly oblong, base obtuse. Disc glabrous. Ovary c.4 x 1.5mm, sub-cylindrical, densely stellately scaly, gradually narrowed distally; style slender, glabrous, nearly equalling the stamens in length; stigma rounded. Fruit c.22 x 3.5mm, fusiform.
Habitat: Epiphytic or terrestrial, in open shrubberies on ridges and epiphytic on high trees in mossy forest
Distribution: Indonesia, New Guinea (W), Lake Habbema and vicinity; Mt Jaya; Valentin Mts.
Altitude: 1900-3345m
Latin – rubro – red; bractea – bract. Alluding to the red colour of the bracts on the flower bud.
Similar to R. calosanthes; for differences see under that species. Also very similar to and possibly to be united with R. subcrenulatum (see under that species).
Type: Brass 9278, Aug. 1938. New Guinea (NW), Lake Habbema, 3345m (A, L, fragment).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: orange, red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:224
Shrub, to 3m; young shoots densely covered with adpressed flattened grey to reddish-brown hairs. Leaves monomorpbic, chartaceous, oblong-lanceolate to elliptic, l-3(-5.5) x 0.5-l(-2.5)cm, 2-3 x as long as broad, apex acute and with a glandular mucro, base cuneate, margin entire, upper surface with pale grey adpressed hairs, lower surface clothed with flattened adpressed red-brown hairs, especially on midrib; petioles 3-5mm, densely covered with flattened red-brown hairs. Inflorescence 2-4-flowered; pedicels 2-4mm, densely strigose, hidden by bud scales. Calyx minute, densely covered with strigose red-brown hairs. Corolla funnel-shaped, pink with rose flecks, 10-15(-25)mm. Stamens 7-10, filaments pilose towards base. Ovary covered with pale grey soft hairs; style with a few flattened brown hairs at base. Capsule conic-ovoid, c.5mm long, covered with shaggy red-brown hairs.
Distribution: Taiwan (Ilan, Nantou, Chiaye)
Altitude: 2400-3000m
Synonymy: R. caryophyllum Hayata, Icon. PI. Formosan. 3:130, t.23 (1913). Type: Taiwan, 1909, Mori s.n., n.v. R. randaiense Hayata, Gen. Index Fl. Formosa 43 (1917) - nomen nudum.
Occurs in Countries: TW Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: pink, rose
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):125
Small shrub, 0-3-1 m, often with twisted and intricate branching. Leaf-bud scales deciduous. Leaves elliptic-oblong, rarely ovate, 10-20 X 5-9 mm, ± rounded at base and apex, dark glossy green above, beneath with dark brown, dense, overlapping scales borne in 2-3 tiers, those of the lowermost tier as dark as, or darker than, the rest. Inflorescences up to 12-flowered, pedicels short, elepidote or sparsely lepidote. Calyx lobes oblong, 3-4 mm, sparsely lepidote or elepidote outside, erose-ciliate with loriform cilia on the margins, glabrous inside. Corolla white, tube 5.5-9-5 mm, lobes 3-5-5-5 mm, often sparsely lepidote outside, mouth of the tube rather sparsely pilose inside. Stamens 5. Ovary lepidote. Capsule lepidote, scarcely exceeding the calyx
Habitat: Open, rocky places
Distribution: China (C Sichuan)
Altitude: 3900-4600m
There is one specimen from Muii (SW Sichuan), Rock 16084, which is probably this species, but it is in early flower and cannot be certainly identified.
Type: China, Sutchuen occidentale sur les montagnes de Tongolo, Soulie (holo. P~-n.v., iso. E)
Synonymy: R. daphniflorum Diels, Acta Horti Gotob. 1:180 (1921). Type: China, Nord Szechuan, Dongrego, 4300 m, 21 vii 1922, Smith 3700 (iso. E)
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):161
Much-branched shrub with slender branches; young shoots densely hirsute, with a dense covering of spreading brownish slrigose and slender pilose hairs. Leaves ? monomorphic, chartaceous, ovate-lanceolate, 2.5-6.5 x 1.3-2.5cm, 2-2.5 x as long as broad, apex acuminate, base cuneate to almost rounded, margin entire, ciliate, upper surface pilose, lower surface pale, pilose, with an admixture of strigose hairs, especially on midrib; petioles 5~10mm, densely hairy. Inflorescence 3-4-flowered; pedicels c.5mm, covered with reddish-brown pilose hairs. Calyx densely covered with reddish-brown strigose hairs, lobes narrowly obovate, c.3mm. Corolla funnel-campanulate, deep rose, c.20mm; tube c.9mm, outer surface glabrous, inner surface papillate-pilose. Stamens 10, as long as corolla, filaments pilose below middle. Ovary densely hairy; style hairy at base. Capsule ovoid, c.8 x 6mm, brown-spreading-hairy.
Habitat: Sandy soil, etc.
Distribution: China (E & S Yunnan, W Guizhou)
Altitude: 1800-2000m
Probably allied to R.flumineum
Type: China, Yunnan, prope Hsinlung at septentr. urbis Yunnanfu, 2000m, 10 iii 1914, Handel-Mazzetti 493 (iso. E)
Occurs in Countries: CN Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: rose
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):101
Shrub of about 1 m. Young growth not loriform-ciliate. Leaves 80-105 x 25-30 mm, narrowly obovate, tapered to the base, acuminate at the apex, not loriform-ciliate, undersurface brownish with dense, contiguous to overlapping scales. Calyx small, disc-like, loriform-ciliate. Corolla white, pinkish in bud, 55-65 mm, tube c. 35 mm; tube pilose at the base, the rest of the outer surface laxly lepidote. Capsule unknown.
Habitat: Hillsides
Distribution: China (S Yunnan—area around Szemao and the Papienho river)
Altitude: Around 1500m
The most southerly representative of the aggregate, known from only two collections: the type, and Rock 3012
Type: China, Yunnan, Szemao, 4800 ft, Henry 11983 (holo. K, iso. E)
Occurs in Countries: CN Altitude Ranges: 1,000 - 2,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: pink
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):47
Shrub, to 2m; young shoots densely covered with spreading rufous glandular hairs. Leaves dimorphic, coriaceous, elliptic to elliptic-oblong, sometimes subfalcate; spring leaves 3.6-6 x 1.5-2.5cm, c.2.3 x as long as broad, apex acuminate, base cuneate, margin entire, upper surface densely strigillose, soon gtabrescent, lower surface densely rufous-strigillose; summer leaves as for spring leaves but half the size; petioles 5-8mm, densely spreading-strigose. Inflorescence 3-14-flowered; pedicels c.lOmm, densely strigose. Calyx densely strigose, lobes minute. Corolla tubular-campanulate, reddish-purple, 15-20mm; tube 7-10 x c.2mm, glabrous. Stamens 5, filaments glabrous. Ovary densely strigose; style glabrous. Capsule ovoid, 6-8 x c.4mm, densely reddish-brown strigose.
Habitat: Mixed woodland
Distribution: China (Fujian)
Altitude: Around 500m
R. rufulum is allied to R. fiorulentum (q.v.)
9*. R. taipaoense T.C. Wu & P.X.Tan, Med. Mat. Guangd. 4: 36, f.5 (1978). Type: China, Guangdong, Dabu Xian, 700m, 9 vi 1957, L. Teng 4963 (holo. IBSC). Map 2. Doubtfully distinct from R. rufulum but with leaf indumentum deciduous and possibly with a crenate calyx.
R. falcinellum differs only in its fewer (3-5-flowered) inflorescence; R. rufulum may also have subfalcate leaves. It is therefore not maintained as a separate taxon. R. spadiceum apparently only differs in the less coarse and spreading indumentum on the young shoots and petioles. It is almost certainly synonymous with or a hybrid of .ft. rufulum, but without reference to further material we are not sure of its status.
Type: China, Fujian, SanmingXian, Ziyangtou, 31 iv 1927, Ling Ying 216 (holo. IBSC, iso. KUN)
Synonymy: R. rufescens P.X.Tan, Bull. Bot. Res. N.E. Forest. Inst.2(4): 86 (1982) nonFranchet (1895). R. apricum P.X.Tan vat. falcinellum P.X.Tan, op. cit. 80 (1982); R. falcinellum P.X.Tan, Survey Gen. Rhododendron S. China 98, f.23 (1983). Type: China, Fujian, Anxi Xian, lu-tin, 20 iv 1974, L.G. Li(L.KLee)740125 (holo. Inst. Mat. Med. Fujian). ? R. spadiceum P.X.Tan, Bull. Bot. Res. N.E. Forest. Inst. 2(4): 87 (1982). Type: China, Fujian, Shanghang Xian, Chungtu, 8 v 1974, Y.Z. Jiang 740703 (holo. Inst. Mat. Med. Fujian).
Occurs in Countries: CN Altitude Ranges: 0 - 1,000m Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: red
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):103
Distribution: China (N Sichuan, Gansu)
Altitude: 3050-3650m
The differences between the cuneate leaf-bases of R. weldianum and the rounded leaf bases of R. rufum do not merit the maintenance of the former at any rank. R. rufum is a distinctive species, probably distantly allied to R. przewalskii.
Type: China, W Sichuan, in valle fluv. Kaernzo, 6 vii 1895, Potanin, n.v.
Synonymy: R. weldianum Rehder & Wilson in Sargent (ed.), PI. Wilsonianae 1: 532 (1913). Type: China, E Sichuan, W of and near Wen-chuan Hsien, 3300m, x 1910, Wilson 4235, n.v. Shrub, 1.3-4.5m. Leaves narrowly obovate to elliptic, 6.5-11 x 2.5-5cm, 2.2—3 x as long as broad, apex apiculate, base rounded to cuneate, lower surface covered with a bistrate indumentum, the upper layer a thin to dense reddish-brown ramiform tomentum, the lower compacted, whitish, embedded in a surface film; petioles c.lcm, tomentose. Inflorescence 6~ 11 -flowered; rhachis c.5mm; pedicels 7-15mm, densely tomentose. Calyx c.0.5mm, tomentose. Corolla campanulate, white to pale pink, with crimson flecks, 20-32mm. Ovary densely reddish-tomentose, with a few stipitate glands below the style; style glabrous or with a few hairs at base. Capsule 15-25 x 5-7mm, falcate.
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m Subgenus: Hymenanthes
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):361
Latin – ruga – a wrinkle or fold, referring to the rugose leaves.
Type: Low s.n., 1858. Borneo, North Borneo, Mt Kinabalu, 2135–3350m (K, CGE).
Occurs in Countries: MY Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:261
Differing from the type variety in the larger, (largest leaves over 60mm wide), smooth, not wrinkled leaves.
Named after the mountain on which it was collected.
Type: Clemens 10892. North Borneo, Mt Kinabalu (A, BM).
Synonymy: R. kinabaluense Merr., J. Str. Br. R. As. Soc. 1917. 76: 108. R. rugosum var. laeve Argent, A.Lamb & Phillipps, Rhododendrons of Sabah, Sabah Parks Publ. 1988. 8: 63.
Shrub or small tree to 8m. Twigs rounded, 3–4mm in diameter, densely covered with brown, deeply stellate-incised, stalked, fragile scales and so early glabrescent; internodes 2–8cm. Leaves 3–6 together in tight pseudowhorls. Blade 60–120 x 25–55mm, elliptic, broadly ovate-elliptic or narrowly elliptic, often variable in shape and size in the same pseudowhorl; apex shortly acuminate, broadly acute, the extreme point deflexed downwards; margin entire or weakly crenulate, broadly revolute, the leaves sometimes with strongly rolled margins; base broadly tapering; with a dense orange-brown, scaly indumentum on both sides initially, quickly glabrescent above, and only slightly less so beneath. Scales fragile, dendroid, with a small centre deepened in the middle and extended into a shorter or longer foot, which stands within a minute epidermal depression, marginal zone narrowly, irregularly, stellate-incised, nearly to the centre, very variable in size. Mid-vein with a cushion-like, triangular, grooved, raised area proximally then distally narrowly and deeply impressed above; extremely prominent throughout its length beneath and usually deep red in colour; lateral veins 5–9 per side, spreading and anastomosing before the edge, deeply impressed above, very prominent beneath; the surface uneven with deep folds, sub-densely reticulate, slightly impressed and prominent above, but often obscure beneath. Petiole 7–25 x 2–4mm, dark red, grooved above, densely brown, stellate-scaly initially. Flower buds to 18 x 10mm, sub-spherical with the outer bracts abruptly contracted to subulate, keeled points which stand vertically. Outer bracts ovate-acuminate, apex short-apiculate or sub-mucronate, laxly to sub-densely scaly and often hairy in the upper ½ outside, margin with scales at first. Bracteoles filiform, laxly hairy and scaly, to 20mm. Inflorescence an 8–14-flowered open umbel, the flowers half-hanging to hanging. Pedicels 10–30 x c.1mm, densely hairy and scaly. Calyx thick, disc-shaped, margin wavy and obtusely shortly 5-lobed, hairy and scaly outside, c.4mm in diameter. Corolla 25–30 x c.25mm, pink or purplish-pink, without scent; tube 15–20 x 5–6 x 7–10mm, cylindrical, straight or slightly curved, densely short-hairy and laxly scaly outside, hairy in the proximal ½ of the tube inside; lobes 12–14 x 10–14mm, obovate to sub-spathulate, sometimes slightly retuse at the apex, curving outwards and overlapping to c.½. Stamens irregularly arranged around the flower but predominantly on the lower side, exserted to c.6mm; filaments c.20mm, white, hairy in the proximal 1⁄3, glabrous distally; anthers 2–3 x c.1mm, obovate-oblong, base of each cell protracted into a short apiculus. Disc hairy at the upper margin, glabrous elsewhere. Ovary 4–5 x 2–2.5mm, sub-cylindrical, grey-green, hairy, the hairs covering small scales, abruptly contracted distally; style c.20 x 1mm, becoming exserted to c.6mm, with some patent hairs at the base or up to the lower 1⁄3, glabrous distally or completely glabrous; stigma 2.5mm in diameter, indistinctly lobed. Fruit 15–20 x 5–6mm, densely hairy and scaly, cylindrical, shortly tapering at apex and base, deeply 5-furrowed, purple, erect, the valves curving back on opening. Seeds c.2.5mm, without tails c.1mm, the longest tail 0.8mm.
Habitat: Epiphytic or terrestrial in low mossy forest and open exposed ridges, in widely different habitats from dense shade to full sun, locally abundant, and with a very broad altitudinal range
Distribution: Malaysia (Borneo), Sabah, Mt Kinabalu, Mt Trus Madi and Mt Alab. Possibly also from Mt Murud in Sarawak but at least some of the records of R. rugosum from this mountain are referable to R. yongii.
Altitude: 2000-3500m
Miss Gibbs, following her visit to Kinabalu in 1910 (Gibbs 1914), commented that ‘the lovely heads of waxy pink flowers formed one of the most vivid impressions in the ascent’.
Often confused with R. acuminatum due to the superficial similarity of the leaves. A close examination of the scales will easily distinguish these species but the flower colour is also different, R. acuminatum being reddish orange not the purplish-pink of this species. Rhododendron acuminatum also lacks the small hairs on the outside of the flowers. Natural hybrids with various species have been recorded: R. x coriifolium, R. x keditii and R. x liewianum have been named but the hybrids with R. maxwellii and R. fallacinum have also been recorded.
Much branched shrub to 0.6(-l-2) m. Leaves 6-5-21 x 3-12.5 mm, broadly elliptic to elliptic, oblong or ovate, apex rounded, mucronate, base broadly cuneate to truncate, undersurface heavily stippled reddish brown on a fawn background, the scales overlapping to slightly separated, bicolorous, dark brown or amber and pale golden, the darker scales usually predominating. Inflorescence up to 6-flowered, pedicels lepidote, rarely pubescent as well, 2-4 mm. Calyx lobes (2-5-)4-5(-6) mm, oblong or broadly ovate, apex obtuse or rounded, rarely deltoid, with a broad central band of scales, occasionally shortly pubescent, margin ciliate. Corolla usually intense purple or yellow, occasionally deep crimson or magenta, very rarely white, broadly funnel-shaped, (8-)10-16(-18) mm, tube 3-6(-8) mm, pubescent in the throat and sometimes on the outside, lepidote outside. Stamens 5-10, number variable even in the one inflorescence, filaments pubescent towards the base. Ovary either entirely pubescent or bearing scales on the upper Vi, occasionally with an apical tuft of hairs, style 10-19 mm (rarely shorter), usually pubescent to some extent. Capsule broadly ovoid, 4-6 mm, pubescent, lepidote above.
Three varieties may be recognised
Occurs in Countries: CN, MM Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: crimson, magenta, purple, white, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):108
Corolla purple to crimson, rarely white
Habitat: Mountainsides, rocky slopes, peaty meadows
Distribution: N Burma, China (N, NW, W & C Yunnan, SW Sichuan, SE Xizang)
rupicola
Type: China, Yunnan, western flank of the Lichiang range, 4260 m, vi 1910, Forrest 5865 (holo. E; iso. A, BM)
Synonymy: R. achroanthum Balfour f. & W. W. Smith, Notes R.B.G. Edinb. 9:208 (1916). Type: China, Yunnan, mountains of the Chungtien plateau, 12-13000 ft, vii 1914, Forrest 12581 (holo. E). R. propinquum Tagg in Rhodo. Soc. Notes 3:30 (1925) nomen nudum.
Corolla yellow. Calyx lobes margined with hairs only.
Habitat: Forest, open moorland
Distribution: NE Burma, China (NW Yunnan, SE Xizang)
Altitude: 3300-4750m
Synonymy: R. chryseum Balfour f. & Kingdon Ward, Notes R.B.G. Edinb. 9:219 (1916). Type: China, Tibet/Yunnan frontier, Ka-gwr-pu glacier valley, 3960-4570 m, vi 1912, Kingdon Ward 540 (holo. E)
Corolla yellow. Calyx lobes margined with scales and hairs.
Habitat: Woodland, open grasslands, alpine meadows
Distribution: China (SW Sichuan)
Altitude: 3050-4875m
The Philipsons record natural hybrids between R. rupicola and several other species (1975, pp. 62-64)
Synonymy: R. muliense Balfour f. & Forrest, Notes R.B.G. Edinb. 11: 101 (1919). Type: China: SW Szechuan, Mu-li mts, valley of Li-tang river, 3650-3960 m, vi 1918, Forrest 16252 (holo. E; iso. BM, K)
Shrub to 60cm. Twigs rounded, rough, scaly and densely papillose with scale bases. Leaves 3–4 together in pseudowhorls. Blade 14–20 x 8–10mm, spathulate-obovate; apex emarginate, apiculate with a small protruding gland; margin conspicuously recurved; base tapering; upper surface yellowish-green, lower paler, sparsely scaly. Mid-vein conspicuous; laterals veins 3–4 per side, just visible above, inconspicuous below. Petiole to 3mm. Inflorescence terminal, 1-flowered. Pedicels 10–15mm, slender, shortly hairy and scaly. Calyx shortly hairy and sparsely scaly, 5-lobed, the lobes rounded, to 1.2 x 1mm, sparsely bristly-ciliate. Corolla 10–12 x c.14mm, broadly campanulate, yellow; tube sparsely scaly outside; lobes 6–7.5mm, ovate-spathulate, spotted with red. Stamens 8–10mm, the filaments hairy about the middle. Ovary to 2.2mm, shortly cylindrical, densely hairy and scaly; style c.5mm, bent downwards; stigma depressed-rounded to broadly 5-lobed. Fruit 9–12mm, oblong, scaly and hairy.
Habitat: Growing terrestrially amongst rocks.
Distribution: China, Guangxi Province, Longsheng Xian, Shaling Da Miao Shan. Guangdong Province, Lechang Xian, Yenbay Shan.
Latin – rupis – a rock; valleculum – little valley. Alluding to the habitat of the species.
A very imperfectly understood species. The red spots on the flowers may be distinctive or could be an imperfect rendering of the orange spots which are common on R. emarginatum.
Type: Qin & Lee 70860, 27 July 1957. Guangxi, Longsheng Xian, Shaling (IBK).
Occurs in Countries: CN Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:31
Erect shrub to 1.5m. Twigs smooth and rounded with a few low disc-shaped scales, somewhat striate after drying. Leaves in loose pseudowhorls, with a few bladeless cataphylls at the base of each flush of growth but quickly changing upwards to fully formed foliage leaves. Blade 18–110 x 17–42mm, elliptic; apex broadly acute and mucronate with the mid-vein protruding as a terminal gland; margin entire, cartilaginous, flat when fresh, narrowly recurved after drying; base tapering with the margin narrowly decurrent; upper surface bluish or silvery-green, at first silvery-scaly, the scales later turning brown and falling off; lower surface pale green, persistently, moderately and finely brown-scaly. Scales circular, variable in size and irregularly distributed, slightly impressed. Mid-vein narrowly impressed to the apex above; strongly and broadly raised below, less so distally but often remaining slightly raised to the apex; lateral veins 5–6 per side, broadly arching upwards and narrowly impressed above, slightly raised below, reticulation distinct when dry less so when fresh. Petiole 8–15 x 2–3mm, grooved above and with narrow marginal wings, scaly. Flower buds 8–10 x 5.5–6.5mm, ovoid. Bracts long acuminate with the apices slightly spreading, the margins somewhat irregular; central bracts broadly ovate, deeply hooded, obtuse and mucronate to almost rounded at the apex, softly white-hairy near the base and apex and also sparsely covered in brown scales outside; inner bracts spathulate with longer white hairs near the apex, margin sometimes slightly irregular in the proximal parts, with both simple white hairs and brown scales distally. Bracteoles small, linear, quickly withering. Inflorescence of 3–8 flowers in an open umbel. Flowers half-erect to half-hanging, stiffly held. Pedicels 10–14 x 1–1.5mm, green, with silvery or pale-brown scales and very short white erect hairs. Calyx with 5 lobes; 3 longer, elliptic with rounded tips, c.4 x 2mm, and 2 shorter, which are triangular with broadly pointed apices, c.3 x 2mm, all scaly and sparsely hairy outside. Corolla 10–15 x 15–20mm, shortly campanulate, yellow; tube 4–7 x 5–6 x 5–6mm, shortly cylindrical, finely scaly outside, white-hairy inside; lobes 6–7 x 6–7mm, scaly and with a greenish vein in the centre of the lobes outside, reflexed to the perpendicular or a little beyond. Stamens protruding regularly from the mouth of the flower; filaments 8 and 9mm, white or pale-yellowish, broadest towards the middle where they also have the longest white hairs, these becoming shorter both proximally and distally and are glabrous at the very base and apex; anthers c.2.5–3 x 1mm, brown with darker brown tips, very finely granular, the pores circular, apical. Disc swollen, circular, with 10 lobes, shortly but densely hairy on the upper side (the inner side when fresh, the hairs mostly in the depression facing the style). Ovary c.4 x 2.5mm, densely covered in white discoid scales (brown after drying) and patent simple white hairs, abruptly contracted distally and impressed at the style junction; style c.5 x 0.75mm, greenish-yellow, depressed to the lower side of the flower on opening, rising towards the centre as the flower ages, sparsely hairy near the base, broadening upwards to the green, 5-lobed stigma which is 1.5–2mm in diameter. Fruit 9–12 x 4–6mm, brown, ellipsoid, but with distinct longitudinal grooves, held erect and surmounted by the curved persistent stigmas; valves opening to c.45°, straight, not twisting. Seeds bright orange-brown, c.2.5mm, without tails 1.3mm, the longest tail broad and flat, often as wide as the seed c.0.8mm, the shorter tail slender and often branched near the base.
Distribution: The original collections were made in Vietnam, Laokai Province, Sapa District, on a roadside bank facing east in secondary, broad-leaved forest with a few conifers.
Altitude: Around 1800m
This species is named after Keith Rushforth, the collector.
The species is presumably normally epiphytic but it was not seen in this state by the collectors. Apart from the type it is also known from a second collection (KR 3097) that was found nearby, 2–3km from Ban Khoang at c.1500m. It is known at present from a very limited area in N Vietnam and from across the border in China. This species was first mentioned in Rushforth (1993) as ‘species 26 aff. sororium’. This species is distinctive in the field even at a distance by its bluish-green leaves which are much larger (particularly longer) than those of all closely related species. It is apparently most closely related to R. kawakamii from Taiwan, sharing the multi-flowered umbel and many other characteristics with this species, but apart from leaf shape and colour it also differs in the hairy and scaly ovary, the hairy style and very unusually the flower bud scales, which are fringed with both simple hairs, branched hairs, and scales. Branched hairs of this type are very rare in subgenus Vireya and the combination of simple hairs and typical scales together is a characteristic which is very rare in the subgenus. Vireyas usually have one or other of these hair types on the scale margins. Of other closely related species: R. sororium is distinguished by its solitary or occasionally paired flowers, shorter obovate leaves and pedicels without simple hairs; R. emarginatum is quite distinct in its rough twigs and solitary flowers; and R. densifolium has very much smaller leaves (to 10mm long) and again solitary flowers.
Type: Rushforth, KR 2357 clone A, 12 May 1992. Side road to Ban Khoang, from Dèo Hoàng Liên Són from the main road Dèo Hoàng Liên Són to Ban Khoang, Sapa District, Laokai Province, Vietnam (HN, E).
Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: green, white, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:34
Habitat: Alpine pasture, forest margins
Distribution: China (N & NW Yunnan, SW Sichuan)
Altitude: 3400-4300m
The Philipsons (1975, pp. 59-60) record the occurrence of natural hybrids with various other species
Type: China, Yunnan, on the Kari pass, 3650 m, vi 1917, Forrest 13915 (holo. E)
Synonymy: R. cantabile [Balfour f. ex] Hutchinson, Bot. Mag. t. 8963 (1922). Type: a cultivated specimen (holo. K). R. osmerum Balfour f. & Forrest in Stevenson (ed.), The Species of Rhododendron 425 (1930) in synon., nom. nud. Shrub, 0-3-1-5 m. Leaves 16-40 x 6-5-17 mm, narrowly to broadly elliptic or oblong, apex obtuse or rounded, mucronate, base cuneate, the undersurface heavily speckled brown or rust or almost uniformly red-brown, the scales contiguous or almost so, the colour varying from pale to dark brown on the one leaf. Inflorescence up to 6-flowered, pedicels lepidote, l-2(-5) mm. Calyx lobes up to 6 mm, broadly oblong, with a few scales at the base and in a central band or ± elepidote, margin ciliate and sometimes with a few scales. Corolla deep indigo blue, purple, pink or rose, broadly funnel-shaped, 10-20 mm, tube 4-9 mm, pubescent in the throat and often also on the outside, elepidote. Stamens 10, filaments pubescent towards the base. Ovary lepidote and sometimes with a tuft of hairs at the apex, style 14-20 mm, pubescent for up to Vi its length, sometimes sparingly. Capsule ovoid, c. 6 mm, lepidote, usually with persistent apical hairs.
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):108
Shrub to 2m. Twigs rounded, smooth, moderately densely brown scaly; internodes 1.7–4.5cm. Leaves 4–6 together in tight pseudowhorls. Blade 30–80 x 12–45mm, obovate to elliptic; apex broadly tapering, obtuse to rounded, sometimes slightly retuse; margin entire, narrowly revolute; base narrowly tapering; laxly scaly initially, glabrescent above, more densely and persistently scaly beneath. Scales variable in size, marginal zone narrow to moderately broad, sub-entire to dentate, the centre sometimes relatively large and dark brown, sometimes slightly impressed. Mid-vein impressed above, distinctly raised beneath; lateral veins 3–8 per side, straight below, curved and anastomosing before the edge, slightly impressed above, inconspicuously raised beneath, reticulation obscure. Petiole 5–8 x 2–3mm, grooved above, scaly. Flower buds to 12 x 8mm, green strongly flushed with dark purple, broadly ellipsoid to obovoid, smooth with all bracts appressed and a broad rounded apex, glabrous apart from the fringe of brown, marginal scales. Bracts, the outer broadly triangular, the inner sub-circular, deeply concave, rounded but often splitting to become emarginate. Bracteoles c.10mm, filiform, basally c.1mm wide, broadening in the distal ½ to c.3mm, glabrous. Inflorescence 4–8-flowered, the flowers held stiffly semi-erect to half-hanging, white or very lightly flushed pink at the lobes as the buds open, strongly and sweetly scented. Pedicels 16–20 x c.1.75mm, red, densely scaly, and with sparse very small hairs. Calyx small, densely scaly, obliquely disc-shaped. Corolla 45–50 x 21–30mm, trumpet-shaped; tube 41–50 x 6–8 x 5–6mm, straight, cylindrical, sparsely covered with small brown scales outside, densely patently short-hairy inside in the proximal ½; lobes 10–13 x 10–12, sub-circular with irregular margins, spreading horizontally on opening, later reflexing, with a few scales outside. Stamens at first clustered centrally or slightly to the lower side of the mouth, later reflexing irregularly back against the lobes, becoming exserted to 6mm; filaments filiform, laxly hairy near the base only; anthers c.1.5 x 1mm. Disc sparsely hairy in the upper ½ or glabrous. Ovary c.7 x 2.5mm, cylindrical, gradually tapering distally; style 15–28 x c.1mm, white, with thick protruding scales almost to the top and a few hairs; stigma c.2mm in diameter, cream. Fruit 20–24 x 5–6mm, scaly, purple.
Habitat: Primary forest, abundant on limestone
Distribution: Indonesia, Maluku, C Seram, Mt Murkele, Mt Binaia.
Altitude: 1900-2500m
Named after L. Rutten, a Dutch geologist who also collected many plants, and leader of the expedition that collected this species.
Type: Rutten (Kornasi) 1472, 1 July 1918. Central Ceram, G. Murkele, 1900–2500m (BO, K, L).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: brown
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:170
Shrub to 2m. Twigs rounded, 2–3mm in diameter, laxly scaly; internodes 3–8cm. Leaves 4–10 together in well-marked pseudowhorls sometimes with one or two much smaller leaves. Blade 50–100 x 6–16mm, narrowly elliptic to sub-linear, often slightly curved; apex acute; margin entire or irregularly sinuate, weakly revolute; base narrowly tapering, glabrescent above when mature, sparsely scaly beneath. Scales flat, circular or irregularly disc-shaped, marginal zone entire or variously, often obtusely and shallowly lobed; centre minute, weakly impressed. Mid-vein narrow, impressed above, prominent beneath in the proximal ½–¾; lateral veins 5–10 per side, ascending and joining towards the margin, slightly raised above, faintly so or not visible beneath, sub-densely reticulate and very slightly raised above only when dry. Petiole 4–6 x 1–1.5mm, grooved above, laxly scaly. Flower buds to 25 x 8mm, very narrowly conical, acute, the bract tips erect, slightly gaping, green or flushed with pink. Bracts to 24 x 5mm, very narrowly ovate, with acute channelled points, glabrous. Bracteoles subulate, glabrous, to 10mm. Inflorescence 1–5-flowered in an open umbel, the flowers horizontal to half-hanging. Pedicels scaly at base and apex, almost glabrous between, 12–17 x c.1.25mm. Calyx disc-shaped, obtusely and very shortly 5-lobed, laxly scaly outside, 3–4mm in diameter. Corolla 25–35 x 30–50mm, funnel-shaped, tubular below, pale yellow or suffused with orange around the edges of the lobes, without scent; tube 15–20 x 5–6 x 10–12mm, straight, constricted about the middle and often fluted in the proximal ½, glabrous outside, hairy inside; lobes 22–26 x 13–26mm, spreading, obovate-spathulate, overlapping up to ½. Stamens irregularly spreading, exserted to c.10mm; filaments linear and densely hairy in the lowest 3–4mm, glabrous and more filiform distally; anthers obovate-oblong, c.2.5 x 0.8mm, base obtuse. Disc prominent, green, hairy on the upper margin. Ovary 6–8 x 2–2.5mm, densely hairy and scaly; style lying on the lower side of the tube, curving upwards to present the stigma in a central position when receptive, hairy at the base for 1–2mm, otherwise glabrous; stigma globose, becoming disc-shaped and deeply 5-lobed. Fruit 20–30 x 4–5mm, fusiform-cylindric. Seeds c.6mm, without tails 0.8mm, the longest tail c.3mm.
Habitat: Terrestrial on summit rocks and amongst moss along the ridges in open sub-montane forest.
Distribution: Malaysia (Borneo), Sarawak, Mt Serapi (Mattang or Mattan) and Mt Santubong.
Altitude: 900-1000m
Named from the resemblance of the leaves to those of the genus Salix (Salicaceae).
Type: Beccari P.B. 2929, 1865–68. Malaysia, Sarawak, Mt Mattan (G. Serapi) (FI, K, L, P).
Occurs in Countries: MY Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: orange, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:264
Prostrate to upright shrublets or shrubs, 0-05-1.5 m. Young growth loriform-setose, the setae persistent. Leaves oblong-orbicular to oblong-elliptic, rarely oblong-obovate, 8-30 x 5-15 mm, upper surface usually rather glossy and elepidote, more rarely matt with persistent dried-out scales, often with a few loriform setae along the midrib near the base, margins loriform-setose, undersurface with dense, overlapping scales which are borne in several tiers but somewhat flattened, the midrib usually with some loriform setae. Inflorescence 1-3-flowered, pedicels lepidote and loriform-setose, 8-18 mm. Calyx lobes oblong-orbicular, rounded to subacute, 4.5-8 x 2-5-6 mm, variably lepidote, loriform-setose and filiform-acicular puberulent, usually loriform-ciliate, puberulent within. Corolla 17-28 mm, the tube 8-15 mm, magenta to purple, rarely bluish purple, pilose and with a few scales outside, pubescent within the tube. Stamens 10. Ovary lepidote, usually puberulent, at least in the impression at the base of the style. Capsule 6-8 mm, lepidote.
Occurs in Countries: CN, MM Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: magenta, purple
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):117
Prostrate or decumbent shrub, rarely to 1 m; leaves usually glossy and elepidote above, without loriform setae
Habitat: Open stony and peaty meadows
Distribution: China (N & NW Yunnan, SE Xizang, SW Sichuan), NE Burma
Altitude: 3500-4500m
A widely distributed taxon with a somewhat dissected distribution pattern. It shows some variability in height and leaf size, but this is related largely to altitude, the smallest variants (those formerly named as R. pro-stratum), occurring above 4250 m; complete transitions from these small variants to more normal plants occur.
Synonymy: R. chameunum Balfour f. & Forrest, Notes R.B.G. Edinb. 13:37 (1920). Type: China, Yunnan, on the Li-ti-ping, vi 1917, Forrest 13904 (holo. E). R. prostratum W. W. Smith, Notes R.B.G. Edinb. 8:202 (1914). Type: China, Yunnan, E flank of the Lichiang range, 15-16000 ft, vi 1910, Forrest 5862 (holo. E). R. cosmetum Balfour f. & Forrest, Notes R.B.G. Edinb. 13:38 (1920). Type: China, NW Yunnan, Bei-ma-shan, vi 1917, Forrest 13985 (holo. E). R. charidotes Balfour f. & Farrer, Notes R.B.G. Edinb. 13:242 (1922). Type: NE Burma, Chawchi pass, 10000 ft, 3 vii 1920, Farrer 1690 (holo. E)
Erect shrub to 1.5 m; upper surface of leaves ± persistently lepidote and usually loriform-setose
Habitat: Forest margins and thickets, stony hillsides, cliffs and ledges
Distribution: NE Burma, China (NW Yunnan, SE Xizang)
Altitude: 3300-4400m
Illustrations:
subsp. saluenense, unfortunately the first described species within this group, is found in only a small area where the much more widely distributed subsp. chameunum and R. calostrotum subsp. riparium and keleticum also occur. Subsp. saluenense appears to be a stable intermediate between chameunum, which occurs further eastwards, and calostrotum subsp. riparium, whose main area of distribution is further west. It is variable in size, bristliness and scaling of the upper leaf surface, and apparently occupies less exposed habitats than subsp. chameunum.
Type: China 'Setchuen'(i.e. Yunnan), vallee du haut Mekong a Dong ching thang, Soulie 1007; Se la, entre le Mekong et Salween, Soulie 1006 (iso. E)
Synonymy: R. amaurophyllum Balfour f. & Forrest, Notes R.B.G. Edinb. 13:230 (1922). Type: China, SE Tibet, Tsarong, Salween/Kiu chiang Divide, vii 1919, Forrest 18905 (holo. E)
Tree, to 5m; young shoots becoming glabrous. Leaves broadly rhombic, 3-8 x 2.5-6cm, apex acuminate, upper surface densely hairy at first, becoming glabrous, lower surface with scattered hairs persisting along midrib; petioles 2-4mm, densely covered with red-brown pilose hairs. Inflorescence 3-4-flowered, flowers appearing before leaves; pedicels 5-10mm, densely pilose. Calyx minute, densely pilose. Corolla funnel-campanulate, 25-35mm, rose-pink, rarely white, with darker flecks, lobes 20mm, oblong. Stamens 10, unequal, glabrous. Ovary densely pilose; style pilose in lower half. Capsule c.lOmm, pilose.
Habitat: Mountain sides
Distribution: Japan (Hondo)
Illustrations:
The type seen differs from Nakai's description in having corollas 25-35mm long; the concept used here is based on this type.
Type: Japan, Hondo, Ise Prov., Ando (TI); Shimajiyama, Nakai, n.v.
Synonymy: R. weyrichii Maxim, var. sanctum (Nakai) Hatusima, Sci. Rep. Yokosuka City Mus. 15: 23 (1969)
Occurs in Countries: JP Subgenus: Tsutsusi Habit: Tree Fl. Colour: rose, white
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):151
Dwarf shrub, 0.3—1.5m; young shoots sparsely white-floccose, rarely also with eglandular setae; perulae persistent or deciduous. Leaves elliptic to obovate, 3-8 x 1.5-3.2cm, 1.9-2.4(-3.2) x as long as broad, apex rounded, apiculate, base ± cuneate, upper surface glabrous, lower surface with a continuous compacted silvery to greyish rosulate indumentum; petioles 0.5-0.8cm, floccose when young, rarely also with glandular setae, usually ± glabrous when mature. Inflorescence 3-6-flowered; rhachis less than 5mm; pedicels 10-25mm, stipitate-glandular. Calyx 3-10mm, coloured, cupular when well-developed, lobes rounded, glandular-ciliate. Corolla fleshy, shortly tubular-campanulate, yellow to pink or crimson to blackish crimson, rarely white, 25-35mm. Ovary tomentose to stipitate-glandular. Capsule 10-15 x 4-6mm.
Habitat: Open stony slopes, amongst scrub
Distribution: China (SE Xizang, NW Yunnan)
Altitude: 3000-4500m
A number of specimens lacking flowers clearly belong to R. sanguineum in the broad sense but cannot be assigned to the infraspecific taxa recognized here.
R. sanguineum is an extremely variable species with a relatively narrow geographical range. The dividing lines between the infraspecific taxa are difficult to define as a result of the number of intermediates that occur, probably because of widespread hybridisation involving several related species as well as the occurrence of infraspecific taxa in R. sanguineum itself.
The most distinct infraspecific taxon is subsp. didymum, which is at one extreme of a more of less continuously varying complex of taxa, and may be one of the original parental stocks involved in the hybridisation. I have therefore treated this as a subspecies even though its distribution is within the range of subsp. sanguineum.
Flower colour separates most of the varieties included here under subsp. sanguineum. Without extensive field studies and a breeding programme, the possibility remains that they are no more than minor colour variants, not even worthy of varietal status. Cowan's treatment of the * Sanguineum Alliance'(op. cit.) recognised many more, narrowly circumscribed, taxa than are maintained here. I have not followed this treatment as I consider that it only confuses an already complicated variation pattern unnecessarily.
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: black, crimson, pink, white, yellow
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):396
Synonymy: R. didymum Balfour f. & Forrest, Notes R.B.G. Edinb. 13: 256 (1922). Type: China, SE Xizang, Salween/Kiu-chiang divide, 14—15000ft, 28°24'N, 98°24'E, ix 1921, Forrest 20220 (holo. E).
Leaves 3 -8cm long; corolla colour as for species; ovary eglandular-tomentose of if glandular then corolla pinkish.
The following flowering specimens without flower colour notes probably belong to var. cloiophorum: Forrest 18642, 18644, 18662, 18686.
Synonymy: R, cloiophorum Balfour f. & Forrest, Notes R.B.G. Edinb. 11: 37 (1919). Type: China, W NW Yunnan, Mekong/Salween divide, 28°12'N, vii 1917, Forrest 14269 (holo. E; iso. K). R. leucopetalum Balfour f. & Forrest, ibid. 11: 86 (1919). Type: China, W NW Yunnan, Mekong/Salween divide, 28°12'N, 12-13000ft, vii 1917, Forrest 14270 (holo. E; iso. K). R. asmenistum Balfour f. & Forrest, ibid. 13: 29 (1920). Type: China, SE Xizang, Salween/Kiu-chiang divide, vii 1919, Forrest 19169 (holo. E; iso. K). R. cloiophorum Balfour f. & Forrest subsp. asmenistum (Balfour f. & Forrest) Tagg in Stevenson (ed.), The Species of Rhododendron 545 (1930). R. sanguineum Franchet subsp. cloiophorum (Balfour f. & Forrest) Cowan and subsp. leucopetalum (Balfour f. & Forrest) Cowan, Notes R.B.G. Edinb. 20: 73 (1940).
Type: China, SE Xizang, Salween/Kiu-chiang divide, 28°14'N, 98°24'E, 14000ft, vii 1921, Forrest 19982 (holo. E)
Synonymy: R. roseotinctum Balfour f. & Forrest, Notes R.B.G. Edinb. 11: 124 (1919). Type: China, W NW Yunnan, Mekong/Salween divide, 28°12'N, 12000ft, vii 1917, Forrest 14211 (holo. E). R. mannophorum Balfour f. & Forrest, ibid. 13:51 (1920). Type: China, SE Xizang, Salween/Kiu-chiang divide, vii 1919, Forrest 19163 (holo. E; iso. K). R. sanguineum Franchet subsp. didymoides (Tagg & Forrest) Cowan and subsp. roseotinctum (Balfour f. & Forrest) Cowan, Notes R.B.G. Edinb. 20:71 & 72 (1940). R. sanguineum Franchet subsp. consanguineum Cowan, ibid. 20: 68 (1940). Type: China, NW Yunnan, Mekong/Yangtze divide, E of A-Wa, 14000ft, vi 1924, Forrest 25307 (holo. E).
Illustrations:
Plants intermediate between var. haemaleum and subsp. didymum, with the general appearance of the former but the glandular ovaries of the latter, have been referred to R. sanguineum Franchet subsp. atrorubrum Cowan (op. cit. 69, 1940). The specimens are as follows: Forrest 18675 (type - holo. E; iso. K), 19204; Rock 10293, 10315.
Synonymy: R. haemaleum Balfour f. & Forrest, Notes R.B.G. Edinb. 11: 71 (1917). Type: China, NW Yunnan, Mekong/Salween divide, NW from Tseku, 11000ft, viii 1904, Forrest 5074 (holo. E). R. sanguineum Franchet subsp. haemaleum (Balfour f. & Forrest) Cowan, Notes R.B.G. Edinb. 20: 69 (1940). R. sanguineum Franchet subsp. mesaeum [Balfour f. exj Cowan, ibid. 20: 70 (1940). Type: China, SE Xizang, Salween/Kiu-chiang divide, 14000ft, viii 1921, Forrest 19958 (holo. E)
Specimens intermediate between var. himertum and R. citriniflorum var. citriniflorum, with glandular ovaries but a ± plastered leaf indumentum have been referred to R. sanguineum Franchet var. melleum Cowan, (op. cit. 73, 1940). They are as follows: Forrest 16727 (holo. E), 22689; Rock 10282.
Rock 22584 has a relatively thick leaf indumentum but a tomentose ovary and is also considered to be intermediate between these two taxa. Plants intermediate between var. himertum and R. temenium var. gilvum, with ± setose shoots, a thin discontinuous leaf indumentum and an epapillate lower epidermis on the leaves, have been referred to R. fulvastrum Balfour f. & Forrest (Notes R.B. G. Edinb. 13: 45, 1920). Specimens seen are: Forrest 19023 (holo. E), 21782; Rock 10304, 10951,22215.
Synonymy: R. himertum Balfour f. & Forrest, Notes R.B.G. Edinb. 13: 48 (1920). Type: China, SE Xizang, Tsarong, vii 1918, Forrest 16725 (holo. E). R. nebrities Balfour f. & Forrest, ibid. 13: 53 (1920). Type: China, SE Xizang, Salween/Kiu-chiang divide, vii 1919, Forrest 19153 (holo. E; iso. K). R. poliopeplum Balfour f. & Forrest, ibid. 13: 56 (1920). Type: China, SE Xizang, Salween/Kiu-chiang divide, vii 1919, Forrest 19175 (holo. E; iso. K). R. himertum Balfour f. & Forrest subsp. poliopeplum (Balfour f. & Forrest) Tagg in Stevenson (ed.), The Species or Rhododendron 553 (1930). R. sanguineum Franchet subsp. himertum (Balfour f. & Forrest) Cowan, Notes R.B.G. Edinb. 20: 72 (1940). R. sanguineum Franchet subsp. aisoides Cowan, ibid. 20: 72 (1940). Type: China, SE Xizang, Mt. Kenyichumpo, Champutong, 1923, Rock 10108 (holo. E).
Type: China, NW Yunnan, Sela, vi 1895, Soulie 1015 (iso. E, K)
Synonymy: R. sanguineum Franchet subsp. sanguinioides Cowan, Notes R.B.G. Edinb. 20: 69 (1940). Type: China, SE Xizang, N slopes of Mt Kenyi-chumpo, N of Sikitung, v-vi 1932, Rock 22203 (holo. E).
Shrub to 1.5m. Twigs slender, spreading, rounded, rough, densely white-scaly, quickly glabrescent; internodes 3–8.5cm with 1–2 deciduous scale leaves. Leaves in tight pseudowhorls of 5–9. Blade 15–30 x 5–12mm, elliptic to obovate, sub-sessile; apex acute to sub-obtuse, shortly apiculate; margin entire, cartilaginous, recurved when dry; base tapering; densely scaly above at first but quickly glabrescent, dark green; below sparsely brown-scaly, pale green. Scales circular or sub-circular, moderately dense, with a broad marginal zone and small centre. Mid-vein prominent, impressed above, raised beneath; lateral veins 3–4 per side, impressed above, obscure beneath. Petiole 2–3 x c.1.5mm, grooved above, sparsely scaly. Bud to 10 x 8mm, green, smooth, sub-spherical. Bracts to 5–8 x 3–6mm, outer ovate mucronate, inner larger, sub-hemispherical, deeply concave, cuspidate, shortly and irregularly ciliate along the margins and sometimes with a few scales. Bracteoles c.10.5 x 0.6mm, subulate with long stalked brown scales around the margins. Inflorescence a 2–6-flowered umbel. Pedicels 10–20mm, slender, slightly curved, densely silvery scaly. Calyx of low triangular lobes to 1 x 1.5mm, densely pale brown scaly outside and with a fringe of scales. Corolla c.10 x 15–25mm, campanulate, white, fleshy; tube 3.5–8 x c.4 x c.8mm, sparsely scaly outside, hairy inside in a broad band just above the base; lobes 6–8 x 5–8mm, sparsely scaly outside, rounded or broadly oblong, sub-acute, or obtuse, erect gradually becoming reflexed. Stamens c.12mm, slightly dimorphic, exserted to 7mm; filaments white, hairy in the middle; anthers c.2.5mm, oblong, cream with brown margins to the pores. Disc circular, 10-lobed, glabrous. Ovary c.5 x 2.5mm, ovoid, 5-ridged, densely scaly; style c.5mm, thick, bent to the lower side of the flower, glabrous, slightly enlarged upwards, often becoming deciduous later; stigma truncate. Fruit 20–27 x 4–5mm, straight, spindle-shaped with persistent brown scales; splitting without peeling an irregular layer but the outer layer sometimes separating after the capsule has split; valves opening to a wide angle and the placentae opening lantern-like. Seeds to 11mm, without tails 1.2mm, the longest tail 5.5mm, the tails extremely slender, filiform and wavy.
Distribution: India: Arunachal Pradesh
Altitude: 900-1600m
Named after the Rev. H. Santapau for his devoted service in the cause of taxonomic research and the promotion of the floristic exploration of India.
First collected from the Api Tani valley, Arunachal Pradesh, India where it was growing hanging from large tree trunks with little moss at 1600m (Cox 1985). A second locality was discovered in 2005 by Kenneth Cox, Steve Hootman and Hartwig Schepker along a tributary of the Upper Siang River, close to the Indian/Tibetan border, at c.900m.
Type: Sastry 45720, 23 May 1966. Begi, Subansiri District, N.E.F.A. India (CAL)
Occurs in Countries: IN Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:29
Small shrub to 0.6 m. Leaf-bud scales persistent. Leaves elliptic, 9-15 X 5-8 mm, tapered to the base, apex rounded with conspicuous mucro, dark green and elepidote above, lower surface brown or pale brown with densely overlapping scales arranged in 2-3 tiers, those of the lowermost tier golden, paler than the others. Inflorescence 5-12-flowered, pedicels lepidote, 5-7 mm. Calyx lobes oblong-obovate, obtuse, c. 3 mm, sparsely lepidote outside, the margins conspicuously loriform-ciliate, the inner surface puberulent. Corolla whitish to yellow, tube c. 8 mm, lobes c. 4 mm, the tube and bases of the lobes conspicuously lepidote outside and also somewhat puberulent with short, filiform-acicular hairs; mouth of the tube densely pilose inside. Stamens 5. Capsule sparsely lepidote, c. 4 mm
Habitat: Exposed rocks
Distribution: China (C Sichuan)
Altitude: 3000-3600m
Illustrations:
R. sargentianum is represented in herbaria by very few collections. Material in cultivation under Wilson 1208 (the type number) is more variable than the herbarium material (e.g. some plants have pure white flowers), but the significance of this variation is uncertain.
Type: China, western Szechuan, Mupin, 3000-3600 m, Wilson 1208 (iso. E)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):163
Shrub, 3-6m; young shoots at first covered with adpressed red-brown setose hairs, soon glabrescent. Leaves dimorphic, persistent, subcoriaceous; spring leaves ovate to ovate-oblong 4-7.5 x 2-3.5cm, 2-2.2 x as long as broad, apex acuminate, gland-tipped, base broadly cuneate, margin entire, upper surface glabrescent though with a few persistent strigose hairs on the midrib, lower surface with scattered adpressed strigose hairs, persisting on the lamina; summer leaves 15-20 x 5-10mm, otherwise as for spring leaves; petioles 3-7mm, densely adpressed-stirgose. Inflorescence 3-4(-5)-flowered; pedicels 3-7mm, densely rufous-strigose. Calyx c.2mm, covered with strigose hairs, lobes lanceolate. Corolla funnel-shaped, white tinged with rose, 15-20mm; tube 5-7mm, glabrous on outer surface, papillate within. Stamens 5, slightly longer than corolla, hairy below middle. Ovary densely rufous-strigose; style hairy at base. Capsule ovoid, 7-9mm long.
Habitat: Rocky soil in forest
Distribution: Vietnam
Altitude: 400-1800m
A specimen from Thailand (Garrett 837), may belong to this species but differs in its larger flowers (25mm) and its glabrous style. Sleumer (op. cit.) refers this and one other specimen, also from Thailand (Put 3325), to R. microphyton on account of the glabrous styles. The latter, however, has flowers with lobes significantly longer than tube, a characteristic of R. saxicolum. In any case size of flowers and leaves is more extreme for R. microphyton than it is for R. saxicolum.
Allied to R. seniavinii but with a laxer inflorescence, etc.
Type: Vietnam, Tonkin, prov., Lac-Kay, Col de Le Qui-Ho, environs de Cha-Pa, 1800m, Poilane 25419 (holo. L, iso. P)
Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: rose, white
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):130
Dwarf shrub, to 15cm, forming tussocks, large cushions or dense mats, up to 1m in diameter, with subterranean spreading woody branches. Twigs thick, those above ground very short, stellate-scaly near the apex which is densely packed with spreading leaves, sometimes more elongate and decumbent, with 2 internodes. Leaves 6–10 together in pseudowhorls at the apex and the ultimate node. Blade 16–34 x 3–7mm, linear to narrowly elliptic or narrowly elliptic-obovate; apex shortly acuminate, often apiculate or almost mucronate; margin weakly revolute; base gradually tapering; glabrescent above, laxly scaly beneath. Scales small, the marginal zone irregularly and often obtusely dentate or angular with the centre impressed. Mid-vein impressed above, obtusely prominent beneath; lateral veins 2–3 steeply ascending on each side, very slightly impressed above, or often inconspicuous, below inconspicuous. Petiole 3–7 x 1–2mm, grooved, flat, not clearly distinct from the leaf blade. Flower buds to 12 x 6mm, ovate to obovate, acutely pointed. Bracts to 15 x 5mm, the outer acutely pointed, green, scaly outside, inner ovate and broadly pointed, pink glossy, glabrous except for the fringe of scales round the margins, often becoming brown on opening, innermost spathulate. Bracteoles 16 x c.1mm, linear, glabrous, or with a few short hairs but fringed with scales on long hair-like stalks. Flowers solitary, or rarely in twos, half-hanging to hanging. Pedicels erect, red, 25–100 x 2–3mm, laxly to sub-densely scaly, sometimes also laxly covered with short patent hairs. Calyx c.6mm in diameter, oblique, disc-shaped, wavy and obtusely 5-lobed (sometimes with longer, irregular lobes up to 2mm), scaly and sometimes shortly hairy, often fringed with hairs. Corolla 30–35 x 25–30mm, pink to red, without scent; tube 17–25 x 5–8 x 10–15mm, curved, cylindrical, often grooved, densely stellate-scaly outside, shortly hairy inside; lobes 13–15 x 11–16mm, broadly spathulate or sub-circular. Stamens mostly clustered on the upper side of the corolla but often irregularly arranged, exserted to 10mm, sub-equal; filaments linear, laxly patently hairy in the proximal 1⁄3, glabrous above, red; anthers c.2.8 x 1.5mm, broadly oblong-obovate. Disc prominent, glabrous or hairy along the upper margin. Ovary c.7 x 5mm, conical, tapering distally; style 12–22 x 1–2mm, held on the upper side of the corolla tube, densely hairy with semi-appressed white hairs and obscurely scaly, the hairs covering the scales; style as long as or slightly shorter than the stamens, thick, hairy and scaly in the basal 1⁄3, then with hairs only to c.halfway, glabrous distally; stigma to 3mm in diameter, oblique. Fruit 15–20 x 6–8mm, erect, narrowly ellipsoid, shortly hairy and scaly, the outer coat irregularly splitting and then dividing from the apex into 5 valves, the axis and style persistent for a long time, the valves becoming reflexed and twisted, fruit pedicel 60–110mm. Seeds 2.5–3.2mm, without tails c.1mm, the longest tail c.1.2mm.
Habitat: In open alpine grassland, occasionally on shrubby ridges; locally abundant and a conspicuous feature in bogs or forest openings, on peaty soil.
Distribution: Indonesia, New Guinea (W), along the Main Range in suitable habitats; recorded from: Mt Jaya, Mt Wilhelmina, Oranje Mts; Star Mts. Papua New Guinea, Star Mts, Western and Southern Highlands: Hagen Range, Mt Giluwe and Mt Sugarloaf.
Altitude: 3225-4000m
Named after the genus Saxifraga from the similarity of its tussock forming habit.
Professor R.J. Johns excavated what appeared to be separate plants in a bog on Mt Giluwe and found they were all interconnected by woody rhizomes. In cultivation the plants form extended horizontal branches when growing vigorously; these no doubt become buried by normal upward growth of a bog and thus form the rhizomes. The implication of this is that some of the colonies in the wild must be very old.
Type: Pulle (Versteeg) 2475, 15 Feb. 1913. New Guinea (W), Oranje Mts, Watervalbivak, 3400–3500m (L, BO, K, U).
Occurs in Countries: ID, PG Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: pink, red, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:153
Shrub, c.1.8m. Twigs 1.5–3mm in diameter, rounded, at first densely reddish-stellate-scaly, quickly glabrescent and smooth; internodes 3–7cm. Leaves 3–5 together in pseudowhorls. Blade 35–65 x 20–40mm, broadly elliptic, sometimes obovate-elliptic or obovate; apex broadly tapering, obtuse to rounded; margin slightly revolute proximally or quite flat; base rounded or broadly tapering; glabrescent above, sub-persistently densely reddish-scaly beneath. Scales small, deeply stellately lobed in the marginal zone; centre minute, dark and very slightly impressed. Mid-vein slightly impressed above, markedly prominent proximally beneath; lateral veins 6–8 per side, irregular, spreading, anastomosing before the margin, somewhat impressed or raised above, prominent beneath, reticulation distinct. Petiole 4–7 x 1–1.5mm, flattened and grooved above, scaly. Bracts to 10 x 8mm, ovate to obovate, obtuse, glabrous outside, very shortly fringed with scales. Bracteoles to 12 x 0.5–1.5mm, linear below, sub-spathulate distally. Inflorescence 1–4-flowered. Pedicels 15–23 x c.0.6mm, densely reddish-stellate-scaly. Calyx obliquely disc-shaped, irregularly 5-toothed, with triangular sub-acute teeth 0.5–3mm, scaly at the base outside, spreading. Corolla 40–45mm, tubular below, sub-oblique; tube c.30 x 4–5 x 7–8mm, curved, lobed at the base, laxly stellate-scaly outside, laxly and long patent-hairy inside; lobes 9–13 x 9–13mm, sub-circular. Stamens as long as the corolla tube; filaments linear, laxly patently long-hairy in the proximal 2⁄3; anthers 2.5 x c.1.2mm, sub-obovoid obtuse at the base. Disc prominent, sparsely hairy on the upper margin. Ovary 5–6 x 2–2.5mm, sub-cylindrical, abruptly narrowed distally, densely stellate-scaly, without hairs; style as long as the stamens, laxly stellate-scaly in the proximal 1⁄3, glabrous distally; stigma thick-rounded.
Distribution: Papua New Guinea, Central District, Mt Obree, growing in profusion on brink of precipitous cliffs at Howers Lake
Altitude: Around 2135m
Named after the collector, W.A. Sayer, an Australian naturalist.
Known only from the type collection
Type: Sayer s.n., Aug. 1887. New Guinea (SE), Central District, Mt Obree, Howers Lake, c.2135m (MEL, L).
Occurs in Countries: PG Altitude Ranges: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:299
Shrub or tree to 12m. Twigs 4–5mm in diameter, laxly sub-stellately scaly becoming glabrescent; internodes 4–18cm. Leaves 3–5 together in tight pseudowhorls. Blade 60–120 x 25–60mm, elliptic; apex broadly tapering, obtuse, sometimes rounded or emarginate, occasionally with an inconspicuous apical gland; margin entire, flat or weakly and narrowly revolute; base broadly tapering, the extreme base sometimes truncate or rounded; glabrescent above when mature, laxly scaly beneath. Scales brown, rounded, lobed or sub-stellate, with a broad marginal zone and small centre, slightly impressed. Mid-vein narrowly impressed above, grooved in the proximal 1cm; strongly raised throughout its length below; lateral veins 10–12 per side, spreading, at first straight then curved upwards and anastomosing before the margin, with some additional intermediate veins, faintly impressed above, prominent beneath, reticulation dense, hardly impressed above, raised beneath. Petiole 8–18 x 3–4mm, grooved above, brown-scaly. Flower buds to 45 x 22mm, ellipsoid, smooth, imbricate, with all bracts appressed, and rounded apex, pale yellowish-green. Outer bracts to 30 x 18mm, ovate, with appressed silvery or yellowish hairs which are swollen at the base, along the middle line are some small, brown, scales; inside shortly hairy, and on the margins fringed with brown, stellate scales; inner bracts obovate to spathulate, obtuse to rounded or emarginate. Bracteoles c.20 x 0.5–1mm, filiform, densely white-hairy. Inflorescence of 6–10 flowers in an open umbel. Pedicels 18–27 x c.2mm, densely brown scaly with low, stellate scales. Calyx 4–5mm in diameter, disc-shaped, shortly lobed or rounded with occasionally one lobe up to 4mm, densely scaly outside. Corolla 45–60 x 35–40mm, tubular, pale to deep red, distinctly zygomorphic; tube 35–40 x 7–8 x 12–16mm, curved, densely stellate-scaly outside, hairy with retrorse hairs inside; the three upper lobes 16–20 x 16–18mm, the two lower lobes c.20 x 12–13mm, wide-spreading forming an oblique mouth, sometimes becoming a little reflexed, the three upper lobes overlapping to c.1⁄3, the two lower not or only slightly overlapping, obovate-spathulate, the apices sometimes slightly retuse. Stamens tightly clustered on the upper side of the mouth, exserted to 15mm; filaments linear and densely covered with strong, distally pointing hairs below, more laxly so distally, ultimately glabrous; anthers 4–5 x c.1.5mm, brown. Disc thick and prominent, glabrous below, hairy on the upper margin. Ovary 8–10 x 3–4mm, narrowly ellipsoid, tapering distally, densely hairy and scaly, (the scales completely hidden by the hairs); style thick, densely hairy and with minute scales below, more laxly so above nearly to the top, lying along the upper side of the corolla tube; stigma c.3mm in diameter, obconical, red, positioned just below the mouth at first, becoming exserted to 20mm.
Habitat: In lower montane rain forest or in Castanopsis- or Nothofagus-forest, terrestrial or often on tree trunks.
Distribution: Papua New Guinea, Mt Antares, Western, Southern and Eastern Highlands.
Altitude: 1950-2400m
Latin – scabri – rough; bractea – a bract. Alluding to the rough or scabrid bracts.
Cultivated at Edinburgh since 1972 when it was introduced by Lou Searle from the Eastern Highlands of Papua New Guinea; later also distributed by Canon Cruttwell from the Gaihaivisuka Botanical Garden near Goroka where it was cultivated and also grew wild in the forest around the garden.
Type: Womersley NGF 4889, 7 April 1953. New Guinea (E), Western Highlands, Al River, Nondugl (L, A, BRI, CANB, K, LAE).
Occurs in Countries: PG Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Tree Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:321
Shrub to 3 m. Young shoots with a dimorphic indumentum of filiform-acicular hairs and longer, loriform setae which have swollen bases. Leaves narrowly elliptic to oblanceolate, 15-90 x 4-15 mm, indumentum of the upper surface like that of the young shoots, lower surface lepidote and with a dense indumentum of loriform hairs. Inflorescences 2-3(-5)-flowered. Calyx rim-like or clearly 5-lobed, with lobes 2-3 mm, fringed with loriform setae. Corolla variable in shape and size (see below), white to deep pink, the tube glabrous inside. Stamens 10, filaments pubescent towards the base, usually densely so. Ovary lepidote and densely pilose, the scales obscured by the hairs. Style sparsely pubescent at the base. Capsule lepidote and pilose, 6-9 mm.
A complex and variable species divided here into three varieties. Var. scabrifolium represents the 'pure* species; the other two varieties show more or less intergradation towards R. spinuliferum, particularly in corolla shape.
Occurs in Countries: CN Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: pink, white
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):84
Corolla narrowly funnel-shaped, 12 • 5-23 mm, tube 6-17 mm. Corolla 16-23 mm; leaves usually larger, c. 25-90 x 8-25 mm
Habitat: Rocky slopes
Distribution: China (C & S Yunnan)
Altitude: 2000-2600m
This variety is closer to R. spinuliferum, particularly in corolla shape than the other two varieties of R. scabrifolium. The prominent and elongate pedicels noted by Franchet do occur in some specimens, but do not appear to be diagnostic; they are perhaps a modification due to shade.
Type: China, Yunnan central, aux environs de Yunnansen dans les ravines de la mon-tagne, 16 ii 1897, Ducloux 15 (holo. P—n.v.; iso. E, K)
Synonymy: R. dielsianum Handel-Mazzetti nomen nudum (R. scabrifolium x R. spinuliferum) non Schlechter.
Corolla openly funnel-shaped, 9-15 mm, tube 3-7 mm
Habitat: Rocky slopes in scrub
Distribution: China (N Yunnan)
Altitude: 1800-3000m
This is the most northerly taxon of the complex, and is distinct in many localities; to the south of its range it merges into the other two varieties
Type: China, Yunnan, in monte Hee-chan-men supra Lan-kong, Delavay 297 (holo. P—n.v., iso. E)
Corolla narrowly funnel-shaped, 12 • 5-23 mm, tube 6-17 mm. Corolla 12.5-15 mm; leaves mostly narrow, c. 15-30 x 4-10 mm.
Habitat: Rocky slopes,
Distribution: China (C & S Yunnan)
Altitude: Around 2400m
Occurring to the south of var. scabrifolium, often in the same general area as var. pauciflorum and R. spinuliferum. There is a fruiting specimen from Guizhou (Tsiang 8627) which is very similar to var. spiciferum, but, in the absence of flowers, it cannot be accurately identified.
Type: China, Yunnan, sur les coteaux a Kin-lin et pres Yunnansen, Delavay (holo. P—n.v., iso. E)
Synonymy: R. spiciferum Franchet, Journ. de Bot. 9:400 (1895)
Loosely branched shrub, l-2m; young shoots covered with adpressed grey-brown hairs that gradually disappear. Leaves persistent, coriaceous, dimorphic; spring leaves elliptic to lanceolate, 3-9 x 2-3.5cm,(1.5-)2-3.2 x as long as broad, apex acute, base broadly cuneate, margin entire to subcrenulate, ciliate, both surfaces with scattered adpressed pilose hairs, lower surface paler than upper; summer leaves elliptic to lanceolate, 30-40 x 10-15mm, apex acute to rounded and mucronuiate, otherwise as for spring leaves; petioles 2-4mm, stout, flattened, covered with adpressed flattened grey-brown strigose hairs. Inflorescence 2-6-flowered; pedicels 10mm, densely fulvous-strigose hairs glandular or eglandular. Calyx covered with adpressed grey pilose or giandular-pilose hairs, lobes oval, rounded, c.5mm. Corolla broadly funnel-shaped, 45-60mm long, c.50mm across, rose-red to scarlet, with dark flecks on upper lobes; tube ,15-20mm, glabrous. Stamens 10, shorter than corolla, filaments pilose below middle. Ovary eglandular- or glandular-pilose; style glabrous. Capsule ovoid c. 10mm, sparsely hairy.
Type: Type not designated
Occurs in Countries: JP Subgenus: Tsutsusi Habit: Non-Tree
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):112
Pedicels, calyx and ovary glandular-pilose
Distribution: Japan (S Ryukyu Islands)
Subsp. amanoi apparently differs in its glandular indumentum and slightly smaller flowers. Furthermore, it replaces subsp. scabrum in the Southern Ryukyu Islands.
Synonymy: R. amanoi Owhi, Bull. Nat. Sci. Mus. Tokyo n.s. 1,1: 4 (1954). Type: Japan, Ryukyu, Ins. Iriomote, Inaba, secundum fluvii Uranchi, 21 vi 1953, T. Amano 7185, n.v. Ic.: Togashi et-al., Species Rhododendron Japan 134-137 (1982).
Pedicels, calyx and ovary eglandular-pilose
Habitat: In open forest
Distribution: Japan (Ryukyu Islands)
Illustrations:
In Ohwi & Kitagawa (New Flora Japan: 1157, 1983) R. yakuinsulare is mentioned under R. scabrum and there is no entry for R. simsii. Since we have seen neither the type specimen nor the original description we are uncertain of the true status and affinities of this taxon.
Synonymy: R. maximum sensu Thunberg, Fl. Japan 181 (1784), non L. (1753). R. indicum Sweet var. sinensis Miquel, Ann. Mus. Lugduno-Batavum 1: 33 (1863). Type: Japan, locis clivosis, Thunberg, Siebold, Burger, n.v. R. sublanceolatum Miquel, Ann. Mus. Lugduno-Batavum 2: 163 (1866); R. indicum Sweet var. sublanceolatum (Miquel) Makino, Bot. Mag. Tokyo 18: 100 (1904). Type not known. R. sublateritium Komatzu, Bot. Mag. (Tokyo) 32: 12 (1918). Type not known. R. liukiuense Komatzu, loc cil. (1918). Type not known. ? R. yakuinsulare Masamune, Trans. Trop. Agric. 2: 38 (1930); ? R. simsii Planchon var. yakuinsulare (Masamune) Yamazaki, J. Jap. Bot. 49: 272 (1974). Type not known. R. scabrum G.Don f. linearisepalum Sugimoto, J. Geobot. 22: 52 (1975). Type not known.
Small and slender shrub. Twigs 1–1.5mm in diameter, rounded, laxly scaly and often whitish, lower parts glabrescent and smooth; internodes 2.5–5cm. Leaves spirally arranged or in loose pseudowhorls. Blade 20–30 x 10–18mm, elliptic, apex rounded, often very shortly apiculate; margin sub-cartilaginous, undulate, crenulate or almost entire; base nearly rounded or broadly tapering; laxly scaly initially, glabrescent and a little rugose with age above, laxly and persistently scaly beneath. Scales flat, sub-circular, the brown marginal zone angular or irregularly lobed; centre minute, darker, weakly impressed. Mid-vein narrowly impressed above, broader, flattened and weakly, or not, prominent beneath; lateral veins inconspicuous. Petiole 2–3 x 1–2mm, somewhat flattened. Bracteoles c.13mm, filiform, glabrous. Inflorescence a 3–6-flowered open umbel. Pedicels 15–30 x 0.5mm, sub-densely covered with stellate scales and short patent hairs. Calyx c.3mm in diameter, disc-shaped, irregularly and shortly 5-lobed, scaly and hairy outside. Corolla c.35mm, tubular, red; tube c.25 x 5–6 x 7–8mm, straight, cylindrical, the base pouched, glabrous inside and out; lobes c.10 x 7–8mm, spreading, broadly obovate-spathulate, slightly retuse. Stamens unequal, 27–33mm; filaments linear, glabrous; anthers c.3 x 1.5mm, oblongoid-obovoid; cells tapering towards the base, apiculate at the very base. Disc prominent, glabrous. Ovary 28–32mm, sub-ovoid-cylindrical, densely sub-stellately scaly, without hairs, abruptly contracted distally; style 28–32mm, slender, glabrous; stigma obconical. Fruit (immature) 15 x 4mm, sub-cylindrical.
Habitat: In forest
Distribution: Indonesia, Sulawesi, Latimodjong Range, W slope of Mt Rantemario.
Altitude: Around 2950m
Latin – scarlatinus – scarlet or red, alluding to the flowers.
Known only from the type collection.
Type: Eyma 782, 19 June 1937. Celebes (C), Enrekang, Rante Mario, W slope, 2950m (BO, L).
Occurs in Countries: ID Altitude Ranges: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:212
Shrub, 2-2.5m; young shoots rufous stellate-tomentose, eglandular. Leaves oblanceolate to elliptic, 7-15 x 2.5-5.1cm, 2.8-3.2 x as long as broad, apex rounded, apiculate, base rounded, both surfaces glabrous when mature except for a few stellate hairs on the midrib below; petioles 0.5—1.5cm, stellate-tomentose when young, later glabrescent. Inflorescence 5-10-flowered; rhachis c.5mm; pedicels 10-15mm, stellate-tomentose. Calyx large, reddish, cupular, 10-17mm, lobes rounded, irregular, ciliate, otherwise glabrous. Corolla tubular-campanulate, crimson, 45—50mm. Ovary densely brown stellate-tomentose, eglandular; style tomentose below. Capsule c. 15mm long, curved.
Habitat: Pine forests, Rhododendron thickets
Distribution: China (W Yunnan)
Altitude: 2700-3350m
Superficially resembling R. diphrocalyx (subsection Maculifera) but differing in its apiculate (not acuminate) leaves and eglandular shoots. The well-developed calyx suggests that R. schistocalyx may have arisen as a hybrid between R. facetum and a species in subsection Neriiflora, perhaps R. neriiflorum.
Type: China, W Yunnan, Shweli/Salween divide, vii 1918, Forrest 17637 (holo. E; iso. BM, K)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: crimson
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):379
Shrub to 1.5m. Twigs erect, slender, tips laxly scaly with stalked scales, lower parts covered with the scars and thick leaf-cushions of the fallen leaves. Leaves densely spiral. Blade 5–14 x 3–8mm, ovate, elliptic-ovate or elliptic; apex shortly acuminate or acute with a small terminal gland; margin slightly cartilaginous, flat, crenulate where marginal scales are attached; base sub-truncate, rounded, or broadly tapering; very laxly scaly and early glabrescent above, laxly and persistently scaly beneath. Scales circular or nearly so; margin entire or sub-entire; centre mostly small, not or weakly impressed. Mid-vein minutely or not impressed above, slightly raised beneath; lateral veins obscure or 1 or 2 per side faintly visible. Petiole 1–2 x c.2mm, laxly scaly. Bracts to 13 x 8mm, ovate-acuminate, membranous, glabrous or laxly scaly outside along the mid-vein, glossy, the margin crenulate with sunken glands distally, entire proximally. Bracteoles 6–10 x 1–2mm, linear-sub-spathulate, glabrous. Flowers solitary or in pairs. Pedicels 10–14mm, thick, densely covered with sub-sessile scales. Calyx minute, oblique, disc-shaped with an undulate margin, laxly scaly outside. Corolla 25–32mm, tubular, dark to light red; tube 16–22 x 3–4 x 8–10mm, laxly scaly proximally, almost glabrous distally, glabrous inside; lobes 6–8 x 4–6mm, broadly elliptic to sub-circular, erect or slightly spreading, overlapping to c.¾, margin undulate. Stamens c.25mm, unequal; filaments linear, glabrous, somewhat dilated towards the base, filiform distally; anthers 1.5–1.7 x c.1mm, brown, broadly sub-obovate-elliptic. Disc glabrous, the lobes thick and a little prominent. Ovary c.4 x 2mm, obliquely ovoid-conical, very densely scaly, without hairs, abruptly narrowed distally; style c.15mm, glabrous; stigma gradually thickened or conical, its numerous lobes irregularly club-shaped.
Habitat: Usually terrestrial in open vegetation, near Lake Habbema said to be plentiful in shrubberies with thick ground moss, or on peaty ridges
Distribution: Indonesia, New Guinea (W), Lake Habbema and Hubrecht Mts. Papua New Guinea, Mt Auriga.
Altitude: 3100-3450m
Greek – schizo – split, deeply divided, alluding to the deeply lobed stigma.
Type: Brass 9567, Oct. 1938. New Guinea (W), Lake Habbema, 3225–3345m (A, BO, L).
Occurs in Countries: ID, PG Altitude Ranges: 3,000 - 4,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:142
Shrub to 1.5m. Twigs rounded, glabrous; internodes 6–10cm. Leaves spiral or in loose pseudowhorls, crowded apically, spreading. Blade 130–170 x 60–80mm, elliptic; apex obtuse; margin entire, flat; base broadly tapering to rounded, glabrescent above at maturity, densely scaly beneath. Scales small, irregularly stellately lobed in the marginal zone; centre not or very slightly impressed, fragile, leaving blackish points beneath. Mid-vein weakly raised above in the proximal ½, then flat; strongly raised below almost to the apex; lateral veins 8–9 per side, slender, straight or slightly curved, obscurely anastomosing, slightly raised on both sides when dry, reticulation obscure. Petiole 15–20 x 2–3mm, semi-rounded, without a groove, scaly. Inflorescence 7–12-flowered in an open umbel. Pedicels 12–20 x 3–4mm, densely covered with brown scales, which are deeply divided to, or nearly to, the small centre, sometimes laxly hairy distally. Calyx 6–7mm in diameter, disc-shaped, oblique, shallowly 5-lobed and wavy, stellate-scaly outside, glabrous inside. Corolla 150–170mm, tubular-funnel-shaped, snow white, very fragrant; tube 90–120 x 10–11 x 22–28mm, cylindrical, 5-lobed at the base, laxly scaly to glabrescent outside, densely hairy and laxly scaly inside; lobes 50–70 x 35–50mm, obliquely and broadly obovate, rounded at the apex, spreading, margin wavy. Stamens strongly exserted; filaments 110–135mm, linear, flat, gradually tapering and finally filiform distally, densely hairy, the hairs denser, and retrorse at the margin, glabrescent in the distal 1⁄3; anthers 16–18 x 1.8mm, with elongate-oblong cells, minutely apiculate at the base. Disc lobed, with tufts of short hairs. Ovary c.25 x 7–9mm, cylindrical, very densely covered with yellowish, spreading hairs, which cover stellate scales, gradually tapering distally; style c.125 x 3.5mm, cylindrical, covered with yellow, sub-patent hairs and stellate scales for the proximal c.70mm, becoming almost exclusively scaly distally and ultimately glabrous for 20mm; stigma broadly and shortly obconical, 5-lobed.
Habitat: Epiphytic in rain forest on tall trees.
Distribution: Papua New Guinea, New Guinea (E), Bismarck Mts; Kani Mts (Madang Province). Indonesia, New Guinea (W), Mt Jaya (Carstensz).
Altitude: 1000-1700m
Named after the collector, Friedrich Schlechter, a German botanist most famous for his studies on orchids but who also took a great interest in vireya rhododendrons, publishing many species.
This species is very similar to R. leucogigas but is said to differ in having 5-lobed flowers and leaves spirally arranged or in loose pseudowhorls. The recent collection of a specimen attributed to this species on Mt Carstensz with flowers with 5, 6 and 7 lobes on the same plant questions the real difference between these species, although there does appear to be a difference in leaf shape, petiole and scales. There are also strong similarities to R. konori, the biggest difference being that scales are mounted on persistent epidermal tubercles in R. konori whereas the scales are from a flat epidermis or even a little impressed in R. schlechteri. Seedlings from the Carstensz locality have scales on epidermal tubercles although the wild collected adults do not!
Type: Schlechter 14045. New Guinea (NE), Bismarck Mts, 1700m (B†). Neotype: Schlechter 17845, 22 June 1908. New Guinea (NE), Kani Mts, 1000–1100m (K, E, P).
Occurs in Countries: ID, PG Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:315
Shrub or small tree to 2.5(-5)m tall; bark thinly and vertically furrowed; young twigs pale brown, very sparsely to moderately covered with unicellular hairs and with scattered multicellular gland-headed hairs, sometimes with multicellular eglandular hairs intermixed; new foliage shoots arising from axillary buds associated with the lowest scaly leaves of the present year's shoots (i.e. within the terminal bud), and from some terminal buds. Vegetative bud scales sparsely to densely covered with pale to ferrugineous, multicellular eglandular hairs intermixed with a few inconspicuous unicellular hairs on both surfaces; margin fringed with multicellular eglandular and unicellular hairs; lowermost scales with long aristate apices or rudimentary blades. Leaves deciduous, dark green adaxially, pale abaxially, turning yellow, orange and red in autumn, pseudo-verticillate, with (4 or) 5(-9) leaves clustered at apex of shoot and sometimes 1 or 2 smaller leaves borne along shoot below terminal cluster. Blade membranaceous, obovate, often very broadly so, to nearly orbicular or elliptic, 2.5-11.7 x 0.9-7.2cm; base narrowly to broadly cuneate to attenuate; apex occasionally obtuse but more commonly rounded to emarginate, with a short mucro; midvein and secondary veins slightly to strongly raised and prominent abaxially; adaxial surface sparsely to moderately covered with + curled unicellular hairs and scattered multicellular gland-headed hairs, the midvein moderately to densely covered with curled to straight unicellular hairs and scattered multicellular gland-headed hairs; abaxial surface glabrous to sparsely unicellular-pubescent (especially at base of blade), the lateral surfaces of mid vein + densely fringed with long, straight to crisped, unicellular hairs (especially near base), and the middle portion sparsely to moderately covered with short, curled unicellular hairs, or such hairs lacking, throughout with scattered multicellular short- to long-stalked gland-headed hairs, the secondary veins with only scattered multicellular gland-headed or eglandular hairs with indumentum similar to that of midvein (especially towards base of blade); margin entire to irregularly undulate/crenate with fringe of multicellular gland-headed to eglandular hairs; petiole 2-6.5mm long, very sparsely to densely covered with unicellular hairs and with scattered multicellular gland-headed hairs, sometimes with a few multicellular eglandular hairs, the base of petiole abruptly expanded into a somewhat broadened point of attachment. Flower bud scales with abaxial surface moderately to densely covered with ± ferrugineous elongate multicellular eglandular hairs and sparsely covered with unicellular hairs; margin ciliate with multicellular eglandular (and sometimes also gland-headed) hairs and unicellular hairs. Flowers appearing before or with the leaves; inflorescence an umbellate raceme of 3 to 6 flowers. Pedicels 8-23mm long, moderately to densely covered with multicellular gland-headed hairs, sometimes also very sparsely unicellular-pubescent. Calyx lobes broadly Ungulate, ovate or nearly orbicular, to obovate or ovate, 1.5-7 x 1.5-4.7mm; apex rounded; margin fringed with unicellular hairs and multicellular gland-headed hairs; adaxial surface glabrous to moderately unicellular-pubescent; abaxial surface moderately covered with multicellular gland-headed hairs, often also very sparsely unicellular-pubescent. Corolla very light to deep pink, with red-brown spots on the upper three lobes, fragrant, zygomorphic, broadly rotate to funnelform, the tube much shorter than the limb and gradually expanding into it; upper corolla lobe 1.5-2.8 x 1.6-2.9cm; lateral lobes 1.5-3.5 x 1.2-2.5cm; corolla tube 0.8-1.2am long; outer surface of corolla glabrous; inner surface of corolla sparsely unicellular-pubescent towards base. Stamens 10, declinate, dimorphic, the upper 5, 1.5-2.6cm long, the lower 5, 3-4.5cm long, included to slightly exserted; filament glabrous distally, becoming densely covered with flattened unicellular hairs proximally. Ovary 3.5-4mm long, moderately covered with multicellular gland-headed hairs; style declinate, 2.7-4cm long, glabrous distally, but with scattered multicellular gland-headed hairs on proximal portion. Capsules ovoid, 1-1.9 x0.6~lcm, moderately covered with multicellular gland-headed hairs. Seeds shiny and dark chestnut-brown, angular-ovoid to ellipsoid, 1.6-2.7 x 0.7-lmm; testa tightly appressed to body, tails lacking, the cells elongate. Cotyledons with multicellular gland-headed hairs along margin and well-developed reticulate venation. 2k ó26 (Sax, 1930).
Habitat: Forests and thickets
Distribution: Korea and adjacent Russia (SW of Vladivostok)
Altitude: 400-1500m
Illustrations:
Rhododendron schlippenbachii is probably most closely related to R. quinquefolium and R. pentaphyllum because all three species usually have five leaves forming a pseudowhorl at the tip of each of their branches, cotyledons with a well-developed reticulate venation and margin conspicuously fringed with multicellular gland-headed hairs, and seeds lacking tails (see Cladistic Analysis; M. Philipson, 1980; W. Philipson, 1980). In addition, it shares with R. quinquefolium the character of having vegetative shoots that develop from buds included within the terminal inflorescence bud. This feature may have been lost in R. pentaphyllum, in which the vegetative shoots arise from buds in the axils of foliage leaves below the terminal (inflorescence) bud. As discussed by W. Philipson (1980) and Kron & Judd (1990), the position of buds giving rise to vegetative shoots has probably been overstressed by systematists working in Rhododendron, and it is probably subject to developmen-tally simple modification through reduction of the subtending leaf. This species may be distinguished easily by the characters given in the key, especially its style with multicellular gland-headed hairs.
Synonymy: Azalea schlippenbachii (Maxim.) Kuntze, Revis. Gen. PI. 2: 387 (1891). Type: [Russia] Manchuria, shores of Possiet Bay, [SW of Vladivostok], 1860, C. Maximowicz (lecto., n.v., designated here, LE; isolecto. GH, NY).
Occurs in Countries: RU Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Pentanthera Habit: Tree Fl. Colour: pink, red
Judd, W.S. & Kron, K.A. (1995) A Revision of Rhododendron VI. Subgenus Pentanthera (Sections Sciadorhodion, Rhodora and Viscidula). Edinburgh Journal of Botany 52(1):15
Shrub to 2-6 m. Young growth loriform-setose, the older twigs smooth and sparsely lepidote. Leaves elliptic to obovate-elliptic, tapered to the base, the apex obtuse to rounded, 47-75 X 18-32 mm, drying a distinctive pale greyish green, upper surface elepidote or very sparsely lepidote, lower surface with distant, unequal, golden scales; petioles sparsely lepidote. Inflorescence 2-4-fIowered, pedicels lepidote. Calyx 5-lobed, the lobes broadly triangular, obtuse, c. 3 mm, lepidote outside, not ciliate. Corolla funnel-campanulate, white or white flushed pink with a yellow or golden blotch inside, 50-55 mm, the tube c. 30 mm, rather sparsely pilose over most of the tube outside, the outsides of the lobes lepidote. Stamens 10, filaments densely pubescent towards the base. Ovary densely lepidote, style impressed, lepidote at the extreme base, rarely pubescent there as well. Capsule c. 16 mm, lepidote.
Habitat: Cliffs, forested slopes
Distribution: China (SE Xizang—Tsangpo and Po-Tsangpo valleys)
Altitude: 1950-2450m
Illustrations:
Easily recognised in the herbarium by the distinctive light colour of the leaves; this coloration is found to a lesser extent in cultivated living material. The style may be lepidote only or both lepidote and pubescent at the extreme base; this feature appears to be of no taxonomic significance.
Type: S Tibet, Tsangpo gorge, Gompo Ne, 6000 ft, Kingdon Ward 6354 (iso. E)
Occurs in Countries: CN Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: pink, white, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):43
Shrub or small tree. Twigs rounded, the youngest parts red-brown with dense scales and minutely patently hairy; internodes 1.5–5cm. Leaves 3–7 together in well-marked pseudowhorls. Blade 25–35 x 15–30mm, elliptic, broadly elliptic, obovate to sub-circular; apex obtuse to rounded and with a small terminal gland, sometimes a little emarginate; margin strongly recurved; base tapering; upper surface light green, glabrescent, shining, undersurface yellowish when fresh, paler brown when dry, densely scaly. Scales sessile, round; marginal zone narrow, entire or nearly so; centre thick, dark, large and impressed. Mid-vein impressed above, thick and obtusely prominent beneath; lateral veins 4–6 per side, spreading at a wide angle (45–90°), sometimes obscure, anastomosing, slightly to deeply depressed above, distinct and raised beneath, reticulation obscure. Petiole 2–5 x 1.5–2mm, grooved above, brown-scaly except in the groove which is minutely but densely patently hairy. Bracts to 7 x 4mm, ovate to spathulate, obtuse, scaly and hairy distally outside, ciliate on the margins. Bracteoles to 5mm, linear, slightly hairy. Inflorescence a 4–7-flowered open umbel. Pedicels 15–20mm, densely scaly, without hairs. Calyx short-cupular, scaly, with 5 ovate, obtuse, lobes sometimes ciliate on the margins. Corolla c.18 x 15–20mm, yellow, sometimes paler, white, or yellow at the lobes, orange at the tube, funnel-shaped; tube 9–14 x 3–4 x 8–10mm, densely covered with dark scales, glabrous inside; lobes 6–8 x 5–7mm, broadly obovate to sub-circular, overlapping up to ¼. Stamens unequal, the longest exserted to 8mm; filaments linear, dilated to 0.5mm at the base, filiform upwards, glabrous; anthers c.1.8mm, oblong. Disc glabrous. Ovary c.2.8 x 1.8mm, conical, densely covered with scales, gradually tapering distally; style glabrous, becoming exserted; stigma conical-globose, slightly 5-lobed. Fruit 10–13 x 3.5mm, cylindrical, shortly apiculate, densely scaly.
Habitat: Epiphytic or terrestrial shrub in summit vegetation, sometimes regenerating along roadside cuttings
Distribution: Malaysia (W), Main Range from Perak to Selangor. A record for Borneo was from a misidentification of R. buxoides.
Altitude: 1465-2135m
Named after the collector, Rev. Father Benedetto Scortechini, Roman Catholic Priest and Government botanist, Perak (Malaysia), 1884–1886.
Type: Scortechini 401b, 1884. Malay Peninsula, Perak: without locality (CAL, K, L, fragment).
Synonymy: R. orion Ridl., J. Fed. Mal. St. Mus. 1914. 5: 39.
Occurs in Countries: MY Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:41
Shrub to 4m. Twigs 6–8mm in diameter, densely scaly; internodes 5–12cm. Leaves 4–6 together in tight pseudowhorls. Blade 60–110 x 40–75mm, broadly elliptic or elliptic; apex obtuse to rounded; margin very narrowly cartilaginous, flat or minutely revolute; base broadly tapering to rounded occasionally sub-cordate; at first densely scaly above with fragile scales standing up on stalks, slightly less densely scaly below. Scales sub- circular, very variable in size, deeply impressed with large centres and narrow lobed margins. Mid-vein weakly raised above in the proximal ¼–1⁄3 but deeply grooved here also; broadly raised in the proximal ½–2⁄3 below; lateral veins 4–7 per side, spreading at c.45°, looping and joining before the margin, reticulation somewhat obscure above, distinct below. Petiole 7–20 x 3–4mm, weakly grooved in the distal part only, densely brown-scaly. Bracts to 50 x 30mm, sub-spathulate, obovate, densely scaly and shortly appressed hairy outside, inside shortly appressed hairy. Bracteoles to 40 x 5mm, linear proximally, spathulate distally, hairy. Inflorescence of 11–16 flowers in an open, flat, umbel; the flowers held horizontally. Pedicels 8–10 x 2–2.5mm, densely scaly and sparsely hairy distally. Corolla 80–125 × 40–55mm, trumpet-shaped, pink, scented; tube 65–75 × 4–5 x 10–14mm, straight, very sparsely scaly outside, densely retrorse-hairy inside; lobes c.25 × 25mm, sub-circular, sometimes slightly retuse, spreading and overlapping to c.½. Stamens exserted to 10mm, clustered in a group in the mouth; filaments densely hairy at the base, becoming less so and glabrous for the distal 1⁄3; anthers 3.5–4.5 × c.1.5mm. Disc prominent, densely hairy. Ovary 10–13 × 3–4mm, densely covered in appressed hairs which cover scales, tapering gradually distally; style densely hairy and scaly proximally, becoming less hairy distally, the central part entirely scaly, glabrous for the ultimate 15mm; stigma 4–5mm in diameter, disc-shaped. Fruit 55–80 x 7–9mm.
Distribution: Papua New Guinea, Simbu (Chimbu) District, Gumine subdistrict, towards the lower slopes of Mt Digine, 2134m. Enga Province, on the Laiagam–Porgera road, Mt Maip (Tipinini side)
Altitude: 2100-2600m
Named after the collector, L.K. Searle, who worked in New Guinea for many years and who had a passionate interest in vireyas, collecting and growing many specimens.
Type: Searle 39, 10 June 1972. New Guinea, Eastern Highlands District, Gumine subdistrict, Yani area, Dirima–Gomgali road, 2135m (LAE, L).
Synonymy: R. reevei Argent, Folia Malaysiana 2003. 4(2): 106.
Occurs in Countries: PG Altitude Ranges: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: pink
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:69
Very similar to R. concinnum, differing as follows: leaves much longer than broad, c. 70 x 20 mm, narrowly elliptic or very narrowly elliptic, cuneate at the base, usually greyish or silvery beneath with scales which are trimorphic as to size and colour—(a) small, milky and golden, (b) larger milky, and golden, and (c) larger still and golden; corolla white or pale purple, elepidote, c. 22 mm, tube c. 12 mm
Habitat: Thickets
Distribution: China (SW Sichuan)
Altitude: 2300-2800m
Illustrations:
Known only from two collections made by Wilson on W'a-shan, and material widely distributed in cultivation
Type: China, Szechuan, Wa-shan, 2300-2800 m, vi & xi 1908, Wilson 1343 (iso. E)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: purple
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):76
Shrub. Twigs slender, patent, minutely patently hairy and laxly covered with sessile scales; internodes 0.7–6cm. Leaves in 4–10 together in pseudowhorls at the upper nodes. Blade 13–28 x 5–11mm, elliptic-obovate to narrowly elliptic; apex broadly tapering, obtuse and ending in a small protruding gland; margin entire or minutely crenulate with impressed scales, slightly revolute; base tapering, rugulose when dry, shining above, laxly scaly initially, becoming glabrescent above, dull and laxly scaly beneath. Scales sessile, circular; margin entire or nearly so; centre thick, darker and distinctly impressed. Mid-vein impressed above, strongly raised beneath; lateral veins obscure or sometimes faintly visible underneath. Petiole 2–4mm, slender, scaly and minutely hairy. Bracts to 7 x 4mm, ovate, obtuse, densely shortly hairy outside, laxly scaly and with a ciliate margin. Bracteoles to 6mm, filiform, hairy. Inflorescence 2–4- flowered. Pedicels 9–12mm, slender, densely covered with sessile scales, sometimes also minutely hairy. Calyx oblique, unequally obtusely 5-lobed, scaly but not ciliate. Corolla 16–19 x 15–25mm, funnel-shaped; tube 8–9 x c.2.5 x 4–6mm, laxly scaly outside, glabrous inside; lobes 9–10 x 6–7mm, obovate, with scales outside except near the margins. Stamens very slightly or not exserted; filaments linear, glabrous; anthers c.1.5mm, oblong. Disc glabrous. Ovary c.2.5 x 2mm, ovoid-conical, obtuse, 5-grooved longitudinally, densely scaly, gradually tapering distally; style c.16mm, glabrous; stigma 5-lobed. Fruit 8 x 2.5mm.
Distribution: Malaysia (W), Pahang, Mt Tahan, 1675m.
Named after the collector, E. Seimund, who for some time worked in the Museums Department of what was then the Federated Malay States.
Flowers Feb.–March.
Type: Seimund 343, March 1921. Malay Peninsula, Pahang, G. Tahan, 1675m (SING, lectotype, L, fragment).
Occurs in Countries: MY Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:41
Very similar to R. pendulum, differing as follows: leaves usually somewhat bullate above, elliptic or narrowly ovate, acuminate, 40-55 x 22-30 mm, the indumentum often dark brown, the upper surface pale brownish green, corolla campanulate, bright yellow, ovary densely tomentose all over, style glabrous.
Habitat: Epiphytic on trees or stumps and on rocks in dense forest
Distribution: NE Burma, China (NW Yunnan, SE Xizang)
Altitude: 1800-3000m
The characters used in the literature to separate R. seinghkuense and R. pendulum are unreliable. One specimen (Kingdon Ward 5440), is reported as climbing by means of nodal roots and the apparent remains of these are visible on the specimen. Such a climbing mechanism is otherwise unknown in the genus.
Type: Burma, Seinghku Wang, 6000-10000 ft, Kingdon Ward 6793 (iso. E)
Occurs in Countries: CN, MM Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Rhododendron Habit: Epiphyte, Non-Tree Fl. Colour: yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):27
Shrub or small tree, 1 -5m; young shoots stipitate- to setose-glandular. Leaves ± herbaceous, ovate or obovate to elliptic, 3.5-9 x 1.8-4cm, 1.7-2.5 x as long as broad, apex rounded, apiculate, base rounded, upper surface glabrous, lower surface occasionally with a few persistent hairs near the base when mature, otherwise glabrous, or with a sparse brownish indumentum on lamina; petioles 1 -1.5(-2)cm, sparsely stipitate-glandular to densely glandular-setose, sometimes becoming glandular with age. Inflorescence lax, 3-8-flowered; rhachis 2-3mm; pedicels 15-20mm, stipitate-glandular. Calyx l-8mm, stipitate-glandular, when well-developed with rounded ovate to Ungulate lobes. Corolla funnel-campanulate, white or pale cream to deep pink, with or without purple flecks, 25-40mm. Ovary densely stipitate-glandular; style glabrous or glandular at base, rarely glandular for half its length. Capsule 12-35 x 3.5mm, curved.
A very variable species with the infraspecific taxa at least partially geographically differentiated. Subsp. selense approaches R. martinianum but has larger leaves and more flowers per inflorescence. Subsp. dasycladum has a more southerly distribution than does subsp. selense and is more extreme in its characters (with larger leaves and a denser setose indumentum on the young shoots) outside the range of subsp. selense. Where their ranges overlap however, the two taxa intergrade. Subsp. setiferum also intergrades with subsp. selense. Subsp. jucundum is apparently geographically isolated but the diagnostic differences, while constant, are small.
4*. R. x erthrocalyx Balfour f. & Forrest, Notes R.B.G. Edinb. 12: 110 (1920) - R. selense x R. wardii, Type: China, NW Yunnan, Bei-ma-shan, 13000ft, Forrest 13989 (holo. E; iso. K). R. cymbomorphum Balfour f. & Forrest, ibid. 12: 102 (1920). Type: China, NW Yunnan, Bei-ma-shan, ll-12000ft, vi 1917, Forrest 13939 (holo. E). R. beimaense Balfour f. & Forrest, ibid. 13: 32 (1920). Type: China, NW Yunnan, Bei-ma-shan, 12000ft, vi 1917, Forrest 13961b (holo. E). R. eucallum Balfour f. & Forrest, ibid. 13:63 (1920). Type: China, NW Yunnan, Bei-ma-shan, 12000ft, vi 1917, Forrest 13938 (holo. E; iso. K). R. truncatulum Balfour f. & Forrest, ibid. 13: 63 (1920). Type: China, N NW Yunnan, Mekong/Salween divide, 28° 12'N, 11000ft, vi 1917, Forrest 13936 (holo. E; iso. K). R. erythrocalyx Balfour f. & Forrest subsp. docimum [Balfour f. ex] Tagg in Stevenson (ed.), The Species of Rhododendron716(1930). Type: China, NW Yunnan, Bei-ma-shan, 12000ft, vi 1917, Forrest 13951a (holo. E; iso. K). ? R. panteumorphum Balfour f. & W. W. Smith, Notes R.B.G. Edinb. 9: 257 (1916). Type: China, Mekong/Salween divide, NW of Tseku, 11000-12000ft, ix 1904, Forrest 5068 (holo. E). Shrub, l-2.5m; young shoots covered with short stipitate glands. Leaves ± herbaceous, broadly obovate to oblong, 6-10 x 3.6-5cm, 1.7-2.3 x as long as broad, apex rounded, apiculate, base rounded to cordate, upper surface glabrous, lower surface with vestiges of hairs when mature, or glabrous, pale green; petioles 1.5-2.5cm, glabrous to stipitate-glandular. inflorescence lax, 4-10-flowered; rhachis c.3mm; pedicels 15-30mm, stipitate-glandular. Calyx 3-7mm, stipitate-glandular, lobes triangular with rounded tips. Corolla funnel-campanulate, pale yellow or white flushed rose, with or without purple flecks and a basal blotch, 35-45mm. Ovary stipitate-glandular; style glabrous or stipitate-glandular for up to half its length. Capsule c.20 x 7mm, curved. china (NW Yunnan, SE Xizang). Open pine forests, etc., 3350-3950m 85, p. 282. The variability of this taxon, indicated by the extensive synonymy, suggests that hybrid swarms occur in the wild. Its range is within an area where R. selense and R. wardii both occur. The position of R. panteumorphum remains in doubt; the corolla of the type appears to have been more openly campanulate than is usual in R. x erythrocalyx. It is however obviously closely allied and occurs within the range of the hybrid.
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: cream, pink, purple, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):277
Leaves 4-9 x 2.2~4.2cm, glabrous beneath, only rarely with a glaucous bloom; young shoots with long-stipitate glands to densely setose-glandular; longest calyx lobes 1 -2(-5)mm.
Habitat: Bouldery slopes, open pine forest, scrub, etc.
Distribution: China(W Yunnan, SW Sichuan)
Altitude: 3350-4000m
Illustrations:
Kingdon-Ward 7190, which has well-developed calyces, up to 5mm long, and leaves hairy below, is probably a hybrid of subsp. dasycladum.
Synonymy: R. dasycladum Balfour f. & W. W. Smith, Notes R.B.G. Edinb. 10: 98 (1917). Type: China, E NW Yunnan, mountains in the NE of the Yangtze Bend, 12000ft, vii 1913, Forrest 10430 (holo. E; iso. BM, K). R. rhaibocarpum Balfour f. & W. W. Smith, ibid. 10: 142 (1917). Type: China, E NW Yunnan, Mountains in the NE of the Yangtze Bend, ix 1913, Forrest 11312 (holo. E). R. dolerum Balfour f. & Forrest, Notes R.B.G. Edinb. 13: 40 (1920). Type: China, SW Sichuan, Mountains around Muli, 12000ft, vi 1918, Forrest 16318 (holo. E; iso. K).
Leaves 5-7.5 x 2.8-4cm, glabrous beneath, with a glaucous bloom; young shoots long-stipitate-glandular to setose-glandular; longest calyx lobes (2-)4-6mm.
Distribution: China (mid W Yunnan)
Synonymy: R. jucundum Balfour f. & W. W. Smith, Notes R.B.G. Edinb. 9: 242 (1916). Type: China, Yunnan, eastern flank of the Tali Range, 10- 11000ft, Forrest 4148 (holo. E). R. blandulum Balfour f. & W. W. Smith, ibid. 10:87 (1917). Type: China, mid W Yunnan, western flank of the Tali Range, 11 -12000ft, Forrest 11277 (holo. E;iso. K).
Leaves 4.5-7 x 2.2—3.6cm, with or without a glaucous bloom beneath, entirely glabrous; young shoots at maturity shortly stipitate-glandular, longest calyx lobes l-2(—5)mm.
Habitat: Stony slopes, open pine forests, Rhododendron thickets
Distribution: China(NW Yunnan, SE Xizang)
Altitude: 3350-4550m
The following specimens are intermediate between subsp. selense and subsp. dasycladum: Forrest 15018, 20066; Rock 9162, 9166, 22640; Yu 7922, 10729.
Type: China, NW Yunnan, Sela (Tsekou), au sommet de la montagne entre le Mekong et la Salween, 28 vi 1895, Soulie 1001 (E), 1002 (BM, E, K).
Synonymy: R. pagophilum Balfour f. & Kingdon-Ward, Notes R.B.G. Edinb. 9: 256 (1916). Type: China, Yunnan/Tibet frontier, Ka-gwr-pw glacier valley, 14000ft, Kingdon-Ward ATI (holo. E). R. axium Balfour f. & Forrest, Notes R.B.G. Edinb. 13: 30 (1920). Type: China, SE Xizang, Dokar-la, 10-11000ft, vii 1918, Forrest 16684 (holo. E; iso. K). R. metrium Balfour f. & Forrest, ibid. 13: 52 (1920). Type: China, SE Xizang, Tsarong, Dokar-la, 10-11000ft, vii 1918, Forrest 16679 (holo. E; iso. K). R. nanothamnum Balfour f. & Forrest, ibid. 13: 53 (1920). Type: China, SE Xizang, Tsarong, Salween/Kiu-chiang divide, vii 1919, Forrest 19019 (holo. E;iso. K). R. chalarocladum Balfour f. & Forrest, ibid. 13: 240 (1922). Type:China, SE Xizang, Tsarong, 1917, Forrest 18646 (holo E; iso. K). R. probum Balfour f. & Forrest, ibid. 13:288 (1922). Type: China, W NW Yunnan, Mekong/Salween divide, 12000ft, vii 1917, Forrest 14227 (holo. E; iso. K). R. selense Franchet var. probum (Balfour f. & Forrest) Cowan & Davidian, Rhododendron Yearbook 6: 158 (1952). R. selense Franchet var. pagophilum (Balfour f. & Kingdon-Ward) Cowan & Davidian, ibid. 6: 158 (1952).
Leaves 5-7.5(-12) x 2.5-3.3(-4)cm, with a ± persistent though often discontinuous indumentum beneath, not glaucous; young shoots ± setose-glandular; longest calyx lobes (2-)4-8mm.
Distribution: China (NW Yunnan, SE Xizang)
Subsp. setiferum is intermediate between R. bainbridgeanum and subsp. selense and is probably of hybrid origin.
Synonymy: R. setiferum Balfour f. & Forrest, Notes R.B.G. Edinb. 11: 137 (1919). Type: China, W NW Yunnan, Mekong/Salween divide, 12- 13000ft, vi 1917, Forrest 14066 (holo. E; iso. K). R. vestitum Tagg & Forrest, Notes R.B.G. Edinb. 16: 210 (1931). Type: China, SE Xizang, Tsarong, Salween/Kiu-chiang divide, NW of Si-chi- to, 14000ft, vi 1922, Forrest 21877 (holo. E).
Deciduous shrub, to 2 m high, young branches puberulous and with glandular hairs. Leaves clustered at the end of short-growing shoots, or spaced along free-growing shoots; blade elliptic or ovate, c.20-60 x 10-26 mm, base rounded or cuneate, apex sub-acute, apiculate, or obtuse, sometimes slightly emarginate and mucronate, margin serrulate and sometimes finely ciliate, mid-rib puberulous above and below, veins on lower surface ciliate; petiole c.5-12 mm long, puberulous and glandular. Inflorescence buds lateral, 1-flowered, borne below the expanded leaves; bud-scales persistent; pedicel c.5-8 mm long, pubescent and glandular. Calyx lobes broadly rounded, c.2mm, ciliate outside and fringed with prominent glandular hairs. Corolla white with pink flush and rose-purple markings, rotate with a short wide tube and spreading lobes, c.20mm across. Stamens 5, unequal; the 2 upper short (c.7mm), erect with filaments densely pilose for most of their length, the 3 lower with longer filaments (c. 12 mm) almost glabrous or shortly pubescent at the base, spreading. Ovary subglobose, c.2mm long, setose and densely glandular; style glabrous. Capsule subglobose, c.4 x 4 mm, densely glandular.
Habitat: Thickets and forests in mountainous localities.
Distribution: Japan (Kyushu, Shikoku Honshu)
Type: Japan, high alps, Tschonovski s.n. (iso. K); [prope Nambu] (iso. BM).
Occurs in Countries: JP Subgenus: Mumeazalea Habit: Non-Tree Fl. Colour: pink, rose
Philipson, W.R. & Philipson, M.N. (1986) A Revision of Rhododendron III. Subgenera Azaleastrum, Mumeazalea, Candidastrum and Therorhodion. Notes from the Royal Botanic Garden Edinburgh 44(1):17
Shrub, 4-6m. Leaves obovate-lanceolate, up to 24 X 11.5cm,c.2.1 x as long as broad, apex rounded, minutely apiculate, base + cuneate, upper surface glabrous when mature, ± smooth, lower surface with a bistrate indumentum, the lower layer compacted, the upper whitish to buff, loosely tomentose, composed of strongly fimbriate, narrowly cup-shaped hairs; petioles 1 —2cm, flattened and narrowly winged (in cultivation ± terete and scarcely winged), giabrescent. Inflorescence c.l5-flowered; rhachis c.l2mm; pedicels 30-45mm, sparsely floccose-tomentose. Calyx c.2mm, tomentose, lobes triangular. CoroOa c.8-lobed, obliquely campanulate, white flushed rose, 40-50mm. Stamens 16. Ovary densely brownish tomentose. Capsule c. 35 x 8mm.
Habitat: Rhododendron forests
Distribution: China(SE Xizang, NW Yunnan)
Altitude: 3700-4000m
Closely allied to R. rothschildii and R. basilicum. R. semnoides apparently replaces R. basilicum in NW Yunnan and differs in its much more strongly fimbriate cup-shaped hairs on the leaves. The occurrence of these cup-shaped hairs clearly places this species in subsection Falconera and not in subsection Grandia, its traditional position.
Type: China, SE Xizang, Tsarong, Salween/Kiu-chiang divide, W of Chamatong, 12-13000ft, vi 1922, Forrest 21780 (holo. E); x 1922, Forrest 22788 (-21780) (E,K).
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):253
Shrub, to 2m; shoots densely covered with adpressed flattened grey or rufous-grey hairs. Leaves dimorphic, persistent or subpersistent; spring leaves ovate-oblong to lanceolate, 1.5-6 x 0.8-2.5cm, 2-3 x as long as broad, apex acuminate or acute, base broadly cuneate, upper surface glabrous or glabrescent when mature, lower surface densely clothed with long strigose rufous or grey-brown hairs; summer leaves smaller, 10-20 x 5-8mm, ovate to broadly oval, apex acute to obtuse; petioles 3-8mm, densely strigose. Inflorescence 3-10-flowered; pedicels 3-5mm, densely stigose. Calyx c.3mm, lobes lanceolate, covered with straight grey or rufous-grey hairs. Corolla funnelform, white suffused rose to light purple, with upper lobe spotted, 12-17mm; tube 7-lOmm, 2mm wide at base, sparsely hairy within outer surface sparsely hairy to stipitale-glandular. Stamens 5, clothed with strigose hairs; style villose at base. Capsule up to 8mm, narrowly ovoid, densely strigose.
Habitat: Thickets, wooded slopes
Distribution: China (Guizhou, Hunan, Fujian)
Altitude: 600-1400m
Illustrations:
54* R. qianyangense M.Y.He, Bull. Bot. Res. N.E. Forest. Inst. 5(4): 115 (1985). Type: China, Hunan, Qianyang Xian, Luo-ong-ha-mian-shan, Xia-ping-kou, 1120m, 7 v 1959, P.X.Tan 60590 (holo. IBSC, n.v.). Map 16. From the description this species appears to be very close to R. seniavinii but apparently differs in its stamens having glabrous filaments. While Tan does not cite this specimen, there is another (Tan 60559) which was collected in the same locality, that is referable to R. seniavinii.
Type: S China, Seniavin (holo. LE, n.v., iso. PE)
Occurs in Countries: CN Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: purple, rose, white
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):131
Shrub to 5m. Twigs 2.5–4mm, rounded, laxly scaly but quickly glabrescent, smooth; internodes 2–11.5cm. Leaves spirally arranged. Blade 50–85 x 20–40mm, elliptic, sub-ovate; apex shortly acuminate, acute; margin entire, shortly and narrowly recurved; base broadly tapering to nearly rounded; quickly glabrescent above; more persistently laxly scaly beneath but eventually glabrescent. Scales small, flat, marginal zone irregularly lobed; centre weakly or not impressed. Mid-vein raised above in the proximal ½, then smooth or very slightly impressed, strongly raised beneath almost to the apex; lateral veins 8–10 per side, spreading at c.45°, straight at the base, then sharply curving upwards before the margin and obscurely anastomosing, slightly prominent or smooth on both sides, reticulation faint or obscure. Petiole 5–20 x 2–3.5mm, without a groove, laxly scaly. Bracts to 35 x 10mm, elliptic to narrowly elliptic, obtuse, membranous, glabrous. Bracteoles c.25 x 1mm, linear, glabrous. Inflorescence 7–11-flowered in a complete umbel. Pedicels 20–34 x 2–3mm, thickened at the apex, sparsely scaly or practically glabrous. Calyx c.5mm in diameter, oblique, shortly cup- or disc-shaped, thickened, obscurely or not lobed, occasionally with slender petaloid lobes up to 40mm, laxly scaly outside. Corolla 50–56 x 80mm, broadly funnel-shaped, light violet, orange, yellow or red; tube 18–26 x 6–10 x 15–20mm, base lobed, glabrous outside and inside; lobes 35–40 x 22–23mm, unequal, elliptic to obovate, spreading, overlapping up to 1⁄5. Stamens exserted to c.10mm, irregularly arranged mostly in the lower ½ of the mouth; filaments yellow, flat, linear, glabrous; anthers 3–4 x c.1mm, cream, oblong, somewhat curved, base blunt or minutely apiculate. Disc prominent, glabrous. Ovary c.6 x 3mm, oblong-conical, glabrous, minutely rugulose, abruptly contracted distally; style 15–20mm, green, glabrous, at first on the lower side of the corolla tube, curving in the distal ¼ so that the stigma is presented centrally; stigma 3–4mm in diameter, lobed. Fruit 35–40 x 7–8mm, fusiform, glabrous.
Habitat: Light forest and gaps in primary forest. Often in limestone areas, locally abundant.
Distribution: Indonesia, Maluku, (Seram, Buru, and Ambon); Sulawesi, pass between Lake Poso and Wotu; Mt Wawonoeru, SW of Soroako.
Altitude: 900-1700m
Named after Seram, the island on which it was first found.
Sleumer (1960) recorded a specimen from C Sulawesi (Palopo–Rantepao road at 900m) differing by 35mm corollas and distinctly appendaged anthers.
Type: Stresemann 360, Sept.–Dec. 1911. Moluccas, Ceram (C), Hatu Soka Plateau, 1450m (L).
Occurs in Countries: ID Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: orange, red, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:267
Low, much-branched shrub; shoots slender, clothed with adpressed flattened chestnut-brown hairs. Leaves monomorphic, deciduous, crowded at end of short branchlets, obovate-oblong or elliptic, 0.3-1 x 0.3-0.5cm, 1-2 x as long as broad, apex obtuse or acute, base cuneate, upper surface with scattered strigose brown hairs and pustules, lower surface with hairs mainly on midrib, with pustules; petioles 1mm, strigose. Inflorescence l(-2)~fiowered; pedicels 3mm, strigose, hidden beneath the bud scales. Calyx small. Corolla short, funnel-form, a 17mm, rose-pink; tube with outer surface glabrous, papillate within. Stamens 5, papillate for most of their length. Ovary densely covered with pale flattened hairs; style glabrous. Capsule unknown.
Distribution: Japan (Central and Southern)
Illustrations:
Type: Japan, cult., Morrow & Williams, n.v.
Synonymy: Azalea serpyllifolia A. Gray, Perry Jap. Exped.2: 315 (1857). Rhododendron serpyllifolium var. albiflorum Makino, Bot. Mag (Tokyo) 22:57 (1908). Described from the western mountains of Japan.
Occurs in Countries: JP Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: rose
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):129
Shrub to 3m. Twigs rounded, green, 2–3mm in diameter, sparsely to sub-densely covered with flat, pale brown scales; internodes 4–10cm. Leaves 4–6 together in tight pseudowhorls, sessile or sub-sessile. Blade 80–175 x 24–50mm, elliptic; apex gradually or abruptly acuminate, acute or broadly acute; margin entire, flat, often red; base broadly tapering to rounded or sub-truncate, occasionally slightly cordate, often with conspicuous ‘ear-like’ folds at the base; sparsely scaly and quickly glabrescent above, persistently and more densely scaly beneath. Scales small, irregularly shallowly lobed with dark centres, slightly impressed, remaining brownish punctate after the scales have gone. Mid-vein wide, as thick as the petiole at the base, raised above for the proximal ½–¾, impressed in a broad shallow groove beneath; lateral veins 10–13 per side, spreading at an acute to a wide angle, straight below, curved distally, indistinctly anastomosing, very slightly raised above, smooth and often obscure beneath, reticulation mostly obscure. Petiole 2–4 x 2–4mm, without a groove, densely scaly. Flower buds (see p.327) ovoid, to 35 x 18mm, pale green or sometimes flushed with pink, outer bracts standing out away from the bud, the larger ones with deeply channelled sub-subulate points. Bracts almost totally glabrous outside, with a minute fringe of fragile marginal scales, glabrous inside, ovate to ovate-long-acuminate. Bracteoles to 15 x 2mm, sub-filiform, glabrous. Inflorescence an open to full umbel of 5–10 semi-erect to horizontal, pale yellow, scentless flowers. Pedicels 25–30 x 1–1.5mm, laxly-scaly, without hairs. Calyx c.4mm in diameter, oblique, rim-like, obscurely lobed. Corolla 25–50 x 41–50mm, broadly funnel-shaped; tube 20–22 x 8–9 x 17–18mm, glabrous outside and laxly hairy inside, base deeply sulcate; lobes 20–30 x 15–22mm, reflexed to the perpendicular or beyond, overlapping 1⁄3–½, obovate. Stamens exserted to c.15mm, irregularly arranged around or mostly on the lower side of the mouth, sub-equal; filaments linear and densely sub-patently hairy in the proximal ¼, glabrous distally; anthers c.4 x 1.3mm, broadly oblong, cream coloured. Disc prominent, deeply lobed, glabrous. Ovary 5–7 x 2.5–3mm, cylindrical, narrowed towards the base, sub-glabrous, with just a few scattered scales and sometimes with a few hairs near the base, abruptly contracted distally; style 12–28mm, glabrous, lying on the lower side of the tube, curving upwards distally as the stigma becomes receptive; stigma 3–4mm in diameter, rounded. Fruit 35–40 x 8–10mm, sub-cylindrical.
Habitat: Terrestrial, or rarely epiphytic, in open primary or secondary forest, roadsides and crater sides, locally common.
Distribution: Indonesia, Sumatra, Tapanuli, East Coast, West Coast.
Altitude: 1100-1980m
Latin – sessili – sessile; folium – leaf. The rhododendron with the sessile or stalk-less leaves.
Sleumer (1966) mentions plants with light orange or possibly also red flowers. These have not been evident in extensive field work in Sumatra recently but may occur and may indicate hybrids (see R. beccarii and R. perplexum). David Binney in New Zealand grows two distinct forms: a large-flowered and a small-flowered. They differ mainly in the size of the corolla lobes, which are 30 x 22mm vs. 20 x 15mm, but the overall flower size and tube length are also slightly different. This species is easy to grow and has good clear pale yellow flowers, mostly in April–May, in Edinburgh, but it can flower at any time and usually flowers more than once a year. It occurs at relatively low altitude and although plants in Edinburgh have not displayed symptoms of cold in the winter it might be expected to be a relatively heat tolerant species in cultivation.
Type: Heusser 1, 17 Dec. 1930. Sumatra, Near Prapat, Road to Pangulubao (Pengkulu Bao), 1600m (BO).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:251
Small, intricate shrublet to 0.3 m; young shoots densely lepidote and conspicuously loriform-setose. Leaves elliptic, oblong or obovate, 10-15 x 6-8 mm, rounded to the very obtuse though mucronate apex, ± rounded to the base; upper surface dark green, persistently lepidote with golden, ± vesicular scales, occasionally loriform-setose, margins loriform-ciliate, lower surface pale green, slightly papillose, densely lepidote with dimorphic scales, vesicular and golden, and flat, broadly rimmed, pale to dark brown. Inflorescence 1-3-flowered, pedicels lepidote and filiform-acicular pubescent, 4-10 mm. Calyx lobes 5-8 mm, oblong-orbicular, obtuse, lepidote, sometimes loriform-ciliate. Corolla purple or pinkish, openly funnel-shaped, 15-18 mm, tube 7-8 mm, pilose inside the tube, glabrous outside. Stamens 10, exserted, filaments pubescent towards the base. Ovary lepidote and filiform-acicular pubescent towards the apex, style exceeding the stamens, glabrous and elepidote. Capsule lepidote, oblong-cylindric, up to 5 mm.
Habitat: Open hillsides and slopes
Distribution: Nepal, India (Sikkim, W Bengal), Bhutan, China (S Xizang—Chumbi valley only)
Altitude: 3650-4550m
Type: Habitat in Alpe immense nivosa Gossain than Nepalensium dicta, Wallich'
Occurs in Countries: BT, CN, IN, NP Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: pink
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):109
Large shrub or small tree, 4.5-6m; young shoots stipitate-glandular, also with a mealy tomentum. Leaves obovate, c.7.5 x 4cm, 1.9 x as long as broad, apex rounded, minutely apiculate, base rounded, upper surface glabrous, lower surface densely fulvous-tomentose; petioles c. 1.5cm, glabrous when mature. Inflorescence 4—5-flowered; rhachis c.3mm; pedicels c.lOmm, glabrous. Calyx 3-5mm, glabrous, lobes broad and rounded. Corolla funnel-campanulate, deep carmine, with darker nectar pouches, 35—40mm. Ovary glabrous. Capsule c. 13 x 7mm.
Distribution: China (S Xizang)
Altitude: Around 4000m
Illustrations:
R. sherriffii closely resembles R. thomsonii subsp. lopsangianum (subsection Thomsonia), particularly in the lax inflorescence and in the deep red flowers. The latter does however differ in its glabrous, strongly papillate lower leaf surface.
The fulvous lanate leaf indumentum of R. sherriffii effectively excludes it from subsection Thomsonia and suggests an affinity with R. fulgens.
Type: China, S Xizang, Chayul Chu, Lung, 12500ft, 29 iv 1936, Ludlow & Sherriff 1390 (holo. BM; iso. A, E)
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: carmine
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):416
Very similar to R. chariiopes, differing as follows: leaves narrowly elliptic to narrowly obovate, 32-40 x 15-16 mm; corolla (only one poor specimen available) c. 11 mm, yellowish flushed pink; style puberulent over the whole of its length
Habitat: Open cliffs and grassy slopes
Distribution: China (SW Yunnan)
Altitude: 3050-3350m
This species is known from only (wo collections, the type and Forrest 24154. There is only one poor flower available on the sheets, but it shows quite clearly that the corolla is totally elepidote and not 'densely to moderately scaly'as described by Cowan & Davidian (Rhodo. Yearbook 3: 87, 1948). This characteristic must have been described from material cultivated as R. shweliense; all such material that 1 have seen is either R. glaucophyllum or a hybrid of it. ( A plant from Rowallane seen for the first lime this year (1980) may prove to be genuine R. shweliense.)
Type: China, Yunnan, Shweli/Salween Divide, 10-11000 ft, vi 1919, Forrest 18151 (holo. E)
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m Subgenus: Rhododendron Habit: Non-Tree
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):143
Shrub or small tree, 3-9m. Leaves oblanceolate to narrowly (rarely broadly) elliptic, (9—)16—23 x 4-6.3cm, (2.5-)3-5 x as long as broad, apex acute to rounded, apiculate, base rounded to attenuate, upper surface glabrous, lower surface with a buff to silvery, sometimes ± shining, compacted and agglutinated indumentum; petioles 2-2.5cm, ±terete, glabrous when mature, Inflorescence 12-20-flowered; rhachis 50-60mm; pedicels 25-35 mm, brownish-tomentose. Calyx c. 1mm, tomentose. Corolla 8-lobed, ventricose-campanulate, cream to clear yellow, sometimes with a red basal blotch, 30-40mm. Stamens 16. Ovary densely rufous-tomentose. Capsule 25-30 x 10mm, straight or curved.
Habitat: Thickets, mixed forests
Distribution: NE Upper Burma, China (adjacent parts of W Yunnan)
Altitude: 2500-3700m
Illustrations:
Allied to R. grande and R. sinogrande though with narrower leaves
Type: NE Upper Burma, Tamgam, v 1912, Abbay 5 (holo. E)
Occurs in Countries: CN, MM Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: cream, red, yellow
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):246
Shrub, 1-7 m. Young growth brownish. Leaves broadly elliptic to elliptic, rarely obovate or ovate, 48-84 x (16-)24-32 mm, apex acute, base cuneate (rarely with rounded apex and base on fast-growing extension shoots), ± elepidote above, with a dense covering beneath of large, flat, broadly rimmed scales (the darker centre making up less than Vi the diameter of the scale), 1-2 x their own diameter apart. Inflorescences very dense and crowded, coalescing into a many-flowered compound inflorescence, pedicels lepidote, 5-11 mm, the outer ones recurved, particularly in fruit. Corolla white or pinkish violet, 18~22(-25) mm, elepidote outside. Capsule 11-14 mm
Distribution: China (C & S Yunnan, Guizhou). Open ridges and dry, wooded hills, 840-2100(-2600) m
Illustrations:
Very similar to R. tatsienense but occurring well to the south and at lower altitudes; differing mainly in the size of the leaves and the nature of the scales as well as the compound inflorescence, which is usually clearly developed. A few specimens (Forrest 20490, 20468 and Ten 444) are intermediate between the two species.
Type: (Syntypes) China, Yunnan, Yunnansen, Detavay (holo. P—n.v.); Mitsao et montagnes de Yunnansen, Ducloux 122 & 123 (holo. P—n.v., iso. E); Tsekou, Soulie 1013 (holo. P—n.v.)
Synonymy: R. rubro-punctatum Leveille & Vant., Feddes Rep. 9:448 (1911). Type: China, Kouy tcheou, Pin-fa, 1908, Cavalerie (holo. E). R. leucandrum Leveille, ibid. 12:103 (1913). Type: China, Kouytcheou, Kiao-tche che, 1902, Cavalerie 1254 at least in part (E). R. jahandiezii Leveille, ibid. 13:340 (1914). Type: China, Yunnan, flancs du lo chan, 3200 m, v 1913, Maire (holo. E). R. ioanthum Balfour f., Notes R.B.G. Edinb. 13:270 (1922). Type: China, Yunnan, Maire (holo. E). R. obscurum [Franchet ex] Balfour f., op. cit.: 278. Type: China, Yunnan, prope Yunnansen, 4 iii 1891, Delavay (holo. P, iso. E)
Occurs in Countries: CN Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: pink
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):67
Shrub or tree, 1.5-8m; young shoots ± densely rufous- to white-stellate-tomentose and glandular. Leaves elliptic to oblanceolate, (7—)10—15 x 2.8-6cm, 2-2.5 x as long as broad, apex rounded, apiculate to acute, base rounded, both surfaces ± glabrous when mature; petioles l-2cm, soon glabrous. Inflorescence 5-15-flowered; rhachis up to 27mm; pedicels 17-30mm, brownish stellate-tomentose. Calyx c.2mm, lobes fleshy, glabrous though with sessile glands on the margin. Corolla campanulate, nectar pouches lacking, white to pink, with or without a purplish basal blotch, 35 -50mm. Ovary densely to very sparsely brownish stellate-tomentose, also sometimes with sessile glands. Capsule 20-30 x 3-4mm, strongly curved.
Habitat: Forests, alpine slopes
Distribution: China (SW Sichuan)
Altitude: 3700-4550m
Originally assigned to subsection Parishia on account of its stellate indumentum but otherwise more closely resembling species in subsection Maculifera, especially in flower characters.
5*. R. exquisitum T. L. Ming, Acta Bot. Yunnanica 3: 121, t.3 (1981), non Hutchinson (1932). Type: China, NE Yunnan,'Luquan Xian, Wumeng Shan, 3500m, 24 v 1952, Mao, P. I. 994 (holo. Herb. Inst. Bot. Kunming). Differs from the closely allied R. sikangense in the floccose rufous indumentum that apparently persists on the underside of the leaves towards the base, the stellate-tomentose young shoots and pedicels, and the corolla with a well-marked blotch as in R. sikangense. china (NE Yunnan), 35O0-45O0m. Known from several specimens, all from NE Yunnan. Almost certainly synonymous with R. sikangense; the significance of the floccose stellate indumentum on the leaves is not known though this is not found on any of the material of R. sikangense. The species was originally wrongly placed in subsection Taliensia from which it may be excluded by its stellate indumentum.
Type: China, Sichuan, Erh-lang-shan, Tien-chuan hsien, 7 vii 1951, Hu, W. K. & Ho, C. 10255 (holo. SZ)
Synonymy: R. cookeanum Davidian, Rhododendron Yearbook 16: 105 (1961). Type: China, SW Sichuan, Muli, Muti Konka, 12000ft, v-vi 1932, Rock 23698 (holo. E). lc: Acta Phytotax. Sinica 2: 81, t.7 (1952).
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: pink, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):271
Shrub; young shoots covered with adpressed-strigose hairs. Leaves monomorphic, coriaceous, oblong to ovate-oblong, 0.4-1.4 x 0.2-0.6cm, 2-2.2 x as long as broad, apex apiculate, base cuneate, upper surface sparsely adpressed-hirsute, lower surface adpressed-hirsute, with a densely pilose midrib; petioles not known. Inflorescence 2-3-flowered; pedicels c.lOmm, ± pilose. Calyx with linear-lanceolate, ciliate lobes, c.4mm long. Corolla campanulate, red, c.20mm. Stamens 4-6, unequal, filaments sparsely hirsute. Ovary densely hirsute; style glabrous. Capsule not known.
Distribution: Taiwan
Resembles R. rubropilosum, R. nakaharai and R. noriakianum but differs in having fewer stamens. We have seen no material of this species.
Type: Taiwan, Mt Sikayotaiz;an, 1936, Mori s.n., n.v.
Occurs in Countries: TW Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: red
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):125
Shrub, 2—6m. Leaves narrowly elliptic to broadly oblanceolate, 7—14.5 x 1.8—4.5cm, 2.5-4 x as long as broad, apex rounded to acuminate, upper surface glabrous, lower surface with a thin compacted whitish indumentum, lacking a surface film; petioles 1.5-2cm, floccose-tomentose at first, soon glabrescent. Inflorescence lax, 4-7-flowered; rhachis 5-15mm; pedicels 20-35mm, whitish to rusty floccose-tomentose. Calyx 1—2mm, floccose-tomentose, lobes minute. Corolla open-campanulate, pink with a few darker flecks, 25-35mm. Ovary rufous stellate-tomentose and shortly stipitate-glandular; style glabrous or with a few glands at base. Capsule 10-20 x 6mm, cylindrical, ± curved.
Habitat: Rocky slopes, etc.
Distribution: S & E China (from Sichuan & Guangxi to Zhejiang), HONGKONG.
Altitude: 600-1000m
Illustrations:
From the specimens seen there appears to be a complete range of variants with respect to leaf shape, from those with acute apices to those with rounded apices. The former are typical of R. fokiense and the latter of R. simiarum in the strict sense. The specimen seen from Hong Kong (Tang 490) is extreme in its oblong leaves and in the styles that are glandular for half their length.
Type: China, Guangdong, Lofaushan, 3200ft, Henry (Hance 2205) (holo. BM)
Synonymy: R. fordii Hemsley, Kew Bull. 1894: 5 (1894). Type: Hongkong, Lantow Island, Ford 111 (holo. K; iso. A). R. fokiense Franchet, Bull. Soc. Bot. France 44:210(1899). Type: China, Fujian, Kuatan, 1898, Latouche (iso. E). R. versicolor Chun & Fang, Acta Phytotax. Sin. 6: 172, t.43 (1957). Type: China, Guangxi, Hungtan, Tatan Kou, 850m, 11-13 iv 1955, Kwangfu Exped. 61 (holo. Hb. Inst. Bot. Guangzhou).
Occurs in Countries: CN Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: pink
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):320
Much-branched twiggy shrub, l-3m; young shoots densely covered with adpressed flattened shining brown strigose hairs; bud scales viscid on inner surface. Leaves dimorphic, chartacerous; spring leaves ovate-lanceolate to linear-elliptic, 3-7 x (0.6-)l-2cm, (2-)2.5-4(-7) x as long as broad, apex acute, base cuneate, margin entire, upper surface sparingly adpressed-strigose, lower surface paler, more densely strigose, especially on the midrib and veins; summer leaves elliptic to oblong-elliptic, 10-20 x 5ó10mm, apex often rounded, otherwise as for spring leaves; petioles 3-6mm, covered with adpressed red-brown strigose hairs. Inflorescence 2-6-flowered; pedicels 5-10mm, densely strigose. Calyx strigose; lobes ovate-lanceolate, 3-7mm, ciliate, apex blunt. Corolla broadly funnel-shaped, 25-60mm, white to dark red, upper lobes with darker flecks; tube 7-33mm, glabrous. Stamens (8-)10, as long as corolla, filaments pubescent below middle. Ovary densely strigose; style strigose at base. Capsule 5-10mm, strigose.
Occurs in Countries: CN, JP, MM, TH, TW Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: carmine, red, rose, white
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):115
Corolla white to rose-pink, 25-40mm long
Habitat: Forest margins, etc.
Distribution: Ne Upper Burma, China (Yunnan)
Altitude: 1800-2700m
The purple-flowered R. bellum from Guangxi Province will probably key down to R. simsii.
Close to var. simsii but with a more restricted distribution; differing in its generally smaller and paler flowers.
R. simsii is cultivated widely in the warm temperate parts of E Asia and many cultivars are known. R. vittatum (Fortune) Planchon (R. simsii var. vittatum (Fortune) Wilson) is one of these cultivated forms with flowers white striped lilac-purple, occasionally with individual flowers that are pure white or lilac-purple.
Type: Lectotype: China, Yunnan, Jang-tzow Shan, Shweli-Salween Divide, 2500m, v 1919, Forrest 17914 (holo. E).
Corolla rich red to carmine, 35-60mm long
Habitat: Open woodland, amongst scrub, often near water
Distribution: Ne Upper Burma, China (widespread in W, C, S & E), Hongkong, S Taiwan, Laos, Thailand, S Japan (Ryukyu Is.).
Altitude: 600-2700m
We can see no reason for maintaining R. viburnifohum as distinct from var. simsii.
The type of R. bicolor has relatively small flowers but within the range of var. simsii. The bicoloured nature of the stamens mentioned in the type description may by an artifact due to drying conditions.
R. annamense is a narrow-leaved form (leaves 4-7 x as long as broad) that occurs sporadically with the typical broad-leaved form in Laos, Vietnam, S China, and NE Burma (Kingdon-Ward 1792, 3007, 5568, 6607 & 22036). This form is not formally recognized as there is no clear demarcartion between it and var. simsii sensu stricto.
There is some doubt as to the identity of the type of R. simsii as the plate cited is atypical in its narrowly lanceolate calyx lobes and in its hairy corolla. It is not clear whether the type had a spreading or adpressed indumentum on its young shoots. However, in other respects it matches our concept of var. simsii.
Synonymy: R. indicum Sweet var. ignescens Sweet, Brit. Fl. Garden ser. 2,2: t.128 (1833). Type: the plate cited, painted from a specimen that originated from China. R, calleryiPla.nch.on, Fl. des Serres 9: 81 (1854). Syntypes: China, Gallery 50, 150 (P, n.v.); Fortune 72 (P, n.v.). R. indicum Sweet var. simsii (Planchon) Maxim. Rhododendr. As. Orient. 38(1870). R. indicum Sweet var.formosanum Hayata, Icon. PI. Formosan. 3: 134 (1913). Type: Taiwan, Kusukusu, iii 1898, C. Owarari, n.v. R. annamense Render, J. Arnold Arb. 10:182 (1929). Type: Vietnam, prov. Thua-Thien, Hue, i-iv 1927, Squires 94 (iso. BM, E,K). R. bicolor P.X.Tan, Survey Gen. Rhododendron S. China 101 (1983). Type : China, Guangdong, Conghua Xian, Rui-tin, 16 iii 1973, S.Q. Chen (SM. Chun) 18492 (holo. IBSC). R. viburnifolium W.P. Fang, Acta Phytotax. Sin. 21: 469 (1983). Syntypes: China, Sichuan, Hejiang, Fubaolinchang, Jiaozi Shan, 680-l750m, 20-25 v 1981, D.W. Liao et al. 1-63 (syn. SZ); 3-28 (syn. SZ); 4-2, n.v.
Shrub to 70cm. Twigs 1.5–2mm in diameter, rounded, tips densely covered with stalked scales, older parts glabrescent, densely warty and rough; internodes 2–6cm. Leaves crowded at the tips or 3–5 together in pseudowhorls. Blade 15–20 x 6–10mm, narrowly elliptic to elliptic or sub-obovate-elliptic; apex shortly acuminate, broadly acute, with a very small terminal gland; margin cartilaginous, distinctly revolute, especially proximally; base tapering and decurrent, the extreme base often sub-truncate; glabrescent above when mature; sub-densely scaly beneath. Scales angular or lobed, flat; centre small, slightly elevated on small protrusions. Mid-vein impressed above; thick and strong proximally beneath, gradually narrowed distally; lateral veins inconspicuous. Petiole 2–3 x c.1mm, nearly rounded. Flower buds to 18 x 8mm, narrowly ovate, narrowly acute, the subulate points to the bracts standing slightly out. Bracts to 20 x 6mm, membranous, outer ones subulate, inner ones ovate-acuminate, apex subulate, glabrous and glossy. Inflorescence 2–4-flowered. Pedicels c.15mm, thick, densely covered with reddish stellate scales, without hairs. Calyx c.3mm in diameter, obliquely disc-shaped, red, shortly irregularly 5-lobed, scaly outside. Corolla c.25mm, tubular below, funnel-shaped distally, fleshy, red, with a few scales, or glabrous outside, glabrous inside; tube 16–20 x c.5 x 7–10mm, straight, base lobed; lobes 7–10 x 7–10mm, spreading, broadly obovate or sub-circular. Stamens sub-equal, 22–24mm long; filaments linear, glabrous; anthers 2–2.5 x 1mm, ellipsoid. Disc very prominent, glabrous. Ovary c.5 x 2.5mm, sub-ovoid-cylindrical, densely reddish-brown-stellate-scaly, gradually tapering distally; style c.17mm, glabrous; stigma thick-obconical, distinctly 5-lobed. Fruit 20–23 x 6mm, sub-cylindrical, the thin valves twisted.
Distribution: Indonesia, New Guinea (W), Mt Doorman, on steep open slopes with rocks.
Altitude: 3300-3500m
Latin – simulans – imitating or resembling, presumably due to the resemblance to R. wrightianum.
Not recently recollected and never cultivated.
Type: Lam 1622, 17 Oct. 1920. New Guinea (N), Doormantop, 3300m (BO, L).
Synonymy: R. simulans J.J.Sm. ex Lam, Nat. Tijd. N.I. 1929. 89: 95, 99, 133, 134 nom. nud. R. wrightianum Koord. var. ovalifolium J.J.Sm., Nova Guinea 1936. 18: 94, pro parte.
Occurs in Countries: CN, ID Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:230
Tree, to 7m. Leaves broadly obovate, 17-28 x 11.8-16cm, 1.5-1.8 x as long as broad, apex rounded, apiculate, base + cuneate, upper surface glabrous, rugulose, lower surface with a unistrate or bistrate indumentum, the lower layer (when present) compacted, the upper layer dense, light brown, composed of moderately fimbriate, broadly cupular hairs; petioles terete, up to 5cm, sparsely tomentose. Inflorescence c.lO-flowered; rhachis c.8mm; pedicels c.30mm, lanate-tomentose. Calyx c.3mm, lobes rounded, sparsely tomentose. Corolla 8-lobed, obliquely campanulate, pale yellow, 50-60mm. Stamens 16. Ovary densely fulvous lanate-tomentose. Capsule not known.
Distribution: China (SE Yunnan) & adjacent parts of n Vietnam
Most of the material seen has a unistrate indumentum, often with narrower cupular hairs than are present on the type, which has a bistrate indumentum. Probably allied to R. falconeri.
Type: S Yunnan, Mangtsz, 9000ft, Henry 9449 (holo. E; iso. K).
Occurs in Countries: CN Subgenus: Hymenanthes Habit: Tree Fl. Colour: yellow
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):260
Tree, 6-12m. Leaves oblanceolate to broadly elliptic, 20-60(-70) x 8-28(-30)cm, 2.2-2.8 x as long as broad, apex rounded or retuse, minutely apiculate, base rounded, upper surface glabrous, lower surface with a silvery compacted and agglutinated indumentum; petioles 3-5cm, with a silvery agglutinated indumentum. Inflorescence 15-20-flowered; rhachis 30-65mm; pedicels 30-60mm, densely villous-tomentose. Calyx c. 2mm, lobes minute, triangular, tomentose. Corolla 8-10-lobed, ventricose-campanulate, pale creamy white with a crimson blotch at base, 40-60mm. Stamens 18-20. Ovary densely rufous-tomentose. Capsule 40-70 x 14-17mm, slightly curved.
Habitat: Mixed forests
Distribution: NE Upper Burma, China (W Yunnan, SE Xizang)
Altitude: 2450-4250m
Illustrations:
Plants, that have been referred to R. sinogrande var. boreale, with smaller, more coriaceous leaves, occur in the northern part of the species'range and at higher altitudes. These differences probably represent minor habitat modifications.
Type: China, Yunnan, Western flank of the Shweli/Salween divide, 11000 ft, viii 1912, Forrest 9021 (holo. E)
Synonymy: R. sinogrande Balfour f. & W. W. Smith var. boreale Tagg & Forrest, Notes R.B.G. Edinb. 15: 119 (1926). Type: China, SE Xizang, Tsarong, W of Chamatong, Salween/Kiu-chiang divide, 13000 -14000ft, vi 1922, Forrest 21705 (holo. E).
Occurs in Countries: CN, MM Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: cream, crimson, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):245
Shrub, 1—4m; young shoots whitish lanate-tomentose, with a few scattered glands. Leaves oblanceolate to elliptic, 7.5-11.5(-14) x 2.5-3.2cm, 2.8-4.5 x as long as broad, apex usually rounded or occasionally ± acute, base cuneate, upper surface glabrous when mature, lower surface with a dense white to cinnamon indumentum; petioles 1 —1.5cm, densely lanate. Inflorescence 7—15-flowered; rhachis 20(-40)mm; pedicels densely stipitate-glandular, also with a sparse floccose indumentum, 30—35mm, apparently hardly elongating in fruit. Calyx 2-3mm, lobes broadly triangular, sparsely stipitate-glandular. Corolla funnel-campanulate, pink with yellowish flecks, 35-40mm. Ovary densely white-strigillose, eglandular. Capsuled5 X 5mm.
Habitat: Under Pinus, Rhododendron scrub
Distribution: NE Turkey & adjacent USSR (Georgia)
Altitude: 500-2300m
Illustrations:
Map in Grossgeim, Fl. Kavk. 7: Map 158 (1967)
Closely allied to R. ungernii and apparently hybridising with it and with R. caucasicum.
Type: NE Turkey, prope Artvin, distr. Batum, Smirnow (LE, n.v.)
Occurs in Countries: RU, TR Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: pink, yellow
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):312
Shrub or small tree, 2-7.5m; young shoots clothed with long stiff setae. Leaves elliptic to obovate-lanceolate, 8-13 x 2.7-4cm, 2-3.2 x as long as broad, apex acute to rounded, base rounded, upper surface glabrous, lower surface with a thin continuous layer of pale brown dendroid hairs, often becoming whitish with age, usually also with a few setae on the midrib towards the base; petioles l-2cm, densely covered with long gland-tipped bristles. Inflorescence dense, 15-20-flowered; rhachis short, c.5mm; pedicels 10-15mm, glandular-setose. Calyx fleshy, reddish, 5-10mm, lobes rounded, glanduiar-ciliate. Corolla fleshy, tubular-campanulate, scarlet to crimson, with darker nectar pouches, 30-45mm. Ovary with a dense rufous tomentum intermixed with long glandular hairs; style glabrous. Capsule c.15 x 4mm, straight.
Habitat: Mixed forests, etc.
Distribution: NE India (Sikkim, Arunachal Pradesh), Bhutan, China (S Xizang)
Altitude: 2700-3600m
A variable species allied to R. exasperatum and R. barbatum. Some forms approach the former species in their broad ± bullate leaves with cordate bases. These have been referred to R. argipeplum. I have not seen the type of R. smithii, though, from the plate cited above, R. argipeplum is apparently synonymous with that species.
The narrower-leaved forms of R. smithii tend to be less markedly bullate and are more common in the west, especially in Sikkim. These are apparently closer to R. barbatum and are possibly of hybrid origin.
Type: NE India, Arunachal Pradesh, 'Bhutan', Lablung Pass, Booth, n.v.
Synonymy: R. argipeplum Balfour f. & Cooper, Notes R.B.G. Edinb. 9: 213 (1916). Type: Bhutan, Pumthang, 11000ft, 5 vii 1915, Cooper 4115 (holo. E).
Occurs in Countries: BT, CN, IN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: crimson, scarlet
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):381
Erect shrub, sprawling, one- or few-stemmed, to 1.5m. Twigs covered with dense dark-brown, stellate scales, which disappear quickly in the wild; internodes 4–7cm. Leaves 4–6 together in pseudowhorls. Blade 65–120 x 35–60mm, broadly elliptic, or elliptic, sometimes sub-obovate-elliptic; apex rounded or broadly obtuse occasionally slightly retuse, often very shortly mucronate; margin slightly sinuate, flat or weakly recurved; base broadly tapering to rounded; mature leaves glabrescent above, remaining scaly for longer below especially on major veins. Scales dendroid, with the marginal zone stellately divided; the small centre deepened and protracted downwards into a short foot, which sits on top of an epidermal tubercle. Mid-vein raised and rapidly tapering for 10–15mm above, then becoming grooved and impressed for the remainder of the proximal ½, finally narrowly impressed distally to the apex; beneath very strongly raised throughout its length; lateral veins 7–9 per side, irregular and often deeply forked, wide-spreading, anastomosing quite a distance before the edge, dissolving into a coarse network of veins, all veinlets deeply impressed above, sharply prominent beneath, the leaves distinctly rugose, dark green above, yellowish-green below. Petiole 10–20 x 3–4mm, not or sometimes very weakly grooved above, densely brown-scaly initially, often becoming pink with age as the scales disappear. Flower buds to 20 x 12mm, ovoid, densely brown scaly, the outermost bracts spreading out, others appressed. Bracteoles 10–15 x 1–2mm, linear to sub-spathulate, with a fragile scaly fringe. Inflorescence of 4–6 flowers in an open or one-sided umbel. Pedicels c.15 x 1mm, densely brown-scaly. Calyx c.3mm in diameter, obliquely rimmed, the lobes sometimes elongate. Corolla 50–80 x 40–45mm, trumpet-ventricose, expanded towards the lobes, white; tube 40–75 x c.4–6 x c.7–12mm, curved, densely brown, stellately scaly outside, densely covered with retrorse hairs inside; lobes c.15–20 x 15–20mm, obovate-spathulate, scaly outside, except near the margins. Stamens c.50mm, at first clustered on the lower side of the mouth becoming exserted from the throat to c.10mm, and irregularly spreading; filaments linear, laxly hairy in the proximal ¾, glabrous distally; anthers 3–3.5mm, oblong, the base obtuse. Disc glabrous below, hairy on the upper margin. Ovary c.10 x 2.5mm, sub-cylindrical, densely covered with yellowish hairs and scales, tapering gradually distally; style densely to laxly hairy and scaly in the proximal ¾, glabrous distally, lying on the lower side of the tube and becoming exserted to 20mm. Fruit c.30 x 7mm, fusiform, the valves irregularly twisting and the placentae breaking away from the central column at the top. Seeds variable, 3.5–5mm, without tails c.1mm, the longest tail to 2.4mm, the tails often broad with irregularly divided margins, crimped especially distally.
Distribution: Papua New Guinea, Morobe District, Edie Creek and Merri Creeks; common on Mt Kaindi. At present known only from this very small area. Growing terrestrially on eroded gold workings, on open, Vaccinium shrubbery and grass-covered slopes
Altitude: Around 1850m
Latin – solitarius – by itself, alluding to the rare, solitary nature of the original find.
Type: Womersley & Thorne NGF 12253, June 1960. New Guinea (E), Morobe District, Edie Creek (L, LAE).
Occurs in Countries: PG Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:99
Shrub. Twigs rounded, c.2mm in diameter, smooth, laxly covered with rounded, sessile scales, older parts glabrescent. Leaves arranged up to 5 together in pseudowhorls, very variable. Blade 25–45 x 10–20mm, obovate; apex rounded to minutely emarginate and with a small apical gland; margin very slightly revolute; base narrowly tapering and partly decurrent; above dark green becoming glabrescent, below paler and laxly scaly. Mid-vein distinct, impressed above and raised below; lateral veins 2–3 per side, curved, impressed above, slightly raised beneath. Petiole 3–5 x 1.5–2mm, flattened. Bracts to 10 x 5mm, the outer shortly ovate and obtuse, long-hairy outside, with the margin densely white ciliate; the inner narrowly ovate with longer sub- acuminate apices. Inflorescence of solitary flowers or rarely in pairs. Pedicels densely scaly, without simple hairs, at flowering 15–20mm. Calyx c.3mm in diameter, oblique, with obtuse lobes to 1mm, frequently indistinct. Corolla c.14mm long, colour not recorded but presumably yellow, tubular-campanulate; tube c.8 x 4mm, shortly cylindrical, outside densely scaly, inside white-hairy; lobes 6–7 x c.4mm, spreading, obovate, outside laxly scaly, inside glabrous. Stamens dimorphic, 8 and 10mm long; filaments linear, flattened, at the base glabrous, in the middle part white-hairy, the upper part glabrous; anthers c.3 x 0.7mm. Disc glabrous. Ovary c.5 x 2.5mm, conical, strongly contracted distally, densely scaly; style columnar, club-shaped above, glabrous; stigma truncate, rounded. Fruit (immature) c.17 x 3mm, with a thick persistent glabrous 5–6mm style.
Distribution: Vietnam, Province Lao-Kay, on the summit ridge of the Chaa-pa, massif de Fan-Si-Pan
Altitude: 1400-1700m
Latin – soror – of the sisters, presumably referring to the closely related species in this group.
Flowers July
Differing from R. emarginatum in the smooth not rough twigs, a slightly longer corolla (14mm vs. to 12mm in R. emarginatum) and having thicker pedicels. This appears to be doubtfully distinct from R. emarginatum. The type material in Paris has minute protruding scale bases on the very youngest twigs and the other differences between these species do not seem particularly significant. There is however one herbarium specimen in Edinburgh (Y. Tsiang 4698) from Na-kan, Chengfeng, Kewichow with smooth twigs, fruits with long-tailed seeds and distinctive leaves that unfortunately has no flowers but could represent this species, or an undescribed one. However, Keith Rushforth is growing material from Vietnam which is said to be more erect and vigorous than R. emarginatum and has almost completely smooth vegetative stems. These plants have short flowering stems that are distinctly rough with scale bases and they would appear to conform to R. sororium.
Type: Pételot s.n., July 1931. N Vietnam, Prov. Lao-Kay, environs de Chaa-pa, massif de Fan-Si-Pan (P)
Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:32
Shrub, 1.2—5m; young shoots glabrous or glandular. Leaves broadly ovate, 5.5-8 x 3.5-4cm, 1.4-2 x as long as broad, apex rounded, apiculate, base rounded to cordate, upper and lower surfaces glabrous; petioles l,5-2.3cm, glabrous or sparsely stipitate-glandular. Inflorescence lax, 3-5-flowered; rhachis c.3mm; pedicels 1.5-2.5cm, with a sparse covering of subsessile glands. Calyx 3-8mm, lobes rounded, glandular-ciliate. Corolla saucer-shaped, pale purplish-pink, 25-40mm. Ovary densely stipitate-glandular; style glandular to tip. Capsule 18—22 x c.6mm, slightly curved.
Habitat: Bouldery mountain summits
Distribution: China (Sichuan)
Altitude: Around 4500m
Illustrations:
Closely allied to R. wardii but distinguished by the more open corollas that are generally pale pink.
Type: China, W Sichuan, aux environs du Tatsien-lou (Kangding), Soulie 793 (E, K); 52, n.v.
Synonymy: R. cordatum Leveille, Bull. Geog. Bot. 24: 282 (1914). Type: China, NE Yunnan, sommet de Io-chan, 3400m, vi 1913, Maire (holo. E).
Occurs in Countries: CN Altitude Ranges: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):266
Tree, c.6m. Leaves coriaceous, oblanceolate, 9-11 x 1.3-4cm, 2.8-3.5 x as long as broad, apex acuminate, base ± cuneate, margin not undulate, upper surface glabrous, lower surface glabrous when mature though with red punctate hair bases overlying the veins; petioles 1.5-2cm, glabrous. Inflorescence 7-10-flowered; rhachis short; pedicels c.lOmm, sparsely stellate-tomentose. Calyx c.lmm, glabrous. Corolla probably open-campanulate, glabrous within, crimson, c.45mm. Ovary sparsely rufous-tomentose; style glabrous. Capsule not known.
Habitat: Forests, etc.
Distribution: China (SE Yunnan)
Altitude: Around 2300m
A species of doubtful affinities though there is a superficial resemblance to both R. irroratum and R. mengtszense, both of which occur near the type locality.
Type: SE Yunnan, Fung chen lin Mountains (nr Mengtsz), 7500ft, Henry 10853 (holo. E; iso. K).
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: crimson
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):293
Shrub to 1.5m. Twigs dark brown, slender, the upper internodes densely covered with stalked scales, rough with persistent stalks when the scales have gone, finally smooth; internodes 0.5–2cm. Leaves 3–7 together in well-marked pseudowhorls at the upper nodes. Blade 10–20 x 5–10mm, obovate-spathulate; apex rounded, mostly slightly retuse; margin flat or slightly revolute; base tapering, laxly impressed-scaly, becoming glabrescent and shining above, more densely and minutely scaly and dull beneath. Scales circular, marginal zone narrow, entire or nearly so; centre dark and thick, distinctly impressed, entire or minutely crenulate. Mid-vein mostly impressed above proximally, prominent beneath; lateral veins 3–4 per side, faintly impressed above and raised beneath, or almost invisible. Petiole c.2mm, scaly, slender. Bracts to 5 x 3mm, ovate, sub-acute, scaly outside distally, ciliate on the margins. Flowers solitary, or rarely in twos. Pedicels 6–8mm, slender, densely scaly, sometimes also minutely laxly hairy. Calyx oblique, very small, scaly, obscurely obtusely 5-lobed. Corolla 20–26mm, tubular, slightly dilated towards the mouth, zygomorphic and laterally compressed, straight, dark or orange-red; tube 18–22 x c.3 x 5–6mm, laxly scaly outside, glabrous inside; lobes 4–5 x 2.5–3mm, obovate, spreading, distinctly ciliate. Stamens unequal, exserted; filaments glabrous, linear; anthers 2 x 0.8mm, oblong. Disc glabrous. Ovary 2.5 x 1.5mm, broadly ellipsoid, densely scaly, without hairs, gradually tapering distally; style glabrous becoming long exserted; stigma rounded to indistinctly lobed. Fruit 7–8 x 2.5–3mm, shortly cylindrical or conical, densely scaly.
Habitat: Epiphytic in mossy forest or on moss-covered ground, said to be locally plentiful on Mt Kerbau
Distribution: Malaysia (W), Perak, Mt Kerbau; Pahang, Mt Siku, Ulu Telom.
Altitude: 1525-2135m
Latin – spathulatus – spatula-shaped, alluding to the shape of the leaves.
Type: Haniff SF 3973, May 1909. Malay Peninsula: Perak, G. Kerbau, 1525–2135m (SING, K, L, fragment).
Occurs in Countries: MY Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: orange
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:42
Shrub, l-2m; indumentum of young shoots densely whitish stellate-tomentose intermixed with long stipitate glands (rarely eglandular). Leaves elliptic, 5-9.5 x 1-2.6cm, 2.5-4(-8) x as long as broad, apex acute to rounded, base rounded, upper surface glabrous, lower surface with a dense but loose continuous whitish to cinnamon ramiform indumentum with glandular setae on the midrib, lower epidermis glaucous-papillate; petioles 1-1.5cm, densely tomentose, with some setulose glands. Inflorescence 4-5-flowered; rhachis 2-3mm; pedicels 15-20mm, setulose-glandular, also with a few stellate hairs. Calyx 2-3mm, with broad, coloured, rounded, glandular-ciliate lobes. Corolla fleshy, tubular-campanulate, crimson, 35-40mm. Ovary densely rufous-tomentose and stipitate-glandular, tapering into the glabrous style. Capsule c.15 x 6mm, curved.
Habitat: Amongst scrub and on cliffs
Distribution: China (NW Yunnan) and adjacent NE Upper Burma
Altitude: 3000-3650m
There is apparently some geographical separation between the two varieties, var. weihsiense generally having a more northerly distribution than var. sperabile.
Occurs in Countries: CN, MM Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: crimson
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):411
Leaf indumentum cinnamon when mature; leaves 2.5-3.5 X as long as broad.
Illustrations:
Three plants, Forrest 14195b, 15022 & 17222, all probably from NW Yunnan, lack the setulose glands and have an indumentum that is redder than is usual in R. sperabile. In these characters they show some affinity with R. floccigerum but the leaf shape and persistent indumentum are more typical of R. sperabile.
Type: NE Upper Burma, Hpimaw Pass, 10000ft, 7 v 1919, Farrer 888 (holo. E; iso. K)
Leaf indumentum whitish when mature; leaves 3-4(-8) x as long as broad.
Type: China, NW Yunnan, Mekong/Salween divide, 27° 12' N, 99°2'E, Forrest 25447 (holo. E)
Dwarf shrub, 1 —1.5m; young shoots stellate-tomentose, eglandular. Leaves elliptic, 5.5-6.5 x 1.8—2.5cm, 1.6—3 x as long as broad, apex blunt, apiculate, base rounded, upper surface glabrous, lower surface with a floccose ± unistrate, rufous, discontinuous ramiform to sub-rosulate tomentum, lower epidermis epapillate, green; petioles 0.5-lcm, slightly winged, floccose-tomentose, eglandular. Inflorescence 4-5-fIowered; rhachis minute; pedicels c.lOmm, sparsely stellate-tomentose. Calyx 4-7mm, cupular, lobes rounded, ±ciliate. Corolla fleshy, tubular-campanulate, crimson to deep red, 25-35mm. Ovary densely fulvous-tomentose, ± truncate to tapering into the glabrous style. Capsuled 3 x 3mm.
Habitat: Alpine scrub, rocky slopes
Distribution: China (SE Xizang)
Altitude: 3650-3950m
The ovary is apparently variable in the degree to which it tapers into the style, suggesting a transitional state between that found in R. neriiflorum and its immediate allies and that typical of the remaining species of the subsection.
Type: China, SE Xizang, Tsarong, Salween/Kiu-chiang divide, W of Chamatong, 12-13000ft, vi 1922, Forrest 21824 (holo. E).
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: crimson, red
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):412
Shrub, l-3(-7)m. Leaves broadly ovate-lanceolate, (6-)9-12 x 3.6-6.2cm, 1.7-2.3 x as long as broad, apex acute to apiculate, base rounded to ± cordate, lower surface with a dense bistrate indumentum that is usually rust-red, the upper layer lanate-tomentose, ramiform, felted, the lower compacted; petioles 1 -1.5cm, glabrescent. Inflorescence 10-20-flowered; rhachis 10-15mm; pedicels 10-15mm, glabrous when mature. Calyx 1.5-2mm, glabrous, lobes acute. Corolla white to pink, with purple flecks, 35-40mm. Ovary and style glabrous. Capsule 20-22 X 6-8mm.
Habitat: Thickets, open forests, etc.
Distribution: China (N Yunnan, SW Sichuan)
Altitude: 3350-4550m
Closely allied to R. simulans (q.v.) and to R. taliense
Type: China, SW Sichuan, mountains around Muli, Forrest 17360 (holo. E; iso. K).
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: pink, purple
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):343
Small tree; young shoots glandular-setose. Leaves elliptic, 7-11x3-4.2cm, c.2.5 x as long as broad, apex acuminate, base rounded, upper surface glabrous at maturity, lower surface with punctate hair bases persistent over the main lateral veins, with scattered setose glands towards the base and a thin indumentum, especially near the midrib; petioles 1 —1.5cm, glandular-setose. Inflorescence c. 8-flowered; rhachis 2-3mm; pedicels 25-30mm, glandular-setose. Calyx c. 10mm, lobes narrowly triangular, glandular-ciliate. Corolla funnel-campanulate, pink with a basal blotch, c.30mm. Ovary densely stipitate-glandular; style glabrous. Capsule ? unknown.
Habitat: Alpine woodlands
Only known for certain from the type, though two fruiting specimens, Kingdon- Ward 10959 and 13327, from SE Xizang and N Burma respectively, are a close match. Possibly a hybrid of a species in subsection Glischra. Further material is required before the status of R. spilotum is confirmed, especially as the origin of plants under that name in cultivation is not known; they almost certainly have no connection with the type.
Type: NE Upper Burma, Nyitadi, 9 v 1920, Farrer 1539 (holo. E; iso. K).
Subgenus: Hymenanthes Habit: Tree Fl. Colour: pink
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):429
Very like R. scabrifolium in general appearance, differing as follows: leaves large, ultimately glabrous above (though with filiform-acicular hairs persisting along the midrib and the bases of the setae persistent around the margins), calyx usually disc-like, unlobed, densely pubescent, the corolla ± erect, tubular to very narrowly funnel-shaped, filled with watery nectar, 17-23 mm, tube 11-17 mm, stamens and style exserted, filaments glabrous, capsule 11-17 mm.
Habitat: Thickets, (800-) 1800-2500 m
Distribution: China (C & S Yunnan)
Illustrations:
Very distinct in its pure form, but merging into R. scabrifolium in the northern part of its range. A most remarkable species, not likely to be confused with any other, presumably with a distinctive pollination syndrome.
Type: China, Yunnan meridional, dans le bois au dessus de Tonghay, Delavay 4883 (holo.P—n.v.; iso. E, K)
Synonymy: R. duclouxii Leveilie, Bull. Soc. Agr. Sarthe 39:46 (1903). Types: China, Yunnan, env. de Yunnansen, 24 ii & 2 hi 1897, Bodinier 115 (iso. E); ibid., 29 i 1897, Ducloux 61 (iso. E). R. fuchsiiflorum Leveille, Feddes Rep. 12:284 (1913). Type: China, Yunnan, montagnes arides de Mo-tsou, 800 m, v 1912, Maire (holo. E)
Occurs in Countries: CN Subgenus: Rhododendron Habit: Non-Tree
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):85
Shrub with rigid branches, to 40cm. Twigs 2–5mm in diameter, rounded, the tips densely stellately scaly, older parts rough; internodes 3–8cm. Leaves 3–5 together in pseudowhorls at the upper 1–2 nodes. Blade 20–40 x 12–25mm, ovate; apex shortly and obtusely acuminate; margin distinctly revolute; base rounded to cordate, almost sessile; youngest leaves densely reddish-brown, stellately scaly on both sides becoming smooth above but rough from the tuberculate scale bases below. Scales irregularly divided at the margin, dendroid, each on top of a small permanent paler-coloured tubercle. Mid-vein distinctly grooved and impressed above, prominently raised beneath; lateral veins up to 6 per side or obscure. Petiole 0.5–1 x 1mm. Bracts to 15 x 8mm, membranous; outer ones ovate, apiculate, with a prominent keel and scaly at the apex outside, otherwise glabrous apart from the fringe of scales; inner ones ovate-oblong to obovate or truncate-spathulate, glabrous. Bracteoles to 15 x 1mm, narrowly linear below, sub-spathulate at the apex, laxly hairy. Inflorescence a 3–5-flowered umbel. Pedicels 6–20 x 0.7–0.8mm, densely stellately scaly, not hairy at all. Calyx 3–5mm in diameter, disc-shaped, very shortly obtusely 5-lobed, wavy, scaly and sparsely hairy outside, ciliate. Corolla 25–45mm, broadly tubular, zygomorphic, pink; tube c.18–30 x 4–6 x 6–10mm, minutely stellately scaly and with a few hairs outside, sparsely sub-patently hairy inside, a little curved; lobes 8–13 x 8–10cm, obovate to sub-circular, half-erect to spreading, scaly outside in the proximal ½ except near the margins. Stamens as long as the corolla; filaments linear below, densely hairy in the proximal 1⁄3–½, glabrescent and filiform distally; anthers 2–3 x c.1mm, sub-obovate-oblong, the base very shortly appendaged. Disc glabrous. Ovary 4–6 x 2–4mm, ovoid-conical, densely yellowish hairy, the hairs pointing distally, and covering the scales, abruptly contracted distally; style densely hairy and sparsely scaly proximally, becoming more sparsely hairy and scaly distally eventually becoming glabrous for 6–8mm, as long as or a little longer than the corolla; stigma globose.
Habitat: Epiphyte on grassland tree-ferns
Distribution: Papua New Guinea, Mt Knutsford, Owen Stanley Range; Mt Victoria; Wharton Range, Murray Pass. Said to be a common epiphyte on grassland tree-ferns, at 2840m on the Murray Pass.
Altitude: Around 2840m
Greek – sphondulos – a vertebra; phyllum – leaf. Possibly the rigid branches looking like backbones.
Van Royen & Kores (1982) reduced R. cyatheicolum as a synonym under this name. Sleumer (1966) separated the species at couplet 32 (p.502) with R. cyatheicolum having longer flowers (more than 4cm vs. less than 2.8cm) and a leaf size difference which overlapped considerably. The shorter flowers of the R. spondylophyllum type specimen may well be at least partly due to poor preservation; otherwise the two descriptions are very similar and it seems safe to include R. cyatheicolum under R. spondylophyllum.
Type: MacGregor s.n., 1889. New Guinea (E), Owen Stanley Range, Mt Knutsford (MEL).
Synonymy: R. cyatheicolum Sleumer, Reinwardtia 1960. 5: 86.
Occurs in Countries: PG Altitude Ranges: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: pink
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:100
Shrub or small tree to 13 m high, young branches glabrous. Leaves glabrous; blade elliptic to oblanceolate, 60-140 x 20-45 mm, base broadly cuneate, apex acuminate, coriaceous; petiole 8-15 mm long. Inflorescence buds lateral, 3-5 (~8)-flowered, at the ends of leafy shoots; bud scales glabrous except for ciliate margin, caducous; pedicels 10-30mm long, glabrous. Calyx 5 minute lobes (sometimes unequal), glabrous. Corolla white or pink, with yellow blotch, glabrous, with a narrow tube 10-15 mm long, and spreading, or reflexed, narrowly oblong lobes c. 15-20 mm long. Stamens 10, long exserted, filaments hairy on lower part. Ovary cylindric c.6 mm long, glabrous or slightly pilose; style glabrous. Capsule tapered at each end, often falcate, 25-40 x 4 mm.
Distribution: NE Upper Burma, China (Yunnan, Sichuan, Guizhou, Hunan, Huhei, Guangxi, Anhui)
Illustrations:
The flowers with long exserted stamens and recurved corolla lobes distinguish this species. Sleumer (1958) considers that R. cavaleriei has similar flowers, but this is not our experience. Sleumer (1958) states that R. cavaleriei zx. chaffanjonii is not synonymous with R. stamineum. However, the holotype at Edinburgh is referable to that species.
Occurs in Countries: CN, MM Subgenus: Azaleastrum Habit: Tree Fl. Colour: pink, yellow
Philipson, W.R. & Philipson, M.N. (1986) A Revision of Rhododendron III. Subgenera Azaleastrum, Mumeazalea, Candidastrum and Therorhodion. Notes from the Royal Botanic Garden Edinburgh 44(1):14
Shrub to 2m. Twigs c.3mm in diameter, rounded, densely patently long, white-hairy and laxly covered with brown scales; internodes 1.5–4cm. Leaves in lax pseudowhorls of 7–10 larger and 2–4 smaller leaves, sometimes sub-spirally arranged. Blade 30–55 x 9–20mm, elliptic, often appearing narrowly elliptic as it is strongly revolute; apex broadly acute, obtuse or rounded; margin entire, broadly revolute; base broadly tapering to rounded; densely white hairy and more laxly scaly both above and below. Scales with long narrow arms, sub-dendroid but not on raised epidermal tubercles. Mid-vein slightly raised above proximally, and then impressed distally to the apex, weakly raised below; lateral veins hardly visible in the fresh state, about 6 per side, narrowly angled, sometimes visible after drying. Petiole 2–5 x 2–4mm, with a shallow groove, densely hairy and scaly. Flower buds to 30 x 14mm, ellipsoid, pale green, smooth. Bracts broadly ovate to spathulate, densely appressed hairy outside and with a few very small brown scales, brown scaly and with some hairs along the margins, glabrous inside. Inflorescence an open umbel of 7–18 semi- or fully erect flowers. Pedicels 5–8 x 2mm, pale green, densely hairy and with a few pale scales. Calyx a low ring. Corolla 50 x 25mm, white, sweetly scented or without scent; tube 40–46 x 5 x 3mm, narrowing gradually from the base upwards, straight or slightly curved, sub-densely hairy and brown scaly outside, glabrous inside; lobes 15 x 9mm, not or hardly overlapping, strongly reflexed, scaly and hairy outside except near the margins. Stamens irregularly spread around the flower, exserted to c.10mm before reflexing back against the lobes; filaments white, c.58mm, glabrous; anthers c.1.75 x 1mm, pale-brown. Ovary c.8 x 2mm, cylindrical, densely hairy with semi-appressed white hairs and white scales; style 55 x 1mm, white or pale pink, hairy, the hairs spreading at the base, appressed above and with white scales to within 4mm of the apex; stigma hardly expanded, c.1mm in diameter, strongly exserted to 18mm. Fruit 30–40 x 6mm, the valves twisting on opening. Seeds 5mm, without tails 1.5mm, the longest tail 2.5mm.
Habitat: Mostly epiphytic on the branches of tall trees in sub-montane forest but occasionally growing terrestrially in disturbances such as road cuttings and landslides.
Distribution: Malaysia (Borneo), Sabah, Mt Kinabalu, Mt Tambuyukon and along the Crocker Range to Mt Alab, Mt Trus Madi, Mt Lotung. Sarawak, Mt Mulu, Batu Lawi. Indonesia, Kalimantan from Mt Palimasan. Brunei, Temburong R., Tutong R.
Altitude: 900-1550m
Named after Otto Stapf who first published this species (see below), author of the first flora of Mt Kinabalu and keeper of the Kew Herbarium 1909–1922.
Type: Haviland 1295. North Borneo, Mt Kinabalu, Penokok, 1065–1525m (K, BM, CAL, SAR, SING, L, fragment).
Synonymy: R. lacteum Stapf, Trans. Linn. Soc. London, II, Bot. 1894. 4: 197, t.15 A 1–2.
Occurs in Countries: ID, MY Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: brown, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:161
Erect, much-branched shrub to 1.5m. Twigs 1.5–2mm, the tips densely covered with brown stellate scales, older parts glabrescent; internodes 1.5–7cm. Leaves 4–5 together in pseudowhorls. Blade 20–45 x 3–8mm, sub-linear, to narrowly elliptic; apex sub-acute; margin entire, strongly revolute; base tapering; very densely covered with brown stellate scales, glabrescent and remaining rough to the touch above at maturity, more persistently scaly beneath. Scales overlapping, the marginal area wide, deeply and irregularly stellately divided into narrow filiform lobes; centre large, dark brown, tapering downwards into a short stem, or foot, each scale on top of a minute, persistent epidermal tubercle. Mid-vein hardly visible above, obtuse and strongly prominent beneath; lateral veins inconspicuous. Petiole 4–6 x c.1mm, very densely scaly. Flower buds ovoid-oblong, c.10mm. Bracts to 10 x 5mm, outer bracts broadly subulate, inner ones ovate, narrowed into an acumen of 2–3mm, slightly keeled and scaly in the upper part outside, innermost ones ovate-oblong, obtuse, glabrous but all densely fringed with scales. Bracteoles to 10mm, filiform, laxly scaly with fragile scales. Inflorescence of 2–3 flowers, rarely solitary. Pedicels 12–16 x 0.7–1mm, entirely covered with golden stellate scales. Calyx c.2.5mm in diameter, disc-shaped, shortly 5-lobed, or with one or two lobes elongated up to 8mm, densely scaly outside. Corolla tubular below, gradually sub-campanulate, expanded upwards, curved, zygomorphic, deep pink; tube 20–32 x 5–6 x 7–9mm, sub-densely covered with golden stellate scales and white hairs outside; lobes 7–12 x 6–8mm, spreading, broadly spathulate or obovate, with scales at the base outside. Stamens exserted from the tube to c.7mm, unequal; filaments linear, 1mm wide below, 0.5mm wide in the upper part, glabrous; anthers 2–2.5 x 1.5mm, obovate-oblong. Disc slightly prominent, glabrous. Ovary c.5 x 2.5mm, sub-cylindrical, densely covered with deeply stellately divided golden scales, but no hairs, gradually narrowed distally; style covered with dense or more laxly distributed scales in the proximal ¾, glabrous distally; stigma shortly 5-lobed. Fruit 20–25 x 4mm, sub-cylindrical, slightly curved, densely stellate-scaly, not hairy, splitting into 5 twisted and sub-reflexed valves. Seeds very narrow, almost filiform, 4mm, long-tailed at both ends.
Habitat: Reported to be common in semi-alpine shrub vegetation, on Mt Antares.
Distribution: Indonesia, New Guinea (W), Star Mts, Mt Antares. Papua New Guinea, West Sepik District, Star Mts, Sirius Range.
Altitude: 3000-3050m
Latin – stellula – star; igerum – bearing. With a covering of stars – the stellate scales.
Wild hybrids between R. stelligerum and R. delicatulum were reported by Sleumer from the Star Mts. This species is very similar to R. rarum and replaces it further to the west.
Type: Kalkman 4471, 22 July 1959. New Guinea (W), Star Mts, Mt Antares, c.3000m (L, K).
Occurs in Countries: ID, PG Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: pink, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:101
Greek – stenos – narrow; phyllum – leaf. The narrow-leafed rhododendron.
Type: H. Low s.n., 1867. North Borneo, Mt Kinabalu (K).
Occurs in Countries: ID, MY Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Fl. Colour: orange, red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:255
Differing from ssp. stenophyllum in the longer, narrower leaves, 60–120 x 1.4–2.2mm. Pedicels always softly hairy besides being scaly, 8–18mm. Seeds 6mm, without tails 0.8mm, the longest tail 3mm. Always grows at much lower altitude than the type subspecies.
Habitat: Mossy sub-montane forest
Distribution: Malaysia (Borneo), Sabah, Mt Kinabalu, Mt Trus Madi, Mt Alab, Mt Lumarku and the Long Pa Sia region. Sarawak, Mt Murud and Mt Mulu. Brunei, Mt Pagon. Indonesia, Kalimantan, Batu Tiban and Mt Kemul.
Altitude: 1500-2400m
Notes RBG Edinb. 1984. 42(1): 115.
Latin – angustatus – narrow; folium – leaf. The narrow-leafed rhododendron.
Flowering appears to be less abundant than in ssp. stenophyllum, and large areas are often occupied by this subspecies as a common undershrub which are totally without flowers. It has however been recorded in flower from September to April. Hybrids with this species appear to be common and fairly easily identified as the narrow leaves are characteristic in the progeny. Rhododendron x liewianum has been described from Mt Kinabalu (Argent et al. 1988) as it is quite prominent with its pink flowers and narrow leaves, R. fallacinum x R. stenophyllum has been reported from G. Alab, and there is some evidence that at least some plants referred to R. nervulosum may be R. crassifolium x R. stenophyllum in origin.
Type: Endert 3990, 13 Oct. 1925, Borneo, Central East, W Kutei, Mt Kemul, summit, 1850m (BO, A, K, L, SING).
Synonymy: R. stenophyllum var. angustifolium J.J.Sm., Bull. Jard. Bot. Buit. III, 1935. 13: 452.
Shrub to 3m. Twigs smooth, shiny-green and very finely scaly. Leaves in pseudowhorls, 10–15 together, gradually passing to scale leaves on the elongate parts of the stem and these soon falling off. Vigorously growing shoots may have very loose pseudowhorls or the leaves in a loose spiral. Blade 40–70 x 2.5–5mm, linear; apex acute; margin entire and flat; base narrowly tapering; glabrescent above, sparsely scaly beneath. Scales small, brown, stellately lobed or sub-circular with small centres. Mid-vein slightly impressed above, otherwise smooth; lateral veins obscure or up to 7 pairs issuing at an acute angle; stiff. Petiole c.3 x 2mm, not clearly distinct from the blade, green with a shallow groove on the upper side, sparsely scaly. Flower buds 30–35 x 10–14mm, slenderly conical, acute, purplish or orange-red, with the bract tips free, erect and slightly spreading. Bracts to 24 x 6mm, glabrous or with a very few small scales along the margins, acutely long pointed. Bracteoles filiform, glabrous, c.10mm. Inflorescence 1–3-flowered, the flowers held stiffly horizontally or slightly angled downwards. Pedicels 8–10 x c.1.5mm, red, scaly, occasionally also with simple hairs. Calyx a low scaly disc. Corolla 32 x 45mm, bell-shaped, bright waxy orange to red, without scent; tube 22 x 13 x 16mm; lobes 20 x 22mm, strongly overlapping for c.¾ of their length. Stamens arranged all round the mouth of the flower, slightly dimorphic; filaments 12–15mm, orange or red, hairy at the base; anthers 5mm, cream. Ovary 4.5 x 2.5mm, densely white-hairy; style glabrous, 6.5mm, (elongating in fruit to 13mm); stigma cream, slightly lobed, 2.5mm in diameter. Fruit 18 x 5mm, sub-cylindrical, hairy.
Habitat: Mossy sub-montane forest, mainly terrestrial in light, open situations
Distribution: Malaysia (Borneo), Sabah, Mt Kinabalu.
Altitude: 2700-2800m
This subspecies is very easy to recognise with its very narrow, linear, dark-green, sparsely scaly leaves and waxy orange to red flowers. The type sheet at Kew has both subspecies represented. The top left has been selected as the type as this most closely conforms to the species as described by Stapf and Burbidge. Hybrids with this subspecies have not been recorded.
Shrub to 60cm. Twigs rounded, c.1.5–2mm in diameter, densely brown scaly, the scales on slender stalks which leave the surface appearing shortly hairy after the scales have fallen off; internodes 1–2cm. Leaves in tight pseudowhorls, with 2–3 full-sized leaves and sometimes one or two smaller ones. Blade 15–35 x 10–25mm, ovate, occasionally broadly elliptic; apex obtuse to rounded, sometimes minutely emarginate; margin entire or minutely crenulate, slightly cartilaginous, flat; base cordate, green and sparsely scaly above, quickly becoming glabrescent, sometimes weakly sulcate; below sparsely but more persistently brown scaly. Scales rounded to somewhat lobed and slightly impressed. Mid-vein narrow and slightly impressed in the proximal ½, otherwise smooth above, distinctly raised below, at least in the larger leaves; lateral veins 4–6 per side, wide-spreading, slightly raised above, obscure below. Petiole 2–3 x 1–1.75mm, weakly grooved above, scaly, semi-erect so that the leaves appear almost sessile. Flower buds c.11 x 3mm, smooth, imbricate, green or lightly flushed with purple, narrowly ellipsoid to ovoid, surrounded by one or two cataphylls which are densely scaly and hairy on both sides. Outer bracts broadly ovate brown scaly outside and fringed with scales, glabrous inside, inner bracts ovate, glabrous or with a small group of scales near the apex and a fringe of very fragile scales which leave short hairs when they have fallen off. Inflorescence of solitary, hanging flowers, rarely in twos. Pedicels 8–12 x c.1.25mm, pink, densely covered with short patent hairs. Calyx green, densely patently hairy. Corolla 28–33 x 22–28mm, dull purple; tube 20–25 x 6 x 9–10mm, strongly curved, glabrous outside and inside; lobes c.10–12 x 9–11mm, spreading horizontally or a little reflexed, overlapping to c.¼. Stamens tightly clustered on the upper side of the mouth, sometimes exserted to 4mm; filaments purplish-red, glabrous; anthers c.1.8 x 1mm, brown. Disc green, sub-glabrous to densely hairy on the upper margin. Ovary 4 x 2.5mm, green, conical, covered in silvery scales and distally pointed white hairs; style 7–10mm, (elongating to 20mm in fruit), green or red, glabrous, or with a few patent hairs near the base, held on the upper side of the tube. Fruit 16–21 x c.5mm, horizontal to semi-erect, green and weakly longitudinally grooved with a persistent purple style, the valves curling back beyond the horizontal and becoming slightly twisted, the placentae remaining adherent to the central column. Seeds 4–5mm, without tails c.1mm, the longest tail c.2mm, tails often somewhat crimped.
Habitat: Recorded as both an epiphyte and terrestrial but mostly epiphytic and probably under-recorded due to its rather inconspicuous flowers.
Distribution: Papua New Guinea, known from the Eastern Highlands, Kundiawa subdistrict, Sina Sina, Mt Giluwe, Southern Highlands and Enga Province
Altitude: 2000-2300m
Named after Peter Stevens, botanist who worked in New Guinea and made a considerable contribution to vireya research with collections and observations and was one of the collectors of the type specimen.
Type: Stevens & Searle LAE 58178, 22 March 1973. Papua New Guinea, Eastern Highlands District, Kundiawa subdistrict, Loop road no. 2, Dpom Sina Sina (L, LAE).
Occurs in Countries: PG Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: purple
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:217
Shrub, 0.5-2.5m; bark smooth or rough, peeling on smaller branches; young shoots often glandular. Leaves obovate to elliptic, 4-12 x 2-6.5cm, 1.8-2.5 x as long as broad, apex rounded, apiculate, base rounded, upper surface glabrous, lower surface with mammillate epidermis and a thin ± persistent to evanescent fawn indumentum interspersed with sessile glands, especially towards the base; petioles 0.5-2cm, usually glabrous, occasionally with a few glands, with or without wings. Inflorescence 3-7-flowered; rhachis usually less than 5mm; pedicels c.20mm, glabrous to sparsely stipitate-glandular. Calyx (2-)5-15mm, cupular, lobes broadly ovate, glandular-ciliate or glabrous. Corolla campanulate to tubular-campanulate, white or cream to pale (rarely deep) rose, with or without purple flecks, 35—55mm. Ovary usually densely glandular; style glabrous. Capsule 15—30 x c.6mm.
Habitat: Cane brakes, stony slopes
Distribution: China (SE Xizang, NW Yunnan), NE Upper Burma
Altitude: 3000-4250m
Cowan & Davidian, Rhododendron Yearbook 6:177 (1952), refer forms with small leaves and calyces to var. tantulum and those with large leaves and calyces to var. aiolosalpinx. There is, however, apparently no correlation between these two characters and the forms do not come true from seed. R. stewartianum is closely allied to R. eurysiphon (q.v.) and to R. cyanocarpum.
The following specimens are minor variants or hybrids of R. stewartianum: Forrest 20302, 21687, 22702; Rock 8744; Kingdon-Ward 3880. AU lack the scurfy leaf indumentum typical of R. stewartianum. The following are presumed to be hybrids of R. stewartianum and species of subsection Neriiflora: Forrest 20886, 21846, 21910, 22672.
Type: China, Yunnan, TsedjiongPass, Mekong/Salween divide, 10- 11000ft, vi 1904, Forrest 5069 (holo. E)
Synonymy: R. nipholobum Balfour f. & Farrer, Notes R.B.G. Edinb. 13: 277 (1922) Type: NE Upper Burma, Chawchi Pass, etc., 10500ft, 15 v 1920,Farrer 1552b (holo. E; iso. K). R. aiolosalpinx Balfour f. & Farrer, ibid. 13:227 (1922). Type: NE Upper Burma, Chimili Pass, 11-12000ft, 16 v 1919, Farrer 926 (holo. E; iso. BM). R. stewartianum Diels var. aiolosalpinx (Balfour f. & Farrer) Cowan & Davidian, Rhododendron Yearbook 6: 177 (1951). R. stewartianum Diels var. tantulum Cowan & Davidian, ibid. 6: 177 (1951). Type: China, SE Xizang, Salween/Kiu-chiang divide, W of Si K'ai, vi 1922, Forrest 21918 (holo. E)
Occurs in Countries: CN, MM Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: cream, purple, rose, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):426
Much-branched shrub to 1m. Twigs rounded, scaly and hairy initially. Leaves opposite, narrowly to very narrowly ovate. Blade 40–80 x 12–32mm; apex acute or obtuse; base broadly tapering or rounded; sparsely brown-scaly above, covered beneath with a brown scaly covering initially. Petiole 3–4mm. Umbels 2–4-flowered. Pedicels 13–15mm, slender, densely scaly-hairy. Calyx c.3mm in diameter, saucer-shaped, very shortly and bluntly 5-lobed. Corolla c.25mm, tubular, 5-lobed c.halfway, glabrous outside, minutely shortly hairy inside, lilac, the lobes obliquely obovate-oval, obtuse, glabrous on both sides. Stamens c.20mm long; filaments filiform, sparsely shortly hairy or almost glabrous; anthers c.1.5mm, oblong. Ovary c.8mm, narrowly oblong, very densely and shortly stellate-scaly-hairy; style subulate, glabrous; stigma obliquely globose, 5-lobed.
Habitat: Epiphytic in low mountain forest.
Distribution: Papua New Guinea, Upper Sepik R. region: camp ‘Felsspitze’, c.141°30'E 4°10'S
Named after Herr Stoll who participated in the expedition on which this plant was collected.
The holotype was destroyed in Berlin and no isotype has as yet been found; the description is derived from Professor Sleumer’s translation of the original which was incomplete. Sleumer (1966) noted: ‘The position of R. stolleanum both in and within the subsect. Phaeovireya thus remains somewhat doubtful; yet most of the characters given are those of R. dielsianum’. The essential key difference between these species lies in whether the corolla is completely glabrous outside (R. stolleanum) or sparsely to more densely scaly (R. dielsianum). This difference could easily be accounted for by the scales having been lost in processing of R. stolleanum.
Type: Ledermann 12626. New Guinea (E), Upper Sepik R., Camp Felsspitze, c.141°30E 4°10S (B†).
Occurs in Countries: PG Subgenus: Vireya Habit: Epiphyte, Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:101
Shrub. Twigs 2–3mm in diameter, rounded, brown, sub-densely covered with appressed scales at first, laxly so later. Leaves 3–5 together in pseudowhorls. Blade 85–100 x 42–53mm, ovate- or elliptic; apex shortly acutely acuminate; margin flat; base cordate with rounded lobes; glabrescent above when mature and then covered with minute black pits, laxly to sub-densely scaly beneath. Scales small, marginal zone sub-stellately lobed; centre impressed, finally glabrescent beneath also, leaving dark pitted spots. Mid-vein flat, broad proximally, narrower and slightly impressed for the distal 1⁄3 above; below as large as the petiole proximally, obtusely prominent; lateral veins 7–8 per side, spreading, arching inwards before the margin, slightly impressed above and raised beneath, reticulation inconspicuous. Petiole 5–6 x c.2mm, flattened, scaly. Inflorescence c.7-flowered. Pedicels 24–27 x c.1mm, laxly sub-stellately scaly with flat scales and minute white hairs. Calyx c.4mm in diameter, oblique, disc-shaped, obscurely lobed, fleshy, outside scaly and with short, fine hairs. Corolla 40–45mm, tubular-funnel-shaped, slightly oblique, dark-red; tube 20–23 x 5–6 x 12–15mm, glabrous outside, practically so inside, base dilated and 5-lobed; lobes 20–23 x 15–18mm, obovate-spathulate. Stamens sub-equal, 24–28mm; filaments linear, with sparse, long, spreading hairs in the proximal 1⁄3, glabrous distally; anthers c.3 x 1mm, oblong. Disc low, hairy, except for the base. Ovary 6–7 x c.3mm, sub-ovoid-cylindrical, densely covered with white, forwardly directed hairs, which cover small scales, abruptly contracted distally; style c.20mm, thick, hairy at the base; stigma thick, rounded.
Habitat: On steep limestone ridge in Rhododendron copse with a few high Casuarina
Distribution: Indonesia, Maluku, Ora Mts.
Altitude: Around 1000m
Named after the collector, Erwin Stresemann, a German ornithologist.
Known only from the type collection.
Type: Stresemann 1, May 1911. Moluccas, Ceram (W), Ora Mts, 1000m (L).
Occurs in Countries: ID Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:291
Shrub, 1.5-2.5m; young shoots densely stipitate-glandular. Leaves elliptic to oblanceolate, 7.5-14 x 1.8-3.8cm, 2.7-3.7 x as long as broad, apex cuspidate, base ± cuneate, margins sometimes ciliate, upper surface ± glabrous when mature, lower surface with varying amounts of crisped setae with glandular or branched tips that usually persist, at least near the base, grading into stouter bristles on the midrib; petioles l-2cm, glandular-setose. Inflorescence 8- 12-flowered; rhachis less than 5mm; pedicels 10-20mm, usually covered with long weak glandular hairs. Calyx c.lmm. Corolla tubular-campanulate, with depressed nectar pouches, deep red, 40-60mm. Ovary with a dense covering of long weak glandular hairs; style glabrous. Capsule 15-20 x 4-7mm, usually narrowly cylindrical.
Habitat: Thickets and woodlands
Distribution: China (Sichuan & adjacent parts of NE Yunnan)
Altitude: 2200-3350m
Illustrations:
The leaf indumentum of this species is particularly variable and shows a transition from the glandular bristles typical of subsection Barbata to branched hairs, more typical of subsection Maculifera.
Type: China, Sichuan, Moupine, in montibus ad septentriones versus, 3000m, iv-v 1869, Abbe David (iso. E)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: red
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):270
Shrub or tree to 3m. Twigs 4–5mm in diameter, smooth, rounded, green with a sparse covering of scales; internodes 2–10cm. Leaves in tight pseudowhorls of 3–6, variable in size within the pseudowhorl. Blade 60–100 x 35–70mm, elliptic, about twice as long as wide; apex rounded, or very obtuse to slightly retuse; margin smooth, with a narrow cartilaginous flat edge; base cordate or occasionally rounded; sparsely scaly but quickly glabrescent above, sparsely scaly beneath. Scales small, sub-circular or irregularly lobed with a broad marginal zone and small centre, slightly impressed. Mid-vein 5mm wide at the base, slightly raised both above and below, distinctly grooved on the upper side and quickly tapering within 10mm of the base, beyond which point it is hardly raised either above or below; lateral veins 5–9 per side, pinnate, spreading at 45°, straight or somewhat curved, distinct above, indistinct below; surface smooth, pale-green especially below but with the main vein prominently dark-red in at least the broad basal part, reticulation obscure. Petiole 1–2 x 4–5mm, indistinctly grooved above, laxly scaly. Flower buds (see p.327) narrowly conical in shape, green, the protective bracts with flat narrowly pointed, reflexed, green tips. Inflorescence a 12–25-flowered complete umbel. Pedicels 15–25 x 1.5mm, sparsely covered in silvery or pale-brown scales and spreading white hairs, often distinctively bright red. Flowers stiffly held erect to half-hanging. Calyx an irregular low ring. Corolla 35–70 x 20–25mm, pure white or sometimes lightly flushed pink especially on the tube, usually strongly and sweetly scented; tube 35–55 x 6–9 x 3–5mm, distinctly narrowed distally, glabrous outside but with sparse hairs inside; lobes 13 x 10mm, horizontal, or irregularly reflexed back against the tube, overlapping to c.½ and ‘crimped’. Stamens irregularly clustered at or below the mouth of the flower, not exserted; filaments slender, white, about as long as the corolla tube, shortly hairy proximally for 2–3mm; anthers 2 x 1mm, pale-brown. Disc slightly lobed, circular, green with erect white hairs. Ovary 9 x 2mm, cylindrical, slightly curved and gradually tapering distally, densely covered in silvery scales but also with erect, white hairs to c.halfway; stigma 1.5–2mm wide, irregularly 5-lobed, quickly becoming exserted to c.10mm from the mouth of the flower. Fruit 30–45 x 3–5mm, cylindrical but curved and narrowed to the persistent style and also ribbed longitudinally. Seeds 5–5.5mm, without tails c.1mm, the longest tail 2.5mm often crimped.
Habitat: Epiphytic and terrestrial, common on the trees and ridges on Mt Kinabalu, Crocker Range and Mt Lumarku
Distribution: Malaysia (Borneo), Sabah.
Altitude: 1200-1700m
Latin – suaveolens – sweetly smelling.
This is a very attractive and distinctive species with its long, white, usually scented flowers and pale green leaves with their contrasting red marks at the base. This species was confused with R. orbiculatum but was clearly shown to be different by Hunt (1972) in the much narrower flowers with smaller corolla lobes and in having many more flowers in the inflorescence and longer leaves. The lack of hairs on the corolla, leaves and stems will distinguish it from R. stapfianum. It is very similar to R. lambianum but has consistently narrower flowers and shorter broader leaves. Rhododendron suaveolens has been in cultivation since first introduced by Mr and Mrs Allen from a collection they made from Mt Kinabalu in January 1966. It grows and flowers well as a cool greenhouse plant in temperate countries, flowering mostly in the winter months. Not all forms are strongly scented: those from Mt Kinabalu appear to always have strong scent; the slightly smaller-flowered plants collected on Mt Lotung are totally without scent. The cultivar ‘Painted Snipe’ was named and illustrated (Hunt 1972); this plant is in no way distinctive from the majority of wild plants.
Forma roseum Argent, A.Lamb & Phillipps. Notes RBG Edinb. 42(1): 117. Type: Jukien s.n., April 1981. Sabah, Kinabalu National Park, 1600m (SNP). Derivation: Latin – roseum – rose coloured, with reference to the pink colour of the flowers. Differing from the type in the uniformly pink colour of the flowers. This form was first found by Mr Justin Jukian, Senior Park Ranger, near the Kinabalu Park Headquarters in 1980. It has since been reported as common and the predominant form in the Penataran River area of Kinabalu. It has been in cultivation in Edinburgh since 1982 and grows and flowers freely, producing large inflorescences of luridly pink flowers which appeal to some people but not to others.
Type: Clemens 505076, 30 Nov. 1933. BN Borneo, Mount Kinabalu, Gurulau Spur, 1800m (K).
Occurs in Countries: MY Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Epiphyte, Tree Fl. Colour: pink, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:164
Shrub or tree, up to 14m; bark smooth, peeling; young shoots apparently tomentose. Leaves oblong, 7-10.5 x 2-3.5cm, 3-3.5 x as long as broad, apex rounded and apiculate, base ± rounded, upper surface glabrous, lower surface epapillate, with numerous red punctate hair-bases on the veins, each with the vestige of a branched hair; otherwise glabrous; petioles 1 —1.5cm, glabrous. Inflorescence dense, up to 15-flowered; rhachis c.5mm; pedicels 7-10mm, glabrous. Calyx 4-5mm, cupular, lobes rounded, cihate. Corolla tubular-campanulate, fleshy, scarlet, with a few purple flecks, up to 40mm. Ovary densely tomentose, eglandular, style glabrous. Capsule not known.
Habitat: Mossy rain forest
Distribution: ne India (Arunachal Pradesh)
Altitude: 2600-2800m
Only known from the type specimen though apparently common in the type locality. Allied to R. faucium and R. hookeri but distinguished from both by its tomentose, eglandular ovary, etc.
Type: NE India, Arunachal Pradesh, Subansiri division, ridge of Ziro, Api Tani Valley, 8400-9200ft, Cox & Hutchison 418 (holo. E; iso. K).
Occurs in Countries: IN Altitude Ranges: 2,000 - 3,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: purple, scarlet
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):422
Shrub; young shoots covered with adpressed densely brown strigose hairs. Leaves dimorphic, coriaecous, clustered towards apex; spring leaves obovate to obovate-elliptic, 4.5-5.5 x 2-2.5cm, apex abruptly acuminate to broadly mucronate, base attenuate or narrowly cuneate, margin strongly revolute, upper surface green, yellow when dried, midrib slightly raised, glabrescent, lower surface pale green, sparsely strigose, midrib distinctly raised, with adpressed strigose hairs; summer leaves elliptic, 23 x 4-I0mm, otherwise as for spring leaves; petioles 3-5mm, sparsely strigose. Inflorescence c.6-flowered; pedicels 6-- 10mm, yellow-brown-strigose. Calyx cup-shaped, lobes deltoid, strigose. Corolla funnel-campanulate, c.l9mm, red; tube 9 x 4mm. Stamens 5, unequal, exserted, filaments compressed-puberulous for the most part. Ovary light brown strigose; style strigose in lower third. Capsule ellipsoid, 10mm, brown-strigose.
Distribution: China (Guangdong)
Allied to R. seniavinii, but with larger flowers.
Only known from the type
Type: China, Guangdong, Yangchun Xian, Sian-Ja-Dong, in rimis rupium, 31 x 1935, Huang Zhi {Wang, C.) 38590 (holo. IBSC)
Occurs in Countries: CN Subgenus: Tsutsusi Habit: Non-Tree
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):107
Erect shrub to 50cm. Twigs c.2mm in diameter, at first densely covered with sub-stellate and distinctly stalked scales, quickly glabrescent leaving them minutely warty and rough to the touch; internodes 2.5–5cm. Leaves 3–5 together in tight pseudowhorls. Blade 20–30 x 8–14mm, narrowly elliptic or sub-ovate or sub-obovate; apex shortly acuminate, obtuse at the extreme point with a thick gland; margin narrowly cartilaginous, slightly or not revolute, sub-crenulate or entire; base broadly tapering or sub-truncate; sub-densely scaly on both sides, early glabrescent above, persistently scaly beneath. Scales small, marginal zone thin, lobed or irregularly crenate; centre thick, raised on low protuberances. Mid-vein distinctly and narrowly impressed above, thick and obtusely prominent in the proximal part beneath; lateral veins inconspicuous. Petiole 2–3 x 1.5–2mm, densely scaly, a little flattened. Bracts to 15 x 8mm; outer bracts ovate, with a 4–5mm long, subulate, acumen, inner bracts ovate-elliptic, with a 10mm point, innermost bracts sub-spathulate, obtuse; scaly outside in the distal part or quite glabrous; margin initially fringed with scales. Bracteoles c.10mm, linear. Inflorescence 1–4-flowered, the flowers hanging vertically. Pedicels 15–20 x c.1mm, densely covered with reddish, stellate scales but without hairs. Calyx 3–4mm in diameter, sub-obliquely disc-shaped, shortly obtusely 5-lobed, densely stellate-scaly outside. Corolla 25–30mm, tubular, sub-oblique, dark red; tube 20–23 x c.4 x 8–10mm, straight or only slightly curved, sub-densely stellate-scaly outside, glabrous inside; lobes 5–7 x 5–7mm, half-spreading, sub-circular. Stamens unequal, the longest almost as long as the corolla; filaments linear, glabrous; anthers 2.5 x 1mm, broadly oblong, rounded at the base. Disc glabrous, or shortly hairy at the upper margin only. Ovary 6–7 x c.2.5mm, sub-cylindrical, densely stellate-scaly, gradually tapering distally; style equalling the stamens, scaly proximally to 1⁄5–1⁄3, glabrous distally; stigma rounded.
Habitat: Terrestrial, common at the edges of mossy forest, or in open mossy shrubberies and in an open shrubbery on a dry ridge.
Distribution: Indonesia, New Guinea (W), Lake Habbema=.
Altitude: 3225-3345m
Latin – sub – somewhat; crenulatus – having small rounded teeth. Alluding to the leaf margin.
Differing from R. rubrobracteatum in that the pedicels are scaly but not papillose, the style is scaly 1⁄5–1⁄3 and not glabrous. The difference that Sleumer (1966) uses in his key to separate them – twigs warty vs. twigs smooth – does not separate them according to the van Royen & Kores (1982) descriptions which describe both species with warty twigs, although they use this difference like Sleumer in their key. Further work will probably unite these two species.
Type: Brass 9274, Oct. 1938. New Guinea (NW), Lake Habbema, 3225m camp (A, L).
Occurs in Countries: ID Altitude Ranges: 3,000 - 4,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:232
Shrub, c.2m; young shoots densely adpressed-strigose. Leaves ? dimorphic, chartaceous, elliptic-oblong to narrowly elliptic; spring leaves 2.5ó3(ó3.5) x 0.8-1.4cm, 2.5-3 x as long as broad, apex subacuminate, base cuneate; margin obscurely crenate, ciliate; upper surface adpressed-strigose at first, later glabrescent, lower surface pale at maturity, ± glabrescent except for the strigose midrib reddish-brown-strigose; summer leaves 12-15 x 7-8mm, otherwise as for spring leaves; petioles 2-4mm. Inflorescence 3-6~flowered; pedicels c.5mm, glandular and densely strigose. Calyx c.3 mm, densely strigose, lobes c.lmm, triangular. Corolla funnel-shaped, red, with purple flecks, 12-16mm; tube 6-8mm, c.4mm broad, shortly stipitate-glandular on outer surface, puberulent within; lobes 6-8mm. Stamens 5, filaments puberulent. Ovary densely reddish-brown-strigose; style stipitate-glandular for most of its length, also strigose at base. Capsule not known.
Habitat: Woodland etc
Distribution: China (Guangxi)
Altitude: 1260-1700m
From the descriptions and photographs available it seems most probable that R. glandulostylum is a synonym of R. subenerve. In any case a new name is required if R. glandulostylum Fang & He is maintained as a separate species. The original authors suggest that R. glandulostylum is allied to R. microphytum and, from the evidence before us, this seems likely. The chief differences are in the size and texture of the leaves. Probably also allied to 7?. fuchsiifolium but apparently differing in the less acuminate leaves, etc.
Type: China, Guangxi, Guangyang Xian, Baijing, 22 ix 1958, Chen, Z.Z. 52211 (holo. IBSC, n.v., photo. E)
Synonymy: ? R. glandulostylum Fang & M.Y. He, Bull. Bot. Res. N.E. Forest. Inst. 2(2): 84 (1982), non R. glandulistylum Komatsu (1918). Type: China, Guangxi, Jinxiu Yaozu Zizhi Xian (Dayaoshan Xian, Jinxiuqu), 1260m, 4 v 1964, F.N. Wei 809 (holo. IBK, n.v.)
Occurs in Countries: CN Altitude Ranges: 1,000 - 2,000m Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: purple, red
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):127
Shrub, to 3m; young shoots densely adpressed brown-strigose, becoming pale greyish-brown, sometimes glabrescent. Leaves crowded towards ends of branches, dimorphic, coriaceous, elliptic-oblong; spring leaves 3.5-4.5 x 1.3-1.8cm, apex shortly acute, base cuneate, margin strigose, upper surface brown-strigose, lower surface silky reddi-sh-brown-strigose; summer leaves smaller, oblong-lanceolate, 16-20 x 6-7mm, otherwise as for spring leaves; petioles 4mm, densely brown-strigose. Inflorescence 5-6(-8)-flowered; pedicels 10mm, densely brown-strigose. Calyx minute, strigose, lobes crenulate. Corolla narrowly funnel-campanulate, 28mm, pinkish-red; tube 15mm, glabrous. Stamens 8-9, puberulent to above middle. Ovary densely silky brown-strigose; style glabrous. Capsule 7mm, ovoid, densely strigose.
Habitat: Riversides
Distribution: China (N Guangdong, S Hunan)
Altitude: Around 550m
Close to R. meridionale but more densely hairy and with 8-9 stamens.
Type: China, Hunan, Mang Shan, 500m, 4 v 1957, L.H. Liu (L.H. Lau) 422 (holo. IBSC)
Occurs in Countries: CN Altitude Ranges: 0 - 1,000m Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: pink
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):109
Much-branched shrub; shoots densely covered with adpressed flattened brown hairs. Leaves dimorphic, chartaceous; spring leaves elliptic-lanceolate, 2.5-4 x 0.9-1.2cm, 2-4 x as long as broad, margin entire, slightly recurved, apex acute and mucronate, base cuneatc, both upper and lower surfaces at first clothed with rufous-grey silky hairs, at maturity with white adpressed hairs on upper surface, midrib impressed above, prominent below; summer leaves c.15 x 7mm, otherwise as for spring leaves; petioles 2-5mm, clothed with adpressed chestnut-brown hairs. Inflorescence 2-4-flowered; pedicels 5-7mm, clothed with adpressed ferrugineous hairs, hidden by the bud scales. Calyx small, with oval lobes, densely clothed with flattened brown hairs. Corolla funnel-campanulate, 15-20mm, lilac-purple; tube c.8mm, 3mm wide at base, glabrous. Stamens 6-10, slightly exserted, papillose below the middle. Ovary densely covered with ferrugineous flattened hairs; style exserted, with a few flattened brown hairs at base. Capsule conic-ovoid, densely covered with flattened adpressed rufous hairs.
Distribution: Philippine Islands (Luzon)
Type: Philippines, Luzon district of Lepanto, Mount Data, Whitehead, Merrill 4606 (holo. BM)
Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: lilac
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):127
Shrub to 2m. Twigs 1–1.5mm in diameter, rounded, densely sub-stellate with shortly stalked scales, quickly glabrescent, leaving the surface warty with low scale bases; internodes 3–9cm. Leaves 3–6 together in tight pseudowhorls. Blade 25–45 x 10–23mm, obovate, more rarely elliptic; apex rounded or obtuse, sometimes minutely emarginate; margin entire or minutely crenulate, distinctly revolute in the proximal ½, hardly or not revolute distally; base tapering; glabrescent and densely rugulose above, densely scaly beneath. Scales with the thin marginal zone angular or obtusely sub-stellately lobed; centre persistent, thickened, reddish brown and slightly impressed. Mid-vein narrowly impressed above, prominent beneath but tapering gradually distally; lateral veins 1–3 per side, inconspicuous or obscure. Petiole 3–4 x 1–1.5mm, scaly, flattened. Flower buds to 10 x 4mm, with the outermost bract tips spreading, the inner ones erect. Bracts 10–15 x 5–6mm, ovate but with long subulate points, glabrous outside or with minute, almost papillose hairs and fragile scales along the margins, glabrous inside. Bracteoles c.10mm, filiform. Flowers in pairs or solitary, hanging vertically. Pedicels 10–18 x 0.75mm, densely covered with stellate, stalked scales and short hairs. Calyx c.3mm in diameter, oblique, very shortly irregularly 5-lobed, revolute, scaly and hairy outside, ciliate on the margin. Corolla 30–50 x 20–25mm, tubular, slightly expanded distally, dark-red, without scent; tube 30–35 x 4–5 x 8–13mm, weakly curved, laxly scaly or glabrous outside, glabrous inside; lobes 6–12 x 6–10mm, erect, or half-spreading, spathulate-obovate or sub-circular. Stamens unequal, exserted to 10mm; filaments linear, 1mm wide at the base, glabrous; anthers c.3 x 1mm, broadly oblong, cells obtuse or provided with an indistinct basal apiculus, very dark almost black. Disc prominent, glabrous or with hairs on the upper margin. Ovary 6–8 x c.2mm, sub-cylindrical, densely stellately scaly, gradually tapering distally; style glabrous, or with a few hairs at the base, as long as or slightly longer than the corolla; stigma rounded.
Distribution: Indonesia, New Guinea (W), Bele R. Valley, NE of Lake Habbema; Sibil valley, Snow Mts.
Altitude: 1550-2600m
Latin – subulifer – awl-bearing, alluding to the distinctive subulate bracts.
High epiphyte, frequent in mid-mountain mossy forest, or common terrestrially on white sand in clearings.
Type: Brass 10830, Oct. 1938. New Guinea (W), Bele Valley, 25km NE of Lake Habbema (A, BO, L).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:227
Weak shrub to 30cm. Twigs to 1.5mm in diameter, at first sub-densely covered with star-shaped and shortly stalked, fragile scales, becoming glabrescent but remaining minutely warty near the tips; internodes 1–4cm. Leaves 3–5 together in pseudowhorls. Blade 35–80 x 1.5–3mm, linear; apex acute or nearly so; margin slightly revolute; base narrowly tapering; glabrescent above, more persistently scaly beneath. Scales the marginal zone angular or obtusely lobed; centre much darker and hardly impressed. Mid-vein distinctly impressed above, prominent beneath, red; lateral veins obscure. Petiole 2–4 x 0.5mm, rounded, red, much darker than the lamina in dry specimens. Bracts to 20 x 5mm; outer bracts subulate, inner ones, ovate-subulate, innermost ones ovate, abruptly subulate-acuminate in the upper ½ and acute, glabrous outside, reddish. Inflorescence 1–3-flowered. Pedicels 5–7mm, slender, densely stellate-scaly. Calyx c.2mm in diameter, obliquely disc-shaped, margin membranaceous, shortly 5-lobed, scaly outside. Corolla c.15mm, probably red; tube c.10 x 2–3 x 3–4mm, cylindrical, glabrous inside and out; lobes c.4 x 4mm, broadly obovate-sub-circular. Stamens 14–16mm; filaments filiform, glabrous; anthers sub-globose, c.1.5mm in diameter. Disc prominent, glabrous. Ovary c.3 x 1.3mm, sub-cylindrical, densely stellately scaly, abruptly contracted distally; style 5–6mm, slender, glabrous; stigma club-shaped. Fruit c.15 x 4mm, valves reflexed and twisted. Seeds narrow, tailed at both ends, 2–3mm.
Habitat: Epiphytic on ridge
Distribution: Indonesia, New Guinea (W), Doormantop.
Altitude: Around 1450m
Latin – subula – a fine sharp point; osum – full or marked development. Alluding to the narrow ‘awl-shaped’ leaves.
Known only from the type collection.
Type: Lam 1906, 5 Nov. 1920. New Guinea (NW), Doormantop, c.1450m (BO, L).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:294
Shrub or small tree, 1 -6m; young shoots glabrous. Leaves oblong to elliptic, 5—13.5 x 2.5—5.5cm, 2—2.5 x as long as broad, apex rounded, minutely apiculate, base cordate, upper and lower surfaces glabrous; petioles absent or up to 5mm, winged, glabrous. Inflorescence dense, 10-15-flowered; rhachis up to 7mm; pedicels 5-15mm, glabrous. Calyx c.lmm, lobes minute, rounded. Corolla fleshy, tubular-campanulate, crimson, with conspicuous nectar pouches, 28-35mm. Ovary and style glabrous. Capsule at least 20 x 5mm, strongly curved.
Habitat: Mixed forests, etc.
Distribution: Bhutan, NE India (Arunachal Pradesh)
Altitude: 3400-4200m
Illustrations:
An aberrant member of subsection Barbata, completely lacking the characteristic setae or bristles, though with a typical dense inflorescence with relatively small red flowers. An affinity with R. fulgens was originally proposed but the glabrous leaves are against this.
Type: Bhutan, Byasu La, Phobshikha, 13500ft, 18 v 1937, Ludlow & Sherriff 3075 (holo. E; iso. BM)
Synonymy: R. nishiokaeHaia, J. Jap. Bot. 45:94(1970). Type: Bhutan, nr Puwa La, 2 v 1966, Nishioka (holo. TI, n.v.).
Occurs in Countries: BT, IN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: crimson
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):382
Shrub to 1m. Twigs 1–2mm in diameter, rounded, laxly scaly, without simple hairs; internodes 1–5cm. Leaves in tight pseudowhorls 4–6 together, sometimes with one or two much smaller ones. Blade 20–35 x 8–12mm, elliptic or occasionally spathulate; apex rounded or minutely retuse; margin entire, strongly but narrowly revolute; base tapering; laxly silvery scaly above but quickly glabrescent; below densely scaly. Scales sub-stellate, with a broad, thin, silvery, margin and small, darker and slightly impressed centre. Mid-vein impressed into a groove throughout its length above, strongly raised for the whole length beneath; lateral veins not visible. Petiole 2–4 x c.1mm, laxly scaly initially. Inflorescence up to 5-flowered, the flowers hanging. Pedicels 15–18 x c.0.6mm, densely hairy, apparently without scales. Calyx c.4mm in diameter, distinctly lobed and sometimes with one or two much longer lobes, hairy outside. Corolla c.25 x 12mm, bright pink, narrowly funnel-shaped; tube c.13 x 3 x 7mm, glabrous outside, hairy inside in the proximal ½; lobes c.9 x 6mm, broadly elliptic. Disc hairy on the upper side. Stamens c.18mm, exserted to c.4mm; filaments densely hairy in the proximal 1⁄3, glabrous distally; anthers c.2mm. Ovary c.4.5 x 2mm, densely hairy; style c.15mm, hairy for c.2mm proximally, glabrous distally; stigma c.1.5mm in diameter, rounded.
Distribution: Malaysia (Borneo), Sabah, Telupid District, Mt Tawai.
Altitude: Around 1250m
Named after John Sugau, senior botanist working with the Forest Department, Sandakan, who found this plant.
R. burttii affinis sed ramulis glabris et corolla extus glabra differt.
Very similar to R. burttii but with non-hairy twigs and no hairs on the outside of the corolla. Mt Tawai is an isolated mountain and this species is very likely to be endemic. Known only from the type collection.
Type: Sugau et al. SAN 138836, 11 April 1994. Malaysia, Sabah, Telupid District, Mt Tawai, c.1250m (SAN).
Occurs in Countries: MY Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:201
Epiphytic or free-growing shrub, 0.6-1.6 m. Young growth often loriform-setose, the setae usually quickly ciecidouous. Leaves mostly obovate, sometimes broadly so, more rarely narrowly elliptic, (35-)45~65 (-85) x 20-35(-45) mm, very rounded to subacute at the apex, tapering to the base, margins often loriform-ciliate when young, upper surface glabrous, lower surface with close, unequal scales sunk in pits with crenulate edges, the rims of the scales upturned. Inflorescence 3-6-flowered, pedicels longer than the flowers, stout, up to 15 mm, lepidote, sometimes loriform-setose and/or fiiiform-acicular pubescent. Calyx lobes ovate to oblong, 5-6 mm, lepidote, sometimes loriform-ciliate or minutely pubescent along the margin. Corolla campanulate, greenish or bright yellow, unspotted, 15-20 mm, tube 8-11 mm, sparsely to densely lepidote outside, sometimes sparsely pubescent on the tube, pilose inside. Ovary lepidote. Capsule cylindric-ovoid, lepidote, 10-13 mm.
Habitat: Rocks and slopes, or epiphytic, 2500-3650(-4000) m
Distribution: NE Burma, China (NW & SW Yunnan, SE Xizang)
Illustrations:
Type: China, Yunnan, in dumetis ad pedem montis Tsang chan supra Tali, 2500 m, 20 iv 1886, Delavay 2212 (holo. P—n.v., iso. E)
Synonymy: R. theiochroum Balfour f. & W. W. Smith, Notes R.B.G. Edinb. 9:282 (1916). Type: China, Yunnan, Shweli/Salween Divide, 10-11000 ft, iv 1913, Forrest 11910 (holo. E). R. cerinum Balfour f. & Forrest, Notes R.B.G. Edinb. 13:240 (1922). Type: China, Yunnan, Shweli/Salween Divide, vi 1918, Forrest 17592 (holo. E). R. commodum Balfour f. &■ Forrest, op. cit.: 252. Type: China, Yunnan, N'Maikha/Salween Divide, eastern flank, 11-12000 ft, v 1919, Forrest 17866 (holo. E)
Occurs in Countries: CN, MM Subgenus: Rhododendron Habit: Epiphyte, Non-Tree Fl. Colour: green, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):135
Much-branched shrub to 3m. Twigs 1.5–3mm in diameter, rounded, often red, at first sub-densely covered with flat, sub-stellate scales, becoming glabrescent; internodes 2–8.5cm. Leaves 5–7 together in pseudowhorls, unequal. Blade 25–80 x 15–40mm, obovate or obovate-elliptic; apex obtuse or rounded, often emarginate; margin flat, or weakly and narrowly recurved, base tapering and a little decurrent, glabrescent above at maturity, sub-densely and persistently scaly beneath. Scales small, marginal zone irregularly lobed; centre dark and impressed. Mid-vein narrowly impressed above, obtusely prominent proximally beneath; lateral veins 4–6 per side, spreading, distinctly impressed above and raised beneath, often inconspicuous on both sides, reticulation obscure. Petiole 4–10 x c.1.5mm, red, somewhat flattened, grooved above, densely scaly. Flower buds to 8 x 5mm, ovoid; outer bracts sub-circular, inner ones ovate to oblong-ovate, obtuse to acute, white or grey appressed hairy in the upper, outer part, with both scales and hairs along the margins. Inflorescence a 1–4-flowered open umbel, the flowers hanging vertically. Pedicels 10–18mm, slender, densely sub-stellate-scaly, without hairs. Calyx 4–5mm in diameter, obliquely disc-shaped, very shortly obtusely lobed. Corolla 25–30 x 34mm, campanulate or broadly funnel-shaped, bright orange-red, without scent; tube 10–12 x 8–9 x 15–16mm, straight, laxly sub-stellately scaly outside, glabrous inside; lobes 15–18 x 14–16mm, curving outwards and overlapping to ¾, slightly emarginate. Stamens regularly to irregularly arranged in the centre of the flower, exserted to c.6mm; anthers 2–2.5 x c.1mm, obovate-oblong, base sub-obtuse, pale brown, strongly curving inwards; filaments orange, linear, dilated and patently hairy for 2–4mm at the base, glabrous and filiform distally. Disc glabrous, not very prominent. Ovary 4.5 x 3–3.5mm, ovoid-conical, patently long hairy, abruptly contracted distally; style 8–10mm, depressed to the lower side of the flower, glabrous; stigma green, thick-obconical. Fruit 18–30 x 7–9mm, ellipsoid, densely patently hairy and scaly, green often flushed with red, the valves spreading and twisting on opening, the placentae remaining coherent. Seeds 4.5–6mm, without tails 0.8–1mm, the longest tail 3.2mm.
Habitat: Mostly terrestrial, occasionally epiphytic, in open forests, summit vegetation, sub-alpine shrubberies or grassland, locally common.
Distribution: Indonesia, N Sumatra, Atjeh, Tapanuli, East Coast.
Altitude: 1800-2700m
Named after the island of Sumatra, on which it was discovered.
Commonly hybridising with R. retusum, the resulting plants having narrower flowers than the pure species. Also hybridising with R. rarilepidotum to give a range of forms. A probable hybrid with R. adinophyllum was collected on Mt Kemiri by David Binney (982482). A rare yellow-flowered form was noted by the de Wilde’s on Mt Bandahara. This species could be confused with R. ripleyi but that species has a scaly ovary without hairs or with just a few at the apex and usually has more pointed leaves.
Type: Bartlett 7998, 18 May 1927. Sumatra, East Coast, Tapanuli, Habinsaran, summit of Dolok Surungan (MICH, L).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: orange
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:250
Latin – superbus – superb, alluding to the magnificent flowers.
Type: Clemens 12322, 19 June 1941. New Guinea (E), Mt Saruwaged, A-mieng, on Yaneng R. (a tributary of the Buso R.), 1500–1800m (A).
Occurs in Countries: ID, IE, PG Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Fl. Colour: cream, pink, white, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:102
A ssp. superbo corollae tubo brevissimo, disco dense pilis erectis albis piloso et squamis in ovario rotundatis nec lacerato-acutis differt. Twigs c.5mm in diameter, pale green, slightly glaucous, with dense brown scales which quickly fall off. Leaves in loose pseudowhorls, 4–10cm apart. Flower buds green, 35 x 25mm, ovate with a broadly pointed apex, all bracts appressed, the outer broadly ovate or obovate to sub-circular, with the apex splitting to become emarginate, appressed hairy on both sides, and with very sparse small brown scales outside, fringed with scales. Inner floral bracts white, spathulate, hairy on both sides and fringed with scales. Bracteoles white, linear to narrowly spathulate, slightly broadened upwards to 3mm wide, hairy on both sides and fringed with scales. Inflorescence of 2–3 flowers, held horizontally or half-hanging. Pedicels c.16 x 4mm, densely brown scaly and white hairy, becoming densely hairy also distally just below the flower. Flowers 75 x 108mm, white, powerfully carnation-scented, mostly 6-lobed, but occasionally 5; tube 35 x 12 x 19mm, straight, green fading to cream; lobes 45 x 40mm, the sides somewhat reflexed overlapping to c.1⁄3, spreading to the horizontal. Stamens at first loosely clustered on the lower side of the mouth, spreading irregularly as the flower ages, exserted to 25mm; filaments green to cream, patently hairy in the proximal ½; anthers 8–9mm, white becoming pale brown. Disc green, densely hairy with erect white hairs on the upper side, only sparsely hairy on the side. Ovary densely scaly, without hairs; style scaly for c.1mm at the base otherwise completely glabrous; style and stigma green, lying on upper side of tube, the stigma at the mouth of the flower on opening, exserted to c.25mm with age and strongly curving upwards.
Distribution: Indonesia, New Guinea (W), Ibele Valley.
Named after the river valley where this was first collected.
This collection keys out in Sleumer (1966) to R. superbum but differs in the very short corolla tube, the densely hairy disc and the totally different, rounded, not laciniate pointed scales on the ovary. It is otherwise very similar. It was found while searching for R. gardenia in the type locality of this species and was at first thought to be R. gardenia but that species has the ovary covered by long simple hairs as well as the scales. This species was growing with R. inundatum and a hybrid between these species was collected. It is tempting to think that the distinctive rounded scales of this subspecies might be due to introgression with R. inundatum.
Type: Argent, Mendum & Smith 19930918, 27 May 2004. Indonesia, Irian Jaya, Ibele Valley near Wamena (BO, E).
Stiff shrub to 6m. Twigs 5–7mm in diameter, rounded, pale green, densely, fragilely, brown-stellate-scaly, the older parts glabrescent, rough; internodes 5–10cm. Leaves 4 together in pseudowhorls or spirally arranged. Blade 75–120 x 45–80mm, broadly ovate, broadly elliptic, sometimes obovate-elliptic; apex broadly tapering and shortly acuminate or obtuse to rounded; margin entire, flat; base broadly tapering, truncate to rounded or slightly cordate, young ones densely covered on both sides with small, golden scales quickly becoming glabrescent above, more slowly so beneath, eventually rough on both sides. Scales sub-dendroid, irregularly stellately divided at the margin, each on top of a distinct persistent epidermal tubercle. Mid-vein broadly raised at the base, grooved in the proximal ½ above, narrow and impressed distally, beneath broadly raised proximally narrowing and becoming level before the apex; lateral veins 5–8 per side, the two lowest almost from the base of the blade, the upper ones spreading at about 45°, all straight proximally, curved before the edge and anastomosing, a little prominent on both sides, no distinct reticulation visible. Petiole 15–30 x 3–5mm, grooved only distally above otherwise smooth and flattened above, brown-scaly and becoming glaucous white with age. Flower buds to 35 x 25mm, broadly ellipsoid, with a rounded apex, smooth, with all the bracts appressed, green to deep purple. Bracts ovate, tough, densely covered with coarse, thick, hairs and rough to the touch outside. Bracteoles to 50 x 5mm, linear to linear-spathulate, laxly hairy. Inflorescence an open, 3–6-flowered umbel, the flowers horizontal to half-hanging. Pedicels 12–24 x 2–4mm, densely brown, stellate-scaly, sometimes with white hairs especially distally. Calyx 7–9mm in diameter, a low, cup-shaped, disc, scaly outside, with rounded or broadly pointed lobes up to 2mm, distinctly shortly fringed, rarely much larger and petaloid. Corolla 55–140 x 70–120mm, funnel- or widely trumpet-shaped, fleshy or waxy in texture, white to cream or very light yellow, sometimes faintly flushed with pink, and shades to deep pink, strongly scented; tube 65–75 x 10–12 x 20–25mm, gradually broadening from the base upwards, laxly scaly to glabrous outside, covered with white, retrorse, dense hairs in the lower ½ inside, glabrous otherwise; lobes 40–50 x 30–35mm, 6–7, spreading horizontally, broadly obovate or spathulate, glabrous. Stamens 12 or 14, exserted to 12mm, unequal, clustered on the lower side of the flower; filaments green, linear, c.1mm wide at the base, very densely patently hairy below, less so, or even glabrous and narrower in the upper ½–¾; anthers 8–9 x c.1.5mm, linear-oblong, white, the cells minutely lobed at the base. Disc c.1mm high, glabrous to sparsely hairy. Ovary 10–12 x c.4mm, elongate-conical, densely covered with brown, stellate scales, somewhat abruptly narrowed distally; style 55–65 x c.2mm, red or green, lying on the lower side of the tube but curving upwards as the flower ages to present the stigma in a central position when it is receptive, completely glabrous, or with just a few scales at the base; stigma rounded, 7–8mm in diameter, obscurely 6–7-lobed. Fruit c.50 x 13mm, cylindrical, shortly narrowed at both ends, widest above the middle. Seeds 7–8mm including the tails.
Habitat: Generally epiphytic on the upper branches of large trees, apparently with preference just below the true moss forest level; terrestrial on Mt Michael and Mt Giluwe, in low shrubberies and on the edge of cloud forest 1525–3050m, in Uinba (Minj–Nona Divide) recorded in fallow native gardens at 1970m.
Distribution: Papua New Guinea, from Mt Giluwe in the north to Mt Albert Edward in the south on the Central Ranges. It is also known from the Finisterre and Saruwaket Mts and there are records from the outlying islands of New Ireland (Hans Meyer Range), and the Louisiade Archipelago.
Altitude: 1525-3050m
Hybridising in the wild with R. hellwigii where these species overlap to give deep pink intermediate forms. It is possible that all the really pink forms of R. superbum are of hybrid origin.
Usually a free-growing shrub to 4 m. Young growth not loriform-setose. Leaves narrowly elliptic, tapered to the base and the somewhat acuminate apex, 80-120 x 30-50 mm, upper surface brownish green, margins often persistently lorifom-ciliate, lower surface brown, with a dense covering of dark, unequal, overlapping flaky scales; petiole glabrous or sometimes loriform-setose. Inflorescence 3-4-flowered, pedicels densely lepidote. Calyx short, disc-like, scarcely lobed, the margins loriform-ciliate. Corolla pale pink (always?), openly funnel-campanulate, (43-)56-65 mm, tube (25-)33-42 mm, pubescent at the base, sparsely lepidote over the whole surface. Stamens 10, filaments pubescent towards the base. Ovary lepidote, tapered into the style which is lepidote to well above the base. Capsule unknown.
Habitat: Jungle,
Distribution: Thailand (Chiengmai province)
Altitude: Around 1560m
A specimen from the S Shan states of Burma (McGregor 534) appears to be the same as the Siamese material except in its very broad leaves and shorter corolla.
Type: Siam, Chiengmai, Doi Sutep, 1560 m, 7 vi 1914, Kerr 3238 (holo. E)
Occurs in Countries: TH Altitude Ranges: 1,000 - 2,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: pink
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):55
Shrub, 1-5 m. Leaves oblong-lanceolate, 11-25 x 3.5-5cm, 3.3-4.2 x as long as broad, apex acuminate to cuspidate, base broadly cuneate, lower surface with a floccose, ± persistent indumentum along the midrib, otherwise glabrous; petioles 1.7-2.5 cm, with a floccose indumentum. Inflorescence c.lO-flowered; rhachis 10-15 mm; pedicels 20-25 mm, glabrescent. Calyx 1-2 mm, glabrous. Corolla 5(-6)-lobed, widely campanulate, glabrous outside, densely puberulent within, rose-pink, with darker flecks but no basal blotch, 50-75 mm; stamens 12-15, filaments with hairs at base. Ovary and style glabrous; stigma capitate. Capsule 45-50 x c. 12 mm, slightly curved.
Habitat: Forests, etc.
Distribution: China (N Sichuan, Shaanxi, Hubei, Guizhou, Guangxi)
Illustrations:
A specimen, Chu, K. N. 2309, from Sichuan, Tien chuan, has a few-flowered inflorescence as in R. sutchuenense but has glabrous leaves and a large stigma as in R. calophytum var. openshawianum. The status of this plant remains in doubt.
R. X geraldii (Hutchinson) Ivens, Gard. Chron. ser. 3, 101:220(1937) R. sutchuenensex X R. praevernum. Syn: R. sutchuenense Franchet var. geraldii Hutchinson, Gard. Chron. ser. 3, 67:127 (1920). Type: presumed to be a plant grown by Gerald Loder and exhibited in 1920-n.v. Intermediate between the two parents; leaves with a ± persistent indumentum on the lower surface of the midrib; corolla with a pronounced blotch.
Wilson's field notes for plants referred to R. sutchuenense (PL Wilsonianae 1:544, 1913) indicate that the four plants collected under the number 509 had corollas with a blotch, suggesting that they are not referable to R. sutchuenense in the strict sense. Indeed, the two unlocalised herbarium specimens seen {Wilson 509, 509a) are almost certainly referable to R. x geraldii though they are apparently closer to R. praevernum than they are to R. sutchuenense. In cultivation plants raised from seed as Wilson 509 have proved to be very variable (see Osborn in Gard. Chron. ser. 3, 73:159, 1923) suggesting a hybrid origin for at least part of this batch of seed. It therefore seems probable that the hybrid occurs in the wild when the two parents meet.
Type: China, E Sichuan, aux environs de Tchen-keou-tin, Farges (iso.E)
Occurs in Countries: CN Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: rose
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):226
Shrub to 2m. Twigs to 5mm in diameter, obtusely angular or laterally compressed, densely brown, stellate-scaly; internodes 5–12cm. Leaves 5–6 together in loose pseudowhorls or laxly arranged in the upper 1⁄3 of the internodes. Blade 60–90 x 40–60mm, broadly elliptic or sub-ovate-elliptic; apex broadly obtuse to rounded, sometimes slightly retuse; margin entire, narrowly revolute, especially proximally; base broadly tapering to rounded, or sub-cordate, laxly covered with reddish-brown scales on both sides initially. Scales very variable in size, stellate to sub-dendroid, each on top of minute epidermal tubercles. Mid-vein thick and prominent, grooved proximally, gradually becoming flat distally above, strongly raised below, gradually less so distally; lateral veins 7–8 per side, irregular, some deeply forked, indistinctly anastomosing before the margin, smooth when fresh, slightly impressed above, prominent below when dry, reticulation obscure. Petiole 10–20 x c.2mm, weakly grooved above, densely brown-scaly. Outer bracts ovate to sub-circular, to 20 x 20mm, inner ones to 35 x 18mm, spathulate, innermost ones elongate-spathulate, to 50 x 10mm, all laxly short-hairy outside, internally more densely and longer, appressed hairy. Bracteoles 40–50 x 2–5mm, sub-spathulate-linear, hairy especially along the margin. Inflorescence an 8–14-flowered open umbel. Pedicels 5–7 x 1.5–2mm, laxly scaly. Calyx c.5mm in diameter, oblique, rim-like, obscurely lobed. Corolla 100–110 x 55mm, trumpet-shaped, pink, strongly scented, weakly zygomorphic; tube 85–105 x 6–9 x 10–15mm, sub-densely scaly outside, hairy for ¾ of the tube inside, straight or slightly curved, strongly angled in the proximal ½, gradually widening for the proximal 65mm, (where curved), then parallel for the remainder; lobes 26–27 x 24–25mm, spreading, oblong-obovate, in two groups: three upper overlapping to 2/3; two lower, widely separated from the upper three, overlapping 1⁄3–½. Stamens exserted to 15mm, grouped on the lower side of the mouth, becoming reflexed back against the corolla lobes with age; filaments linear, hairy for c.¾ proximally, narrower and glabrous distally; anthers 5–6 x 1–1.3mm, narrowly oblong, base of each cell apiculate. Disc glabrous. Ovary 12–15 x c.3mm, elongate-cylindrical, densely covered with white or yellowish appressed hairs, which cover the scales, tapering distally; style exserted to 15mm, pink, densely covered with hairs and scales proximally, becoming less hairy and more scaly, glabrous for the distal 10mm; stigma c.1.5mm in diameter, 5-lobed, green. Fruit to 50 x 7mm.
Habitat: Both epiphytic in dense forest and terrestrial in open disturbed Nothofagus summit forest or shrubberies
Distribution: Indonesia, New Guinea (W), Arfak Mts: Mt Saru-mot, Anggi Gigi Lake, Mt Carstensz.
Altitude: 2200-3000m
Greek – syrinx – a shepherd’s pipe, alluding to the shape of the flowers.
Type: Sleumer & Vink 4442, 26 Jan. 1962. New Guinea (NW), Arfak Mts, summit of Mt Saru-mot near Iray, Anggi Gigi Lake, 2350m (L, K).
Occurs in Countries: ID Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: pink
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:175
Very similar to R. lindleyi, differing as follows: frequently a free-growing shrub, calyx lobes 17-19 x 11 mm, not filiform-acicular-ciliate but often margined with quickly deciduous scales.
Habitat: Forest margins and scrub
Distribution: NE Burma, China (NW Yunnan)
Altitude: 1800-3700m
Illustrations:
An extremely attractive species, closely related to, and vicariating with, R. lindleyi. The distinctions between it and R. headfortianum (which is thought to have originated from China, SE Xizang—Tsangpo gorge, below Pemakochung, Kingdon Ward 6310) are too slight for recognition as separate species.
Type: NE Upper Burma, western flank of the N'Maikha-Salween Divide, near Pan-ti-lo, 10000-11000 ft, Forrest 26440 (holo. E)
Synonymy: R. headfortianum Hutchinson, Bot. Mag. 163: t. 9614 (1942). Type: a cultivated plant (holo. K)
Occurs in Countries: CN, MM Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Rhododendron Habit: Non-Tree
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):38
Small tree about 10 m high, with glabrous branches. Leaves glabrous; blade oblong-oblanceolate 100-140 x 30-35 mm, base narrowly cuneate, apex acuminate or acute, lateral veins evident; petiole c.l5mm long. Inflorescence buds lateral, 3- or more-flowered; bud scales glabrous except for minute cilia on the margin and apex, caducous; pedicels glandular-pilose, c.l5mm long. Calyx of 5 very short glabrous lobes. Corolla white, c.40 cm long, with a short tube and spreading oblong-elliptic lobes. Stamens 10, slightly shorter than the corolla, filaments slightly pilose, anthers 3 mm long. Ovary cylindric, glabrous; style glabrous, c.40 mm long. Capsule unknown.
Distribution: Thailand (Nakawn Sritamarat Province)
An inadequately known species from northern Thailand. Similar to the neighbouring R. henryi but with larger leaves (in the key published by Sleumer (1958) the characters of this species and of R. henryi were inadvertently transposed).
Type: Thailand, Nakawn, Sritamarat Province, Kao Luang, c. 1400 m, Kerr 15512 (holo. K, iso. BM).
Occurs in Countries: TH Subgenus: Azaleastrum Habit: Tree
Philipson, W.R. & Philipson, M.N. (1986) A Revision of Rhododendron III. Subgenera Azaleastrum, Mumeazalea, Candidastrum and Therorhodion. Notes from the Royal Botanic Garden Edinburgh 44(1):13
Shrub, 1-I.5m; young shoots covered with adpressed brown hairs. Leaves monomorphic, subpersistent, coriaceous, ovate-oblong to oblong-lanceolate, 1.5~2(-3) x 0.7-1.2(-1.8)cm, 1.7-2 x as long as broad, apex acute, mucronate, base cuneate, margin entire, upper surface sparsely strigose, lower surface densely strigose; petioles 2-3mm, adpressed-strigose. Inflorescence (l-)2-3-flowered; pedicels 5-7mm, densely covered with reddish-brown hairs. Calyx densely reddish-brown-hirsute, lobes rounded, l-2mm. Corolla broadly funnel-campanulate, 10-15(-20)mm long, 15-20mm across, pink with rose flecks; tube 4-6mm, glabrous. Stamens 9-10, unequal, filaments villose in lower half. Ovary greyish-pubescent; style pubescent in lower half. Capsule not known.
Habitat: Alpine meadows
Distribution: China (N Taiwan)
Altitude: 2800-3000m
Illustrations:
The holotype cannot be located at Kyoto. Therefore our knowledge of this species is based on a specimen that lacks flowers (Yamazaki et al. 235) from the type locality.
Originally described as being allied to R. oldhamii but lacking the glandular indumentum of that species.
Type: Taiwan, Nankotaisan, O/nW 2580 (holo. KYO, n.v.)
Occurs in Countries: CN, TW Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: pink, rose
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):111
Shrub to 80cm. Twigs c.2mm in diameter, sub-densely scaly with flat appressed scales but without simple hairs; internodes 2.5–10cm. Leaves in tight pseudowhorls of 3–8 together. Blade 25–40 x 12–22mm, elliptic to obovate; apex obtuse to rounded; margin entire, narrowly revolute; base broadly tapering, then decurrent with very narrow flanges on each side of the petiole; upper leaf surface glabrescent; lower surface sparsely and more persistently scaly. Scales disc-shaped with broad, silvery, lobed margins and dark centres, slightly impressed. Mid-vein narrowly impressed above, raised beneath for most of its length; lateral veins 2–5 slender, straight veins arising at an acute angle on each side, and disappearing before the margin or obscure, reticulation obscure. Petiole 2–3 x 1–1.5mm, grooved above, somewhat flattened, smooth, densely scaly when young and with narrow lateral wings. Flower buds to c.7 x 4mm. The outer bracts subulate, the inner ovate, somewhat scaly in the central area outside and with a fringe of scales along the margins, without simple hairs. Bracteoles filiform, glabrous. Inflorescence c.4-flowered umbels. Pedicels 10–14 x 0.6mm, sub-densely scaly but without simple hairs. Flowers narrowly funnel-shaped, pink or red. Calyx a low disc, only weakly lobed, densely scaly outside, glabrous within. Corolla 35–43 x c.30mm; tube c.20 x 4 x 8mm, slightly curved, moderately to densely scaly outside, densely patently hairy inside; lobes c.20–24 x 12mm, laxly scaly outside. Stamens exserted to c.10mm; filaments patently hairy in the proximal 2⁄3, glabrous distally; anthers 1.8 x 0.7mm, with rounded bases to the cells and oblique pores. Disc prominent, densely hairy along the upper margin. Ovary c.4 x 1.8mm, sub-ovoid, densely covered in sub-appressed silvery hairs which partially cover an underlayer of brown scales, tapering abruptly distally; style c.20mm, sparsely patently hairy in the proximal 1⁄3, glabrous distally and entirely without scales along its whole length; stigma c.2.5mm in diameter, a broad irregular disc. Fruit c.17 x 4mm, with the hairs persisting and becoming patent, the outer layer peeling irregularly and the valves spreading and twisting on dehiscence.
Habitat: Epiphytic in mossy montane forest and a ridge dominated by Syzygium and Podocarpus.
Distribution: Papua New Guinea, New Ireland, Hans Meyer Range, ridge adjacent to the Weitin River and Mt Angil.
Altitude: 1175-1800m
Named after Dr Wayne Takeuchi, the senior collector of the type of this species and an experienced botanist in New Guinea.
Very similar to small-leafed forms of R. culminicola from the New Guinea mainland but these are all from very much higher altitude (above 3000m) than the present species. The base of the leaf blade in R. takeuchii is decurrent, with narrow wings which extend for virtually the entire length of the petiole, whereas in R. culminicola the base although sometimes narrowly tapering clearly stops at the petiole. The petioles themselves are quite different: those of R. culminicola are much more robust, being at least 2mm wide and rugose, while in R. takeuchii they are less than 1.5mm wide and quite smooth in comparable dried specimens. The flower measurements given by Sleumer (1966) for R. culminicola are so wide as to encompass those of R. takeuchii but if the ratio of corolla lobes to corolla tube length is used there is a clear distinction between them: R. culminicola has lobes ¼–1⁄3 the length of the tube whereas R. takeuchii has lobes well over ½ the length of the tube. Rhododendron takeuchii superficially resembles R. neobritannicum which would seem a more likely geographical alliance as this species comes from the adjacent island of New Britain; however, R. neobritannicum has totally different scales, being in section Phaeovireya, a glabrous corolla and filaments and an ovary lacking simple hairs.
Type: Takeuchi & Wiakabu 9528, 26 Jan. 1994. Papua New Guinea, New Ireland, Hans Meyer Range, ridge adjacent to the Weitin River, c.1175m (A, LAE, L).
Occurs in Countries: IE, PG Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:221
Shrub, 0.8-4m. Leaves 5-11 x 2-4cm, 2.2-3(-3.5) x as long as broad, apex acute, base rounded to ± cuneate, lower surface with a dense fulvous bistrate indumentum, the upper layer ramiform, tomentose, loose to ± felted, the lower layer compacted; petioles 0.5-lcm, tomentose. Inflorescence 10-20-flowered; rhachis 5-15mm; pedicels 10-20mm, tomentose and glandular. Calyx 0.5-2mm, glabrous. Corolla white to (rarely) yellow, sometimes flushed with pink, with crimson flecks, 30-35mm. Ovary and style glabrous. Capsule 15-20 x c. 7mm.
Habitat: Meadows, rocky slopes, Rhododendron thickets
Distribution: China (W Yunnan)
Altitude: 3050-3650m
The following fruiting material, from W Yunnan though without precise localities, differs in its rufous leaf indumentum but otherwise resembles R. taliense closely: Forrest 29130, 29132, 29252, 29258, 29326, 29328, 29329. The status of these plants is in some doubt, particularly since flowering material is not available.
R. taliense is closely allied to R. sphaeroblastum, from which it differs in its narrower leaves, and to R. alutaceum (q.v.). Plants apparently intermediate between R. taliense and R. roxieanum var. cucullatum are as follows: McLaren C 21; Rock 6253, 6264, 6365.
Type: China, Yunnan, in monte Tsang-chan, supra Tali, 4000m, Delavay 160 (iso. E, K)
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: crimson, pink, yellow
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):343
Shrub to small tree, l-4(-10)m. Leaves coriaceous, elliptic to oblanceolate, 7.5-15 x 3-5cm, 2.5-5 x as long as broad, apex acuminate, base ± cuneate, margin not undulate, upper surface glabrous, lower surface glabrous or with a thin veil of indumentum, numerous red punctate hair-bases also present; petioles l-2cm, glabrous. Inflorescence lax, 4-8-flowered; rhachis c.5mm; pedicels 10-15mm, sparsely to densely tomentose, with or without glands. Calyx c.2mm, glandular, sometimes also tomentose. Corolla tubular-campanulate, glabrous within, deep pink to deep crimson, with black nectar pouches and few to many flecks, 45-55mm. Ovary glabrous to rufous-tomentose and glandular; style glabrous. Capsule 11-23 x 5-8mm.
Habitat: Broad-leaved and pine forests, Rhododendron thickets
Distribution: China (W Yunnan), ne Upper Burma, ne India (Arunachal Pradesh)
Altitude: 1850-3350m
Occurs in Countries: CN, IN, MM Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: black, crimson, pink
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):300
Leaves with a persistent indumentum beneath; pedicels glandular; ovary tomentose and glandular
The persistence of the indumentum of var. pennivenium may be due to adherence caused by a secretion from the more abundant glands on the young leaves; both varieties are apparently equally tomentose when young. R. ombrachares, which has ± glabrous leaves but a tomentose ovary, may be considered intermediate between the two varieties. R. cerochitum, with pink flowers, is apparently no more than a colour variant of var. tanastylum. Sleumer (Blumea, suppl. 3: 55, 1946) treats R. petelotii Dop as a synonym of R. tanastylum. The type is in bud and is too poor for detailed study though the leaves are narrower (c.15 x 3cm) than is usual in Chinese R. tanastylum.
Synonymy: R. pennivenium Balfour f. & Forrest, Notes R.B.G. Edinb. 13: 55 (1920). Type: China, W Yunnan, Shweli/Salween divide, 10000ft, v 1917, Forrest 15745 (holo. E). ?R. petelotii Dop, Fl. Gen. Indo-Chine 3: 733 (1930). Type: Vietnam, Tonkin prov. Lao Kay route de la-Qui-Ho, pres de Cha-pa, 1900m, Petelot 5135 (holo. P).
Leaves at maturity ± glabrous beneath; pedicels eglandular
Type: E Upper Burma, Hpimaw, 9000-10000ft, 19 v 1914, Kingdon-Ward 1566 (holo. E)
Synonymy: R. cerochitum Balfour f. & Forrest, Notes R.B.G. Edinb. 13: 36 (1920). Type: China, W Yunnan, Shweli/Salween divide, vi 1918, Forrest 15766 (holo. E;iso. K). R. ombracharesBalfour f. &Kindon-Ward, Notes R.B.G. Edinb. 13:280 (1922). Type: NE Upper Burma, Laktang, 8000ft, 20 x 1919, Kingdon-Ward 3041 (holo. E).
A low matted or rounded, densely branched shrub, prostrate or up to 90 cm. Leaves 4-12(—17) x (2-)3-8(-9.5) mm, broadly elliptic to rotund, apex obtuse or rounded, emucronate or with slight mucro, base broadly cuneate, undersurface uniformly rufous, densely covered with contiguous scales. Inflorescence l-3(-4)-flowered, pedicels lepidote, sometimes puberulous, 1-5-3 mm. Calyx obsolete or up to 2 mm with rounded or deltoid lobes, variably lepidote or ciliate. Corolla usually purplish or purplish blue, sometimes violet or rose, exceptionally yellow, broadly funnel-shaped, pubescent inside and sometimes on the outside as well, 9-16 mm, tube 3-5 mm. Stamens 10 or rarely 5-6, filaments pubescent towards the base. Ovary lepidote, style exceeding the stamens (very rarely shorter), glabrous or pubescent towards the base. Capsule ovoid, lepidote, 5-7 mm.
Habitat: Open alpine slopes and bare screes
Distribution: NE Burma, China (NW Yunnan, SE Xizang)
Altitude: 3500-4600m
The Philipsons (1975, p. 28) record natural hybrids between R. tapeti-forme and various other species. R. chamaezelum Balfour f. & Forrest, Notes R.B.G. Edinb. 13:241, 1922 (Type: China, Yunnan, Mekong/Sal-ween Divide, 12000 ft, vi 1917, Forrest 14074, holo. E) is considered to be of hybrid origin, between R. tapetifonne and R. rupicola var. chryseum.
Type: China, Tibet/Yunnan frontier, Ka-gwr-pu, 4550 m, vii 1913, Kingdon Ward 195 (holo. E)
Occurs in Countries: CN, MM Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: blue, rose, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):99
Branched shrub, 2-6m; young shoots covered with ± flattened weak brown hairs, soon becoming glabrous. Leaves apparently monomorphic, persistent, 2-3 at apex of branches, elliptic-obovate, 4.5-7 x 1.5-2.5cm, apex acute, base cuneate, margin ± entire, both surfaces at first clothed with adpressed grey-brown hairs, becoming glabrous above, lower surface glabrous except along midrib; petioles 4-10mm, covered with adpressed brown hairs. Inflorescence 2-5-flowered; pedicels 8-15mm, densely clothed with strigose brown hairs. Calyx 1mm, densely clothed with strigose brown hairs. Corolla broadly funnel-campanulate, 25-40mm, pale rose-purple, sparingly spotted. Stamens 10(-12), glabrous. Ovary densely clothed with adpressed, flattened, shiny brown hairs; style thickened towards apex, glabrous, Capsule 8-12mm, clothed with flattened brown hairs.
Habitat: Evergreen forests, on slopes
Distribution: Japan (Liukiu and Kawanabe Islands, Yakushima, Kyushyu), S Taiwan?
Altitude: 0-500m
Illustrations:
The hybrid between R. tashiroi and R. reticulatum has been named R. x tak-amashanianum Sugimoto (J. Geobot. 22: 53, 1975).
Type: in Japoniae australis ins. Tanega-sima, Tashiro (holo. LE, n.v.)
Occurs in Countries: JP, TW Altitude Ranges: 0 - 1,000m Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: rose
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):111
Shrub, 0-3-5 m. Young growth usually deep reddish crimson. Leaves up to 2 x longer than broad, 22-42(-52) x 12-23(-27) mm, broadly to narrowly elliptic, base rounded to subcordate, rarely somewhat cuneate, usually lepidote above with dried-out scales, the undersurface with a dense covering of small, slightly unequal, brown, narrowly rimmed (dark centre making up more than Vi of the scale diameter) scales 1-2 x their own diameter apart; petiole and upper surface of midrib somewhat puberulent. Inflorescence few-flowered; pedicels straight, lepidote, 5—10(—11) mm, rarely slightly puberulent. Calyx disc-like or undulate, often ciliate with filiform-acicular or more rarely loriform hairs. Corolla (16-)17-21 mm, rose, whitish rose-pink or lavender, usually completely elepidote outside. Capsule (7-)8-12 mm.
Habitat: Scrub and thickets and on forest margins, rarely in moist meadows or on stream sides, 2100-4250 m
Distribution: China (N & NW Yunnan, SW Sichuan)
A rather variable species, vicariating with (to the south of) R. davidsonianum. A few specimens are somewhat intermediate between the two, in particular those hitherto referred to R. hypophaeum, which agrees with tatsienense in the shortly pedicelled, small flowers and with davidsonianum in the narrower leaves.
Type: China, Su-tchuen occidental, aux environs de Tatsienlu dans la vallee de Jerikkou, Soutie (holo. P—n.v., iso. E)
Synonymy: R. tapelouense Leveille, Bull. Geogr. Bot. 25:20 (1915). Type: China, Yunnan, mt Ta-pe-Iou, 3200 m, v 1912, Maire (holo. E). R. stereophyllum Balfour f. & W. W. Smith, Notes R.B.G. Edinb. 10:159 (1916). Type: China, Yunnan, mountains in the NE of the Yangtze bend, 10000 ft, Forrest 11299 (holo. E). R. hypophaeum Balfour f. & Forrest, Notes R.B.G. Edinb. 12:120 (1920). Type: China, SW Szechuan, mountains around Muli, 11000 ft, Forrest 16249 (holo. E). R. leilungense Balfour f. & Forrest, Notes R.B.G. Edinb. 13:273 (1922). Type: China, Yunnan, Lei-lung shan, 9000 ft, Forrest 15208 (holo. E). R. heishuense Fang, Acta Phytotax. Sinica2:83 (1933). Type: China, Szechuan, Hei-shou-ho, Mao-hsien, 2900 m, 22 vi-3 vii 1931, Lee 2253 & 2323 (holo. CHENGDU—n.v.)
Occurs in Countries: CN Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: lavender, rose
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):65
Shrub to 1m. Twigs 1–2mm in diameter, rounded, laxly brown scaly and minutely hairy; internodes 1–3cm. Leaves crowded into moderately dense pseudowhorls of 12–25 at the upper 3–4 nodes. Blade 25–43 x 1.5–3mm, linear, sub-sessile; apex acute to obtuse; margin flat, minutely serrulate with impressed scales when young; base tapering, glabrescent above at maturity, laxly and irregularly scaly beneath. Scales flat, sub-circular or weakly lobed; centre small, impressed. Mid-vein in a groove above, smooth below; lateral veins not visible. Petiole 1.5–2.5 x 0.75–1mm, not clearly distinct from the lamina, not grooved above, scaly. Flower buds at first conical, later ovate, acutely pointed, to 12 x 7mm, green, the bracts appressed or slightly spreading at the apex. Bracts broadly ovate, abruptly subulate at the apex, glabrous outside, or with a few scales near the apices, margin densely brown scaly, to 12 x 6mm. Bracteoles linear, laxly hairy and scaly, c.6mm. Flowers occasionally solitary, mostly 3–5 flowers in an open umbel, half-hanging although occasionally caught up in the new leaves and held semi-erect. Pedicels slender, hairy and laxly scaly, c.10mm. Calyx disc-shaped, scaly and shortly hairy outside, obtusely and shortly 5-lobed, 3–4mm in diameter. Corolla 16–20 x 20–25mm, tubular-sub-campanulate, white, without scent; tube 10 x 4 x 7–8mm, laxly sub-stellately-scaly outside, hairy within; lobes c.10 x 8mm, broadly obovate, scaly centrally near the base, apex rounded. Stamens spread evenly all round at the mouth of the corolla, not exserted, distinctly dimorphic; filaments white, linear, sub-densely to laxly patently hairy nearly to the top; anthers c.2mm, brown, oblong. Disc glabrous. Ovary c.3 x 1.5mm, sub-cylindrical, densely, patently, white-hairy, with a few scales between the hairs; style columnar, hairy below, glabrous distally, c.5mm; stigma sub-globose, green at first lying on the lower side of the tube, centrally placed in old flowers. Fruit 9–14 x 4–5mm, pale yellowish-green. Seeds 1.8–2.2mm, without tails 0.9–1mm, the longest tail 0.7mm.
Habitat: Epiphytic on trees in mossy montane forest.
Distribution: Philippines, Luzon, Mt Pulag (Pulog)
Altitude: 2600-2700m
Like a Taxus – a small genus of gymnosperms with similar narrow leaves.
Rhododendron taxifolium must be considered a threatened species in the wild as it is restricted to the montane forest. This vegetation, despite being in a national park, is dwindling in extent due to illegal incursions of farmers from below and fires in the summit grasslands above. The mountains viewed in all directions are devoid of montane forest. This makes it unlikely to be found elsewhere.
Type: Ramos & Edaño B.S. 44880, 27 Feb. 1925. Philippines, Luzon, Benguet, Mt Pulog, c.2700m (PNH†, A, BM, E, K, L, P).
Occurs in Countries: PH Altitude Ranges: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:205
Shrub to 1.5m. Twigs densely covered with fragile scales on short stalks, which remain in form of small, dense warts. Leaves densely spirally arranged. Blade 6–12 x 2–3mm, narrowly elliptic, apex obtusely acuminate, margin recurved in dry specimens, the edge somewhat thickened and crenulate with impressions where the scales are attached; base tapering gradually but finally broadly tapering to rounded, shining green above and light green with brown scales beneath, glabrescent above; beneath laxly scaly, more densely so on the mid-vein, convex. Scales sessile, circular or nearly so, entire to irregularly undulate; marginal zone narrow; centre large, thick, dark and impressed. Mid-vein very slightly grooved proximally above, thick and obtusely raised beneath; lateral veins indistinct. Petiole 1.5–2mm, thick, scaly. Bracts to 6 x 3mm, narrowly ovate, apiculate; outer ones laxly scaly outside, inner ones densely hairy, ciliate along the margins. Bracteoles to 5mm, linear, hairy outside. Flowers mostly in twos, sometimes solitary, hanging vertically down. Pedicels 8–9mm, slender, sub-densely covered with shortly stalked scales and short hairs. Calyx c.3mm in diameter, oblique, small disc-shaped, wavy, shortly obtusely 5-lobed, scaly, margin laxly set with white hairs. Corolla 14–18mm, dark red; tube 10–14 x 2.5 x 5mm, cylindrical, oblique and curved, densely scaly outside, glabrous inside; lobes 2.5–3.5 x 2–3mm, sub-circular to ovate, minutely irregularly crenulate and ciliate, scaly outside except the upper part of the lobes, which bears some sparse hairs. Stamens unequal, the longest nearly equalling the corolla; filaments filiform, glabrous; anthers c.1mm, sub-elliptic. Disc glabrous. Ovary c.2.5 x 1.5mm, obliquely conical, 5-ribbed, densely scaly, gradually tapering distally; style glabrous, c.10mm; stigma thick-obconical, distinctly lobed. Fruit 8.5–12 x 2–3mm, obliquely fusiform, sparsely scaly.
Habitat: On open slopes or summits on serpentine rocks
Distribution: Indonesia, New Guinea (W), Mt Doorman
Altitude: 3250-3520m
Named after Taxus baccata, the ‘yew’, from the resemblance of the leaves to those of this tree.
Known only from the two original collections from the same locality.
Type: Lam 1598, 17 Oct. 1920. New Guinea (W), Doormantop, 3250m (BO, L).
Occurs in Countries: ID Altitude Ranges: 3,000 - 4,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:54
Much branched prostrate shrub forming dense cushions or mats, or erect and up to 1 m. Leaves 3 —12(—14) x 1 -5-5(-6-5) mm, narrowly elliptic or lanceolate to broadly elliptic or rotund, apex acute to rounded, strongly mucronate, base cuneate, undersurface golden-fawn to pale orange or reddish brown with densely overlapping scales, the majority pale gold to reddish brown mixed with few to many darker scales (these rarely absent). Inflorescence l-2(-3)-flowered, pedicels lepidote, sometimes puberulous also, 0.5-1-5(-2) mm. Calyx 0-5-2-5(-3) mm, lobes deltoid to rounded, often unequal, lepidote, margin with scales and/or long cilia. Corolla lavender or rose-pink to purple, broadly funnel-shaped, (6-)7-12(-14) mm, tube 2-4 mm, pubescent in the throat and often also outside, sparingly to densely lepidote outside. Stamens 10, varying in length, ± as long as the corolla. Ovary lepidote, style 3-17 mm, shorter than, equalling or longer than stamens, glabrous or pubescent towards the base, sometimes with a few scales. Capsule ovoid, c. 3 mm, lepidote.
Habitat: Forests, open rocky slopes, cliffs
Distribution: China (N, NW & C Yunnan, SW Sichuan)
Altitude: 2900-5000m
A variable species. The Philipsons (1975, p. 50) record natural hybrids with R. intricatum and R. thymifolium.
Type: China, Yunnan, mountains of the Chungtien plateau, 3650 m, vi 1914, Forrest 12568 (holo. E)
Synonymy: R. diacritum Balfour f. & W. W. Smith, op. cit., 225. Type: China, Yunnan, mountains of the Chungtien plateau, 13-14000 ft, v 1913, Forrest 12614 (holo. E). R. drumonium Balfour f. & W. W. Smith, op. cit.: 226. Type: China, Yunnan, valley of the Chung river, 10500 ft, v 1913, Kingdon Ward 269A (holo. E). R. idoneum Balfour f. & W. W. Smith, op. cit.: 237. Type: China, Yunnan, mountains of Chungtien plateau, 13-14000 ft, vii 1914, Forrest 12623 (holo. E). R. pycnocladum Balfour f. & W. W. Smith, op. cit.: 267. Type: China, Yunnan, Lichiang range, 10-11000 ft, v 1906, Forrest 2181 (holo. E)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m: 5,000m + Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: purple, rose
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):104
Dwarf shrub, 0.3 —1.5m; young shoots tomentose, sometimes very sparsely so, esetose to strongly setose. Leaves elliptic, 3.5—5(—8) x 1.2(-3)cm, 2.8-3.5 x as long as broad, apex rounded, apiculate, base ± rounded, upper surface glabrous, lower surface glabrous or with the remains of a whitish floccose indumentum, especially on the midrib and main veins, lower epidermis ± glaucous-papillate; petioles 0.5-l(-1.5)cm, tomentose, usually also setose. Inflorescence 2-6-flowered, lax or dense; rhachis c.5mm; pedicels 10—20mm, tomentose. Calyx 2-5mm, lobes rounded, ciliate, otherwise glabrous. Corolla fleshy, tubular-campanulate (sometimes ? campanulate), white to pink, yellow or carmine to deep crimson, 35-45mm. Ovary tomentose, sometimes with a few glands. Capsule up to 15 x 7mm.
Habitat: Moorland, cliff ledges, amongst scrub
Distribution: China (borders of SE Xizang & NW Yunnan)
Altitude: 3650-4550m
R. temenium is closely allied to both R. sanguineum and R. eudoxum but may be distinguised by its ± glabrous leaf under-surface with a glaucous epidermis. Three specimens: Rock 22235, 22270, 22645, with reddish orange flowers and leaves with the lower epidermis papillate though with a sparse indumentum, are almost certainly hybrids of R. temenium. This species apparently hybridises with R. citriniflorum (q.v.) and R. catacosmum.
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: carmine, crimson, pink, red, rose, white, yellow
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):404
Young shoots and pedicels tomentose, usually also weakly setose and stipitate-glandular; leaves glabrous beneath at maturity; inflorescence 2—4-flowered, lax; corolla 25—45mm, white to deep rose-pink; ovary tomentose.
The following fruiting specimens probably belong to var. dealbatum: Rock 6, Kingdon-Ward 3363
The type of R. glaphyrum is generally larger than is usual for var. dealbatum, with corollas up to 45 mm (as compared with 25-35mm). There are apparently no other significant differences, suggesting that R. glaphyrum is no more than a luxuriant form of var. dealbatum.
Synonymy: R. temenium Balfour f. & Forrest subsp. dealbatum Cowan, Notes R.B.G. Edinb 20: 83 (1940). Type: China, SE Xizang, Tsarong Salween/Kiu-chiang divide, 28°20'N, 98°27'E, 13-14000ft, vii 1922, Forrest 19900 (holo. E). R. glaphyrum Balfour f. & Forrest, Notes R.B.G. Edinb. 13: 45 (1920). Type: China, SE Xizang, Salween/Kiu-chiang divide, vii 1919, Forrest 18936 (holo. E; iso. K). R. eudoxum Balfour f. & Forrest subsp. glaphyrum (Balfour f. & Forrest) Tagg in Stevenson (ed.), The Species of Rhododendron 549 (1930). R. temenium Balfour f. & Forrest subsp. glaphyrum (Balfour f. & Forrest) Cowan, Notes R.B.G. Edinb. 20: 82 (1940).
Young shoots and pedicels strongly setose; leaves glabrous or with the remains of a whitish indumentum beneath, particularly on the midrib and main veins; inflorescence dense; corolla 30-35(-40)mm, yellow, sometimes faintly flushed red; ovary tomentose.
Two specimens, Forrest 21784 & 22709, with slightly papillate leaves up to 8cm long, and a lax inflorescence, are probably hybrids of var. giivum. Rock 22292 is typical of var. giivum except for the esetose young shoots.
Type: (Cowan) Chamberlain
Synonymy: R. temenium Balfour f. & Forrest subsp. giivum Cowan, Notes R.B.G. Edinb. 20: 82 (1940). Type: China, SE Xizang, Tsarong, Salween/Kiu-chiang divide, NW of Si-chi-to, 13000ft, vi 1922, Forrest 21914 (holo. E). R. temenium Balfour f. & Forrest subsp. chrysanthum Cowan, ibid. 20: 81 (1940). Type: China, SE Xizang, Tsarong, Solo La, 13000ft, Rock 22272 (holo. E).
Young shoots and pedicels strongly glandular to eglandular-setose; leaves glabrous beneath; inflorescence dense; corolla c.40mm, carmine to crimson; ovary tomentose with at most only a few glands.
Type: China, SE Xizang, Tsarong, on Ka-gwr-pw, Mekong/Salween divide, 28°25'N, 14000ft, vii 1917, Forrest 14364 (holo. E; iso. K).
Synonymy: R. pothinum Balfour f. & Forrest, Notes R.B.G. Edinb. 12: 147 (1920). Type: China, SE Xizang, Dokar-La, Mekong/Salween divide, 13-14000ft, vi 1918, Forrest 16702 (holo. E; iso. K). R. eudoxum Balfour f. & Forrest subsp. temenium (Balfour f. & Forrest) Tagg and subsp. pothinum (Balfour f. & Forrest) Tagg in Stevenson (ed.), The Species of Rhododendron 549 (1930). R. temenium Balfour f. & Forrest subsp. pothinum (Balfour f. & Forrest) Cowan, Notes R.B.G. Edinb. 20: 81 (1940).
Shrub, to lm; young shoots adpressed-sericeous. Leaves persistent, dimorphic, chartaceous; spring leaves oblong, 4.5-5 x 1.5-1.8cm, c.3 x as long as broad, apex mucronate, base cuneate, margin indistinctly crenulate-strigose, upper surface with brown strigose hairs, lower surface paler, with adpressed strigose hairs, more dense on midrib; summer leaves ovate to obovate, 20-26 x c. 10mm, otherwise as for spring leaves; petioles l-3mm, densely blackish-brown-strigose. Inflorescence 3-flowered; pedicels 5-6mm, densely brownish-sericeous. Calyx 2mm, strigose, lobes obsolete. Coro/Za funnel-campanulate, 32mm, rose-purple; tube 10 x 3-6mm, sparsely puberul-ous. Stamens 7, filaments puberulent below. Ovary densely strigose; style reddish-pilose at base. Capsule c.9 x 5mm, densely grey-strigose.
Distribution: China (Guangdong)
The author compared this species with R. mariae but it is clearly distinct in the shape of the corolla, etc.
Type: China Guangdong: Conghua Xian, Rui-tin, in monte saxi calcarei, inter dumen-tum, 14 iii 1973, S.Q Chen (S.H. Chun) 18485A (holo IBSC)
Occurs in Countries: CN Subgenus: Tsutsusi Habit: Non-Tree
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):105
Shrub, 0.5-1-3 m; bark scaling, brownish. Leaves narrowly oblanceolate to narrowly elliptic, rarely oblanceolate, rounded at the apex, cuneate at the base, (42-)50-75(-100) x (ll-)16-30(-40) mm, dark green above, brownish grey beneath, papillose and with unequal scales slightly sunk in pits in the surface, contiguous to their own diameter apart, rapidly becoming blackish or dark brown. Inflorescence 3-9-flowered, rachis usually obvious, pedicels densely lepidote, (11 —)16—18(—30) mm. Calyx lobes spreading, orbicular to oblong, rounded at the apex, 5-7(-8) mm, sparsely loriform-ciliate, lepidote at the base and frequently on the margins also. Corolla campanulate, pink to red, (17-)20-24 mm, tube 11-18 mm, variably lepidote outside, glabrous inside. Filaments pubescent towards the base. Ovary lepidote; style impressed, lepidote for approximately Vi its length from the base. Capsule ovoid-cylindric, 7-10 mm.
Habitat: Cliffs, rocky slopes, screes and alpine meadows
Distribution: India (Arunachal Pradesh), NE Burma, China (NW Yunnan, SE Xizang)
Altitude: 2450-4300m
Illustrations:
Type: Burma, Chawchi Pass, Mokuji pass, etc., 10500 ft, 20 v 1920, Farrer 1567 (holo. E)
Synonymy: R. spodopeplum Balfour f. & Farrer, op. cit.: 299. Type: Burma, crags of the Shing Hong, 10000 ft, 21 vi 1920, Farrer 1645 (holo. E). R. deleiense Hutchinson & Kingdon Ward, Notes R.B.G. Edinb. 16: 172 (1931). Type: Assam, Delei valley, 8-10000 ft, Kingdon Ward 8165 (iso. E)
Occurs in Countries: CN, IN, MM Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: pink, red
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):128
Shrub. Twigs flattened at the ultimate internodes (10cm), densely covered with fragile brown-stellate scales, becoming glabrescent. Leaves laxly spirally arranged in the upper ½ of the upper internode, the highest 2 leaves sub-opposite or 3 in a pseudowhorl. Blade 80–130 x 40–70mm, elliptic or sub-ovate-elliptic; apex obtuse, nearly rounded; margin distinctly revolute; base sub-truncate to rounded; young leaves scaly on both sides, quickly glabrescent above, more slowly so beneath, at maturity very densely covered with pale tubercles, that make them rough on both sides. Scales small, stellately divided to dendroid, each on top of a distinct epidermal tubercle. Mid-vein as thick as the petiole below, gradually narrower towards the apex of the lamina, slightly impressed above, prominent beneath; lateral veins c.8 per side, straight and clearly raised below, disappearing upwards on both sides, no distinct reticulation. Petiole 20–25 x 3–4mm, a little flattened, grooved above, densely scaly and minutely warty. Outer bracts c.20 x 10–15mm, ovate, obtuse, rough with numerous, stiff, short hairs both in and outside, middle ones obovate, 25–40 x 20–30mm and similarly rough, innermost ones 40–70 x 25–30mm, spathulate, covered with longer, stiff, appressed hairs at the base outside, minutely tubercled upwards. Bracteoles c.50 x 2mm, linear-spathulate, sub-densely hairy. Inflorescence 3–5-flowered. Pedicels 6–15 x 2–2.5mm, brown-stellate-scaly, not hairy. Calyx disc-shaped, membranous, very short, wavy, obscurely lobed, scaly outside, glabrous inside, the lobes very laxly and shortly whitish ciliate. Corolla c.90mm, funnel-shaped, fleshy, colour not known (white or pinkish?); tube 50 x 8 x 15mm, straight, laxly stellately scaly outside, densely covered with retrorse hairs in the proximal ½ inside; lobes c.40 x 20–25mm, 7, obovate-spathulate. Stamens 14, 70–80mm long; filaments linear and densely patently long-hairy proximally, becoming more laxly hairy, glabrous distally; anthers 10–11 x 1.5mm, linear-oblong, the base obtuse. Disc densely white-hairy. Ovary c.2mm long, c.5mm diameter below, 2.5mm diameter in the upper part, cylindrical, densely hairy and scaly below, constricted upwards in form of a bottle-neck and exclusively scaly there; style c.65mm appearing abruptly joined to the ovary due to the thick scaly covering at its base, completely glabrous above the base, blackish when dry; stigma thick-globose, 7-lobed.
Greek – thauma – a wonder; anthum – flower. A wonderful flower.
Sleumer (1966) commented that this species was ‘similar to R. konori, but [the] style [was] completely glabrous’. Awaiting further collections but it seems very likely that this will turn out to be just a variant of R. konori.
Type: Eyma 4984, 31 July 1939. New Guinea (W), Wissel Lake region, Bivouac on Voorrug-Steenlijst, hehlling voortop (L, BO).
Synonymy: R. magnificum Sleumer, Reinwardtia 1960. 5: 84, non K.F.Ward, J. Bot. 1935. 73: 247.
Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:104
Shrub, 3-4m; perulae persistent, at least on young shoots. Leaves narrowly obianceolate, 8-13 x 1.5-3cm, 3-5 x as long as broad, apex cuspidate, glabrous above, with a dense, fawn, compacted, unistrate indumentum beneath; petioles l-2cm, with a whitish floccose indumentum at first though soon glabrous, lower surface with a thin silvery to fawn compacted indumentum 30-50mm, sparsely glandular. Calyx 2-5mm, lobes rounded, oblong, glandular. Corolla funnel-shaped, white tinged with pink, lobes sometimes with a darker median line and purple flecks, 25-30mm. Ovary exclusively rufous-stipitate-glandular or rufous-tomentose and glandular; style glandular to tip. Capsule c.20 x 4-6mm, cylindrical.
Habitat: Woodland
Distribution: China (Sichuan)
Altitude: Around 2700m
Illustrations:
Remarkable for its persistent peruiae and glandular style though otherwise superficially resembling R. hunnewellianum.
Type: China, W Sichuan, 3000m, x 1910, Wilson 4273 (iso. K)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: pink, purple, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):323
Shrub or small tree, 0.6-3.5(-6)m; young shoots glabrous or sparsely glandular. Leaves orbicular to obovate or elliptic, 3—7.5(—11) x 2-5.5(—7.5)cm, 1.1-2 x as long as broad, apex rounded, minutely apiculate, base rounded to cordate, upper and lower surfaces glabrous, lower epidermis strongly glaucous-papillate, with some red stipitate glands; petioles 0.5-2.5(-3)cm, glabrous or sparsely glandular. Inflorescence 3-10-fIowered, dense; rhachis 5(-18)mm; pedicels 10-25mm, usually glabrous, occasionally glandular. Calyx 2-20mm, irregular to cupular, often coloured, usually glabrous. Corolla campanulate, fleshy, deep crimson, dark flecks usually absent, 35-50mm. Ovary glabrous or glandular; style glabrous. Capsule 1.5-2.5 x 0.5-1.2cm.
A variable species; the smaller, subsp. lopsangianum, replaces subsp. thomsonii almost completely in S Xizang.
One specimen, Ludlow, Sherriff & Taylor 3655 (= 6561, cult. E), differs in the leaves being sparsely hairy below but is otherwise typical. Two plants from the Tsangpo Gorge, Ludlow, Sherriff & Elliot 13589 & 13598, have densely glandular ovaries and are relatively large shrubs, 1.5-3m tall, with leaves up to 7.5cm long. Both clearly have affinities with subsp. lopsangianum.
Both subspecies apparently hybridise in the wild with R. campylocarpum.
4*.R. x candelabrum Hooker f., Rhododendrons Sikkim Himalayat.29(1851)- R. thomsonii x R. campy locarpum. Type: N India, Sikkim, 10-llOOOft, Hooker, n.v. Syn: R. thomsonii Hooker f. var. candelabrum (Hooker f.) C.B. Clarke in Hooker f., Fl. British India 3: 468 (1882). R. thomsonii Hooker f. var. pallidum Cowan, Notes R.B.G. Edinb. 19: 253 (1937). Type: China, S Xizang, Tsari Chu, Migyitun, 11000ft, 29 v 1939, Ludlow & Sherriff 1730 (holo. BM). R. thomsonii Hooker f. subsp. candelabrum (Hooker f.) Chamberlain, Notes R.B.G. Edinb. 36: 121 (1978). Differs from R. thomsonii in its pink flowers, glandular ovaries and relatively small calyces, 2-8(-15)mm long. This hybrid occurs where the ranges of the two parents overlap. Subsp. lopsangianum is assumed to be the parent of R. thomsonii var. pallidum, and subsp. thomsonii the parent of R. x candelabrum sensu stricto.
Occurs in Countries: BT, CN, IN, NP Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: crimson
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):419
Habitat: Rocky slopes, open hillsides
Distribution: China (S Xizang)
Altitude: 2500-4300m
Synonymy: R. lopsangianum Cowan, Notes R.B.G. Edinb. 19: 250 (1937). Type: China, S Xizang, Tsari Chu, Migyitun, 8500ft, 28 v 1937, Ludlow & Sherriff HIS (holo. BM; iso. E).
Habitat: Rhododendron scrub, Abies forest
Distribution: E Nepal, N India (Sikkim, Arunachal Pradesh), Bhutan
Altitude: 3000-4000m
Illustrations:
R. thomsonii var. grandiflorum Millais and var. album Millais {Rhododendrons 153,1917) are horticultural variants not known in the wild; the status ofvax.flocculosum C.B. Clarke (inF/. British India3:46S, 1882) is uncertain (see Cowan & Davidian, Rhododendron Yearbook 6: 179, 1952).
Type: India, Sikkim, inner and outer ranges, 11 - 13000ft, Hooker (holo. K; iso. E)
Erect, openly branched or fastigiate shrub up to 1-25 m. Leaves (3-)5-12(-13-5) x (1 -8-)2-5(-6) mm, elliptic, oblong or narrowly obovate to lanceolate or oblanceolate, apex obtuse, usually shortly mucronate, base narrowly cuneate, undersurface uniformly straw-coloured with contiguous to overlapping scales. Inflorescence l(-2)-flowered, pedicels lepidote, 0.5-2 mm. Calyx 0-5-1.2 mm or rim-like, lobes rounded to deltoid, variously lepidote and/or ciliate. Corolla pale lavender-blue to deep purplish, broadly funnel-shaped, 7-11 mm, tube (2-)3-4 mm, sparingly lepidote outside, pubescent inside. Stamens 10 (rarely more), exceeding the corolla, filaments pubescent towards the base. Ovary lepidote, style short (3-5.8 mm) or long (10-16 mm), glabrous or rarely with a few scales or hairs near the base. Capsule 3-3-5 mm, lepidote.
Habitat: Forest and open alpine slopes
Distribution: China (N Sichuan, Quinghai, Gansu)
Altitude: 2600-4600m
The Philipsons (1975, p. 22) record a natural hybrid with R. telmateium
Type: China Kansu, 1873, PrzewaIski (holo. LE; iso. E, K)
Synonymy: R. polifoiium Franchet, Journ. de Bot. 9:397 (1895). Type: China, Sutchuen occidental, aux environs de Ta-tsien-lou, Souiie (holo. P). R. spilanthwn Hutchinson, Rhodo. Soc. Notes 3, No. 5:287 (1932). Type: China, Szechuan, Muli or Mili kingdom, vi 1922, Rock 6460 (iso. E)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: lavender
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):97
Erect shrub to 1.3m. Twigs cylindrical, 1–2mm in diameter, at first very densely scaly, later densely warty from the scale bases after the scales have fallen. Leaves erect, in tight pseudowhorls of 3–6 leaves near the tips of the twigs. Blade 6–33 x 3–13mm, narrowly elliptic; apex acute to apiculate; margin entire, strongly revolute giving a linear or narrowly oblong appearance; base acutely tapering, the upper side dark green, matt, at first densely scaly but the scales quickly falling leaving a rough densely papillose surface, the lower side densely and more persistently scaly. Scales dense, reddish, irregularly stellate, the centre relatively small, from a stalk attached to a small, pointed, persistent, epidermal protuberance. Mid-vein slightly impressed above, prominent below, lateral veins not visible, very leathery and rigid. Petiole 1–5mm, strong, rigid, flattened and grooved above, at first densely scaly, later only papillose from the scale bases. External bracts triangular to ovate, the apices cuspidate to apiculate, scaly and papillose near the apex outside, scaly at the margin, glabrous inside; inner bracts broadly obovate to obovate spathulate, to 11 x 8mm, emarginate and apiculate at the apex, glabrous or scaly or glabrous near the apex externally, scaly on the margins and glabrous internally. Bracteoles to 10mm, linear-spathulate, rounded or mucronate at the apex, sub-glabrous. Inflorescence of 1–2 hanging flowers. Pedicels 10–20 x c.1.5mm, densely scaly. Calyx c.4mm in diameter, rounded, obscurely 5-lobed, very densely scaly outside. Corolla white, campanulate, 17–24mm; tube 10–13 x 7–8 x 9–10mm, the sides straight, scaly-papillose outside, glabrous inside, slightly 5-grooved at the base; lobes 7–11 x 10–12mm, sub-circular to elliptic, apex rounded, spreading or recurved, overlapping to halfway, scaly outside to the margins near the base, glabrous distally. Stamens erect, regularly disposed within the mouth of the flower, dimorphic; filaments white, glabrous; anthers c.2 x 1mm, brown, oblong to obovoid. Disc 10-lobed, glabrous. Ovary c.5 x 3mm, conical, very densely scaly; style c.2mm, green, glabrous, included within the tube; stigma 5-lobed. Fruit c.12 x 5mm, sub-conical, 5-grooved, densely scaly, the valves a little twisted and recurved on dehiscence. Seeds 3mm including the tails.
Habitat: In montane shrubbery at the transition to the sub-alpine zone.
Distribution: Indonesia, New Guinea (W). Known only from the original collection from the summit ridge of Mt Sendanihanegen between 3470 and 3510m.
Altitude: 3470-3510m
Latin – tintinnabellum – little bell, alluding to the flower shape.
Said to be close to R. revolutum but differing in that the leaves are longer and narrower, the petiole usually much longer, the margins of the corolla lobes are scaly near the base, and the flower is broader and white in colour.
Type: Danet 4319, 15 Jan. 2004. Indonesia, New Guinea, Papua, summit ridge of Mt Sendanihanegen (LYJB, BO, CANB, E, L, LAE, MAN, P).
Occurs in Countries: ID Altitude Ranges: 3,000 - 4,000m Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:107
Much-branched shrub, 1.5-2m; young shoots clothed with adpressed flattened grey-brown strigose hairs. Leaves deciduous or partly persistent, crowded at the ends of branchlets, dimorphic; spring leaves oblanceolate to oblanceolate-spathulate, 0.7-4 x 0.2-lcm, 3.5-4 x as long as broad, apex acute, base cuneate, margin entire, with scattered adpressed grey hairs on both surfaces; summer leaves minute, 3-7mm long, otherwise as for spring leaves; petioles 2-4mm, adpressed-strigose. Inflorescence 1-6-flowered; pedicels 4-10mm, densely adpressed-strigose. Calyx covered with flattened strigose hairs, lobes broadly ovate, c.2mm, ciliate. Corolla funnel-shaped, 18-25mm, purplish-pink with or without darker flecks, rarely white with a faint pink flush; tube 10-I4mm, glabrous. Stamens 5(-10), unequal, c. as long as the corolla, filaments coarsely papillate in lower half. Ovary densely strigose, style glabrous. Capsule not known.
Habitat: Open slopes, etc
Distribution: Japan (Kyushyu, Shikoku, S Honshu)
Altitude: Around lOOm
Illustrations:
R. komiyamae from S Honshu is said to differ from R. tosaense in the strict sense (from Shikoku and S Honshu) in its 10 as opposed to 5-6 stamens. We are unable to confirm the constancy of this difference from the few specimens that we have seen and are following Render's treatment in reducing R. komiyamae to a synonym of R. tosaense.
Type: Syntypes: Japan, Tosa, Takaoka-giri, 1885, Makino, n.v.; Sodayama-mura, 5 iv 1887, Makino, n.v.; Kamibun-mura, xii 1888, Makino, n.v.
Synonymy: R. obtusum Planchon var. tosaense (Makino) Kitamura, Acta Phytotax. Geobot. 25(2-3): 37 (1972). R. komiyamae Makino, J. Jap. Bot. 3(5): 17 (1926). Syntypes: Japan, Prov. Suruga, Mt Ashitaka, Komiyama, 10 vi 1925, Sawada, n.v. R. miyazawae Nakai & Hara, J. Jap. Bot. 11: 823 (1935). Type: Japan, Kyushu, prov. Hiuga circa Tomitaki-machi, Higashi- usuki-gun, 12 iv 1929, Miyazawa 112, n.v. R. surugaense [Sugimoto ex] Kurata, 111. Imp. Tr. Jap. 4: 182, t.37 (1973). Type: as for R. komiyamae.
Occurs in Countries: JP Altitude Ranges: 0 - 1,000m Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: pink, white
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):123
Shrub. Twigs 2–3mm in diameter, rounded, initially scaly, early glabrescent; internodes 2–4cm. Leaves c.4 together in pseudowhorls. Blade 62–100 x 20–46mm, broadly elliptic to ovate; apex gradually and shortly acuminate, broadly acute; margin very narrowly or not revolute; base very broadly tapering to rounded, slightly unequal, glabrescent above, the scale attachments remaining recognisable as numerous minute, blackish pits; laxly sub-persistently scaly beneath. Scales small, marginal zone variously and shortly lobed, but later circular as the marginal zone disintegrates; centre slightly impressed. Mid-vein broadened proximally, wrinkled lengthwise, flat or a little impressed above, distinctly prominent beneath; lateral veins 10–12 per side, curved, spreading, arching inwards near the margin, clearly visible, impressed above, slightly raised beneath, reticulation dense, finely prominent beneath only. Petiole 7–11 x 2–2.5mm, rugose, flattened. Bracteoles linear, glabrous. Inflorescence c.8-flowered. Pedicels 17–21 x 1mm, sparsely scaly at both ends. Calyx 3–4mm in diameter, oblique, disc-shaped, obtusely angled or very shortly lobed, almost glabrous. Corolla 45–50mm, tubular-funnel-shaped, pale pink; tube 20–24 x 5–6 x c.10mm, glabrous outside, laxly hairy in the lower 2⁄3 inside; lobes 23–27 x 10–16mm, spathulate, spreading. Stamens shortly exserted; filaments linear and sub-densely patently hairy proximally, narrower and glabrous in the distal ½; anthers c.4 x 1mm, oblong, curved, base obtuse. Disc prominent, shortly hairy. Ovary 6–8 x c.2.5mm, sub-cylindrical, densely hairy, with numerous minute scales clearly visible between the hairs, gradually tapering distally; style slender, hairy in the lower ¼–1⁄3, c.20mm; stigma c.2.5mm in diameter, rounded.
Habitat: In moorland peat with Sphagnum
Distribution: Indonesia, Maluku, Buru, near Kunturun.
Altitude: Around 1075m
Named after the collector, L.J. Toxopeus, a Dutch entomologist who led the Boeroe Expedition on which this species was collected.
Not recently recollected
Type: Toxopeus Ab. s.n., 6 Feb. 1922. Moluccas, Buru, Kunturun, 1075m (BO, L, fragment).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: pink
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:293
Shrub or small tree, 0.6-8m. Leaves obovate to elliptic, 7-13 x 3-6.5cm, 2-3 x as long as broad, apex apiculate to acuminate, base rounded, lower surface with a dense powdery compacted unistrate indumentum composed of rust-red, short- or long-rayed radiate hairs; petioles 1-2.5cm, floccose. Inflorescence 6-15-flowered; rhachis c.lOmm; pedicels 10-15mm, tomentose. Calyx c.lmm, glabrous. Corolla funnel-campanulate, white, sometimes flushed with rose, with crimson flecks, 25-45mm. Ovaryglabrous or sparsely red-brown tomentose; style glabrous. Capsule 15-25 x 8mm, straight or curved.
Habitat: Open slopes, pine forest margins
Altitude: 3350-4550m
R. traillianum is closely allied to R. phaeochrysum but the characteristic powdery indumentum will usually separate the present species from the latter.
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: crimson, rose, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):354
Hair arms of leaf indumentum long, ribbon-like; leaf apex apiculate to acuminate; corolla (35-)45mm.
Distribution: China (SE Xizang, NW Yunnan)
The differences between the two varieties are small and are chiefly concerned with the leaf indumentum. Var. dictyotum replaces var. traillianum in NW Yunnan.
Synonymy: R. dictyotum [Balfour f. ex| Tagg, Notes R.B.G. Edinb. 15: 309 (1927). Type: China, SE Xizang, Tsarong Prov., on Dokar La, Mekong/Salween divide, vi 1918, Forrest 16734 (holo. E)
Hair arms of leaf indumentum short and pyriform; leaf apex apiculate; corolla 25-35mm.
Distribution: China (W Yunnan, SW Sichuan)
Illustrations:
Type: China, Yunnan, western Flank of the Lichiang Range, 27°30'N, vi 1918, Forrest 5870 (holo. E; iso. K)
Synonymy: R. aberransTugg & Forrest, Notes R.B.G. Edinb. 13: 305 (1927). Type: China, Mid-W Yunnan, Chienchuan/Mekong divide, 26°30'N 99°30'E, 11000ft, vi 1923, Forrest 23395 (holo. E).
Shrub, l-3(-6) m. Young shoots densely loriform-setose, the setae often persisting for more than one year. Leaves evergreen, ovate-elliptic to narrowly elliptic, acute to acuminate at the apex, cuneate to rounded at the base, (55-™)60-80 X (23— )28-35 mm, upper surface glabrous to loriform-setose, elepidote or sparsely lepidote, lower surface pilose (at least on the midrib, lamina sometimes ± glabrous) with filiform-acicular and sometimes a few loriform hairs, scales brown, distant; petiole densely pilose with filiform-acicular and loriform hairs. Inflorescences 2-3-fiowered, pedicels 12-17 mm, lepidote and with a dense indumentum of twisted loriform-setae. Calyx weakly 5-lobed, the lobes 1-2 mm, lepidote and loriform-setose. Corolla 30-36 mm, tube 14-16 mm, light to dark purple, lepidote and with a variably dense indumentum of flattened loriform setae outside. Stamens 10, filaments pubescent towards the base. Ovary lepidote and with a variable indumentum of filiform-acicular hairs and loriform setae. Capsule oblong-cylindric, up to 19 mm, lepidote, variably bristly.
Habitat: Woods and thickets
Distribution: China (NW Sichuan)
Altitude: 2300-3300m
Illustrations:
Although hairy like R. augustinii, this species seems more closely related to R. concinnum. R. x trichophorum Balfour f., Notes R.B.G. Edinb. 12:173 (1920) was based on material cultivated under Wilson 4242, which is R. trichanthum; it is intermediate in every way between trichanthum and augustinii and is almost certainly a hybrid between them.
Type: (syntypes) China, W Szechuan, in thickets and thin woods, 2300-3659 m, Wilson 3944, 3945, 3946 (holo. A)
Synonymy: R. villosum Hemsley & Wilson, Kew Bull. 1910:119 non Roth (1807). Type as for R. trichanthum.
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: purple
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):74
Shrub to 1 -5 m, usually flowering precociously. Young growth lepidote and usually with an indumentum of twisted or curled loriform setae. Leaves deciduous, flat, obovate or obovate-elliptic, 24-40 X 10-20 mm, ± rounded at the apex, cuneate at the base, petiole and lower surface with a ± dense indumentum of twisted and curled loriform setae, scales ± equal, large, golden, distant, upper surface with straight loriform setae and/or puberulent, sometimes lepidote. Inflorescence 1-3-flowered, pedicels lepidote and with numerous loriform setae, 8-13 mm. Calyx lobed, often unequally so, lobes 2-5 mm, lepidote and loriform-ciliate. Corolla yellow or greenish yellow, occasionally tending to orange, 18-23 mm, tube 8-11 mm, lepidote and variably loriform-setose outside. Ovary lepidote, rarely with a few loriform setae towards the apex. Style sometimes puberulent at the base. Capsule cylindric, 8-10 mm, lepidote, sometimes with a few persistent setae.
Habitat: Slopes, rocky places, scrub, cliffs
Distribution: N Burma, China (C & SW Yunnan)
Altitude: 2450-3350m
Illustrations:
Distinguished from the sympatric R. lepidostylum and caesium by strong morphological characters, and from the largely allopatric R. mekongense by weaker characters (indumentum, scales, pedicel length) reinforced by a distinct and ± non-overlapping distribution area. R. trichocladum shows considerable variation in the density (though not the type) of its indumentum. Plants with setose ovaries have been called lophotogynum; those with setose corollas, xanthinum; those with an extremely dense indumentum, oulotrichum; and those with very sparse indumentum, lithophilum. All of these variants are of sporadic occurrence within the overall distribution and grade into each other completely.
Type: China, Yunnan, in monte Tsang chan, Delavay (holo. P—n.v., iso. E)
Synonymy: R. xanthinum Balfour f. & W. W. Smith, Trans. Bot. Soc. Edinb. 27:87 (1916). Type: China, Yunnan, Shweli/Salween Divide, vi 1913, Forrest 12066 (holo. E). R. lithophilum Balfour f. & Kingdon Ward, Notes R.B.G. Edinb. 13:275 (1922). Type: NE Burma, western spur of Imaw Bum, 12000 ft, 2 vii 1919, Kingdon Ward 3305 (iso. E). R. oulotrichum Balfour f. & Forrest, Notes R.B.G. Edinb. 13:281 (1922). Type: China, Yunnan, Shweli/Salween Divide, western flank, 10000 ft, viii 1912, Forrest 8905 (holo. E). R. lophotogynum Balfour f. & Forrest, nomen nudum.
Occurs in Countries: CN, MM Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: green, orange, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):153
Small, intricately branched shrub, 0.3-1(-1.5) m, often forming ± globose bushes. Leaf-bud scales usually deciduous, rarely a few persisting but not conspicuous. Leaves linear, oblong or oblanceolate, 12-30 X 3-5(-6) mm, 4 or more x longer than broad, usually strongly revolute, tapered to the base, ± rounded to the slightly mucronate or emarginate apex, upper surface green, lepidote or not, lower surface usually pale brown with dense, overlapping scales borne in 2-3 tiers, very rarely somewhat plastered, scales of the lowermost tier golden, paler than the others. Inflorescence many-flowered, ± globose, pedicels short, usually lepidote, occasionally puberulent as well, rarely glabrous and elepidote. Calyx lobes oblong or narrowly triangular, 1-2.5 mm, usually lepidote outside, loriform-ciliate on the margins, variably puberulent inside. Corolla white or pink, tube 4-5-8(-10) mm, lobes 1.5-3-5(-5) mm, tube glabrous outside, lobes generally with a few scales on the backs, mouth of the tube variably pilose inside. Stamens 5(-6). Ovary lepidote. Capsule lepidote, 2-4 mm. CHINA (N & NW Yunnan, SW & C Sichuan). Open slopes and in scrub or forest and thicket margins, 3400-4600 m.
Illustrations:
A variable species, particularly in leaf and flower size. The species and varieties formerly recognised appear to be merely horticultural selections from the general variation, and to have no taxonomic significance. Several specimens (Kingdon Ward 4465, 5183 and Rock 9134) are from very large, robust plants with large leaves and flowers, and are perhaps hybrids between R. trichostomum and R. primuliflorum R. hedyosmum Balfour f., Notes R.B.G. Edinb. 9:234, 1916 (R. trichostomum var. hedyosmum (Balfour f.) Cowan & Davidian, Rhodo. Yearbook 2:84, 1947) is the name given to a large-flowered variant occurring in cultivation but not in the wild. It is probably a hybrid of R. trichostomum with some other species of the section.
Type: described on the basis of several syntypes from China, Yunnan & SW Szechuan— Delavay 2211, 2626 (both iso. E), Soulie 150 (iso. E), 764 (n.v.), Pratt 254 (n.v.)
Synonymy: R. fragrans sensu Franchet, Bull. Soc. Bot. Fr. 34:284 (1887) non (Adams) Maximowicz. R. ledoides Balfour f. & W. W. Smith, Notes R.B.G. Edinb. 9:243 (1916). Type: China, Yunnan, mountains in the NE of the Yangtze bend, 13000 ft, ix 1913, Forrest 11246 (holo. E). R. radinum Balfour f. & W. W. Smith, op. cit.: 268. Type: China, Yunnan, Lichiang range, 11-12000 ft, vi 1913, Forrest 10278 (holo. E). R. sphaeranthum Balfour f. & W. W. Smith, op. cit.: 278. Type: China, Yunnan, mountains of the Fengkow valley, 12-13000 ft, vi 1914, Forrest 12505 (holo. E). R. trichostomum var. ledoides (Balfour f. & W. W. Smith) Cowan & Davidian, Rhodo. Yearbook 2:84 (1947). R. trichostomum var. radinum (Balfour f. & W. W. Smith) Cowan & Davidian, loc. cit.
Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: pink
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):168
Straggling shrub, (0-5-)l-5(-7) m, bark of mature shoots smooth, reddish brown, peeling. Leaves usually evergreen, sometimes semi-deciduous, ovate or lanceolate, rarely narrowly elliptic, acute at apex, truncate or cordate at the base, (38-)45-60(-65) x (20-)24-32 mm, upper surface dark green, ± elepidote, lower surface greyish brown with close, very small (less than 0-1 mm in diameter), almost rimless scales. Inflorescences 2-3(-4)-flowered, pedicels lepidote, 8-13 mm. Calyx small, inconspicuous, usually ± undulate, rarely more conspicuously 5-lobed, lepidote. Corolla variable in shape, pale yellow, yellow suffused with red, or with dark red spots, 21-30 mm, tube 7-12 mm, densely lepidote and pubescent at the sinuses outside. Stamens 10, filaments pubescent towards the base. Ovary lepidote, style glabrous or rarely puberulent at base. Capsule lepidote, cylindric, 10-13 mm.
A variable and widespread species, divisible into two varieties on the basis of corolla shape
Occurs in Countries: BT, CN, IN, MM, NP Altitude Ranges: 2,000 - 3,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: red, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):77
Corolla very openly funnel-shaped to almost flat.
Habitat: Hillsides
Distribution: India (Manipur)
Altitude: 2450-2750m
Synonymy: R. triflorum var. bauhiniiflorum "Watt in sched., nom. nud. R. bauhiniiflorum [Watt ex] Hutchinson, The Species of Rhododendron 785 (1930). Type: Manipur, Japvo, Ching Sow & Keyang on the northern Burmese frontier, 8-9000 ft, v 1882, Watt 6582 (holo. E)
Corolla widely funnel-shaped
Habitat: Forests, forest margins and hillsides, (2300-)2750-3650 m
Distribution: Nepal, India (Sikkim, W Bengal, Arunachal Pradesh), Bhutan, ne Burma, China (S Xizang)
Illustrations:
This variety is variable as to corolla colour; the variant with the corolla suffused or spotted dark red has been described as var. mahogani but is of sporadic occurrence, and linked to the typical yellow variant by numerous intermediates.
Type: Sikkim Himalaya, inner ranges on brushy slopes, 7-9000 ft, Hooker (holo. K, iso. E)
Synonymy: R. deflexum Griffith, Notulae 4:303 & t. 519 (1854). Type: Bootan, Griffith (n.v.). R. triflorum var. mahogani Hutchinson, Gard. Chron. 101:135 (1937). Type: none cited.
Dwarf shrub, to c.0.3m; perulae persistent. Leaves obovate to obovate-spathulate, 1-3.2 x 0.6-1.8cm, c.2.5 x as long as broad, apex rounded, mucronate, base attentuate, decurrent, upper and lower surfaces glabrous; petioles short and winged. Inflorescence 2-3(-5)-flowered; rhachis minute; pedicels 20—30mm, glabrous. Calyx 1—3mm, glabrous, lobes fleshy. Corolla infundibular-campanulate, pale yellow, 30-40mm. Ovary glabrous. Capsule not known.
Habitat: Rocky hillsides
Distribution: China (SE Xizang)
Altitude: 3600-4300m
A species of uncertain affinities though in some respects resembling both R. parmulatum and R. forrestii.
Type: China, SE Xizang, Kongbo Prov., Tsari Sama, Langong, 4100-4250m, 16 vi 1938, Ludlow, Sherriff & Taylor 5582 (holo. BM).
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: yellow
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):401
Shrub to 2m. Twigs 4–5mm in diameter, rounded, laxly scaly but quickly glabrescent. Leaves spirally arranged. Blade 140–190 x 55–80mm, elliptic; apex acute to obtuse, sometimes shortly acuminate; margin entire, flat; base tapering, broadly tapering to rounded; sparsely scaly and quickly glabrescent above, densely or sub-densely scaly beneath. Scales sub-stellate with a broad thin marginal zone and small slightly impressed centre. Mid-vein broadly raised above in the proximal 1⁄3 becoming impressed distally; strongly raised beneath throughout although becoming more slender distally; lateral veins 10–14 per side, very slightly raised on both sides when dry. Petiole 18–26 x 2–3mm, not grooved above, laxly scaly. Inflorescence 5–9 flowers in an umbel, red, without scent. Pedicels 38–42 x c.1mm, scaly without hairs. Calyx c.4–5mm in diameter, a low disc, glabrous. Corolla 70–80 x 60–80mm, funnel-shaped; tube 30–40 x 5–7 x 20–27mm, glabrous outside and inside; lobes 40–45 x 32–38mm, obovate, glabrous. Stamens c.40mm; filaments red; anthers up to 5mm, purple, oblong. Ovary c.10 x 4mm, cylindrical or slightly angled, hairy; style to 30mm, slender, glabrous, pink; stigma disc-shaped. Fruit fusiform, angled.
Habitat: Epiphytic on trees or on peat on blocks of granite.
Distribution: Vietnam, Khanh Hoa, Massif du Honba.
Latin – triumphans – winning honours. Named by the authors for the beauty of the flowers and the date when it was seen flowering on which they received good news about the Great War in Europe.
Commonly confused with the old Veitch hybrid ‘Triumphans’ (spelt with a capital letter), which is superficially similar but not of wild origin and still cultivated in various collections worldwide. Professor Sleumer (1958) considered it ‘practically identical to R. brookeanum [R. javanicum ssp. brookeanum]’ but found ‘a striking difference however, between these species in the petiole’. We still have no recent observations on this species which should most likely be included in the R. javanicum complex.
Type: Chevalier 38601, 15 Sept. 1918. Sud Annnam, Massif du Honba (P, L, fragment).
Subgenus: Vireya Habit: Epiphyte, Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:240
Small shrub. Twigs slender, 1.5–2.5mm in diameter, scaly at the tips at first, otherwise minutely rough from the scale bases; internodes 2–4cm. Leaves 3–4 together in pseudowhorls at the upper nodes. Blade 30–45 x 16–27mm, elliptic or broadly elliptic; apex obtuse to rounded, occasionally minutely retuse; margin entire, narrowly revolute; base broadly tapering to truncate or rounded, above glabrescent or with the remains of scales and with minute tubercles; below more persistently scaly especially along the mid-vein. Scales stellate, sub-sessile on top of pale persistent epidermal tubercles. Mid-vein flat or slightly impressed above, slightly prominent beneath especially towards the base of the blade, much more slender than the petiole; lateral veins c.6 per side, irregular, straight below, anastomosing with each other before the margin, forming a lax network which is equally raised on both sides when dry, thick, rigid and rough to the touch. Petiole 7–10 x c.3mm, pale cream, weakly grooved above, densely scaly. Flower buds 20 x 11mm, pale-green, ellipsoid, the margins of the bracts tightly appressed but the bract tips ‘hooded’ with the apex of the ‘hood’ standing out so that the bud has a lumpy appearance. Bracts to 15 x 6mm, ovate to spathulate, the margins only with brown dendroid scales otherwise glabrous, apiculate. Bracteoles to 15mm, filiform with a few long translucent cilia along the edges sometimes with a reduced dendroid scale on the top. Inflorescence a c.3-flowered umbel, the flowers half-hanging except where held by the leaves into horizontal or semi-erect positions. Pedicels 10–15 x c.0.6mm, pink, densely brown stellate-scaly, without hairs. Calyx disc-shaped, hardly lobed, c.2.5mm in diameter, densely scaly and sparsely hairy outside, sparsely ciliate on the margin. Corolla 30–35 x 29mm, zygomorphic, tubular, pink; tube 20–25 x 5–10 x 10–13mm, curved, laxly scaly outside, with a few white hairs within; lobes 10–15 x 10–15mm, broadly obovate-spathulate, half overlapping except not or hardly overlapping between the upper 3 and the lower 2, with a few sparse scales outside. Stamens at first tightly clustered on the upper side of the flower, exserted to 5mm, later to 10mm and becoming irregularly arranged, (sometimes with 12 stamens); filaments linear, laxly patent-hairy below, glabrous in the upper 1⁄3; anthers c.2.5 x 1mm, dark purple, broadly oblong, the cells very shortly apiculate at the base. Disc glabrous below, hairy at the upper margin. Ovary c.4 x 1.8mm, cylindrical, densely scaly and laxly hairy, abruptly contracted distally; style held on upper side of the tube, below the anthers on opening, laxly patently hairy and densely scaly in the lower 1⁄3, glabrous distally; stigma thickly conical-globose, becoming exserted beyond the anthers to c.15mm.
Distribution: Papua New Guinea, Mt Dayman, Mt Maneao and Mt Simpson, Milne Bay District
Altitude: Around 2135m
Latin – truncus – the trunk of a tree; colus – living on. Alluding to the fact that it was described living epiphytically on tree trunks.
A pretty compact species with delightful bright pink flowers.
Type: Cruttwell 540, 11 June 1954. New Guinea, PNG. Mt Dayman, Maneao (K, L, fragment).
Synonymy: R. truncicolum Sleumer (orthographic variant).
Occurs in Countries: PG Altitude Ranges: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: pink, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:105
Shrub to 0-3 m. Leaves 6-12 x 2-5-5 mm, narrowly elliptic or oblong-lanceolate, apex subacute or obtuse, slightly mucronate, base cuneate, undersurface uniform buff, densely covered with overlapping pale scales. Inflorescence 3-7-flowered, pedicels lepidote, 1-2.5 mm. Calyx 0.8-1 mm, the lobes rounded, densely lepidote, margin lepidote and with a few cilia. Corolla pale purplish, broadly funnel-shaped, 4-5-6.8 mm, tube 2-2.8 mm, elepidote outside, slightly pubescent within. Stamens 4-7, shorter than corolla, filaments glabrous. Ovary densely pale lepidote, style c. 2 mm, slightly shorter than the stamens, glabrous. Capsule unknown.
Habitat: Open moss land, 2900 m
Distribution: China (E Yunnan)
Known only from the type collection. The Philipsons (1975, p. 17) suggest the occurrence of natural hybrids between R. tsaii and R. hippophaeoides.
Type: China, Yunnan, Chao-tung hsien, 2900 m, 19 v 1932, Tsai 50928 (holo. A, iso. E)
Occurs in Countries: CN Subgenus: Rhododendron Habit: Non-Tree
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):95
Shrub, 1-3m; young shoots densely tomentose. Leaves coriaceous, obovate to oblong, 3.5-5.5 x 1.5-3cm, 1.6-2.2 x as long as broad, apex rounded and bluntly apiculate to acute, base rounded, upper surface with lamina glabrous though with a persistent indumentum overlying the midrib, lower surface with a dense rufous-tomentose indumentum composed of ramiform hairs; petioles c.lcm, densely tomentose. Inflorescence 3-5-flowered; rhachis 3-5mm; pedicels c.8mm, densely tomentose. Calyx c.2mm, densely tomentose. Corolla open-campanulate, white or pale cream, with a pink flush, or pale pink with crimson flecks, 25-35mm. Ovary densely tomentose. Capsule c. 12 x 4mm.
Habitat: Mixed forests, rock ledges
Distribution: China (S Xizang), NE India (Arunachal Pradesh), ? E Bhutan.
Altitude: 3500-4500m
Illustrations:
Closely allied to R. lanatum and apparently hybridising with it, especially in E Bhutan.
Type: China, S Xizang, Tsari Chu, Podzo Samdo, 11000ft, 22 v 1936, Ludlow & Sherriff1636 (holo. BM; iso. E).
Occurs in Countries: BT, CN, IN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: cream, crimson, pink, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):370
Much-branched shrub, 0.3-1.5m; young shoots densely covered with adpressed flattened rufous hairs. Leaves monomorphic, chartaceous, lanceolate to elliptic, 1-3.5 x 0.3-lcm, 2-2.3 x as long as broad, apex acute, base cuneate, margin entire, both surfaces with scattered adpressed whitish to pale brown villous hairs, especially on midrib; petioles l-5mm, covered with adpressed red-brown hairs. Inflorescence 3-6-flowered, flowers appearing after leaves; pedicels c.3mm, covered with adpressed whitish hairs. Calyx minute, covered with flattened pale brown strigose hairs, lobes c.lmm, Corolla 4-5-lobed, funnel-shaped, white, 7-9mm; tube cylindrical, c.5mm, glabrous on outer surface, hairy within. Stamens 4-5, longer than corolla, filaments pubescent below the middle. Ovary densely covered with pale brown strigose hairs; style glabrous. Capsule ovoid, 2-5mm long, densely strigose.
Type: Japan, in Nippon borealis (Nambu) mediae alpibus, 1865, 1866, Tschonosky (iso. BM, K)
Occurs in Countries: JP, RU Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: white
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):130
Leaves 3-nerved, 20-35mm long
Habitat: Rocky ridges, etc.
Distribution: Japan (NW Honshu)
Altitude: 700-1000m
Illustrations:
Var. trinerve is generally more luxuriant, at least vegetatively, than var. tschonoskii. Togashi (op. cit.) suggests that it replaces var. tschonoskii in NW Honshu
Synonymy: R. trinerve Franchet, Bull. Herb. Boiss. 5: 920 (1897). Syntypes: Japan, Shonai, cult., vi 1888, Faurie 2674, n.v.; Abashiri, viii 1892, Faurie 8566, n.v.
Leaves 4-5-nerved, 10-20mm long
Habitat: Rocky mountain summits
Distribution: S Korea, Japan (Hokkaido, E & S Honshu, Shikoku, Kyushyu), USSR (Kamchatka)
Altitude: 1500-1800m
Illustrations:
Synonymy: R. tschonoskii Maxim, var. typicum f. tetramerum Makino, Bot. Mag. (Tokyo) 18: 66 (1904); R. tschonoskii Maxim, var. tetramerum (Makino) Komatzu, Bot. Mag. (Tokyo) 32: 15 (1918)óJapanese text; R. tetramerum (Makino) Nakai, Bull. Nat. Sci. Mus. Tokyo 31: 82 (1952). Type not designated.
Shrub, l-2m; young shoots covered with adpressed brownish strigose hairs. Leaves thinly to thickly coriaceous, monomorphic ? to dimorphic, elliptic to broadly ovate; spring leaves 1.3-2.2 x 0.6-1,4cm, 1.5-2.2 x as long as broad, apex rounded to acuminate, margin entire, upper surface sparsely villose to setose when young, soon glabrescent, lower surface with scattered brown strigose hairs arising from bulbous bases, especially on midrib; petioles 2~4mm, densely strigose. Inflorescence 3-5~flowered; pedicels 2-6mm, densely strigose. Calyx 3-5mm, indumentum as for pedicels, lobes c.3mm. Corolla funnel-campanulate, 12.5-20mm, rose to purple, with darker flecks on upper lobe; tube 3-9mm long, c.3mm wide, hairy on the inner surface, glabrous on outer surface. Stamens 5, filaments minutely pubescent below. Ovary densely strigose; style glabrous. Capsule 9-10 x 5-6mm, densely strigose.
The three entities recognized are: 1. R. tsoi Merrill, Lingnan Sci. J. 13: 142 (1934). Type: China, Guangdong, Naam Kwan Shan, Tseng-shing distr., 25 iv 1932, W.T. Tsang 20332 (iso. E, IBSC, PE), Syn.: R. tingwuense P.X.Tan, Med. Mat. Guangdong 4: 36, f.6 (1978). Type: Guangdong, Gaoyao Xian, Dingwushan, 900m, P.X* Tom 7317 (holo. IBSC). R. subenerve P.X.Tan var. nudistylum P.X.Tan, Survey Gen. Rhododendron S. China 108, t.29 (1983). Type: China, Guangdong, Huiyang Xian, Lianhua Shan, 11-31 viii 1935, W.T. Tsang 25586 (holo. IBSC, iso. A). Leaves weakly dimorphic, thickly coriaceous; spring leaves 15-18 x 9-11mm, apex rounded to acute. Corolla 8-10mm long. China (Guangdong). Map 20. 2. R. polyraphidoideum P.X.Tan, Bull. Bot. Res. N.E. Forest. Inst. 2(4): 84, f.4 (1983). Type: China, Fujian, ConganXian, Singan chuen, 3 iv 1975, L.G. Li(L.K. /,££) 75103 (holo. Inst. Mat. Med. Fujian, iso. PE). Syn.: ? R. crassimedium P.X.Tan, Bull. Bot. Res. N.E. Forest. Inst. 2(1): 96 (1982). Type: China, Jiangxi, Suichuan Xian, in summo montium, 1000m, 27 iv 1959, S.S.Lai (S.S. Lei) 279 (holo. LBG, n.v.). ? R. hypoblematosum P.X-Tan, Bull. Bot, Res. N.E. Forest. Inst. 2(1): 90, f.2 (1982). Type: China, Jiangxi, Suichuan, Jinggang Shan, iOOOrn, S.S. Lai (S.S. Lei) 660055 (holo. LBG, n.v.). Leaves dimorphic, thinly coriaceous; spring leaves elliptic, 15-18 x c,6mm. Corolla 12-14.5mm. China (Fujian, Jiangxi). Map 20. While Tan describes R. crassimedium as having monomorphic leaves the figure cited suggests that they could have been dimorphic. The one specimen seen of R. hypoblematosum (S.S. Lei 3965) closely resembles the type of R. polyraphidoideum in its elliptic, thinly coriaceous leaves. However, from the cited figure, the type of R. hypoblematosum appears to be closer to R. tsoi. 3. R. aff. polyraphidoideum. Based on two specimens from China, NW Fujian, La Touche (E); Pikeng, Wuyi Mts, 25 v 1988, L.G. Ling 10343 (E). Leaves strongly dimorphic, thinly coriaceous; spring leaves broadly ovate, up to 22 x 14mm, apex blunt to subacute. Corolla up to 20mm. Map 20. Known only from two specimens. Further material is required to confirm the constancy of the differences mentioned above.
We do not follow Tan in considering that the distinction can be made between taxa with dimorphic and those with apparently monomorphic leaves. Indeed, we are not convinced that he has interpreted all the cited specimens within this complex correctly, even if the distinction were to be maintained. Furthermore, the relative length of the style and stamens may well reflect the maturity of the flowers, and again does not have any taxonomic significance.
This aggregate contains several closely allied taxa, some of which have been described as species, although all may be conspecific. As we have not seen two of the crucial types we are not certain of the affinities of all the taxa. However, on present evidence we recognize three entities within the complex.
Subgenus: Tsutsusi Habit: Non-Tree
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):136
Dwarf shrub, to c.30cm; young shoots covered with adpressed flattened strigose hairs. Leaves monomorphic, obovate, 1-1.2 x 0.5-0.7cm, 1.7-2 x as long as broad, apex acute, base cuneate, margin entire, ciliate, upper surface ± glabrous when mature, lower surface with a few strigose hairs on midrib, otherwise glabrous; petiole c.lmm, strigose. Inflorescence l-4~flowered; pedicels very short, apparently hairy. Calyx minute, lobes ciliate. Corolla (4-)5-lobed, tubular-carnpanulate, pink in bud, becoming white, c.9mm; tube c.6mm, broadest towards base, pubescent on outer surface. Stamens (4-)5, as long as corolla, filaments pubescent in lower half. Ovary strigose; style glabrous. Capsule c.5mm, ovoid.
Habitat: Open slopes
Distribution: Japan (S Honshu and adjacent islands)
Illustrations:
A distinct species, apparently without close relatives. The combination R. tanakae (Maxim.) Ohwi is apparently invalid as the source of the basionym was not fully cited.
Type: Japan, 'in Nippon mediae montibus Flakone, Tanaka & Ycutschima'n.v.
Synonymy: Tsusuiophyllum tanakae Maxim., Rhododendr. As. Orient. 12, t.3(1870) - basionym. R. tanakae (Maxim.) Ohwi, Fl. Japan 889 (1953) & Bull. Nat. Sci. Mus. Tokyo 33: 81 (1953) ? comb. Inval, non R. tanakai Hayata, Ic. PI. Formosan. 4: 15 (1914)
Occurs in Countries: JP Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: pink, white
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):138
Shrub to 5m. Twigs somewhat flattened, laxly scaly, often whitish when dry; internodes 3–10cm. Leaves 4–5 together in tight pseudowhorls. Blade 40–70 x 25–50mm, elliptic to broadly elliptic; apex obtuse, broadly acuminate or acute, rarely rounded; margin entire, flat to weakly and narrowly revolute; base broadly tapering, the extreme base sub-truncate or rounded, to sub-cordate, sub-densely scaly on both sides initially, glabrescent above, more persistently scaly beneath. Scales small, marginal zone thin, stellately lobed and quickly disappearing; centre minute and impressed, eventually leaving only fine blackish pits. Mid-vein impressed above, thick, broad and prominent in the proximal part beneath, narrowed upwards; lateral veins 6–8 per side, irregular, divided and anastomosing before the margin, slightly impressed above, a little though distinctly raised beneath, reticulation obscure above, distinct, sub-dense and prominent beneath. Petiole 2–4 x 1.5–2mm, weakly grooved, flattened, scaly. Flower buds to 17 x 10mm, ellipsoid to obovoid, with the outermost tips reflexed, inner ones mucronate, slightly spreading. Outer bracts to 15 x 10mm, ovate; inner ones obovate, ending in a 1–3mm point, membranous, scaly at the tips outside at first, otherwise glabrous, or with some soft hairs outside, shining, scaly on the margins. Bracteoles to 15mm, filiform below, sub-spathulate distally, laxly scaly or glabrous. Inflorescence a 4–7-flowered, open one-sided umbel. Pedicels 12–20 x c.1mm, laxly stellately scaly, without hairs. Calyx c.4mm in diameter, very obliquely disc-shaped, membranous, sub-glabrous, with 5 irregular short teeth or longer lobes to 4mm. Corolla 65–80mm, trumpet-shaped, pink with white lobes; tube 55–65 x 5 x 8mm, weakly curved, laxly scaly outside, laxly hairy in the proximal ¾ inside; lobes 10–15 x 8–12mm, spreading, obovate. Stamens unequal, exserted to 10mm; filaments linear, laxly hairy in the proximal ¾, glabrous distally; anthers c.2.5 x 0.7mm, sub-obovate-oblong, base contracted to a very short apiculus. Disc slightly prominent, hairy on the upper side, glabrous below. Ovary c.8 x 2.5mm, cylindrical, gradually tapering distally; densely white hairy, minutely scaly (the small scales covered by the hairs); style slender, as long as the stamens, laxly covered with long white hairs and scales in the lower ½; stigma yellow, globose, shortly 5-lobed.
Habitat: Terrestrial in margin of moss forest.
Distribution: Papua New Guinea, N side of the summit of Mt Dayman.
Altitude: 2500-2750m
Latin – tuba – a trumpet, alluding to the trumpet-shaped corolla.
Sleumer (1966) commented that ‘R. tuba is in many respects intermediate between R. carringtoniae and R. rhodoleucum, both also known from the Maneau Range, and possibly a local natural hybrid between them’. This has not been critically tested in the field. Rhododendron tuba was introduced into cultivation by R. Weeks and N. Cruttwell (ANRS 150) in 1974 to Australia and has been distributed widely. It grows vigorously, covering itself in the beautiful pink to white, scented bloom usually just once a year in the spring.
Type: Cruttwell 775, 23 June 1956. New Guinea (SE), Mt Daymen (Maneao Range), 2750m (K, E, L, LAE).
Occurs in Countries: PG Altitude Ranges: 2,000 - 3,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: pink, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:185
Shrub to 1.5m. Twigs 2–3mm in diameter, rounded, at first with dendroid, stellate scales, the older parts glabrescent and covered in tubercles; internodes 1.8–11cm. Leaves 5–7 crowded towards the upper nodes, or in pseudowhorls. Blade 17–48 x 10–21mm, ovate, ovate-elliptic or broadly elliptic; apex obtusely acuminate or obtuse, sometimes apiculate; margin weakly to strongly recurved; base rounded-obtuse to slightly cordate, sub-sessile; densely brown-scaly on both sides when very young. Scales stellate, sub-sessile or sub-dendroid, each on top of a minute persistent epidermal tubercle, quickly glabrescent especially above, distinctly tuberculate and rough to the touch on both sides. Mid-vein impressed above, prominent beneath; lateral veins obscure. Petiole 1–4 x 1.5–2mm, at first densely scaly, later rough with tubercles. Bracts to 18 x 6mm; outer bracts triangular, subulate-acuminate at the apex, the inner ones ovate-acuminate to spathulate and shortly apiculate or obtuse, glabrous on both sides, sub-denticulate. Bracteoles to 20 x c.1mm, linear, glabrous. Inflorescence of 2–6 flowers in an umbel. Pedicels 15–30mm, slender, densely scaly. Calyx c.4mm in diameter, disc-shaped, oblique, scaly outside, very shortly obtusely 5-lobed. Corolla 38–45mm, zygomorphic, tubular below, funnel-shaped towards the mouth, red; tube 25–32 x 4–6 x 8–10mm, densely scaly outside, laxly hairy in the lower 2⁄3 of the tube inside, glabrous distally; lobes 9–12mm in diameter, 5 (rarely 6), scaly outside except at the margins, sub-circular, retuse. Stamens 10, (rarely 12), sub-equal, 28–35mm; filaments linear, laxly hairy proximally, less so upwards, glabrous distally; anthers c.3 x 1mm, oblong, the base obtuse. Disc minutely hairy, or practically glabrous. Ovary c.7 x 2.5mm, elongate-conical, abruptly contracted distally, very densely scaly, with some hairs between the scales in the upper part; style c.17mm, with some patent hairs at the base, glabrous distally; stigma globose.
Habitat: In open places
Distribution: Indonesia, New Guinea (W), Wichmann and Hubrecht Mts
Altitude: 3000-3100m
Latin – tubercularis – tubercules; feram – to bear. The rhododendron bearing tubercles.
Only known from two old collections.
Type: Pulle 1045, 10 Feb. 1913. New Guinea (W), Southwestern part, top of Wichmann Mts (BO, lectotype, K, L, U).
Occurs in Countries: ID Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:105
Shrub to 40cm. Twigs rounded, red or green with brown scales on top of white, slender, stalks which appear as short hairs when the scale is removed. Leaves in tight pseudowhorls of c.6 full-sized leaves and one or two smaller ones with some slender fragile scale leaves along the internodes. Blade 8–15 x 7–13mm, sub-circular to elliptic; apex obtuse, rounded or retuse; margin entire when fresh, crenulate after drying; base rounded or broadly tapering, flat or slightly concave, sub-succulent; sub-densely scaly above at first but quickly glabrescent; persistently sub-densely scaly below. Scales highly variable, mostly with a broad irregular margin and small centre but occasionally with a large domed centre and smaller marginal zone, brown, leaving a small dark spot at the point of attachment when they have gone. Mid-vein impressed above mostly for the whole leaf length but sometimes disappearing just below the apex; below, smooth when fresh, broadly raised for the whole length after drying; lateral veins mostly not visible but occasionally one or two spreading at about 45° from near the base. Petiole 1–3 x 1–2mm, green or red, scaly, grooved in the distal ½ on the upper side. Flower buds 13–15 x 6–10mm, ovoid, dark shining red in the upper 1⁄3, red below, the outermost bracts rigidly standing out away from the bud, ovate or triangular with broad bases and long, narrow, subulate points; inner bracts broadly ovate, narrowing to mucronate apices. Bracteoles c.8 x 0.5mm, broadening distally to c.1mm, glabrous but irregularly toothed distally. Inflorescence an open umbel of 2–4 flowers, sometimes solitary, the flowers half-hanging. Pedicels 13–15 x c.1mm, densely hairy and with scattered inconspicuous scales. Calyx a low scaly ring with a few hairs near the attachment to the pedicel. Corolla red, 20–28 x c.20mm; tube 8–16 x 5–6 x 10–14mm, with a few scales outside and some scattered hairs near the base both inside and out; lobes 12–16 x 10–16mm, not overlapping or overlapping to ¾. Stamens arranged regularly or irregularly just below the mouth of the flower, slightly dimorphic, 7 and 8mm; filaments laxly hairy near the base especially on the inner side, glabrous distally; anthers c.3 x 1mm, brown, curving inwards. Ovary c.3 x 3mm, densely white-hairy and with inconspicuous brown scales, abruptly contracting distally; style 5mm, hairy at the base, (up to 1mm), otherwise glabrous. Fruit 7–11 x 5–6mm, broadly cylindrical, the outer layer peeling back before the valves split open. Seeds c.1.5mm, without tails c.1mm, the longest tail 0.3mm, the tails often hook-like.
Distribution: Malaysia (Borneo), Sabah, Mt Kinabalu.
Named from the Dusen word ‘Tuhan’ which means landslide, as the plant is known only from steep landslides in the ultramafic area of Mt Kinabalu.
Discovered by Todd Barkman in July 1994 within less than 300m of the main summit trail. At present known from one landslide area on the ultramafic ‘apron’ of this mountain, where it was first collected. There are several other similar, but much less accessible, sites where it could occur but it is at present known only from about a dozen plants in three groups on this one landslip. The plants are mostly completely exposed and suffer severely in drought years but have not been killed.
This species is similar to R. buxifolium but differs most significantly in the much smaller habit, the hairy ovary and hairy pedicels. It also has nearly glabrous bracts without any white hairs along the margins or outside as in R. buxifolium and should clearly be placed in section Euvireya. It would pass on leaf size as series Linnaeopsis but that series has hitherto been recorded only in New Guinea, and the erect habit with its thick sub-succulent leaves is unlike any of the species in that group. For the present it is placed in series Buxifolia; its true relationships may be with R. baconii or R. rugosum. Introduced into cultivation in Edinburgh by Paul Smith in 1995, it grows very slowly, producing its relatively large pink flower irregularly throughout the year.
Type: Barkman & Beaman 59, 20 Jan. 1995. Sabah, Ranau District, Kinabalu Lipson, 2800–2900m (SNP).
Occurs in Countries: MY Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:203
Tree, 12 m high, young branches with long stiff bristles. Leaf blade oblanceolate, 80-100 x 18-26 mm, base cuneate, apex acuminate, coriaceous, lower surface with well-spaced short hairs (none on the margin) and longer bristles on the mid-rib; petiole c.6-10 mm long, with long bristles. Inflorescence buds lateral, clustered at the ends of leafy shoots, 1-3 (or more)-flowered; bud scales glabrous, caducous; pedicels 15-18 mm long, with sparse but long pilose hairs. Calyx a 5-lobed undulate rim, glabrous. Corolla violet, glabrous, tube c.ll mm long, lobes c.28 X 15 mm. Stamens 10, filaments hairy on the lower part. Ovary cylindric, c.6 mm high, covered with appressed hairs; style glabrous. Capsule not seen.
Distribution: China (S Yunnan)
A rare species. The tree habit and violet flowers, together with the bristly twigs and leaves make a distinctive combination of characters.
Type: China, Mts S of Mengtse, 2000 m, Henry 10636 (holo. K, iso. E).
Occurs in Countries: CN Subgenus: Azaleastrum Habit: Tree
Philipson, W.R. & Philipson, M.N. (1986) A Revision of Rhododendron III. Subgenera Azaleastrum, Mumeazalea, Candidastrum and Therorhodion. Notes from the Royal Botanic Garden Edinburgh 44(1):10
Prostrate shrub to 10cm. Twigs c.2mm in diameter, often pale and sub-densely covered with sub-stellate scales when young, later, glabrescent but with numerous thick cushions of leaf bases remaining; internodes 2.5–6cm. Leaves densely spirally arranged, of a distinctive purple-colour. Blade 18–27 x 10–19mm, broadly elliptic to elliptic-obovate; apex rounded, with a small protruding apical gland; margin minutely crenulate and weakly revolute; base broadly tapering; laxly to sub-densely scaly initially on both sides, early glabrescent above, persistently scaly beneath. Scales small, flat, sub-circular, marginal zone large, thin, variously angled, sub-stellate or crenate; centre small, dark, faintly impressed. Mid-vein slightly impressed above, broad and obtusely prominent beneath in the proximal part; lateral veins inconspicuous. Petiole 2–4 x 1–2mm, rounded or somewhat flattened. Outer bracts 10–15mm, ovate, inner ones to 20–25 x 8–15mm, obovate to spathulate, apex shortly acuminate, or obtuse, membranous, entirely glabrous. Bracteoles to 18 x 1mm, linear, glabrous. Inflorescence 2–4-flowered, flowers half-hanging. Pedicels 12–15 x 0.8mm, densely sub-stellately scaly, without hairs. Calyx c.3mm in diameter, obliquely disc-shaped, obscurely lobed, scaly outside. Corolla 35–45mm, funnel-shaped, bright orange, fleshy; tube 20–30 x c.5 x 9–10mm, straight, glabrous on both sides; lobes 14–17 x 12–15mm, broadly obovate to sub-circular, semi-erect. Stamens exserted to c.6mm, unequal; filaments linear, glabrous; anthers c.2.8–3 x 1.3–1.5mm, obovate-oblong, each cell ending in a short basal apiculus. Disc prominent, glabrous. Ovary c.6 x 2.5mm, sub-cylindrical, densely sub-stellately scaly, tapering distally; style scaly at the base, glabrous distally, slightly longer than the stamens; stigma shortly obconical.
Habitat: Growing on the open valley floor in dark peaty soil with limestone fragments.
Distribution: Indonesia, New Guinea (W), Mt Jaya (Carstensz)
Altitude: 3200-4100m
Latin – ultimum – the last, probably referring to the fact that it is the highest Rhododendron on Mt Carstensz.
Type: Kloss s.n., 31 Jan. 1913. New Guinea (SW), Mt Carstensz, 3200–3810m (BM, L, fragment).
Occurs in Countries: ID Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: orange
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:226
Much-branched shrub; young shoots densely adpressed-strigose. Leaves possibly dimorphic, ovate to broadly elliptic, 2.5-3 x c. 1.2cm, 2-2.4 x as long as broad, apex acute, base cuneate, upper surface ± glabrescent though with some indumentum persisting on midrib, lower surface with adpressed strigose hairs, scattered on lamina, dense on midrib; petioles 3-4mm, adpressed-strigose. Inflorescence 8-12-flowered; pedicels c.3mm, brown-strigose. Calyx minute, brown-strigose. Corolla probably campanulate, colour unknown, c.l2mm; tube c.5 x 3mm, glabrous. Stamens 5, filaments glabrous, anthers with unciform basal appendages. Ovary densely strigose; style glabrous. Capsule unknown.
Distribution: China (Guangxi)
Altitude: Around 740m
Known only from the type. The isotypc seen is insect-damaged; the few remaining anthers apparently lack the appendages described by Tan. Probably close to R. minutiflorum but with larger leaves and with more flowers per inflorescence.
Type: China, Guangxi, Heng Xian, Maan Shan, 740m, Z.Z. Chen 50300 (iso. KUN)
Occurs in Countries: CN Altitude Ranges: 0 - 1,000m Subgenus: Tsutsusi Habit: Non-Tree
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):135
Shrub or small tree, 1—7m; young shoots densely whitish lanate-tomentose, with scattered stipitate glands. Leaves oblanceolate to obovate, 11.5-21 x 3.5-6.2cm, 2.5-3.3 x as long as broad, apex usually rounded, acuminate, base cuneate to rounded, upper surface glabrous, lower surface densely whitish to fawn lanate-tomentose; petioles 1.5—2.5cm, lanate-tomentose and stipitate-glandular at first, later glabrescent. Inflorescence lax, 12-25-flowered; rhachis 25-35(-60)mm; pedicels with a persistent floccose lanate indumentum and persistent glands, 25-35mm in flower, up to 60mm in fruit. Calyx 5-9mm, lobes lanceolate, acute, stipitate-glandular. Corolla funnel-campanulate, white, sometimes flushed pink, with greenish flecks, c.35mm. Ovary brownish stipitate-glandular, with scattered whitish non-glandular hairs. Capsule 12-15 x 4-6mm.
Habitat: Picea forests
Distribution: NE Turkey & adjacent USSR (Georgia)
Altitude: 1200-1850m
Illustrations:
Map in Grossgeim, FL Kavk. 7: Map 157 (1967)
Closely allied to R. smirnowii and apparently hybridising with it in the wild.
Type: NE Turkey, prope Artvin, distr. Batum, Baron Ungern-Sternberg (LE, n.v.)
Occurs in Countries: RU, TR Altitude Ranges: 1,000 - 2,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: green, pink, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):311
Dwarf, ± prostrate shrub, the ends of the branches ascending, to 0-5 m. Young growth lepidote. Leaves oblong-elliptic, acute or rounded at the apex, ± cuneate towards the base, 13-25 x 5-10 mm, upper surface ± elepidote, margins revolute, lower surface with very distant, small, ± equal scales with very narrow rims, at first golden, rapidly becoming dark brown to almost black. Inflorescence l~2-flowered, pedicels lepidote, 10-12 mm, extending to 25 mm in fruit. Calyx lobes 1-5-2-5 mm, oblong, obtuse, lepidote. Corolla purple, densely pilose and sparsely lepidote outside, 21-25 mm, tube 12-14 mm. Stamens 10, filaments pubescent towards the base. Ovary lepidote, style impressed, longer than the stamens, glabrous, elepidote. Capsule lepidote, c. 9 mm.
The species may be divided into two disjunct varieties
Occurs in Countries: CN, MM Altitude Ranges: 3,000 - 4,000m Subgenus: Rhododendron Habit: Non-Tree
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):121
Leaves acute at the apex
Habitat: Bare cliff ledges
Distribution: NE Burma
Altitude: 3050-3350m
Illustrations:
Known only from the type collection and material in cultivation
Synonymy: R. imperator Kingdon Ward, Gard. Chron. 86:299 (1930); Hutchinson & Kingdon Ward, Notes R.B.G. Edinb. 16:176 (1931). Type: NE Upper Burma, Seinghku Wang (advance base), 10-11000 ft, 9 vi 1926, Kingdon Ward 6884 (holo. K, iso. E)
Leaves rounded at the apex
Habitat: Steep, grassy slopes
Distribution: China (SE Xizang)
Altitude: 3350-3650m
Illustrations:
Known only from the type collection and material in cultivation
Type: China, S. Tibet, Doshong La, 11-12000 ft, 29 vi 1924, Kingdon Ward 5876 (holo. K, iso. E)
Large shrub or small tree, 2—10m. Leaves oblanceolate to elliptic or oblong, (8—)14—22 x (3.3-)4.5-6.5cm, 2.3-4.6 x as long as broad, apex rounded to acute, apiculate to acuminate, base rounded to cuneate, upper surface glabrous when mature, lower surface with a unistrate to bistrate silvery indumentum, the upper layer (when present) composed of dendroid hairs, ± floccose, the lower layer compacted, also with scattered stipitate glands, especially near the midrib; petioles 1-2.5cm, with a whitish agglutinated tomentum intermixed with a few glands. Inflorescence 6-30-flowered; rhachis 5-10mm; pedicels 20-30mm, slender, sparsely dendroid-tomentose, also with a few glands. Calyx c.lmm, lobes rounded, glabrous. Corolla campanulate, white to pale pink, with crimson flecks and usually also a purple blotch, 30-35mm. Ovary glabrous. Capsule 25-45 x 4-5mm, strongly curved.
Habitat: Open rocky slopes, Rhododendron thickets, coniferous forests
Distribution: China (NW Yunnan, SE Xizang, SW Sichuan)
Altitude: 2100-4000m
A variable species, both in the degree of development of the leaf indumentum and in leaf shape. Plants from the western part of the range of the species (Ludlow, Sherriff & Elliot 12329, 12342, 12372, 12375, 12388, 12521, 13544, 13567, 15034, 15054, 15080) have been referred to var. griseum Cowan (Notes R.B.G. Edinb. 21: 147, 1953); type: L., S. & E. 13521. These have leaves with rounded bases and consistently compacted indumentum but there is considerable variation in the relative width of the leaves and in the number of flowers per inflorescence. Over most of its range, however, the species is more uniform and almost always has oblanceolate leaves with cuneate bases. The leaf indumentum ranges from bistrate with a persistent dendroid tomentum characteristic of plants referred to R. dendritrichum to unistrate and compacted (as in var. griseum). Without extensive field studies the status of var. griseum remains uncertain.
Type: China, NW Yunnan, on the ascent of the Nin-ching Pass, from the Yangtze Valley to the Chungtien Plateau, 7-8000ft, ix 1904, Forrest 5072 (holo. E).
Synonymy: R. mombeigii Rehder & Wilson in Sargent (ed.), PL Wilsonianae 1: 536 (1913). Type: China, W Yunnan, Tse-kou, valley of the Upper Mekong River, Mombeig 16 (iso. K). R. niphargum Balfour f. &Kingdon-Ward, Notes R.B.G. Edinb. 10:125 (1917). Type: China, Yunnan, Bei-ma-chan, 12000-13000ft, vi 1913, Kingdon- Ward 324 (holo. E). R. dendritrichum Balfour f. & Forrest, Notes R.B.G. Edinb. 12: 103 (1920). Type: China, W NW Yunnan, Mekong/Salween divide, 12-13000ft, iii 1918, Forrest 16366 (holo. E).
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: crimson, pink, purple, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):368
Shrub to 1m. Twigs green, with moderately dense brown scales set on persistent stalks, rough with stalks after the scales have fallen. Leaves spirally arranged along the twigs, although rapid extension growth may look bare with only small cataphylls which quickly fall. Blade 7–30 x 3–13mm, obovate-spathulate or elliptic, glossy dark green above, dull and paler below; apex obtuse or retuse but with a conspicuous mucronate gland; margin narrowly cartilaginous, entire, flat or slightly revolute; base narrowly tapering; moderately to sparsely scaly, the scales set in shallow depressions, glabrescent above, persistently scaly beneath. Scales circular, with narrow marginal zones and variably developed centres. Mid-vein impressed above, broadly and shallowly raised below; lateral veins obscure. Petiole c.1–3 x 1mm, not clearly demarcated from the blade, grooved above, scaly, especially beneath. Flower buds to 5 x 4mm, ovoid, green passing to pale brown, smooth except for the slightly spreading tips of the lowest bracts. Bracts ovate, acutely pointed, scaly outside near the midline and apex and densely fringed with long white hairs, glabrous inside, often persisting around the base of the pedicels until fruiting. Bracteoles 6–7 x 0.75–1.25mm, with a few scales outside distally, long marginal hairs at the apex, much shorter ones on the sides. Flowers solitary, occasionally 2 or 3 together held horizontally or semi-erect. Pedicels 12–20 x c.1mm, scaly. Calyx lobes 2–3 x c.1.5mm, elongate-ovate to sub-rounded, scaly outside and fringed with scales on the margins. Corolla c.8 x 6mm, white or flushed pink; tube c.4 x 3 x 4mm, broadly cylindrical, scaly outside, glabrous inside; lobes c.4 x 3mm, round or obovate, wide- spreading, not overlapping when fully open, glabrous or with a few scales outside. Stamens exserted to c.5mm; filaments densely long-hairy in the upper 2⁄3 to a level with the base of the anthers, but then glabrous; anthers c.2.5 x 1.5mm, pink. Disc glabrous. Ovary c.2 x 1mm, densely scaly but without simple hairs; style c.2.5mm, glabrous, expanded upwards, club-shaped. Fruit 20–25 x c.5mm, sometimes reported as bright red, spindle-shaped, the valves recurving. Seeds 10–15mm, without tails c.1mm, the longest tail 7mm.
Habitat: Epiphytic in forest, sometimes pendulous from the trunks of trees and on exposed rocks and cliffs
Distribution: Nepal (E). Bhutan. Myanmar (N). Tibet (SE). India, Sikkim, Assam Himalaya, Lachen and Darjeeling. China, Yunnan.
Altitude: 1800-4200m
Named from the resemblance of the plants to species of Vaccinium.
Flowers April–May
Type: Hooker s.n., 3 Aug. 1848. Lachen, Sikkim Himalaya, 2400m (K). Flowering material Herb. Sikk. Treutlerianum, 2 July 1874.
Synonymy: R. sino-vaccinioides Balf.f. & Forrest, Notes RBG Edinb. 1922. 13: 295.
Occurs in Countries: BT, CN, IN, MM, NP Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:28
Shrub, 0-3-1-3 m. Young growth densely loriform-setose, older branches smooth with scaling bark. Leaves elliptic, obtuse, 26-38(-50) X 16-22 (-31) mm, upper surface dark green, rugose, often with the remains of dried-out scales, ioriform-setose along the midrib, margin entire, ciliate with variably persistent loriform setae, lower surface brown with dense, overlapping, unequal scales. Petioles very densely loriform-setose. Inflorescence (l-)2-5(-6)-fiowered, pedicels sparsely lepidote, densely loriform-setose. Calyx conspicuous, deeply 5-lobed, the lobes oblong-ovate, obtuse, herbaceous, 5-7 mm, somewhat accrescent in fruit, lepidote on the surface, margins loriform-ciliate. Corolla 20-32 mm, tube 14-19 mm, funnel-campanulate, bright yellow, the tube pubescent outside and inside, the lobes lepidote on the outside. Stamens 10, filaments pilose in the lower part. Ovary densely lepidote, rarely with a few setae towards the apex, style impressed, variably lepidote towards the base. Capsule lepidote, ovoid-globose, 6-9 mm.
Habitat: Cliffs, stony slopes, scrub 2700-3600 m
Distribution: NE Burma, China (SW Yunnan)
Illustrations:
Very closely related to R.fletcheranum with which it vicariates, and to R. ciliatum. A variety changii (Fang, Contr. Biol. Lab. Sci. Soc. China 12:71, 1939) has been described on the basis of a number of specimens from Nan-chuan hsien in Sichuan province. It is reputed to differ in its glabrous calyx and pedicels, but no material has been available for assessment.
Type: China, Yunnan, Shweli/Salween Divide, 11000 ft, v-vi 1917 (fl.), xi 1917 (fr.), Forrest 15899 (holo. E)
Occurs in Countries: CN, MM Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):42
Shrub or small tree to 4m. Twigs 2–5mm in diameter, rounded, at first covered with dense, scurfy, deeply stellate and sub-dendroid, reddish-brown scales, quickly glabrescent; internodes 3–15cm. Leaves mostly spirally arranged, sometimes in loose pseudowhorls. Blade 50–140 x 15–40mm, elliptic to narrowly elliptic or ovate elliptic; apex shortly acuminate, sub-acute; margin entire, slightly or not revolute; base broadly tapering to rounded; densely stellate-scaly on both sides at first, quickly glabrescent above and also below, the fragile, loose scales often only persisting close to the mid-vein or in other protected areas. Scales with the marginal zone deeply and narrowly stellately divided; centre depressed, sub-dendroid. Mid-vein narrowly impressed above, broader and very prominent beneath; lateral veins 6–9 per side, somewhat irregular, spreading at c.45°, straight below, curved-anastomosing before the edge, mostly faintly raised, reticulation obscure. Petiole 5–10 x 1–1.5mm, semi-rounded, densely scaly. Flower buds c.40 x 20mm, narrowly ellipsoid, smooth, green. Bracts to 30 x 6mm, outer bracts ovate, becoming ovate-elliptic to broadly elliptic, innermost ones elliptic-spathulate, all densely shortly appressed-hairy and scaly outside, laxly hairy inside. Bracteoles to 22mm, filiform to linear-spathulate, laxly hairy. Inflorescence a complete umbel of 5–15 flowers. Pedicels 9–25 x c.1mm, densely, or more rarely laxly sub-patently hairy and scaly but the scales fragile tending to persist near the ends, occasionally only laxly to sub-densely scaly and without hairs. Calyx c.5mm in diameter, oblique, shortly obtusely 5-lobed, densely hairy and scaly. Corolla 40–60 x 50–55mm, funnel-shaped, orange to yellow, also occasionally white or pink; tube 25–35 x 6–8 x 13–20mm, obtusely 5-angled, and lobed at the base, laxly, minutely stellate-scaly outside, hairy inside; lobes 20–25 x 15–20mm, broadly obovate. Stamens exserted to c.10–12mm, sub-equal; filaments linear and hairy proximally, filiform and glabrous in the distal ½; anthers 3–5mm, oblong, base obtuse. Disc densely hairy on the upper margin only. Ovary 5–9 x 2–2.5mm, sub-cylindrical, densely long-hairy and scaly, tapering distally; style slender, equalling the stamens, densely hairy and scaly proximally, becoming less so distally, glabrous in the ultimate area; stigma thick-rounded. Fruit 55–70 x 6–7mm, sub-fusiform-cylindric, sub-densely hairy and scaly.
Habitat: Terrestrial in light dry forest, grass and fern shrubberies, on rocks or bare slopes, locally common and gregarious.
Distribution: Indonesia, Sulawesi (C), Mt Masawa, Mt Taburone, Mt Balapioe, Mt Pelali, Mt Rantemario and Mt Lompoh; Lore Lundu (Lake Kalimpaa).
Altitude: 600-1600m
Named after Louis van Vuuren, who led the expedition to Celebes (Sulawesi) on which this species was discovered.
The showy flowers vary in colour and are used for decoration by local people, but it is also known to be poisonous to livestock and sometimes actively removed (Binney 2003).
Type: Rachmat 878, Nov. 1913. Celebes (C), G. Pelali (lectotype) (BO, L).
Occurs in Countries: ID Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Vireya Habit: Tree Fl. Colour: orange, pink, white, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:290
Shrub to small tree to 2.5(-5.5)m tall; bark thin, flaky or longitudinally shredding; young twigs pale to reddish brown, very sparsely covered with multicellular eglandular and gland-headed hairs, very sparsely to sparsely covered with short unicellular hairs, becoming glabrous with age; new foliage shoots arising from axillary buds associated with foliage leaves of previous year's shoot (i.e. below terminal bud), and some terminal buds. Vegetative bud scales glabrous to moderately unicellular-pubescent abaxially and sometimes with scattered multicellular gland-headed hairs, especially near apex, sparsely to moderately unicellular-pubescent adaxially, especially near apex, and sometimes with a few multicellular gland-headed hairs near apex; margin fringed with unicellular hairs with intermixed gland-headed hairs, occasionally also with a few eglandular hairs near apex; lowermost scales sometimes with aristate apices or rudimentary blades. Leaves deciduous, dark green adaxially, pale green abaxially, turning red in autumn, alternate (with internodes becoming more closely spaced towards tip of shoot). Blade membranaceous, elliptic to obovate, 2.3-17 x 0.8-5.5cm; base cuneate to attenuate; apex acuminate, with a short mucro; midvein strongly raised and prominent abaxially, the secondary veins slightly raised abaxially; adaxial surface, including midvein, sparsely covered with multicellular gland-headed and eglandular hairs, glabrescent, the midvein unicellular-pubescent; abaxial surface with scattered multicellular gland-headed hairs, the midvein with scattered gland-headed and longer eglandular hairs, the secondary veins with gland-headed hairs only; margin entire to undulate, with widely scattered to definite fringe of multicellular eglandular hairs; petiole 3-15mm long, sparsely unicellular-pubescent adaxially, and with scattered multicellular gland-headed and eglandular hairs, the base of petiole often expanded into a broadened point of attachment, forming a ± triangular slight protuberance below terete portion. Flower buds larger than vegetative buds, more frequently unicellular-pubescent abaxially, and with portion of margin often completely glandular. Flowers appearing before the leaves; inflorescence an umbellate raceme of 5-15 flowers. Pedicels 5-26mm long, moderately covered with multicellular gland-headed hairs and sparsely to moderately unicellular-pubescent. Calyx lobes broadly subovate to narrowly triangular-Ungulate, 0.3-8.5mm long (often extremely variable, even within a single flower), 1.2-2mm wide; apex rounded; margin fringed with multicellular gland-headed hairs; adaxial surface glabrous; abaxial surface + glabrous to with a few multicellular gland-headed hairs. Corolla pink to occasionally white, with orange-brown to red spots on the upper 3 lobes, fragrant, zygomorphic, broadly rotate-funnelform, appearing ± 2-lipped due to more extensive fusion of the upper 3 lobes and the 2 flaring lower lobes being slightly longer, the tube much shorter than the limb and gradually expanding into it; upper corolla lobe 1-1.8 x 0.8-1.3cm; lateral lobes 1.4-2.4x0.8-1.4cm; lower lobes 1.5-2.6 x 0.8-1.3cm; corolla tube 0.4-0.8cm long; outer and inner surfaces of corolla glabrous. Stamens (5-) 7, declinate, variable in length, 1.2-3.7cm long, the shorter stamens included, longer ones exserted; filaments glabrous throughout their entire length. Ovary 3-5mm long, sparsely to moderately covered with multicellular gland-headed hairs; style declinate, 2-3.8cm long, glabrous to with a few multicellular gland-headed hairs near base. Capsules ovoid to oblong-ellipsoid and slightly grooved, 0.9-1.7 x 0.3-0.6cm, sparsely to moderately covered with multicellular gland-headed hairs. Seeds brown, angular-ellipsoid, 1-1.7 x 0.4-0.6mm; testa tightly appressed to body, with cells at each end elongated, bulging, and fused to form ± stellate tails 0.2-0.5mm long, the cells covering central portion of body elongate and non-bulging, those along angles often ± bulbous and expanded (similar to those of tails) and often forming a slight fringe. Cotyledons lacking multicellular hairs and with venation represented by midvein and a small number of poorly developed secondary veins. 2n=26 (Sax, 1930).
Habitat: Bogs, thickets and deciduous or coniferous forests
Distribution: United States, North Carolina
Altitude: 900-1830m
Illustrations:
Rhododendron vaseyi is a distinctive species probably most closely related to the more northerly R. canadense. The phenetic divergence between these two species (and their separation from other 'azaleas') is seen in the fact that both have, at various times, been recognized as monotypic genera, R. vaseyi as Biltia (Small, 1903) and R. canadense as Rhodora (Linnaeus, 1762). Rhododendron vaseyi and R. canadense both have 2-lipped corollas with a glabrous inner surface, and tailed and ornamented (or fringed) seeds (of flattened or bulging cells). Together these species comprise the North American sect. Rhodora. The taxonomic connection between R. vaseyi and R. canadense has long been recognized (Sargent, 1888; Rehder, 1921a; Wood, 1961). Rhododendron vaseyi is easily distinguished from R. canadense by its corolla which is not cut to the base, less strongly 2-lipped, with a longer upper lobe (1-1.8 vs. 0.3-0.8cm), leaves with acuminate (vs. acute to rounded) apices, and plane (vs. revolute) margins, usually 7 (vs. 10) stamens, glabrous (vs. basally pubescent) filaments, capsules with sparse to moderate covering of gland-headed hairs (vs. densely unicellular-pubescent with gland-headed and eglandular hairs intermixed), seeds with fringe of bulging (vs. flattened) cells, and a diploid (vs. tetraploid) karyotype.
Synonymy: Azalea vaseyi (A. Gray) Rehder in Moller's Deutsch. Gartn.-Zeitung. 14: 332 (1899). Biltia vaseyi (A. Gray) Small, Fl. S.E. U.S. 884 (1903). Type: United States, North Carolina, Jackson Co., summit of a balsam mountain c.7mi SW of Webster, 3 vi 1878, Vasey s.n. (holo. GH; iso. NY, US, US (frag.)). Rhododendron vaseyi A. Gray var. album Bean, Trees and Shrubs Brit. Isles 2: 384 (1914). Rhododendron vaseyi f. album (Bean) Rehder in Mitt. Deutsch. Dendrol. Ges. 24: 225 (1916). Type: n.v.
Occurs in Countries: US Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Pentanthera Habit: Tree Fl. Colour: orange, red, white
Judd, W.S. & Kron, K.A. (1995) A Revision of Rhododendron VI. Subgenus Pentanthera (Sections Sciadorhodion, Rhodora and Viscidula). Edinburgh Journal of Botany 52(1):27
Epiphytic or free-growing shrub up to 2 m. Young growth sparsely loriform-setose, the setae usually quickly deciduous. Leaves obovate or narrowly elliptic, gradually tapered to tne base, the apex shortly acuminate, 65-100 x 28-40 mm, upper surface dark green, lower surface paler with distant, unequal, golden scales; petiole lepidote. Inflorescence (l-)2-5-flowered, pedicels short, lepidote. Calyx disc-like, scarcely lobed, lepidote, loriform-ciliate. Corolla white, often with a yellow blotch at the base, openly funnel-campanulate, 50-60(-65) mm, tube 26-34(-40) mm, sparsely pubescent at the base, lepidote along the adaxial part only; lobes with crisped margins. Stamens 10 (not 12-14 as described by Hooker), pubescent towards the base. Ovary lepidote, tapering into the style which is lepidote well above the base. Capsule up to 30 mm, lepidote.
Habitat: Usually epiphytic in forests, but also on cliffs or ridges
Distribution: Burma, Laos, Thailand
Altitude: 1200-2400m
Illustrations:
Type: A cultivated plant originating from Burma (holo. K)
Synonymy: R. formosum Wallich var. veitchianum (Hooker) Kurz, Journ. As. Soc. Bengal 46(2):276 (1887). R. cubitii Hutchinson, Notes R.B.G. Edinb. 12:78 (1919). Type: N Burma, Bhamo Division, Maru-kahtung (Surdum), 5500 ft, iii 1910. Cubitt 385 (holo. E), non hort. R. smilesiiHutchinson, op. cit.: 71. Type: N Siam, Pu Sai Leng, 1 iv 1893, Smiles (holo. K)
Occurs in Countries: MM, TH Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Rhododendron Habit: Epiphyte, Non-Tree Fl. Colour: yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):55
Straggling shrub, 2-3m; young shoots setose-glandular and with an evanescent indumentum. Leaves elliptic to lanceolate, 8.5-14 x 2-2.4cm, 3.5-4 x as long as broad, apex acute to acuminate, base rounded, upper and lower surfaces glabrous except for a thin stellate indumentum intermixed with folioliferous hairs on the midrib below; petioles 1-1.5cm, stellate-tomentose and setose-glandular. Inflorescence 7-10-flowered; rhachis c.5mm; pedicels c.lOmm, rufous stellate-tomentose and setulose-glandular. Calyx 3-5mm, tomentose and glandular at base, lobes broad, rounded, ciliate-glandular. Corolla fleshy, tubular-campanulate, crimson, with darker nectar pouches, 30-35mm. Ovary with a dense tomentum intermixed with stipitate glands. Capsule c.20mm, curved.
Distribution: China (SE Xizang)
A distinctive species with no close allies.
Type: China, SE Xizang, Tsangpo Gorge, Pemakochung, 8000ft, 19 xi 1924, Kingdon-Ward62S5 (iso. E).
Occurs in Countries: CN Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: crimson
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):290
Shrub or tree, 1.3-8 m. Leaves elliptic to ovate- or obovate-elliptic, (4.5-) 7-10 x 2.7-5 cm, 1.5-2.2 x as long as broad, apex rounded, mucronate, base rounded, lower surface with minute punctulate hairs; petioles 2-3 cm, glabrous. Inflorescence 6-10-flowered; rhachis 5-10 mm; pedicels 17-30 mm, stipitate-glandular. Calyx a 2 mm, lobes rounded, stipitate-glandular. Corolla 6-7-lobed, broadly funnel-campanulate, glabrous, pale rose to pinkish-purple, with crimson flecks, 35-50 mm. Stamens c. 14, filaments glabrous. Ovary and style stipitate-glandular, glands red. Capsule 17-30 x 7-12 mm, curved.
Habitat: Thickets, mixed forest, open slopes
Distribution: China (N Yunnan, SW Sichuan)
Altitude: 2600-3650m
Illustrations:
The following specimens without flowers probably belong to this species: Forrest 23025; Rock 18139; Yti 13961, 14694
Closely allied to R. decorum (q.v.) and to R. fortunei but differing in its red stylar glands. From the type description R. hexamerum is apparently closer to R. vernicosum than it is to R. decorum on account of its broad leaves and glabrous filaments.
Type: China, W Sichuan, Tongolo, Soulie 812 (iso. E)
Synonymy: R. lucidum Franchet, J. Bot. (Morot) 9: 390 (1895), non Nutall (1853). R. sheltonii Hemsley & Wilson, Kew Bull. 1910: 108 (1910). Type: China, Sichuan, neighbourhood of Tatsienlu, 2750-3000 m, Wilson (Veitch) 3977 (iso. K). R. euanthum Balfour f. & W. W. Smith, Notes R.B.G. Edinb. 10: 103 (1917). Type: China, NW Yunnan, western flank of the Lichiang Range, 11-12000 ft, vi 1910, Forrest 5880 (holo. E; iso. K). R. rhantum Balfour f. & W. W. Smith, ibid. 10: 145 (1917). Type: China, NW Yunnan, Lichiang Range, 10-11000 ft, vi 1913, Forrest 10075 (holo. E). R. hexamerum Handel-Mazzetti, Akad. Wiss. Wien Math.-Naturwiss. Kl. Anz. 4-5 (1921). Type: China, Sichuan, in fruticetis jugi Schao-schan, ad merid. urbis Ningyuen, 22-2700 m, 15 iv 1914, Handel-Mazzetti 1343-n.v. R. adoxum Balfour f. & Forrest, Notes R.B.G. Edinb. 13: 28 (1922). Type: NW Yunnan, Yunling Mountains, 13000 ft, vii 1917, Forrest 15226 (holo. E;iso. K). R. araliiforme Balfour f. & Forrest, ibid. 13:232 (1922). Type: China, NW Yunnan, Mekong/Salween Divide, 10000 ft, vii 1917, Forrest 14151 (holo. E)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: crimson, pink, rose
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):230
Erect shrub to 1m, with arching branches sometimes appearing from below ground. Twigs rounded, densely covered with sessile scales, early glabrescent and smooth, with conspicuous rounded lateral buds; internodes 2–12cm. Leaves spiral or in loose pseudowhorls in the upper ½–2⁄3 of the internodes. Blade 15–35 x 8–20mm, elliptic or broadly elliptic, sometimes slightly obovate, or rarely ovate-elliptic; apex obtuse to rounded, sometimes with a shortly protruding apical gland; margin flat or weakly revolute when dry, minutely crenulate; base truncate, rounded, or broadly tapering, very densely scaly on both sides initially, glabrescent above, scaly for a longer time beneath. Scales forming a coherent layer, irregularly stellate, slightly overlapping, marginal zone wide; centres small and impressed leaving pits after the scales have gone. Mid-vein narrowly grooved above in the proximal ½, thick and obtusely prominent in the proximal ½ beneath, often becoming obscure distally; lateral veins 2–4 per side, often obscure. Petiole 2–3 x 1–2mm, flattened and grooved above, scaly. Bracts to 19 x 8mm; outer bracts ovate-elliptic, sub-acuminate or obtuse, inner ones elliptic to elliptic-spathulate, membranous, scaly along the outside midline, otherwise glabrous. Bracteoles to 16mm, linear to linear-sub-spathulate, glabrous. Inflorescence of 3–8 flowers, in an open umbel. Pedicels 9–20 x c.1mm, very densely brown scaly but without hairs. Flowers 30–40 x 30–35mm, hanging to half-hanging. Calyx 4–5mm in diameter, oblique, disc-shaped, densely scaly, obtusely 5-lobed, sometimes with one or more lobes larger and more elongate. Corolla funnel-shaped, red and yellow, in an irregular pattern, the yellow mostly on the lobes where the surface has been recently exposed as the flower finally opens; tube 18–22 x 4–5 x 6–8mm, laxly to sub-densely scaly outside, glabrous inside, somewhat angular, slightly pouched at the base; lobes 10–14 x 10–13mm, obovate to sub-circular, half-spreading, and overlapping to c.halfway, scaly outside near the base except near the margins. Stamens exserted to c.4mm, unequal; filaments linear, glabrous; anthers c.2.5 x 1mm, obovate-oblong. Disc prominent, green, glabrous. Ovary 5–6 x 2.5–3mm, shortly conical, very densely scaly and patently hairy (the hairs obscuring the scales), abruptly contracted distally; style slender, as long as the corolla, densely scaly and laxly to sparsely hairy in the lower 1⁄3–2⁄5, or almost completely glabrous; stigma globose, distinctly 5-lobed. Fruit 13–20 x 5–6mm, oblong-conical, 5-ribbed, densely scaly and hairy, broadest below the middle, held erect.
Habitat: Grassy edges of Podocarpus forest, alpine grassland or boggy slopes, scattered through open mossy shrubberies on exposed ridges. Sporadic, but locally common, in wet shallow sandy or peaty soil.
Distribution: Indonesia, New Guinea (W), Mt Carstensz and Mt Trichora and vicinity.
Altitude: 3200-3950m
Named after the collector, Gerard Martinus Versteeg, Medical Officer in the Dutch East Indies army who was attached to two New Guinea expeditions.
First brought into cultivation to Edinburgh by Ian Edwards in 1991, but this plant subsequently died. It grew slowly and did not have the brilliantly coloured flowers that it did in the wild, the flowers being pale orange with a green cast. It is being used extensively around the Mt Jaya (Carstensz) mine in New Guinea in the rehabilitation of disturbed land, where it is one of the most favoured species, growing well at high altitude and flowering continuously.
Type: Pulle (Versteeg) 2573, 18 Feb. 1913. W New Guinea, Oranje Mts, S ridge of the Quarles Valley, 4000m (L, BO, K, U).
Occurs in Countries: ID Altitude Ranges: 3,000 - 4,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: red, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:139
Generally epiphytic shrub to 2m, the roots reported to be long and fleshy. Twigs 3–5mm in diameter, densely shortly patent white hairy and sparsely scaly with small dark brown scales; internodes 5–10cm. Leaves 4–7 together in tight pseudowhorls usually with 1–3 much smaller leaves. Blade 60–100 x 20–40mm, broadly elliptic, elliptic to narrowly ovate; apex acute to rounded, with very short hairs particularly on the underside near the petiole; margin entire, flat or weakly revolute; base broadly tapering to rounded or sub-cordate, scaly initially on both sides, glabrescent above except for the mid-vein where the scales tend to persist, beneath, remaining laxly scaly for a long time. Scales very small, dark brown, rounded to stellately lobed; centre small, slightly impressed. Mid-vein broad and raised above for up to 10mm but rapidly tapering and becoming narrowly grooved distally; below bright red, raised throughout most of its length and tapering gradually; lateral veins 7–10 per side, curved-ascending, somewhat impressed above, indistinctly raised beneath, often obscure on both sides. Petiole 10–25 x 2–3.5mm, smooth, rounded, without a groove, scaly and very shortly hairy. Flower buds to 20 x 15mm, dark purple, the tips of the bracts reflexed outwards. Bracts broadly elliptic, broadly ovate to broadly obovate, with a broad spreading to reflexed apiculus, appressed hairy all over outside and with a patch of scales about the centre line distally, inside glabrous except for the apiculus which is both scaly and hairy inside and out, fringed with small dark brown scales; inner bracts narrowly spathulate, glabrous except for the fringe of scales. Bracteoles to 25mm, filiform, with just a few scales distally. Inflorescence a full umbel with 8–15 flowers, which are erect to horizontal. Pedicels 30–40 x 2–3mm, densely covered with long patent hairs and laxly with small scales. Calyx oblique, c.4mm in diameter, sub-circular, irregularly and shortly 5-lobed with one lobe occasionally up to 2mm long, shortly hairy and scaly outside. Corolla 50–60 x 40–50mm, narrowly funnel-shaped, red to reddish-orange; tube 30–36 x 5–10 x 11–15mm, deeply grooved in the proximal part, densely to laxly scaly and with some scattered hairs outside, sub-densely hairy inside; lobes 20–30 x 13–22mm, semi-erect to spreading horizontally, broadly elliptic. Stamens exserted to c.10mm, irregularly grouped around the mouth, or in two fairly coherent groups on either side; filaments 35–45 x c.1mm, filiform, laxly hairy in the proximal 1⁄3, glabrous distally; anthers c.2.5 x 0.7mm, oblong, curved, the cells sometimes with a small basal apiculus. Disc densely white-hairy at its upper margin, glabrous below. Ovary 5–8 x 3–4mm, sub-cylindric-conical, abruptly contracted distally, densely to sparsely covered with hairs, and very small scales; style held on the lower side of the tube, at first at the mouth, later exserted up to 15mm, hairy and scaly for the lower 3⁄5–4⁄5, glabrous distally; stigma rounded. Fruit 33 x 6mm, cylindrical, reddish-purple, patently hairy and scaly. Seeds 3–3.3mm, with crimped tails, without tails c.1mm, the longest tail 1.2mm.
Habitat: Epiphytic in moss forest, and occasionally on the ground.
Distribution: Malaysia (Borneo), Sarawak, Mt Penrissen, Mt Santubong, Lundu, top of Mt Gading, Bongo Mts, Batang Lupar, Merurong Plateau (Bintulu), Hose Mts, Batu Laga, Kapit. Indonesia (Borneo), Kalimantan (W), Mt Kenepai.
Altitude: 700-1500m
Latin – verticillatus – whorled, alluding to the tight pseudowhorls of leaves.
An old record from near Kuching reports it from ‘swampy jungle’ implying it was growing at near sea level.
The type specimen in Cambridge has hairy petioles and leaves so that R. velutinum cannot be maintained even as a forma. It is doubtful if forms exist without the short hairs on the leaves except by erosion in old stems.
It is similar to R. polyanthemum but has a much longer corolla tube than that species, different scales and quite different flower bud morphology.
Type: Low s.n. Borneo, Sarawak, G. Penrissen, c.1430m (CGE, K).
Synonymy: R. velutinum Becc., Malesia 1878. I: 204. R. verticillatum f. velutinum (Becc.) Sleumer, Reinwardtia 1960. 5: 185.
Occurs in Countries: ID, MY Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:256
Large shrub or small tree; young shoots densely covered with glandular setae. Leaves herbaceous, obovate to oblanceolate, 12-14.5 x 3.5-5cm, 2.4-2.9 x as long as broad, apex cuspidate, base rounded, margin ciliate, upper surface bullate, with strongly impressed veins, glabrous or with a few bristles at base when mature; lower surface with veins covered with glandular setae that are longer on the midrib near the base, also with white vesiculate hairs; petioles 1—2cm, glandular-setose. Inflorescence 10—15-flowered; rhachis up to 5mm; pedicels 15—20mm, densely glandular-setulose, also with short vesiculate hairs. Calyx 8-10mm, glandular-setulose, lobes Ungulate. Corolla funnel-campanulate, white to rose-purple, darker in bud, with purple flecks and a basal blotch. Ovary densely rufous-stipitate-glandular with an understory of short white vesiculate hairs; style glabrous. Capsule not known.
Habitat: Rocky slopes, in mixed forests
Distribution: China (W Yunnan, SE Xizang), NE Upper Burma
Altitude: 2500-3350m
Illustrations:
Closely allied to R. glischrum but differing in the characteristic vesiculate hairs and in the more strongly bullate leaves.
Type: NE Upper Burma, Seingku Wang, 9000ft, v 1926, Kingdon- Ward 6152 (holo. E; iso. K).
Occurs in Countries: CN, MM Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: purple, rose, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):286
Shrub to 3 m, minutely puberulous on the young branches, petioles and upper mid-ribs. Leaves elliptic or obovate, 40-70 x 15-30 mm, base broadly cuneate, apex obtuse or emarginate, mucronate; petiole 7-15 mm long. Inflorescence buds lateral, 1-flowered, clustered near the ends of leafy shoots; outer bud scales short, rounded, inner elongate (to 12 mm long); pedicel only slightly longer than the inner bud scales, with many glandular hairs. Calyx lobes oblong, up to 8 x 4mm, apex rounded, densely bristly at the base, margin fringed with glandular hairs. Corolla crimson, glabrous; tube gradually widening, c.l5mm long; lobes rotund, c.lOmm long. Stamens 5, about equalling the corolla, filaments stout, slightly hairy on the lower half. Ovary subglobose, c.3 mm high, with glandular hairs, 5-locular; style exserted, glabrous. Capsule unknown.
Distribution: China (S Yunnan), N Laos, Vietnam (Northern).
A distinctive species whose distribution and range of variability are inadequately known.
Occurs in Countries: CN Subgenus: Azaleastrum Habit: Non-Tree
Philipson, W.R. & Philipson, M.N. (1986) A Revision of Rhododendron III. Subgenera Azaleastrum, Mumeazalea, Candidastrum and Therorhodion. Notes from the Royal Botanic Garden Edinburgh 44(1):6
Named after Sebastian Vidal y Soler, Spanish botanist who worked and collected in the Philippines, who ‘was the first of the local botanists … to recognize the necessity of a local botanical library and herbarium’ (Steenis-Kruseman 1950).
Type: Vidal 1529. Philippines, Luzon, Mt Polis, Bontoc, 1000–1200m (K, FI, L).
Synonymy: R. verticillatum (non Low ex Lindl.) S.Vidal, Rev. Pl. Vasc. Filip. 1886. 171. R. lussoniense Rendle, J. Bot. 1896. 34: 356.
Occurs in Countries: PH Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Fl. Colour: white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:210
Distribution: Differing from the type subspecies in that the stamens are shorter, clustered in the mouth of the flower not exserted and the ovary is shorter, c.3mm, and gradually tapering distally.
Greek – brachy – short; stemon – stamen. Alluding to the characteristic short stamens clustered below the mouth of the corolla tube.
At present known only from the type locality.
Type: Argent et al. HAL 20, 26 Oct. 1999. Philippines, Mindoro Oriental Province, Mt Halcon. Mossy ridge at c.1200m (PNH, A, E, L).
Shrub to 3m. Twigs 1–2mm in diameter, minutely hairy, sometimes very sparsely so, and often laxly scaly; internodes 1.5–5cm. Leaves 3–5 together in tight pseudowhorls. Blade 15–40 x 10–20mm, elliptic, narrowly ovate or narrowly obovate; apex rounded, sometimes minutely emarginate, and sometimes with a minutely protruding terminal gland; margin entire or slightly irregular, flat or narrowly and weakly revolute, distinctly so when dry; base tapering, slightly decurrent, pale green, laxly to sub-densely scaly on both sides at first, quickly glabrescent above, more persistently scaly beneath. Scales very variable in size, the largest irregularly lobed, with small dark brown centres, smaller ones, circular dark brown, all impressed in shallow pits. Mid-vein impressed above, smooth, shallowly impressed or weakly prominent beneath (distinctly raised when dry); lateral veins 4–6 per side, emerging at c.45°, often only faintly visible above, smooth and faintly visible beneath, reticulation inconspicuous. Petiole 3–8 x 1–1.5mm, grooved above, flattened, brown-scaly and sometimes minutely hairy. Flower buds to 10 x 4mm, narrow-ovoid, or ellipsoid, imbricate, green but with distinctly brown scaly margins, terminal but sometimes with lateral flower buds around the terminal. Bracts membranous, glabrous or sub-densely to laxly hairy outside, fringed with dark brown scales, outer ones broadly ovate, acuminate to subulate, inner ones larger, to 10 x 6mm, ovate to spathulate, often mucronate. Bracteoles to 10mm, filiform, laxly hairy. Inflorescence 2–4-flowered, (sometimes appearing more when several lateral buds are flowering together), an open umbel. Flowers half-hanging. Pedicels 12–25 x c.1mm, scaly and long-hairy, or sometimes entirely without hairs. Calyx c.3mm in diameter, small, disc-shaped, obscurely lobed, shortly hairy outside. Corolla 22–30 x 20–25mm, funnel-shaped, white, with or without scent; tube 10–15 x 4–4.5 x 5–8mm, straight, grooved, laxly hairy and scaly outside, glabrous or laxly hairy inside; lobes 10–16 x 10–13mm, obovate-spathulate, spreading almost to the horizontal, not overlapping, laxly scaly and sometimes with a few hairs proximally outside. Stamens exserted 8–12mm, spreading all round the mouth or weakly disposed in two groups on either side; filaments linear and more or less densely sub-patently hairy in the lower ½, filiform and glabrous distally; anthers narrowly oblongoid, c.2 x 1mm. Disc prominent, glabrous below, shortly hairy on the upper margin. Ovary c.5 x 1mm, cylindrical, densely hairy with appressed hairs which cover small scales, abruptly tapering distally; style patently hairy in its lower 1⁄3–2⁄3, glabrous distally, green, lying on the lower side of the tube; stigma round, green, centrally placed when receptive. Fruit 15–30 x 4–5mm, sub-cylindrical-fusiform, often curved, becoming erect, when immature green but distinctly white-hairy, on opening the valves becoming recurved and twisted. Seeds c.3mm including the long tails at both ends.
Habitat: Mostly epiphytic in mossy forest, but also terrestrial on banks in barren places, shrubberies or grassland and on exposed ridges, locally common.
Distribution: Philippines, Luzon, Mountain Province, Mt Polis, Mt Caua, Mt Data. Benguet Province, Loö, Bandschan. Isabella, Bayabat. Cagayan, Cagua Volcano. Bataan, Mt Mariveles. Laguna, Mt Maquiling, Lukban Cone. Batangas Province, Mt Malarayat. Zambales Province, Mt Tapulao. Penicuason Province, Mt Isarog. Mindoro, Mt Halcon.
Altitude: 1000-2100m
This species has been in cultivation since 1997 from Mt Halcon and Mt Isarog when it was collected by an Edinburgh/National Museum Manila expedition. The earlier collection from Sibuyan Island which was distributed under the name R. vidalii is now considered to be R. rousei. It is a pleasant, easily grown species but suffers in comparison with R. rousei which has both better foliage and better flowers.
Erect shrub to c.1m. Twigs rounded, 2–4mm in diameter, at first rough with fragile, brown stellate scales, quickly glabrescent and smooth; internodes 4–16cm. Leaves 3–5 together in tight pseudowhorls, often with 1 or 2 much smaller leaves. Blade 40–70 x 25–40mm, ovate or broadly elliptic; apex shortly to long acuminate, characteristically decurved, obtuse to acute; apex often slightly mucronate with the protruding mid-vein; margin entire, broadly recurved; base broadly tapering to rounded; glabrescent above at maturity; persistently and sub-densely scaly beneath. Scales flat, marginal zone variously and irregularly sub-stellately lobed; centre dark, slightly impressed. Mid-vein narrow, strongly impressed above, strong and very prominent beneath; lateral veins 4–8 per side, irregular, spreading and anastomosing, faintly or not impressed above and weakly raised beneath, reticulation dense and prominent on both sides. Petiole 5–7 x 2–3mm, grooved above, densely scaly, held at 45° to the stem. Flower buds to 25 x 14mm, ovoid, smooth with the bract tips appressed, pale green or pink; outer bracts broadly ovate, apex shortly subulate or apiculate, with a few scales along the midline near the apex and along the margins otherwise glabrous; inner ones to 25 x 10mm, ovate to obovate-spathulate, obtuse, densely appressed-hairy outside, the innermost narrowly spathulate. Bracteoles to 20 x 1mm, linear, hairy throughout and with a few scales at the apex. Inflorescence 2–5 flowers in an open umbel, half-hanging to hanging. Pedicels 12–29 x 1.25–2mm, red, densely patently hairy and sparsely scaly. Calyx c.4mm in diameter, disc-shaped, obliquely 5- angular, densely hairy. Corolla 35–40 x 35–40mm, tubular below, expanded distally, oblique, dark to light red, without scent; tube 20–26 x 7–8 x 10–13mm, curved, laxly to densely, shortly patently hairy all over, outside and at the base inside; lobes 15–16 x 14–18mm, sub-circular, slightly retuse, spreading horizontally, overlapping ½–2⁄3, hairy outside in the basal central region. Stamens tightly clustered on the upper side of the mouth, exserted to 8mm; filaments red, filiform, hairy in the proximal 1⁄3–½; anthers 2–3 x 1–1.5mm, brown. Disc densely hairy at the upper margin only. Ovary 5–6 x 2.5–3mm, sub-ovoid-cylindrical, densely patently white hairy, the hairs covering scales, gradually tapering distally; style white patent-hairy almost to the top, without scales, held on the upper side of the corolla tube; stigma broad, distinctly lobed. Fruit 25–35 x 4–5mm, fusiform, persistently hairy. Seeds 5mm, without tails 0.9mm, the longest tail 2.4mm.
Habitat: Epiphytic in moss forest
Distribution: Indonesia, New Guinea (W), Wissel Lakes region, Oranje and Nassau Mts, Mt Trichora. Papua New Guinea, Eastern Highlands.
Altitude: 2000-3000m
Latin – villosus – with long soft hairs; ulum – diminutive. Alluding to the shortly hairy flowers.
Sleumer (1966) noted that this species is ‘much related to R. christi, distinguished mainly by the non-cordate, more distinctly petioled leaves’.
Type: Pulle 589, 2 Dec. 1912. New Guinea (W), Hellwig Mts, 2500m (BO, lectotype, L).
Occurs in Countries: ID, PG Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:302
Shrub to 80cm. Twigs 3–4mm in diameter, rounded, dark brown with a dense rough covering of scales; internodes 5–10cm. Leaves 8–10 together, in loose pseudowhorls, often with up to 4 leaves at some distance below the pseudowhorl. Blade 50–120 x 4–8mm, linear; apex gradually tapering, the extreme point rounded and often deflexed; margin irregular, distinctly revolute when living, strongly so when dry; base narrowly tapering; sub-persistently silvery scaly above with occasional dark spots visible from the centres of the largest scales; densely and persistently brown scaly below. Scales variously sized, with broad striate, lobed flanges, and broad swollen centres; the largest with very dark brown swollen centres. Mid-vein impressed above, strongly raised beneath throughout its length; lateral veins not visible, reticulation obscure. Petiole 5–10 x 1–2mm, grooved above, densely brown-scaly. Flower buds to 12 x 6mm, predominantly brown. Bracts to 12 x 5mm, smoothly appressed, ovate, densely brown-scaly outside with a narrow green glabrous, or minutely appressed hairy border and a white-ciliate margin; outer bracts densely appressed white-hairy inside, inner ones less densely hairy. Bracteoles to 10 x 1mm, narrowly subulate, glabrous. Pedicels 8–12 x 0.75mm, green, slender, laxly scaly. Calyx minute, disc-like, densely scaly. Corolla 22–24 x 16mm, reddish-purple, without scent; tube 18 x 4 x 5mm, cylindrical, laterally compressed, slightly keeled on the upper side and grooved in the basal ½, curved, laxly and inconspicuously scaly outside, glabrous inside; lobes 7 x 5mm (the upper three), 7 x 4mm (the lower two), the three upper overlapping to c.1⁄3, the two lower hardly overlapping, spreading horizontally, broadly elliptic to obovate, scaly in a broad central band outside. Stamens 17–19mm, clustered in a group on the lower side of the flower, exserted to c.4mm; filaments linear, filiform distally, slightly unequal, glabrous; anthers c.1.5mm, broadly obovate. Disc glabrous. Ovary c.4 x 1.5mm, obconical-cylindrical, densely scaly, gradually tapering distally; style 8–12mm, glabrous, scaly at the base or up to the proximal 1⁄3, green, lying on the lower side of the tube; stigma shortly club-shaped and obscurely lobed. Fruit c.22 x 3.5mm, fusiform, brown-scaly. Seeds 5.5–6.5mm, without tails 0.8mm, the longest tail 3mm.
Habitat: Mostly epiphytic in sub-montane mossy forest ridges and on old volcanic vents, also on peat overlying limestone.
Distribution: Indonesia, Sumatra, Atjeh Province: Mt Lembuh region; Tapanuli, near Sidikalang; Mt Bandahara, above Lawe Peunaggalan; Northern Province: Karo District, near Brestagi.
Altitude: 1100-1500m
Latin – vinicolor – wine coloured, the flowers on the collecting label of the type being described as wine-red.
In the wild found hybridising with R. malayanum, the leaves of the hybrid being intermediate in shape between the two parents which were both growing locally on Mt Bandahara.
Type: Steenis 9928, 21 March 1937. Indonesia, Sumatra, Atjeh, Gajo Lands on the confluence of the rivers Kapi and Aoenan (L, A, BO, K, SING).
Occurs in Countries: ID Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:125
Shrub. Twigs 1.5–3mm in diameter, rounded, densely covered at the ends with sub-circular, sessile or sub-sessile scales; internodes 2–5cm. Leaves 3–5 together in pseudowhorls at the upper 2–3 nodes. Blade 35–60 x 15–22mm, elliptic to slightly obovate; apex broadly tapering, obtuse, rarely slightly retuse; margin slightly revolute especially proximally; base tapering into the petiole; densely scaly on both sides initially, glabrescent above with age, persistently scaly beneath. Scales circular or almost so, thick, impressed, distant (for 2–3 times their diameter). Mid-vein slightly impressed above, prominent proximally beneath but gradually narrowed and less prominent distally; lateral veins 6–8 per side, impressed above, obscure beneath, reticulation faintly impressed above, or almost inconspicuous. Petiole 5–8 x c.1mm, grooved above, densely scaly. Outer bracts to 10mm, ovate, inner ones obovate to spathulate, glabrous outside, but with a scaly margin. Bracteoles filiform. Inflorescence 2–3-flowered. Pedicels 12–18mm, slender, densely patently hairy and scaly. Calyx c.2.5mm in diameter, obliquely rounded, indistinctly obtusely 5-lobed. Corolla c.25mm, sub-obliquely tubular, light red, sub-densely covered with thick sub-circular scales outside, laxly hairy inside; tube c.20 x 3–4 x c.6mm, lobes c.5 x 6–7mm, spathulate-obovate. Stamens slightly exserted from the throat; filaments linear and shortly hairy below, glabrescent in the upper ¼; anthers broadly oblong, c.2mm. Disc densely erect-hairy. Ovary c.4 x 2mm, cylindrical, yellowish hairy, the hairs covering scales, abruptly contracted distally; style 12–16mm, thick, densely patently hairy proximally, less so distally, glabrous for c.2mm below the globose stigma.
Habitat: In primary Agathis forest on clayey soil.
Distribution: Indonesia, New Guinea (W), hinterland of Fak-Fak
Altitude: Around 840m
Named after W. Vink, forest botanist at Manokwari (later on the staff at Leiden), who collected this plant with Professor Sleumer.
Once found. Not yet recollected and never cultivated.
This species was anomalous amongst the New Guinea discovireyas in having such large leaves; the bud scales on the type specimen clearly are fringed with stalked scales and although many of the scales have large centres they are very variable and it is better placed in subsection Malesia. It is tempting to regard it as a hybrid but only observations in the field will provide the answer to this.
Type: W. Vink BW 12177, 26 Feb. 1962. New Guinea (W), Fak-fak, hinterland, bivouac Hambar, 840m (L, A, CANB, K, LAE, UC).
Occurs in Countries: ID Altitude Ranges: 0 - 1,000m Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:215
Shrub 0.3-1 -5 m. Young growth lepidote. Leaves up to 50 mm, narrowly oblong or oblong-elliptic, laxly lepidote above particularly along the midrib and near the base, densely lepidote beneath with unequal scales, the surface of the leaf papillose. Inflorescences 1 (—2)-flowered. Calyx 2-3 mm, the tube lepidote, the lobes occasionally fringed with filiform-acicular hairs. Corolla 15-37 mm, tube 8-20 mm, the tube pubescent and sparsely lepidote outside, the lobes lepidote outside. Stamens 10, filaments pubescent near the base. Ovary densely lepidote, style lepidote and/or pilose towards the base. Capsule lepidote, 9-12.5 mm.
A very variable species, showing variability in corolla length and colour, density of scales on the leaves and density of indumentum on the style. The variation in corolla length is clinal, with larger corollas in the western part of the range; this allows for the recognition of two subspecies
Intermediates between the subspecies occur in the Xizang/Yunnan border area, and a few large-flowered specimens have been found near Tali.
Occurs in Countries: BT, CN, IN, NP Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: mauve, pink
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):130
Habitat: Forest margins, scrub
Distribution: China (SE Xizang, N, NW, W & SW Yunnan)
Altitude: 2000-4000m
Illustrations:
Synonymy: R. oleifoiium Franchet, Bull. Soc. Bot. Fr. 33:235 (1886). Type: China, Yunnan, in montibus circa Talifou, Delavay (holo. P—n.v., iso. E). R. sinovirgatum Hort., ined.
Corolla 25-37 mm, the tube 11-20 mm, pale to deep pink or mauve
Habitat: Forest margins, scrub, stony slopes
Distribution: Nepal, India (Sikkim, Arunachal Pradesh), Bhutan, China (S & SE Xizang)
Altitude: 2500-3800m
Illustrations:
Type: Sikkim Himalaya, Lachen valley, 8-9000 ft, v & x, Hooker (holo. K)
Shrub to 3m. Twigs 2–4mm in diameter, rounded, moderately to laxly scaly, becoming glabrescent; internodes 1–20cm. Leaves 2–6 together in tight pseudowhorls. Blade 25–110 x 10–70mm, elliptic to broadly elliptic or obovate; apex shortly acuminate to obtuse; margin entire, narrowly revolute or flat; base broadly tapering to tapering; quickly glabrescent above, more persistently sub-densely scaly below. Scales small, flat, marginal zone irregularly lobed or almost entire; centre flat or slightly raised. Mid-vein narrowly impressed above; broadly prominent proximally beneath, gradually tapering distally but remaining prominent to the apex, often coloured red; lateral veins 4–7 per side, wide-spreading, slender, minutely impressed above and minutely raised beneath or obscure, reticulation obscure. Petiole 5–20 x 1.5–2mm, grooved above, scaly, usually red. Inflorescence 2–7-flowered in an open umbel, the flowers half-hanging to hanging. Pedicels 18–35 x c.1.5mm, laxly scaly often becoming sub-densely scaly distally and often hairy. Calyx an angular disc c.4mm in diameter, sometimes shortly 5-lobed. Corolla 50–58 x 50–58mm, red or deep pink, without scent; tube 30–35 x 9–11 x 16–20mm, funnel-shaped, straight, laxly scaly and sparsely hairy outside, hairy inside; lobes 20–27 x 20–27mm, semi-erect to spreading, obovate to sub-circular, usually emarginate, overlapping ½–2⁄3, scaly on the lower part outside. Stamens irregularly spreading all round the mouth, or round the lower 2⁄3 of the mouth, not or only slightly exserted, slightly dimorphic; filaments 23–30 and 21–28mm, hairy; anthers c.3mm, oblong, dark red. Disc 10-lobed, hairy. Ovary 3–6 x 2–2.5mm, sub-cylindrical, densely scaly and densely hairy, tapering distally; style 14–23mm, central, or appressed to the lower side of the tube, scaly and hairy in the proximal ½–¾, then scaly for 1–2mm and finally glabrous distally; stigma c.1.5mm in diameter, rounded. Fruit 15–30 x c.5mm, ellipsoid.
Habitat: Terrestrial or epiphytic in rain forest, on open boulder outcrops and mossy shrubberies, reported as epiphytic with a Vaccinium in the tops of large Eugenia trees on Mt Spurgeon by C.A. White, but it is normally found above the tree line (this however may reflect the difficulty of seeing epiphytes in the tops of trees) said to be common above 1050m.
Distribution: Australia, Queensland: Mt Finnigan; Thornton Peak; Mount Windsor Tableland; and the Main Coast Range.
Altitude: 910-1330m
Latin – viriosus – robust or strong, in recognition of its dominant qualities when used in hybridising programmes.
Type: Craven 9394, Cultivated Canberra 22 Feb. 1994. Originally from: Jones & Clements 4420, 27 May 1989. Queensland, Mount Windsor Tableland (CANB, A, B, BRI, E, L, MEL, QRS).
Occurs in Countries: AU Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: pink, red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:324
Shrub, 0.6-2.4m; bark smooth; young shoots glabrous or glandular. Leaves oval to sub-orbicular, 4-9.7 x 2.8-6.6cm, c.1.5 x as long as broad, apex rounded, mucronate, base rounded to sub-cordate, upper and lower surfaces glabrous; lower epidermis strongly glaucous-papillate, with scattered viscid glands; petioles 1-2.5cm, glabrous. Inflorescence 1-2-flowered; rhachis l-3mm; pedicels c.lOmm, stipitate-glandular. Calyx cupular, 4-9mm, green, lobes rounded. Corolla tubular-campanulate, fleshy, coppery red, with dark nectar pouches and flecks, 35-45mm. Ovary densely tomentose and stipitate-glandular; style glabrous. Capsule c.20 x 9mm.
Habitat: Cliff faces near waterfalls
Distribution: China (SE Xizang)
Altitude: 2700-3350m
The labels suggest that this species is common at the type locality though the only two specimens known may originate from a single plant. Closely allied to R. thomsonii.
Type: China, S Xizang, Lo La, Pachakshiri, 9-10000ft, 13 v 1938, Ludlow, Sherriff & Taylor 3750 (holo. BM)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: red
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):420
Shrub, c.3.5m, shoots punctulate, adpressed-hairy; floral buds viscid. Leaves dimorphic, chartaceous; spring leaves elliptic to oblong-elliptic, 1.5-1.8 x c.0.7cm, apex shortly acute or acuminate, margin entire, ciliate, upper surface adprcssed-strigose, lower surface paler, with a brown pannose indumentum intermixed with brownish strigose hairs; summer leaves 5~9mm long, otherwise as for spring leaves; petioles 4-6mm, densely brownish-sericeous-strigose. Inflorescence 3-4~flowered; floral buds viscid; pedicels 3-4.5mm, densely strigose. Calyx small, brownish-strigose, lobes cren-ate. Corolla funnel-campanulate, c.9mm, colour unknown; tube 4 x 3mm, outer surface hairy, inner surface glabrous. Stamens 5, filaments puberulent below. Ovary strigose; style densely strigose in lower half. Capsule ovoid, 5-6 x c.4.5mm, strigose.
Distribution: China (NE Guangxi)
59*. R. hejiangense M.Y.He, Bull. Bot. Res. N.E. Forest. Inst. 5(4): 118 (1985). Type: China, S Sichuan, Hejiang Xian, Fubaodawuji Banchanggou, 23 v 1980, Agricultural Exp. 44 (holo. SZ, n.v.). Shrub, elm; young shoots densely reddish-strigose. Leaves subcoriaceous, oblong, 1-2.5 x 0.7-1.3cm, apex acute, mucronate, base rounded, margin recurved, upper surface sparsely stngose, the hairs sometimes restricted to the base of the midrib, lower surface yellowish-brown-strigose; petioles 3mm, strigose. Inflorescence 3-6-flowered; pedicels c.6mm, densely reddish-strigose. Calyx minute. Corolla funnel-campanulate, white, with purple flecks on the upper lobes, c.llmm; tube c.6mm, slightly strigose on outer surface, puberulous within. Stamens 5, filaments glabrous. Ovary densely sericeous-strigose; style sparsely strigose in lower half. China (S Sichuan). Map 19. This species should key down to R.viscigemmatum but it may be distinguished by its white flowers, glabrous filaments, etc. Since we have not seen the types of either species we are not certain whether there is a true affinity between them although we note that there is a marked disjunction in their ranges.
Allied by the author to R. polyraphidoideum and R. mariae but apparently closer to R. minutiflorum, a species that also occurs in Eastern Guangxi, in the same general area as the type of R. viscigemmatum.
We have seen only a photograph of the type of R. viscigemmatum from which the leaf measurements have been taken. Tan describes them as being 25-35mm long but this does not tally with the photograph which is of the only specimen known.
Type: China, Guangxi, He Xian, Gupo Shan, 1000m,9viii 1958, Y.K. Li 401515, (holo. IBSC, n.v.)
Occurs in Countries: CN Subgenus: Tsutsusi Habit: Non-Tree
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):134
Shrub, 2-3m; young shoots soon glabrescent. Leaves rhombic, 1.4-4.3 x 0.7-1.3cm, apex acute, upper surface with a brown pilose indumentum at first, later glabrescent, lower surface pale, with punctate glands, sometimes viscous; petioles 3-5mm, with long eglandular hairs, at least when young. Inflorescence l(-2)-flowered, flowers appearing before the leaves; pedicels 5-6mm, brown-pilose and glandular-verrucose. Calyx minute, brown-ciliate. Corolla open funnel-campanulate, a 17mm, reddish-purple, with flecks, lobes oblong or elliptic, a 12mm. Stamens 10, unequal, filaments glabrous. Ovary glandular and viscous, with brown hairs at apex; style glabrous, viscous. Capsule c.4mm.
Habitat: Upland forests
Distribution: Japan (Kyushyu)
Illustrations:
Close to R. decandrum
Synonymy: R. decandrum Makino var. viscistylum (Nakai) Hatusima, Sci. Rep. Yukosuka City Mus. 15: 21 (1969)
Occurs in Countries: JP Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: red
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):147
Shrub or small tree to 6m tall, usually non-rhizomatous (often strongly rhizomatous on the Coastal Plain), young twigs red-brown, occasionally yellow-brown, sparsely to densely covered with unicellular and multicellular eglandular hairs or with only multicellular eglandular hairs, rarely with only unicellular hairs or with unicellular and multicellular gland-tipped hairs. Vegetative bud scales glabrous or sparsely to densely covered with unicellular hairs abaxially; margin ciliate, rarely ciliate above and glandular below or completely glandular. Leaf blade membranaceous, ovate or obovate to elliptic, (3.1-)4.0-6.0(-7.9) x (1.3-)1.5-2.3(-3.1)cm; base acute to oblique; apex acute to obtuse, often mucronate; adaxial surface glabrous, occasionally sparsely to densely covered with unicellular hairs and multicellular eglandular hairs or both, rarely with only multicellular eglandular hairs or gland-tipped hairs or both unicellular hairs and multicellular gland-tipped hairs, the midvein sparsely to densely covered with unicellular hairs; abaxial surface glabrous, sometimes also glaucous, occasionally sparsely to densely covered with unicellular hairs, the midvein sparsely to densely covered with multicellular eglandular hairs, or with unicellular hairs and multicellular eglandular hairs; margin entire, occasionally minutely serrulate, ciliate with multicellular eglandular hairs; petiole 0.1-0.4(-0.6)cm long, sparsely to densely covered with unicellular hairs and multicellular eglandular hairs, rarely with unicellular hairs and multicellular gland-tipped hairs or with all three types. Flower bud scales chestnut brown, occasionally with a darker brown band following the margin near the apex; abaxial surface sparsely to densely covered with unicellular hairs but frequently glabrous; margin unicellular-cil-iate, occasionally ciliate above and glandular below, rarely completely glandular. Flowers appearing after the leaves have expanded, or sometimes as the leaves expand at higher elevations in the mountains; inflorescence a shortened raceme of 3 to 14 flowers. Pedicels (0.5-)0.7-1.4 (-2.7)cm long, sparsely to densely covered with unicellular hairs and multicellular gland-tipped hairs, occasionally with unicellular hairs and multicellular eglandular and gland-tipped hairs, rarely with unicellular hairs and multicellular eglandular hairs, or with only gland-tipped hairs. Sepals less than 0.1-0.2(-0.5)cm long, often varying in length on the same flower; margins glandular-fimbriate, occasionally setose or with both multicellular eglandular and gland-tipped hairs; abaxial surface densely covered with unicellular hairs and sparsely to densely covered with multicellular gland-tipped hairs, occasionally sparsely to densely covered with only unicellular hairs, or with unicellular hairs and multicellular eglandular hairs. Corolla white, occasionally with a pink or purplish tinge, rarely completely pink, fragrance sweet, the tube longer than the limb and gradually expanding into it; upper corolla lobe (0.6-)0.8-1.3(-1.6) x (0.3-)0.5-0.9(-1.2)cm; lateral lobes (0.7-)1.0-1.5(-2.1) x (0.2-)0.3-0.6(-0.9)cm; corolla tube (1.3-)2.0-2.8(-3.6)cm long, (0. l-)0.2-0.3(-0.4)cm wide at base; outer surface of corolla densely covered with unicellular hairs and multicellular gland-tipped hairs, the gland-tipped hairs continuing in lines up the corolla lobes, rarely also with multicellular eglandular hairs or lacking any one of the three types of hairs; inner surface of corolla sparsely to densely covered with unicellular hairs or glabrous. Stamens (2. l-)3.8-5.1 (-6.5)cm long, with dense terete or flattened unicellular hairs on proximal (1,9-)2.5-3.4(-4.0)cm of filament, exserted (1.2-) 1.6-2.5(-5.8)cm beyond throat of corolla. Style (3.0-)4.2-5.6(-7.2)cm long, exserted (1.5-)2.0-3.5(-4.3)cm beyond throat of corolla, with dense unicellular hairs on proximal (0.0-)0.4-1.7(-2.8)cm; stigma 0.1-0.2(-0.4)cm wide. Ovary 0.2-0.4(-0.5)cm long, 0. l-0.2(-0.4)cm wide at the base, densely covered with multicellular gland-tipped hairs and unicellular hairs, occasionally also with multicellular eglandular hairs or with only multicellular eglandular hairs over unicellular hairs. Capsules (0.7-)1.0-1.5(-1.8) x (0.3-)0.4-0.6cm, ovate to ovate-cylindric, moderately densely covered with unicellular hairs and sparsely to moderately densely covered with multicellular eglandular or gland-tipped hairs. Seeds pale to dark chestnut brown, ovate or elliptic to fusiform, (1.2-)1.5-2.6(-3.2) x 0.3-1.l(-1.2)mm, body (0.6-)0.8-1.4 (-1.9) x (0.2-)0.3-0.5(-0.7)mm; testa expanded and dorsiventrally flattened, surrounding the body, the cells elongate over the body of the seed, and shorter in the expanded portion of the testa, with tapering end-walls.
Habitat: Stream banks, moist thickets, swamps, bayheads, low flatwoods, shrub balds, acid bogs.
Distribution: USA: Vermont and Maine to peninsular Florida, west to Texas and north to Arkansas
Altitude: 0-1500m
Illustrations:
Chromosome number: 2n = 26 (Sax, 1930; Janaki-Ammal et al., 1950; Li, 1957).
Flowering primarily from May to August. However, this variable species may flower as early as March and as late as December, especially at the southern limits of its range.
Rhododendron viscosum is the most widespread and variable species in the section and has been segregated into as many as four species: R. coryi, R. oblongifolium,R. serrulatum and R. viscosum s. str. All of these previously recognized taxa are white-flowered, with conspicuous multicellular gland-tipped hairs which occur in continuous lines along the abaxial surface of the corolla lobes. They flower after the leaves have expanded, usually in the late spring or early summer. Rhododendron viscosum s. str. has been regarded as the more northern element (Rehder, 1921; Skinner, 1955, 1961), with smaller flowers which are often tinged with pink. Small (1903) described a distinct southern taxon, also recognized by Rehder (1921) as R. serrulatum, based on the longer corolla tube, and the distinctive narrow brown band which ruiis along the margin of the abaxial surface of the bud scales. In eastern Oklahoma, Arkansas and northern Texas, R. oblongifolium has been recognized as a separate species (Small, 1903; Rehder, 1921) based on the long corolla tube, the densely pubescent bud scales, and the larger and more pubescent leaves (Rehder, 1921). Shinners (1961) described R. coryi from eastern Texas. He considered it a distinct species because of its low, rhizomatous habit and its large flowers. This species was later submerged into R. viscosum by Solymosy (1974) who considered R. coryi a morphological variant within the natural range of variation of R. viscosum. King (1977a, 1980) suggested, on the basis of the great similarity of the flavonoid compounds, that all of the above-mentioned names be submerged under R. viscosum, as was also done by Godfrey & Wooten (1981).
The results of principal component analysis of 64 OTUs and 26 floral characters (Table 5, Fig. 41) indicate that there are no morphological gaps within this complex. The characters which most influenced the first component are style length, sepal length and upper corolla lobe length. Those which were most influential on the second component are width of the ovary, ovary length and lateral corolla lobe width. The individuals from the more northern part of the range tend to have slightly shorter sepals and styles, as well as slightly smaller ovaries. The corolla is also slightly smaller. However, these trends are not very strong because individuals of J?, serrulatum andi?. oblongifolium are often not only morphologically similar to each other, but also similar to the northern individuals. In' addition, the morphological variation does not correlate with any geographical or ecological subdivision. Even the distinctive brown band on the bud scales of R. serrulatum is variable, and occasionally can be found in northern individuals, and is absent in some of the more southern populations. Bud-scale pubescence is also variable but shows no clinal pattern. Even in localized areas, in some populations the bud scales are glabrous, while in others they are densely pubescent. Since correlated or geographically coherent sets of characters (showing gaps in the pattern of variation) could not be discerned, subspecies are not recognized within this complex. Therefore R. viscosum is recognized as a widespread and highly variable species which includes R. serrulatum, R. oblongifolium and J?, coryi. The entities which these names represent are morphological "types'found at the southern and western limits of the geographic range ofR. viscosum, and are most likely derived from different populations within the range of variability of6 typical9 R. viscosum. Therefore, recognizing these entities at the specific level, in addition to being phenetically arbitrary and unworkable from a practical identification standpoint, would also make R. viscosum a paraphyletic species (Mishler & Donoghue 1982; Donoghue 1985; Mishler 1985).
Synonymy: Azalea viscosah., Sp. PL ed. 1,1:151 (1753). Type: in Virginia (holo, LINN; IDC 118:111.4). Azalea glauca Lamarck, Ency. Method. 1: 340 (1783). Rhododendron glaucum (Lam.) Sweet, Hon. Brit, ed, 2, 344 (1830). Type: (lecto. P (n.v.); photo of lecto. GH). Azalea viscosa var. glauca Aiton, Hort. Kew. 1: 204 (1789); Rhododendron viscosum var. glaucum (Aiton) Wood, Class Book Bot. 376 (1851), nom. illeg.; Rhododendron viscosum f. glaucum Fern., Rhodora 43: 623 (1941). Type: n.v,; no specimens or illustrations cited. Azalea viscosa var. glauca Michaux, FL Bor.-Amer. 1: 151 (1803), nom. illeg.; Rhododendron viscosum var. glaucum (Michaux) Torrey, FL N. Middle United States 1:425 (1824), nom. illeg. Type: in Carolina inferiore (lecto. P-MICHX; IDC 6211, 361.5). Azalea viscosa Marshall vm.palustris Marshall, Arbust. Amer. 16 (1785). Type: (probably at DWC, n.v.). Azalea viscosa L. vm.floribunda Aiton, Hort. Kew. 1: 203 (1789). Type: n.v. Azalea viscosa var. virens Michaux, FL Bor.-Amer. 1:151 (1803). Type: in Carolina inferiore (lecto. P-MICHX; IDC 6211, 361.6). Azalea tomentosa Dumont de Courset, Bot. Cult. ed. 2, 3: 336 (1811). Rhododendron viscosum var. tomentosum Rehder, Monogr. Azaleas 162-163 (1921). Type: n.v. Azalea hispida Pursh, FL Am. Septentr. 1:154 (1814). Rhododendron hispidum (Pursh) Torr., FL U.S. 1: 425 (1824). Azalea viscosa var. hispida (Pursh) Hook., Comp. Bot. Mag. 1: 100 (1835). A. glauca Lam. var. hispida (Pursh) Heynhold, Nomen. Bot. 1:108 (1840). Rhododendron viscosum (L.) Torr. f. hispidum (Pursh) Voss, in Vilm. Blumengart. 1: 588 (1894). R. viscosum (L.) Torr. var. hispidum (Pursh) Rehder, in Bailey Stan. CycL Hort. 121 (1900). Type: n.v. Azalea nitida Pursh, FL Am. Septentr. 1: 153-154 (1814). Rhododendron nitidum (Pursh) Torr., Fl. U.S. 1: 425 (1824). R. viscosum (L.) Torr. var. nitidum (Pursh) A. Gray, Manual of Botany, ed. 2, 257 (1856). Rhododendron viscosum (L.) Torr. var. nitidum (Pursh) A. Gray, Synop. FL N. A. 1: 41 (1878). Azalea viscosa L. var. nitida (Pursh) Britton, in Mem. Torrey Bot. Club 5: 248 (1893). Type: n.v. Azalea viscosa L. var. pubescens Lodd., Bot. Cab. 5: 441, (1821). Type: n.v. Azalea viscosa L. var. rubescens Lodd., Bot. Cab. 16: 1518 (1829). Rhododendron viscosum (L.) Torr. var. rubescens (Lodd.) Sweet, Hort. Brit. ed. 2, 344 (1830). R. viscosum (L.) Torr. f. rubescens (Lodd.) Rehder, Monogr. Azaleas 161 (1921). Type: n.v. Rhododendron viscosum (L.) Torr. f. roseum Hollick, in Bull. Torrey Bot. Club 18: 256 (1891). Type: n.v. Azalea oblongifolia Small, Fl. S.E. U.S. 883 (1903). Rhododendron oblongifolium (Small) Millais, Rhodod. 219 (1917). Type: Texas, Houston Co.: Grapeland, 1879, F. Tweedy s.n. (holo. NY). Azalea serrulata Small, Fl. SJE. U.S. 883 (1903). Rhododendron serrulatum (Small) Millais, Rhodod. 241 (1917). R. viscosum (L.) Torr. var. serrulatum (Small) Ahles, J. Elisha Mitchell Sci. Soc. 80: 173 (1964). Type: Florida, Lake Co.: vicinity of Eustis, 1-15 vi 1894, G. V. Nash 967 (holo. NY; photo of holo. A). Rhododendron viscosum (L.) Torr. var. aemulans Rehder, Monogr. Azaleas 165 (1921). Azalea viscosa L. var. aemulans (Rehder) Ashe, J. Elisha Mitchell Sci. Soc. 38:91 (1922). Type: Georgia, Randolph Co.: in low woods near Cuthbert, 9 v 1918, T. G. Harbison 39 (holo. A). Rhododendron viscosum (L.) Torr. f. coerulescens Rehder, Monogr. Azaleas 165 (1921). Type: North Carolina, Macon Co.: Highlands, 9 vii 1918, A. Rehder 66 (lecto., designated here, A). Rhododendron serrulatum (Small) Millais var. georgianum Rehder, Monogr. Azaleas 156 (1921). Azalea serrulata Small var. georgiana (Rehder) Ashe, J. Elisha Mitchell Sci. Soc. 38: 91 (1922). Type: Georgia, Charlton Co.: Folkston, 16 vii 1918, T. G. Harbison 68 (holo. A). Rhododendron serrulatum (Small) Millais f. molliculum Rehder, Monogr. Azaleas 155 (1921). Type: Florida, Lake Co.: Eustis, 23 vi 1919, T. G. Harbison 17 (holo. A). Rhododendron viscosum (L.) Torr. var. montanum Rehder, Monogr. Azaleas 164 (1921). Azalea viscosa L. var. montana (Rehder) Ashe, J. Elisha Mitchell Sci. Soc. 38:91 (1922). Type: North Carolina, Macon Co.: Highlands, 9 vii and 30 ix 1918, A. Rehder 58 (lecto., designated here as 9 vii 1918, A). Rhododendron viscosum (L.) Torr. f. rhodantha Rehder, Monogr. Azaleas 160 (1921). Type: Maryland, Prince Georges Co.: opposite Hyattsville, eastward. 31 v 1915, E. S. Steele s.n. (holo. US). Rhododendron coryi Shinners, Castanea 26: 156-157 (1961). Type: Texas, Tyler Co.: frequent on railroad right-of-way at pitcher-plant bog, Hyatt Bog, 2 mi S of Warren, 18iv 1930, V. L. Cory 57145 (iso. MINN).
Occurs in Countries: US Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Pentanthera Habit: Tree Fl. Colour: pink
Kron, K.A. (1993) A Revision of Rhododendron Section Pentanthera. Edinburgh Journal of Botany 50(3):329
Slender shrub to 2m. Twigs 1–2mm in diameter, at first densely covered with stalked stellate scales, glabrescent and densely warty later, without hairs; internodes 2.5–6cm. Leaves 3–5 together in tight pseudowhorls. Blade 8–50 x 5–25mm, obovate-elliptic or obovate; apex obtuse to rounded, not apiculate; margin cartilaginous, distinctly revolute; base tapering; sub-densely or laxly scaly on both sides initially, glabrescent and shining above with age, persistently scaly beneath. Scales flat, marginal zone irregularly stellately lobed; centre impressed, eventually glabrescent beneath leaving only impressed black points. Mid-vein impressed above, obtusely prominent beneath; lateral veins c.3 per side, obscure above, somewhat raised and curved-anastomosing beneath, reticulation obscure. Petiole 2–3 x 0.8–1mm, almost rounded in section, scaly. Flower buds to 12 x 7mm, ovate, smooth. Bracts to 10 x 5mm, the outermost subulate with a few scales outside, then ovate, often with a mucronate point, membranous, minutely hairy outside but without scales except along the margins. Flowers solitary or paired, hanging vertically. Pedicels 8–20mm, slender, densely covered with reddish-brown, stellate scales and short spreading hairs. Calyx c.2.5mm in diameter, obliquely disc-shaped, shortly obtusely 5-lobed, scaly outside. Corolla 15–55mm, tubular, bright red, sometimes with a darker purplish margin to the lobes; tube 8–45 x 3–4 x 12–15mm, laxly stellate-scaly and minutely hairy outside, glabrous inside, somewhat curved; lobes 8–10 x 6–8mm, half-spreading, broadly obovate or sub-circular. Stamens exserted to c.5mm; filaments linear, glabrous; anthers 1.8–2 x c.1mm, obovate-oblong. Disc prominent, glabrous below, hairy on the upper margin. Ovary c.4 x 1.5mm, sub-cylindrical, slightly tapering at the base, densely shortly patent-hairy and sub-densely scaly; style slender, as long as the stamens, patently hairy in the lower 1⁄3–½; stigma sub-globose. Fruit c.40 x 6mm, cylindrical, laxly hairy and scaly.
Habitat: Epiphytic or terrestrial, forest or open hillside, common in sub-alpine shrubberies
Distribution: Papua New Guinea, Owen Stanley Range; Morobe District, Rawlinson Range, Mt Bangeta, Porget, Merimanta, Mt Wilhelm area, Porul road, Owen Stanley Mts near ‘The Gap’, Mt Ganeve, above Bakaia.
Altitude: 2195-2590m
Latin – vitis – vine; ida – from Mt Ida (Greece) (Smid 1990), but this is indirect and an allusion to the similarity of the leaves to those of Vaccinium vitis-idaea, the cowberry of Europe.
Van Royen & Kores (1982) synonymised R. vandeursenii with R. vitis-idaea as a result of field work showing that the corolla length difference that had been used to separate these species was unworkable. This extends the range of the species considerably.
Type: Carr 15098, 15 Jan. 1936. New Guinea (SE), Owen Stanley Range, NW of ‘The Gap’, c.2895m (BM, A, K, L, fragment, NY, SING).
Occurs in Countries: PG Altitude Ranges: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:217
Shrub or small tree; young shoots villose. Leaves rhombic, 3-5 x 2-4cm, apex acute but with blunt tip, upper surface sparsely villose when young, soon glabrescent, lower surface sparsely villose, more densely so on midrib; petioles 4-7mm, densely villose. Inflorescence 1-2-flowered, flowers appearing before leaves; pedicels 3-10mm, with eglandular or glandular hairs. Calyx minute, ciliate. Corolla funnel-campanulate, rich rose-pink, 22-30mm. Stamens 10, unequal, filaments glabrous. Ovary densely villose; style stipitate-glandular in lower half. Capsule 8-15 x 4-5mm.
Habitat: Mixed forest
Distribution: Japan (SE Honshu)
Altitude: 950-1500m
Illustrations:
A distinct species on account of its glandular style. A white-flowered form has been referred to var. leucanthum Makino.
Synonymy: R. glandulistylum Komatsu, Bot. Mag. (Tokyo) 32: 10 (1918)ó Japanese text. R. wadanum Makino var. leucanthum Makino, J. Jap. Bot. 3: 11 (1926)óEnglish text. Type: Japan, Prov. Sagmai, Hakone, Sawada, n.v. R. reticulatum D.Don var. wadanum (Makino) Hatusima, Sci. Rep. Yokosuka City Mus. 15: 22 (1969)
Occurs in Countries: JP Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Tsutsusi Habit: Tree Fl. Colour: rose
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):146
Shrub, l-4.5m; young shoots with a whitish floccose tomentum. Leaves coriaceous, elliptic to ovate, 7-11(-14) x 3.5-5.5(-6.5)cm, 2-2.5 x as long as broad, apex rounded, apiculate, base rounded to ± cordate, glabrous above, with a sparse dark brown indumentum beneath composed of fasciculate hairs; petioles 1—2cm, with a floccose tomentum. Inflorescence lax, 5—8-flowered; rhachis c.lOmm; pedicels 10-15mm, ± glabrous or with a sparse covering of fasciculate hairs. Calyx irregular, sparsely tomentose to glabrous, lobes 1 -3mm. Corolla funnel-campanulate, whitish to pale mauve or lilac, with or without flecks, 25-40(-50)mm. Ovary ± glabrous. Capsule 15-30 X 5-7mm.
Habitat: Mixed forests, Rhododendron scrub, etc.
Distribution: e Nepal, Bhutan, N India (Sikkim, Bengal), China (S Xizang)
Altitude: 3000-4000m
Closely allied to R. campanulatum but differing in the type of hairs that make up the leaf indumentum. R. wallichii apparently replaces R. campanulatum in the more humid areas at slightly lower altitudes on the outer slopes of the C Himalayas.
2*. R. wallichii Hooker f. x R. arboreum Smith, s.l. Syn: ? R. batemannii Hooker f., Bot. Mag. 89: t. 5387 (1863). Type: a plant raised by Mr J. Bateman from seed supposedly collected by Booth in Bhutan (iso. E). ? R. campanulatum D. Don var. campbellii Millais, Rhododendrons ed. 1: 134 (1917). Described from plants in cultivation, thought to have been raised from seed supplied by Col. Sykesin 1840. Differs from R. wallichii in its acute leaves with prominent lateral veins beneath and in its more intensely coloured flowers. It occurs where the ranges of the parents overlap. The origin of R. batemanii is uncertain though the type specimen could have arisen as a chance hybrid of R. arboreum and R. wallichii or (less likely) R. campanulatum. The type, however, has surprisingly large leaves (up to 20cm long) for such an origin.
Type: the interior of Sikkim Himalaya'(10-11000ft, v 1848), Hooker (holo. E).
Occurs in Countries: BT, CN, IN, NP Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: lilac, mauve
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):373
Shrub 2-3 m. Young growth not loriform-setose. Leaves elliptic, tapered to the base, slightly acute at the apex, sometimes with a short drip-tip, 100-110 x 38-45 mm, undersurface brownish with lax, unequal scales. Calyx small, disc-like, somewhat undulately lobed, lepidote, margins loriform-ciliate. Inflorescence 3-6-flowered. Corolla creamy white with a greenish blotch, c. 60 mm, tube c. 38 mm, the outside completely pilose except for the tips of the lobes, sparsely lepidote on the lobes. Capsule c. 15 mm.
Habitat: Rocks, cliffs, ravines, rarely epiphytic
Distribution: India (Arunachal Pradesh), China (SE Xizang)
Altitude: 1500-2150m
Type: Tibet, near Rima, 7000 ft, 28 iii 1950, Kingdon Ward 19259 (holo. BM, iso. E)
Occurs in Countries: CN, IN Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Rhododendron Habit: Epiphyte, Non-Tree Fl. Colour: green, white
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):48
Shrub or small tree, 0.6-8m; young shoots glandular to glabrous. Leaves narrowly obovate to broadly ovate, 6-11 x 2.3-6cm, 1.5-2.5 x as long as broad, apex rounded, acuminate, base cordate, upper and lower surfaces glabrous, glaucous or green below; petioles 1-3.5cm, glabrous or stipitate-glandular. Inflorescence 5—10(— 15)-flowered; rhachis c.5mm; pedicels 1.5 -5cm, glandular. Calyx 5-15mm, when well-developed ± cupular, lobes rounded, glandular-ciliate. Corolla saucer-shaped, white to sulphur yellow, with or without a purple basal blotch, 25-40mm. Ovary stipitate-glandular; style glandular to tip. Capsule 20-25 x 5-10mm, straight or curved.
Habitat: Rhododendron thickets, pine forests, open places, etc.
Distribution: China (SE Xizang, NW Yunnan, SW Sichuan)
Altitude: 3000-4300m
R. litiense was recognised as a distinct species, both by Tagg and by Cowan & Davidian, distinguished from R. wardii by its narrow leaves with the lower surface glaucous. However, even the type of R. wardii has a slight glaucous bloom and the type of R, litiense has at least some broad leaves that have lost their bloom, at least partially. Clearly, there is a complete range of intermediates, from forms with broadle&ves that are green below (that would traditionally be placed in R. wardii) to those with narrow leaves that have a marked bloom below (that would be referred to R. litiense). Therefore R. litiense is not maintained, even at varietal rank.
Plants intermediate between R. wardii and R. campylocarpum occur where there distributions overlap. They are as follows: Ludlow & Sherriff 2085; Ludlow, Sherriff & Elliot 13661, 13664, 13754, 13756, 15010, 15014, 15081, 15087, 15089, 15093,15099. The last three approach R. campylocarpum subsp. caloxanthum in their almost orbicular leaves. All are best treated as hybrids between the two species.
The hybrid between R. wardii and R. selense (R. x erythrocalyx) is discussed fully in the account of subsection Selensia.
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: purple, white, yellow
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):265
Corolla white
Synonymy: R. puralbum Balfour f. & W. W. Smith, Notes R.B.G. Edinb. 9: 266 (1916). Type: China, mountains NE of the Yangtze bend, 11000ft, Forrest 10616 (holo. E; iso. K).
Corolla yellow
Illustrations:
Type: China, W Yunnan, Doker La, 13-14000ft, vi 1913, Kingdon-Ward529 (holo. E)
Synonymy: R. mussoti Franchet, nom. nud. R. croceum Balfour f. & W. W. Smith, Notes R.B.G. Edinb. 10: 93 (1917). Type: China, NW Yunnan, mountains of the Yangtze bend, 12000ft, vii 1913, Forrest 10428 (holo. E; iso. A, BM, K). R. astrocalyx Balfour f. & Forrest, Notes R.B.G. Edinb. 13: 30 (1920). Type: NW Yunnan, Mekong/Salween divide, 11000ft, vi 1917 Forrest 14128 (holo. E; iso. K). R. prasinocalyx Balfour f. & Forrest, ibid. 13:57 (1920). Type: China, NW Yunnan, Mountains NE of Chungtieu, vn 1918, Forrest 16511 (holo. E; iso. K). R. oresterum Balfour f. & Forrest, ibid. 13:56 (1920). Type: China, SE Xizang, Tsarong, on Ka-gwr-pw, 13000ft, vii 1918, Forrest 16715 (holo. E; iso. K). R. litiense Balfour f. & Forrest, ibid. 12: 126 (1920). Type: China, Yunnan, on the Li-ti-ping, 10000ft, vi 1917, Forrest 13922 (holo. E). R. gloeblastum Balfour f. & Forrest, ibid. 13: 200 (1922). Type: China, SE Xizang, Tsargon, Forrest 18672 (holo. E; iso. K).
Sprawling shrub, 0.6-1.5m. Leaves ovate-lanceolate, 7-8 x 2.5-4cm, 1.6-3 x as long as broad, apex apiculate to shortly acuminate, base cuneate, lower surface with a sparse to dense unistrate reddish-brown mdumentum of long-rayed hairs intermixed with a few glands, rarely glabrescent; petioles 1 —1.5cm, tomentose and sparsely glandular. Inflorescence 8-15-flowered; rhachis c.lOmm; pedicels 20-30mm, tomentose. Calyx c.0.5mm, tomentose. Corolla open-campanulate, yellow or white to pink, with purple flecks, 35-40mm. Ovary densely reddish-hairy, eglandular; style glabrous. Capsule cylindrical.
Distribution: China (C Sichuan)
Altitude: 2300-3000m
A variable species. In cultivation two forms are known, one with creamy yellow corollas and the other with whitish to pink corollas (forma rhododactylum). The latter matches the syntype Wilson 3956. The status of this form will remain uncertain until further field-work is carried out.
Type: China, W Sichuan, nr Tatsienlu, 2800-3000m, Wilson 3955 (BM, E), 3956 (BM, K), 3965a (A)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: pink, purple, white, yellow
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):362
Shrub or small tree, 2-6m. Leaves 10-17(-23) X 4.3-8.5(-10)cm, 2-2.3 x as long as broad, apex acute to acuminate, base cuneate, upper surface glabrous, lower surface with a whitish thin compacted and agglutinated indumentum; petioles at most 5mm, ± flattened, stout, glabrous. Inflorescence 12—15-flowered; rhachis c.7mm; pedicels c.20mm, very sparsely floccose-tomentose. Calyx c.2mm, lobes fleshy, broadly triangular. Corolla 7-lobed, campanulate, white with a crimson basal blotch, 35-40mm. Stamens 14. Ovary glabrous. Capsule 30-35 X 7-8mm, usually slightly curved.
Habitat: Woodland
Distribution: China (C 8c N Sichuan, S Gansu)
Altitude: 2600-3300m
A distinctive species on account of its short, flattened petioles and glabrous ovaries. R. watsonii has no obvious close allies.
Type: China, Sichuan, in thin forests, 3300-3800m, iv & v 1904, Wilson 3964 (iso. BM, K)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: crimson, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):251
Shrub or small tree, 3-7m. Leaves obovate to oblong, 11-16 x 5.5-7cm, 2-2.3 X as long as broad, apex rounded, apiculate, base rounded, glabrous above, with a sparse whitish felted indumentum beneath, with prominent lateral veins; petioles c. 2cm, terete, glabrous when mature. Inflorescence c. 15-flowered, dense; rhachis not known; pedicels c. 10mm, densely glandular. Calyx 1 -2mm, glandular; lobes broadly triangular. Corolla 6-lobed, tubular-campanulate, pink with darker flecks and purplish basal patches (?nectarpouches), 35-?55mm. Ovary with a densely lanate-pilose, brownish indumentum; style glabrous. Capsule not known.
Habitat: Ridges
Distribution: NE India (Manipur), only known from the type locality
Altitude: Around 2700m
Judging from a plate at Edinburgh drawn by Watt in the field, R. wattii is apparently better placed in subsection Grandia rather than in subsection Arborea, as suggested by Cowan. Plants raised from seed collected by Watt at the type locality and considered by him to have originated from R. wattii, have scarlet, 5-lobed corollas, usually a more well-developed calyx (lobes 3-4mm) and leaves ranging from 6.5-12cm long. The plants were given the name R. arboreum Smith var. kingianum Hooker (in Bot. Mag. 126: t. 7696, 1900) or R. kingianum (Hooker f.) Watson (in Rhododendrons and Azaleas 106,1911). They are almost certainly hybrids of R. arboreum s.1. and possibly R. wattii. R. wattii itself may be a hybrid between R. arboreum and some other species in subsection Grandia but there is no real evidence to support this suggestion.
Type: NE India, Ching Sow, 9000ft, iv 1882, Watt 6535 (holo. E; iso. K)
Occurs in Countries: IN Altitude Ranges: 2,000 - 3,000m Subgenus: Hymenanthes Habit: Tree Fl. Colour: pink
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):242
Erect, much branched shrub to 1 -5 m. Leaves 6-15 X 3-9 mm, ovate or oblong-elliptic to ovate-lanceolate, apex obtuse, base cuneate, undersurface straw-coloured or golden brown, densely covered with contiguous scales. Inflorescence l(-2)-flowered, pedicel 1-2 mm, lepidote. Calyx 2.8-5 mm, lobes broadly rounded or strap-shaped, margin usually densely ciliate, sometimes with a few marginal scales. Corolla pale purple or yellow, funnel-shaped, 13-5-19 mm, tube 4.5-7 mm, pubescent in the throat and sometimes on the outside. Stamens 10, ± equalling the corolla, filaments pubescent towards the base. Ovary lepidote, style exceeding the stamens, slightly pubescent and with some scales near the base. Capsule ovoid, densely lepidote, 4-5 mm.
Two varieties may be distinguished
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: purple, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):97
Corolla pale purple
Habitat: Heath and moorland
Distribution: China (NW Sichuan)
Altitude: 3300-4900m
Type: China, Szechuan W, north of Tachien-lu, Ta-pao-shan, 4100-4900 m, Wilson 1225 (holo. A; iso. BM, E, K)
Habitat: Grassland
Distribution: China (NW Sichuan)
Altitude: 4300-4770m
Known from only two collections
Type: China, Szechuan, Yulong-ksi, Minya country, S of Tatsienlu, vii 1929, Rock 17429 (holo. E)
Shrub to 2m. Twigs 2–4mm in diameter, laxly to densely covered with flat scales; internodes 2–20cm. Leaves 3–5 large and often with 1 or 2 much smaller in a tight pseudowhorl. Blade 60–160 x 30–63mm, ovate, sub-sessile; apex gradually long acuminate to sub-caudate, acute or nearly so; margin entire, narrowly revolute; base rounded to cordate, rarely very broadly tapering, glabrescent above, laxly scaly beneath. Scales thin, marginal zone irregularly lobed, impressed. Mid-vein slightly impressed above, prominent beneath; lateral veins 8–11 per side, upper ones spreading and straight at the base, curved towards the edge and arching inwards, hardly prominent on both sides, reticulation dense, only faintly visible on both sides, or only above. Petiole 2–7 x 2–4mm, weakly or not grooved above, scaly, dark red. Buds to 30 x 15mm, ovate, acute, green, the bract points standing out away from the surface. Outer bracts ovate acuminate, c.18 x 10mm, laxly scaly outside in the distal ½ and along the margins, inner bracts to 30 x 8mm, spathulate, laxly scaly and minutely hairy outside, glabrous inside, with long stalked scales along the margins. Bracteoles subulate, to 20 x c.1mm, grooved, with a few scales outside and long stalked scales on the margins. Inflorescence 3–6-flowered in an open or almost complete umbel, the flowers held semi-erect to half-hanging. Pedicels 30–42 x c.2.5mm, densely to laxly scaly, not hairy, pink. Calyx irregularly 5-lobed, wavy, densely scaly, c.4mm in diameter. Corolla shortly funnel-shaped-campanulate, red or orange, with a white or greenish tube and triangular yellow guides inside the base of the upper three lobes; tube 10–14 x 6–7 x 12–15mm, deeply sulcate, sparsely scaly outside, laxly hairy to glabrous inside; lobes c.30 x 25mm, broadly obovate, spreading, the three upper overlapping to c.½, the two lower not overlapping. Stamens clustered in two groups on the lower side of the flower or in a semi-circle on the lower side exserted to c.10mm; filaments linear, densely patently hairy in the proximal ½, glabrous distally; anthers 2.5–3mm, oblong. Disc glabrous below, hairy on the upper ½. Ovary 4–6 x 1.5–2mm, conical, obtusely 5-angular, densely scaly and hairy, gradually tapering distally; style lying on the lower side of the flower, pale green, hairy and scaly in the proximal ½–1⁄3, glabrous distally; stigma thickly globose, green. Fruit 65–90 x 4–5mm, slenderly fusiform, laxly scaly and hairy on slender pedicels up to 40mm.
Habitat: Epiphytic in forest, locally common.
Distribution: Indonesia, New Guinea (W), Main Range, from Mt Carstensz to the Star Mts. Papua New Guinea, Upper Sepik R. region; Southern Highlands Province near Erave.
Altitude: 600-1500m
Named after F.A.F.C. Went who worked for several years in Indonesia, later becoming professor of botany at Utrecht in the Netherlands.
Type: Pulle (Versteeg) 1629, 21 Aug. 1907. New Guinea (W), Resi Mts, Noord R., c.600m (BO, K, L, U).
Synonymy: R. callichilioides Wernham, Trans. Linn. Soc. London, II, Bot. 1916. 9: 95. R. wollastonii Wernham, Trans. Linn. Soc. London, II, Bot. 1916. 9: 99.
Occurs in Countries: ID, PG Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: green, orange, red, white, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:313
Shrub or small tree; young shoots soon becoming glabrous. Leaves broadly rhombic 3.5-8 x 1.5-6cm, apex acute, upper surface at first with scattered brown pilose hairs, soon glabrescent, lower surface with scattered brown hairs, mainly on midrib; petioles 5-7mm, covered with brown pilose hairs, later glabrous. Inflorescence 2-4-flowered, flowers appearing before the leaves; pedicels 2-4mm, densely covered with brown pilose hairs. Calyx minute, ciliate. Corolla open funnel-campanulate, 30-40mm, pink with darker flecks, lobes c.20mm, oblong. Stamens 10, unequal, filaments glabrous. Ovary densely pilose; style glabrous or pubescent below, sometimes also papillate. Capsule 10-20mm, curved, with adpressed villose hairs.
Distribution: Japan (Kyushyu, Shikoku, SE Honshu), Korea
Illustrations:
Type: in Archipelago Gotto , Insula Sylvestri,1853, Weyrich, n.v.
Synonymy: R. shikokianum Makino, Bot. Mag. (Tokyo) 6: 53 (1892). Type: Japan, Tosa, Sa/cawa (iso. K)
Occurs in Countries: JP Subgenus: Tsutsusi Habit: Tree Fl. Colour: pink
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):151
Shrub to 2.5m. Twigs 2–4mm in diameter, densely hairy and scaly; internodes 2–5cm. Leaves 3–7 together in tight pseudowhorls. Blade 25–40 x 15–35mm, elliptic, obovate, or ovate; apex rounded, sometimes minutely emarginate, and sometimes with a minutely protruding terminal gland; margin entire or slightly irregular, flat or narrowly and weakly revolute; base tapering, slightly decurrent; laxly to sub-densely scaly on both sides at first, quickly glabrescent above, more persistently scaly beneath. Scales variable in size, the largest irregularly lobed, with small dark brown centres, smaller ones, circular dark brown, all impressed in shallow pits. Mid-vein impressed above, smooth, shallowly impressed or weakly prominent beneath (distinctly raised when dry); lateral veins 4–6 per side, emerging at c.45°, often only faintly visible above, smooth and faintly visible beneath, reticulation inconspicuous. Petiole 4–5 x 1–1.5mm, grooved above, flattened, brown-scaly and sometimes minutely hairy. Bracts 9–13 x 6–8mm, ovate, obtuse, laxly hairy outside, fringed with dark brown scales. Inflorescence 2–4-flowered, in an open umbel, flowers half-hanging. Pedicels c.13mm, scaly and long-hairy, or sometimes entirely without hairs. Calyx c.3mm in diameter, small, disc-shaped, obscurely lobed, shortly hairy outside. Corolla 22–30 x 23–27mm, funnel-shaped, red, without scent; tube 10–15 x 4–4.5 x 5–8mm, straight, grooved, laxly hairy and scaly outside, glabrous or laxly hairy inside; lobes c.12 x 12mm, obovate-spathulate, spreading almost to the horizontal, not overlapping, laxly scaly and sometimes with a few hairs proximally outside. Stamens exserted 17–20mm; filaments linear and densely sub-patently hairy in the lower ½, filiform and glabrous distally; anthers narrowly oblong, c.3 x 1mm. Disc prominent, glabrous below, shortly hairy on the upper margin. Ovary c.5 x 1mm, cylindrical, densely hairy with appressed hairs which cover small scales, abruptly tapering distally; style c.10mm, patently hairy in its lower 1⁄3–2⁄3, glabrous distally; stigma round. Fruit c.25 x 5–6mm.
Habitat: Epiphytic or terrestrial in shrubberies, banks or open mossy forest, considered to be rare.
Distribution: Philippines, Luzon, Mountain Province, Ifugao subprovince, Mt Polis; Mt Tabayoc; Benguet subprovince, Mt Pulag; Zambales Province, Mt Tapulao.
Altitude: 1800-2400m
Named after John Whitehead, an ornithologist who collected plants.
Sleumer (1966) sank this species into R. vidalii on the grounds that only flower colour separated the two species but later (Sleumer 1973) asserted the distinctness due to the large fruit of a specimen collected on Mt Pulag which meant fruit size could be used as well. Hybrids between these two species with pink flowers appear to exist, and the status of R. whiteheadii is far from satisfactorily established. The type specimen in the Natural History Museum, London has larger leaves than is usual for R. vidalii and the hairs on the stems are much longer and coarser.
Type: Whitehead s.n. Philippines, Luzon, Mountain Province, Ifugao subprovince, Mt Polis, 1830m (PNH†, BM).
Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:209
Shrub, 2—4.5m. Leaves broadly elliptic to obovate, 5 — 14 x 3.5-6.5cm, 2-2.5 x as long as broad, apex apiculate, base ± cuneate to rounded, lower surface with a dense unistrate rust-brown indumentum composed of ramiform hairs; petioles 1-2.5cm, sparsely tomentose to glabrescent. Inflorescence 10-20-flowered; rhachis 15-20mm; pedicels 15-30mm, tomentose. Calyx c.0.5mm, glabrous. Corolla 5(-7)-lobed, campanulate to mortar-shaped, pale-to lemon-yellow, with brown or purple flecks, 35-45mm. Ovary densely red-brown tomentose; style glabrous. Capsule 20-30 X c.5mm, straight or curved.
Habitat: Among scrub, stony ground, on ridges
Distribution: Nepal, NE India (Sikkim, Arunachal Pradesh), Bhutan, China (S Xizang).
Altitude: 3350-4550m
Illustrations:
Cultivated material seen has a lobed corolla resembling species of subsection Grandia and an inflorescence reminiscent of that subsection. However, it is not known how typical these plants are of the species in the wild, especially as most of the herbarium material seen has 5-lobed corollas. R. wightii clearly has aberrant features in subsection Taliensia and further field studies may result in its transfer to subsection Grandia.
Type: N India, Sikkim, wooded valleys and on spurs of all the mountains, 12-14000ft, abundant (holo. K).
Occurs in Countries: BT, CN, IN, NP Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: brown, lemon, purple
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):365
Weak shrub to c.30cm. Stems pale green, rounded, c.1.5mm in diameter, moderately densely covered in brown stellate scales. Leaves in pseudowhorls 1–2cm apart, consisting of 3–4 larger and 2–3 smaller leaves, mostly only possessing leaves at the terminal node. Blade 25–40 x 10–15mm, elliptic; apex broadly acute to obtuse, sometimes with an obscure, white, non-protruding, gland-like structure at the point; margin entire, flat; base broadly tapering; with some sparse silvery, stellate scales at first but quickly glabrescent above; below moderately brown scaly. Scales rounded, or sub-stellately lobed, impressed into small pits; centres small and indistinct; distributed 2–4 diameters apart in the mature leaves. Mid-vein narrowly impressed above; below, slightly prominent just beyond the petiole but then somewhat impressed distally, translucent green especially towards the base; lateral veins 2–4 per side, smooth, broadly spreading, but disappearing before the margin, distinct above but obscure below. Petiole 2–3 x c.1.5mm, not distinctly grooved above but with a central line, pale green with brown stellate scales. Flower buds green, to 18 x 8mm, narrowly conical but contracted near the base, sharply pointed with the basal bracts spreading, the upper (inner) bracts mostly appressed. Bracts glabrous or with a few small, scattered scales outside and with scales along the margins. Inflorescence terminal, of solitary or paired flowers, held half-hanging. Pedicels 10–15 x 1–2mm, moderately scaly but without simple hairs. Flowers narrowly funnel-shaped. Calyx a low scaly disc or with two irregular longer lobes up to 2mm long. Corolla c.27 x 44mm, red, without scent; tube c.15 x 4 x 10mm, glabrous both inside and out; lobes c.19 x 21mm, spreading horizontally, overlapping to about ½–2⁄3, emarginate. Stamens regularly arranged around the mouth of the flower; filaments pale pink, glabrous; anthers 2–2.5 x c.1.25mm, dark purple. Disc green, glabrous. Ovary c.6 x 2.5mm, ellipsoid, sparsely brown-scaly, without simple hairs; style c.20mm, pink, at first lying on the lower side of the corolla tube, rising to a central position as the flower ages, glabrous; stigma c.1.25mm in diameter, purplish-red, hardly expanded from the style. Fruit 33 x 5mm, fusiform but slightly wider in the distal ½. Seeds 4.5–5mm, without tails 0.8mm, the longest tail 2mm.
Habitat: Low mossy sub-montane forest
Distribution: Philippines, Palawan, Thumb Peak
Altitude: Around 1200m
Named after Peter Wilkie, botanist and explorer in SE Asia, who nearly died of a malarial attack helping to collect this species.
Known only from the type locality. This species is similar to R. acrophilum, which is from the same island, but differs in the flower colour, which is usually bicoloured with a yellow tube and orange lobes in that species. The filaments and inside of the corolla are glabrous in R. wilkiei, not hairy as in R. acrophilum, and it lacks the white waxy substance associated with the flower buds which that species possesses. It is also much less vigorous in its growth habit. Introduced into cultivation in 1998, it first flowered in July 2003 and has flowered in June and July subsequently. It is an attractive species but so far has grown very slowly.
Type: Argent et al. 48. Philippines, Palawan, Thumb Peak, Original collection 30 Jan. 1998, 1200m; Acc. No. 19981810: 11 July 2003 (PNH, E).
Occurs in Countries: PH Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Non-Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:207
Spreading dwarf shrub, 0.6-1.5m; young shoots setose-glandular. Leaves ovate-orbicular, 2—4.5 x 1.4-3.5cm, c.1.3 x as long as broad, apex rounded, minutely apiculate, base cordate, upper and lower surfaces glabrous although with red sessile glands below; petioles 0.7-lcm, glabrous to setose-glandular. Calyx c.lmm, glandular-ciliate. Corolla campanulate, lacking nectar pouches, pale rose, with darker flecks, 30-40mm. Ovary glandular; style glandular to tip. Stamens with filaments glabrous. Capsule 15—18 X c.5mm. CHINA (C Sichuan).
Altitude: Around 2800m
Illustrations:
A distinctive species with no close allies.
Type: China, W Sichuan, Wa-shan, 2800m, vi-x 1902, Wilson 1350 (holo. A; iso. E, K)
Altitude Ranges: 2,000 - 3,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: rose
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):261
Tree to 6m. Twigs 2–3mm in diameter, rounded, at first laxly scaly, later glabrescent, often whitish; internodes 3–10cm. Leaves 3–4 together in pseudowhorls. Blade 80–110 x 30–50mm, elliptic-ovate, or elliptic; apex mucronate, acute; margin entire, narrowly or not revolute; base broadly to narrowly tapering, glabrescent above with age, laxly scaly beneath initially. Scales small, flat, irregularly lobed in the very thin, fragile marginal zone; centre slightly darker, weakly impressed, finally glabrescent beneath also, leaving shallow dark pits. Mid-vein broad (1.5–2mm) at the base, quickly narrowed distally, impressed in the upper 2⁄3 above, prominent below throughout its length; lateral veins 6–10 per side, diverging at c.45° somewhat ascending, slightly impressed or raised above, more conspicuously prominent beneath, obscurely anastomosing before the margin, reticulation inconspicuous. Petiole 10–20 x 1.5–2.5mm, somewhat flattened, scaly. Bracts to 20 x 10mm; outer bracts broadly ovate, mucronate, c.15 x 12mm, with a few scales outside; inner ones broadly elliptic or elliptic, obtuse, margin very shallowly impressed with the attachments of fragile scales. Bracteoles to 20 x 0.5mm, linear, glabrous. Inflorescence a 5–8-flowered open umbel. Pedicels 20–25 x c.1mm, very densely covered with reddish-brown flat scales, especially towards the apex, without hairs. Calyx 4–5mm in diameter, oblique, disc-shaped, shortly irregularly 5-lobed, the lobes up to 1mm. Corolla 25–40 x c.30mm, funnel-shaped, white, sparsely scaly or glabrous outside, glabrous inside; tube 18–23 x 6–7 x 10–16mm, base 5-pouched; lobes 10–15 x 10–15mm, obovate-sub-circular. Stamens exserted to c.5mm; filaments linear, glabrous; anthers c.3 x 1mm, oblong, each cell with a short basal apiculus. Disc glabrous, prominent, deeply lobed. Ovary 5–8 x 2.5–3mm, sub-ovoid-cylindric, initially with dense, flat, reddish-brown, stellate scales, becoming glabrescent, sub-abruptly contracted distally; style c.20mm, scaly in the proximal ½–2⁄3, glabrous distally; stigma 3mm in diameter, thick. Fruit 25–30 x 6–7mm, fusiform. Seeds 5–6 x 0.2mm including the tails.
Habitat: Along streams, in ravines
Distribution: Philippines, Luzon, Mountain and Zambales Provinces.
Altitude: 1500-2200m
Named after one of the early collectors of this species, Robert S. Williams, an American whose main interests were birds and mosses.
Often reported in cultivation but all material examined with this name has turned out to be R. kochii which is easily distinguished by its hairy ovary and filaments.
Type: Elmer 6519, June 1904. Philippines, Luzon, Mountain Province, Benguet, Baguio (US, K, L, NY, P).
Occurs in Countries: PH Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Tree
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:279
Shrub, l-4.5m. Leaves oblanceolate to broadly elliptic, 5-12 x 1.5-4cm, 2.5-6 x as long as broad, apex apiculate, base cuneate, upper surface with deeply impressed veins so appearing bullate, lower surface with a dense unistrate cinnamon to rust-red fasciculate to ramiform tomentum; petioles 1.5-3cm, tomentose at first, soon glabrescent. Inflorescence c.!0-flowered; rhachis 5-7mm; pedicels 15-25mm, usually lanate-pubescent. Calyx c.lmm, tomentose. Corolla campanulate, white to pink, with red flecks, 30-40mm. Ovary densely rust-red lanate-tomentose, eglandular; style glabrous or hairy at base. Capsule 22-25 x 4-5mm, falcate.
Habitat: Rocky pastures and slopes
Distribution: China (C Sichuan)
Altitude: 2450-3350m
Illustrations:
A distinctive species on account of its bullate leaves, apparently without close allies.
Type: China, Sichuan, in thin woods, 3300m, v 1904, Wilson 3952 (holo. A; iso. BM, K, SYS)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: pink, red, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):362
Stiffly erect shrub to 2m. Twigs 1–2mm in diameter, rounded, tips densely covered with brown, stellate, stalked scales, glabrescent below with the small peg-like bases persisting. Leaves densely spirally arranged along the upper part of the twigs. Blade 7–14 x 4–9mm, ovate to ovate-elliptic, broadly elliptic or sub-circular; apex shortly acuminate, broadly acute to obtuse or rounded; margin entire or very weakly crenulate from indentations of scale bases, sometimes slightly revolute in the basal ½; base broadly tapering to rounded, sub-densely scaly on both sides initially, glabrescent and often a little shining above at maturity, persistently sub-densely or more sparsely scaly beneath. Scales flat, or somewhat domed, with the marginal zone irregularly obtusely stellate-incised to almost entire and circular; centre often broad and slightly domed. Mid-vein distinctly impressed above, weakly prominent beneath; lateral veins not visible. Petiole 1–2 x 1–1.5mm, weakly grooved and with dense, short, white hairs above and brown scales mostly beneath. Flower buds to 12 x 6mm, green often with a pink flush, ovoid but acutely pointed, with the bracts appressed except for the basal, partly leaf-like bracts which are wide-spreading. Outer bracts ovate-acuminate, shortly apiculate, or narrowly pointed, the outermost with a few scales outside; inner ones narrower, glabrous inside and out, except for the margins which are densely fringed with brown scales of which those in the lower parts are long stalked, the more distal ones almost sessile. Inflorescence of 1–4 hanging flowers. Bracteoles c.5mm, filiform. Pedicels 15–20 x c.1mm, densely covered with very shortly stalked stellate scales and more laxly with short patent white hairs. Calyx disc-shaped, spreading or reflexed, c.2.5mm in diameter, lobes broadly triangular, obtuse, scaly and finely hairy, c.1mm. Corolla 20–25 x 16–20mm, tubular, slightly dilated at the mouth, bright or deep red; tube 15–18 x 5–7 x 8–10mm, almost parallel sided but expanded just below the mouth, laxly stellately scaly outside and patently white hairy especially in the basal ½, glabrous inside; lobes c.8 x 9mm, sub-circular, overlapping ½–2⁄3, curved, the lower ½ almost vertical, the upper ½ widely spreading, with a few scales outside at the base and sometimes along the midline. Stamens arranged around the lower ½–2⁄3 of the mouth, exserted to c.5mm; filaments filiform, deep pink, glabrous; anthers 2 x 1mm, oblong, dark purplish-black and with grey pollen. Disc prominent, hairy on the upper margin. Ovary 3–4 x 1–1.5mm, sub-cylindrical, densely semi-erect to patently white hairy and sub-densely scaly, gradually tapering distally; style lying on the lower side of the mouth and nearly equalling the corolla in length, covered with spreading white hairs in the lower ½–2⁄3, glabrous distally; stigma club-shaped or sub-globose. Fruit 15–20 x 3–4mm, fusiform, hairy, greyish or purplish when almost ripe. Seeds 4mm including the tails.
Habitat: Mostly in open mossy forest or along forest margins, also in grassland above the timber line; mostly terrestrial, rarely epiphytic on mossy trunks. Locally common
Distribution: Papua New Guinea, Eastern, Western and Southern Highlands; Morobe District: Rawlinson Range.
Altitude: 3200-3960m
Named after John Womersley, long time Chief of Division of Botany in Lae, Papua New Guinea, collector of the type specimen and rhododendron enthusiast.
Recorded as hybridising with R. atropurpureum and R. commonae on Mt Wilhelm.
Type: Womersley NGF 8871, 1 Aug. 1956. Papua New Guinea, Central Highlands, Mt Wilhelm, vicinity of Lake Piunde, 3600m (LAE, BRI, K, L).
Synonymy: R. aff. inconspicuum Stonor, Rhod. Yearbook 1951. 6: 51, f.52.
Occurs in Countries: PG Altitude Ranges: 3,000 - 4,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: red, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:151
Shrub or small tree, 1.5- 10m. Leaves coriaceous, oblanceolate to elliptic, 6-15 X 2.5-3.5cm, 2.5-3.8 X as long as broad, apex bluntly acuminate, base cuneate, margin not or only slightly undulate, upper surface glabrous when mature, lower surface usually with conspicuous veins and a thin veil of a persistent white indumentum, punctate hair-bases conspicuous, overlying the veins and midrib; petioles 1.5-3.5cm, minutely white-tomentose or ± glabrous when mature. Inflorescence 8- 12-flowered; rhachis 5- 10mm; pedicels 15-20mm, rusty-floccose and shortly stipitate-glandular. Calyx c. 1mm, tomentose and glandular, lobes rounded. Corolla open-campanulate, nectar pouches lacking, glabrous within, white sometimes flushed pink, with purple flecks, 25—35(—45)mm. Ovary densely rufous-tomentose, also with a few stipitate glands; style glandular at base or entirely glabrous. Capsule 10-20 x 5-8mm.
Habitat: Montane rain forests, occasionally epiphytic
Distribution: Malay peninsula.
Altitude: 850-2150m
Illustrations:
The open-campanulate corolla suggests a possible affinity with R. annae and its allies. R. wrayi does, however, clearly differ from them in its ± persistent leaf indumentum.
Type: Syntypes: Malaya, Perak, 3500-7000ft, Wray 322, 886, 1569; Scortechini, n.v.
Synonymy: R. wrayi King & Gamble var. ellipticum Ridley & var. minor Ridley, J. Fed. Malay States Mus. 6: 49, 157 (1915). R. corruscum Ridley, J. Fed. Malay States Mus. 5: 37 (1914). Type: Malaya, Ganong Mengkuang Labah, 4800-5800ft, 1918, Ridley etal. (iso. BM). R. dubium King & Gamble, J. Fed. Malay States Mus. 6: 78 (1915). Type: Malaya, Perak, 3400ft, Wray 233, 460, n.v.; Scortechini 367 (E).
Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Hymenanthes Habit: Epiphyte, Tree Fl. Colour: pink, purple, white
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):294
Named after C.H. Wright, formerly assistant keeper of the Kew Herbarium.
Type: Römer 1059. New Guinea (SW), Oranje Mts, Erica top, c.1460m (BO).
Occurs in Countries: ID, PG Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Fl. Colour: pink, red, white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:231
Leaves 13–40 x 7–17mm. Pedicels scaly and densely, shortly hairy. Bracts as in var. wrightianum.
Distribution: Indonesia, New Guinea (W), Mt Cyclops. Epiphytic or on moss-covered soil, in open Nothofagus–Rapanea ridge forest.
Altitude: 1480-1800m
Named after Mt Cyclops, the mountain on which it was collected.
Type: Gjellerup 542, 20 June 1911. New Guinea (W), Mt Cyclops (BO, L).
Leaves 10–20 x 6–15mm. Bracts laxly scaly outside, not hairy, up to 8mm in length. Pedicels scaly and sometimes laxly and very shortly hairy.
Habitat: Common high epiphyte in tall mossy forest
Distribution: Papua New Guinea, Milne Bay District, Normanby and Goodenough Is.
Altitude: 820-1600m
Latin – insularis – pertaining to islands, alluding to the islands from which it is recorded.
Type: Brass 25637, 5 Jan. 1956. New Guinea (SE), Milne Bay District, Mt Pabiname, 820m (L, A).
Shrub to 1m. Twigs 1–2mm in diameter, rounded, densely covered with shortly stalked, stellate scales, not hairy, becoming glabrescent and then warty with the persistent scale stalks; internodes 1–6cm. Leaves 3–5 together in tight pseudowhorls. Blade 10–20 x 5–10mm, obovate-elliptic to obovate; apex obtuse or rounded; margin sub-crenulate with impressed scales or entire, minutely cartilaginous and slightly recurved; base tapering or broadly tapering; laxly silvery scaly above at first, quickly glabrescent; beneath laxly brown-scaly but these very fragile and falling early. Scales with the narrow marginal zone irregularly crenulate or sub-stellately lobed; centre dark, proportionally large and somewhat impressed. Mid-vein narrowly slightly or not impressed above, distinctly but only weakly prominent beneath; lateral veins 1–3 per side, or obscure, reticulation obscure. Petiole 1–2 x 0.5–1mm. Bracts to 8 x 4mm; outer bracts ovate, sub-acuminate or obtuse, inner ones elliptic, all distinctly hairy and laxly scaly outside at least in the distal ½, and fringed with scales, often still persistent at flowering time. Bracteoles to 7mm, filiform. Inflorescence 1–4-flowered in an open umbel, the flowers hanging vertically. Pedicels 5–15mm, slender, densely covered with stellate and shortly stalked scales, and often with short papillose hairs. Calyx c.2.5mm in diameter, shortly cup-shaped, oblique, with irregular lobes, densely scaly outside. Corolla 22–30 x 10–15mm, tubular, slightly dilated upwards, red, pink or rarely white; tube 20 x 4–5 x 8–10mm, laxly to sub-densely stellate-scaly outside, glabrous inside, straight or slightly curved; lobes c.7 x 7mm, half-spreading, sub-circular. Stamens exserted to c.4mm, unequal; filaments linear, glabrous; anthers c.2 x 1mm, broadly ellipsoid, the base of each cell sub-apiculate. Disc glabrous. Ovary 4–5 x 1.5–2mm, sub-cylindrical, densely scaly, gradually tapering distally; style 17–20mm, scaly in the proximal 1⁄5–1⁄3; stigma club-shaped. Fruit 30–35 x c.3.5mm, fusiform; valves reflexing and twisting, the placentae at first remaining attached to the central column, eventually irregularly breaking away from the base. Seeds c.6mm, without tails to 1mm, the longest tail 3.2mm.
Habitat: Epiphytic in mossy forest, or terrestrial in openings, on sandy or peaty soil.
Distribution: Indonesia, New Guinea (W), Oranje and Nassau Mts. Papua New Guinea, Milne Bay District, Mt Garatun.
Altitude: 1370-3250m
Epiphytic shrub, to 80cm, with a thick, simple or but slightly branched stem. Twigs c.4mm in diameter, scaly. Leaves spirally arranged. Blade 90–120 x 35–50mm, elliptic; apex acuminate or acute; margin flat; base broadly tapering to almost rounded, glabrescent above, scaly below. Mid-vein thick and prominent, raised above in the proximal ½, raised below almost to the apex. Petiole 12–15 x 3–4mm, ungrooved, scaly. Inflorescence 3–4-flowered. Pedicels c.15mm, glabrous. Calyx reduced to an obscure disc. Corolla 30–40 x 30–55mm, campanulate, yellow flushed with orange; tube 15–25 x 12 x 25mm, glabrous both outside and inside; lobes c.30 x 22mm, sub-circular. Stamens c.18mm, distributed irregularly around the mouth, exserted 2–3mm; filaments hairy proximally; anthers c.4mm, linear, without any basal apiculus. Disc with a few hairs at the top. Ovary 8mm, scaly, without hairs, abruptly contracted distally; style c.12mm, glabrous, lying on the lower side of the tube.
Habitat: Epiphyte in moss forest, or terrestrial in montane grassland. Apparently rare.
Distribution: Philippines, Luzon, Bataan Province, Mt Mariveles; Rizal Province, Montalban; Nueva Vizcaya Province, Carballo Sur Mountains. Possibly also from Mindoro at Ibolo (Copeland 1929). Camiguin Island, near Mindanao.
Altitude: Around 1200m
Greek – xantho – yellow; petalum – petals. Alluding to the yellow colour of the flowers.
An imperfectly known species of which Sleumer had examined only the single leaf in the Edinburgh herbarium. It appears to be characterised by the spiral leaf arrangement, and a calyx that is much broader than the base of the scaly but non-hairy ovary. A recent expedition to Mt Mariveles failed to find this species in the type locality, but surprisingly material closely matching the description was collected on Camiguin Island off Mindanao in 1999. This has been cultivated and the description above is augmented from this material. The chief differences from the type description are that the stems are not glabrous (which is likely to have been inaccurate in the original), the leaf bases not acute and the margins flat and not revolute. The flower measurements are considerably larger, which is understandable as they have been made from living material. It would appear to be very similar to R. javanicum ssp. schadenbergii.
Type: Whitford 322. Bataan, Mt Mariveles (PNH†).
Occurs in Countries: PH Altitude Ranges: 1,000 - 2,000m Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: orange, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:284
Shrub, 0.6-2 m, mature bark smooth, reddish brown, somewhat pruinose. Leaves oblong-narrowly elliptic to elliptic, acute at apex, cuneate at the base, (50-)60-80(-105) X (15-)20-25(-30) mm, upper surface brownish green, lower surface silvery brown with unequal scales about their own diameter apart, the smaller and more numerous scales deeply sunk in pits, scarcely reaching the surface of the leaf, the larger borne ± on the surface, though with the stalks in pits. Inflorescences usually terminal, rarely a few axillary inflorescences present as well, (3-)4-5-fIowered, pedicels lepidote, 10-12 mm. Calyx lobes suborbicular to ovate or oblong, rounded at the apex, (2-)5-7 mm, variably lepidote, not ciliate, erect or spreading. Corolla rather narrowly campanulate, (18-)20-25(-28) mm, tube (11-)14-16(-20) mm, deep yellow, deep lemon-yellow or tending to yellow-orange, variably lepidote and sometimes slightly pubescent outside. Filaments pubescent towards the base. Ovary lepidote, tapering into the style which is lepidote at the base. Capsule lepidote, cylindric, 8-11 mm.
Habitat: In forests, on forest margins and in scrub, 1600-3000(-3900) m
Distribution: India (Arunachal Pradesh), NE Burma, China (NW & C Yunnan, SE Xizang)
Illustrations:
Type: China, Yunnan, Tali, dans les broussailles au pied du Tong chuan, Delavay 4728 (holo. P—n.v., iso. E)
Synonymy: R. aureum Franchet, Journ. de Bot. 9:394 (1895), non Georgi, Bemerk. Reise Russ. Reich 1:214 (1775) Type: as for R. xanthostephanum.
Occurs in Countries: CN, IN, MM Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: lemon, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):127
Prostrate shrub to c.20cm. Twigs rounded, moderately to densely scaly. Leaves spirally arranged. Blade 3–8 x 2–4.5mm, ovate to ovate-elliptic; apex shortly acuminate; margin entire, slightly revolute; base broadly tapering. Mid-vein impressed above in the proximal ½–2⁄3, inconspicuous; lateral veins obscure, initially scaly on both sides, quickly glabrescent above, persistently, sub-densely to laxly scaly below. Scales irregularly lobed, brown, sessile. Petiole 1–1.6 x 0.5mm, flat, scaly. Flower buds 4.5–6.5 x c.2.5mm. Bracts ovate, acuminate, sparsely scaly outside and fringed with stalked scales, inner bracts narrower and more shortly acuminate. Inflorescence a solitary flower, horizontal to semi-erect. Pedicels 15–31 x 0.6–0.9mm, densely scaly and hairy. Calyx c.2mm in diameter, 5-lobed, the lobes up to 1.5mm, scaly and hairy, margin with stalked scales. Corolla 15–20 x 13–15mm, red, sub-campanulate; tube 9–14 x 3.5–5 x 6–8mm, slightly curved, scaly outside, glabrous inside; lobes 5.5–8.5 x 6.5–8.5mm, wide-spreading, circular to circular-obovate, scaly outside in the lower middle part, overlapping for ¼–½. Stamens arranged all round the mouth, exserted to c.3mm; filaments 10–11mm, glabrous except for a few hairs at the base; anthers 1.2–1.6 x c.1mm. Disc 10-lobed, with dense, erect, white, hairs on the upper margin. Ovary 3–4 x c.2mm, sub-cylindrical, densely covered in short white hairs over a sub-dense to lax layer of scales, broadly tapering distally; style 4.3–8.4mm, hairy in the proximal ¼–½, glabrous distally; stigma globose, 5-lobed. Fruit 15–20 x c.3.5mm, fusiform.
Habitat: Growing in peaty crevices on limestone slopes and cliffs.
Distribution: Indonesia, New Guinea (W), Mt Jaya (Carstensz), Carstensz Meadow.
Altitude: 3520-3540m
Greek – xenium – gift for a guest, alluding to the long pedicel that makes the flower more accessible to visiting birds.
Distinct in its very long pedicels which are reminiscent of R. saxifragoides.
Type: Hope, ANU 10847, 13 Dec. 1971. Indonesia, West Papua, limestone hill at S end of Carstensz meadow, Mount Jaya, 3540m (CANB, BO).
Altitude Ranges: 3,000 - 4,000m Subgenus: Vireya Habit: Non-Tree Fl. Colour: red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:145
Shrub, l-2.5m; young shoots floccose-tomentose, eglandular; perulae persistent or deciduous. Leaves narrowly to broadly elliptic or linear-lanceolate, 6-21 x l-3cm, 2.3-10 x as long as broad, apex rounded to acute, base rounded to cuneate, upper surface glabrous or with a thin floccose indumentum towards the base, lower surface with a thick white to fulvous lanate tomentum that obscures the midrib; petioles 1-1.5cm, tomentose at first, usually soon glabrescent. Inflorescence lax, 5—10-flowered; rhachis 2—5mm; pedicels 15—25mm, densely fulvous-tomentose. Calyx 2—5(~7)mm, densely tomentose. Corolla 5-lobed, funnel-campanulate, pale rose, with or without flecks, 30-40mm. Ovary densely whitish to brown-tomentose. Capsule at least 15 x 7mm.
Habitat: Mountains
Altitude: 500-2000m
See also Doleshy (1968)—ref. p. 305.
Closely allied to R. japonicum and possibly conspecific, though consistently with a denser leaf indumentum and differently shaped leaves. R. makinoi is usually treated as a separate species on account of its persistent perulae and narrow leaves, while R. yakushimanum in the strict sense is sometimes treated as a subspecies of R. japonicum (see Doleshy, 1968).
Subsp. yakushimanum varies with respect to size and leaf length; the more dwarf and compact forms occurring in more exposed sites and the more lax forms (var. intermedium) in more sheltered sites. Var. intermedium approaches R. japonicum but the denser leaf indumentum will generally distinguish it. It apparently replaces R. japonicum on the southern island of Yakushima.
Occurs in Countries: JP Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Hymenanthes Habit: Non-Tree Fl. Colour: rose
Chamberlain, D.F. (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. Notes From the Royal Botanic Garden Edinburgh 39(2):310
Leaves7.5-10 x as long as broad; perulae persistent
Distribution: Japan (C Honshu)
Synonymy: R. makinoi Tagg in Nakai & Koidzumi, Trees Shrubs Japan ed. 2, 1: 61 (1927) — basionym. R. stenophyllum Makino, Bot. Mag. (Tokyo) 24: 99 (1910), non Hooker f. (1878). R. metternichii Siebold & Zuccarini var. pentamerum Maximovicz forma angustifolium Makino, Bot. Mag. (Tokyo) 10: 211 (1896). Type: a specimen cultivated in Tokyo, dated 8 v 1890, n.v., also type for the above two species. Azalea makinoi (Tagg) Makino in J. Jap. Bot. 6: 3 (1929), incl. var. muranoana Makino, J. Jap. Bot. 6: 4, t.(1929).
Leaves 2.3-6 x as long as broad; perulae deciduous
Distribution: Japan (Yakushima)
Described from Yakushima, S Japan
Synonymy: R. metternichii Siebold & Zuccarini var. yakushimanum (Nakai) Ohwi, Bull. Natl. Sci. Mus. 33: 81 (1953). R. metternichii Siebold & Zuccarini subsp. yakushimanum (Nakai) Sugimoto, New Key Jap. Trees, 470 (1961). 1R. metternichii Siebold & Zuccarini var. intermedium Sugimoto, ibid., 471 (1961). R. degronianum Carriere var. yakushimanum (Nakai) Kitamura, Acta Phytotax. Geobot. 25: 38 (1972).
Shrub; young shoots densely greyish-brown sericeous-strigose. Leaves dimorphic, coriaceous; spring leaves oblong-lanceolate, 2.5-3 x 1.2-1.3cm, c.1.5 x as long as broad, apex acuminate, base cuneate, margin undulate, densely ciliate, upper surface grey-strigose; summer leaves oblong-elliptic to elliptic, 10-20 x 5-8mm; petioles 5-10mm, densely spreading-strigose. Inflorescence 5-8-flowered; pedicels 4-5mm, densely strigose. Calyx 1.5-2mm, densely brownish-strigose, lobes crenulate. Corolla funnel-campanulate, 8-10mm, reddish to pale purple; tube 5-6mm, glabrous. Stamens 5, filaments pubescent below. Ovary densely sericeous-strigose; style base strigose. Capsule ovoid, c.6 x 3.5mm, strigose.
Habitat: Open woodland
Distribution: China (Hunan)
Altitude: Around 250m
Probably allied to R. seniavinii, with which it shares a characteristic sericeous indumentum, but differing in its less hairy leaves, and corollas glabrous on the outer surface.
Type: China, Hunan, Ningyuan Xian, Yangming Shan, 250m, 4 iv 1942, T. Tsiang & S.Q. Chen (S.H. Chun) 365 (holo. IBSC)
Occurs in Countries: CN Altitude Ranges: 0 - 1,000m Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: purple, red
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):132
Small shrub; young shoots spreading-glandular-setose; indumentum becoming pale greyish-brown, sometimes glabrous. Leaves chartaceous, scattered along branches; spring leaves oblong to oblong-lanceolate, 9~15(-20) x 3-8cm, apex acuminate, base broadly cuneate, margin setulose, upper surface glabrescent, lower surface sparsely setulose; summer leaves smaller, up to c.10 x 4mm, otherwise as for spring leaves; petioles 5-15mm, densely spreading-brownish-setose, also with short glandular hairs. Inflorescence 10-15~flowered; pedicels c. 10mm, densely setulose. Calyx c.3mm, densely setulose, teeth minute. Corolla funnel-campanulate, 13-15mm, red; tube 7-8mm, glabrous. Stamens 5, filaments glabrous. Ovary brown-setulose; style glandular-setose in lower half. Capsule oblong to oblong-ovoid, 5-7mm.
Distribution: China (Guangxi)
Closely allied to R. jinxiuense but differing in its glandular style and glabrous filaments. Probably also allied to R. kwangtungense.
Type: China, Guangxi, Xiangzhou Xian, Guehen, 5 v 1931, S.S. Ying 2118 (holo. IBSC, iso. E)
Occurs in Countries: CN Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: red
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):100
Compact densely branched shrub, l-2m; young shoots clothed with adpressed flattened strigose hairs, glabrescent in second year. Leaves dimorphic, ± deciduous, chartaceous; spring leaves elliptic-lanceolate to oblanceolate, 3-8 x 1-2.5cm, 2-3 x as long as broad, apex acute and mucronate, base cuneate, margin entire, ciliate, both surfaces with scattered adpressed shining brown strigose hairs, lower surface paler than upper; summer leaves thicker, upper surface soon glabrescent, otherwise as for spring leaves; petioles 3-6mm, covered with loosely adpressed strigose hairs. Inflorescence 2-3-flowered, flowers opening with or shortly before the leaves; pedicels 5-10mm, covered with loosely adpressed strigose hairs. Calyx green, covered with adpressed strigose hairs, lobes ovate, acute or obtuse, 5-8mm. Corolla broadly funnel-shaped, 35-40mm, 50mm across, rose to pale lilac-purple (sometimes double in cultivated varieties), with flecks, fragrant, lobes c.25mm; tube glabrous. Stamens 10, subequal, shorter than corolla, filaments papillose below middle. Ovary densely covered with adpressed hairs; style glabrous or pilose towards base. Capsule ovoid, 5-8mm, densely strigose, with persistent calyx.
Type: a cultivated plant exhibited in St Petersburg in 1884, originating from Japan [n.v.], or the plate cited above.
Occurs in Countries: JP Altitude Ranges: 1,000 - 2,000m Subgenus: Tsutsusi Habit: Non-Tree Fl. Colour: lilac, rose
Chamberlain, D.F. & Rae, S.J. (1990) A Revision of Rhododendron IV Subgenus Tsutsusi. Edinburgh Journal of Botany 47(2):114
Flowers single; calyx 5-8mm (native)
Habitat: Rocky ground among shrubs
Distribution: Korea, Japan (Tsushima), native.
Altitude: Around 1100m
Illustrations:
Probably most closely allied to R. mucronatum.
Synonymy: R. poukhanense Levi., Repert. Spec. Nov. Regni Veg. 5: 100 (1908). Type: Korea, in acre Pouk Han, 3 vi 1901, Faurie s.n. (holo. E). R. hallaisanense Levi., Repert. Spec. Nov. Regni Veg. 12: 101 (1913); R. yedoense Maxim, var. hallaisanense (Levi.) Yamazaki, J. Jap. Bot. 62: 260(1987). Type Korea, Quelpaert, Hal-laisan, 1200m, x 1907, Taquet 305 (holo. E). R. coreanum Render, Mitt. Deutsch. Dendrol. Ges. 22: 259 (1913). Type: a cultivated specimen flowering in the Arnold Arboretum on 6 v 1911, raised from seed collected by J.G. Jack in Korea, Pack Han, Seoul, on 25 ix 1905 (n.v.).
Flowers double; calyx to 15mm (cultivated)
Known only in cultivation
Erect, much-branched and mostly compact shrub or tree, to 12m. Twigs 1–2mm in diameter, rounded, slender, densely covered with stellate scales, the largest ones brown and distinctly stalked, the many smaller ones silvery and sessile; rough after the scales have gone. Leaves regularly spirally arranged, densely to laxly covering the twigs. Blade 7–25 x 5–15mm, broadly-elliptic to ovate-elliptic, rarely ovate or obovate; apex mostly broadly obtuse, sometimes rounded, the terminal gland small but usually protruding; margin cartilaginous, distinctly irregularly crenulate, slightly revolute; base rounded or truncate-sub-cordate, greyish dark green and shining above, pale brownish, silvery or pale yellow beneath, glabrous or very laxly scaly above at maturity, very densely scaly beneath. Scales pale yellow to brown, mostly small, touching each other, and forming a coherent layer initially, marginal zone lobed, the centre small and deeply depressed, a few scattered much larger and deeper brown scales can give the surface a spotted appearance. Mid-vein slightly impressed above, clearly obtusely raised beneath; lateral veins 4–6 per side, straight below, curved towards the margin and anastomosing distally, very slightly impressed above, faintly raised beneath. Petiole 1–3 x c.1mm, a little flattened, grooved above, densely scaly. Flower buds c.8 x 5mm, ovoid, pale green to brown, smooth, densely scaly and very shortly, to long hairy. Outer bracts to 8 x 5mm, ovate, sub-acute, inner ones spathulate, obtuse, all scaly outside and with short hairs, also scaly towards the tips inside and fringed with scales. Bracteoles to 8mm, linear-sub-spathulate, crimped, glabrous or laxly hairy apically. Inflorescence of 3–5 flowers in an open umbel, the flowers hanging to half-hanging. Pedicels 8–13 x c.1mm, slender, densely covered with sub-sessile scales, without hairs. Calyx 2.5–3.5mm in diameter, disc-shaped, oblique, very densely scaly outside, irregularly obtusely 5-lobed. Corolla 13–16 x 8–10mm, cylindrical, zygomorphic, pale to deep red, without scent; tube 10–12 x 4–5 x 5–7mm, straight or a little curved, densely yellowish scaly outside, glabrous inside; lobes 3–5mm in diameter, sub-erect, overlapping c.halfway, unequal, sub-circular, often shortly retuse and irregularly crenulate. Stamens irregularly arranged, slightly exserted; filaments narrowly linear, glabrous; anthers c.1mm, sub-globose. Disc glabrous. Ovary c.5 x 2.5mm, ovoid-conical, densely scaly, broadly tapering distally; style 3–4mm, centrally positioned or irregularly displaced to one side, glabrous; stigma 5-lobed. Fruit 12–15 x 5–6mm, with a persistent short style. Seeds 2mm, without tails c.0.8mm, the longest tail 0.8mm.
Habitat: Epiphytic in montane forest, but mostly terrestrial at the forest margins, on steep slopes or exposed rocks or grassland above the forest line, often along streams
Distribution: Papua New Guinea, Star Mts, Finisterre Mts, Mt Saruwaged region, Mt Wilhelm, Kubor Range, Mt Michael, Mt Giluwe, Mt Dickson, Mt Albert Edward, Murray Pass and the Owen Stanley Range.
Altitude: 1300-3680m
Named after Herr Yelliot, member of the Finisterre Expedition on which this was first collected and who contributed greatly to the success of the expedition.
Often confused with R. inconspicuum; for differences see under that species. I have followed van Royen & Kores (1982) in treating this species in a broad sense and including R. saruwagedicum as a synonym. I have not seen the type material to examine the bud scales. All the material to hand shows the bract margins fringed with scales, not ciliate, as is described for R. yelliotii, although, with hairs present on the outside of the bracts, it often looks as if the bracts are ciliate. The fact that Sleumer’s (1966) description of the bracts (perulae) of R. sarawagedicum did not mention a ciliate margin is further evidence that this species does not belong in Discovireya. There is a great deal of variation in the many specimens, much of it due to the very broad altitudinal range ascribed to this species: the high altitude forms have very small leaves as might be expected. A specimen collected by Vinas & Thomas (LAE 59673) from the north valley of Mt Capella (Star Mts) has stalked scales on the ovary and very irregularly toothed leaf margins but there are no bracts present in the specimen seen. This may represent a hybrid or an undescribed species.
Type: Hellwig 312, 14 Oct. 1888. Papua New Guinea, Finisterre Mts (B†), lectotype from the same locality; Schlechter 19153 (P).
Synonymy: R. saruwagedicum Foerster, Fedde Rep. 1914. 13: 222. R. saruwagedicum Foerster var. alpinum Sleumer, Flora Malesiana 1966. I, 6(4): 487, f.5. R. yelliottii Warb. loc. cit. (orthographic error).
Occurs in Countries: PG Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Epiphyte, Tree Fl. Colour: red, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:138
Shrub to 3m. Twigs smooth, rounded, sparsely covered with pale brown, lobed scales; internodes 2–20cm. Leaves in tight pseudowhorls of 4–5 large and a similar number of very small leaves and with well-spaced cataphylls on the internodes when young. Blade 60–110 x 20–55mm, elliptic; apex rounded or slightly retuse; margin entire, broadly revolute, the whole leaf being convex; base broadly tapering. Mid-vein impressed in a channel above and strongly raised below throughout its length; lateral veins 5–8 per side, diverging at c.45°, slightly raised; above sparsely covered with small, lobed, pale scales with brown centres, quickly glabrescent; below sparsely covered with more persistent scales impressed in shallow depressions. Scales small, brown, lobed. Petiole 10–25 x 3–5mm, weakly grooved above, especially distally, sparsely scaly. Flower buds to 15 x 12mm, ellipsoid to ovate, the tips of the scales spreading outwards and dark, shiny, red, remainder pale green flushed with pink, the outermost bracts often becoming brown, with appressed hairs and brown scales outside. Outermost bracts mucronate, main bracts broadly elliptic with rounded apices, scaly and appressed hairy in the distal ½ outside, glabrous inside. Bracteoles c.12 x 1mm, filiform but channelled adaxially, sometimes sub-spathulate, with a few scales especially along the margins and occasionally with sparse simple white hairs. Inflorescence 5–10-flowered, in an open umbel, the flowers semi-erect to horizontal. Pedicels 13–18 x 1–1.5mm, dark red with scattered scales and patent white hairs. Calyx disc-shaped, shallowly 5-lobed, patently hairy. Corolla 30–36 x 20–30mm, dark purplish-red, without scent; tube 20–25 x 5–6 x 8–9mm, cylindrical, curved, sulcate near the base, shortly patently white hairy outside and with a few small silvery scales; inside with white hairs only in the proximal 2–3mm otherwise glabrous; lobes 10–12 x 9–10mm, overlapping ¼–½, spreading, hairy outside and with some small silvery scales, rounded or weakly emarginate. Stamens clustered on the upper side of the mouth, exserted to c.4mm; filaments 22mm, hairy at the base for c.3mm, glabrous distally; anthers 1.5–2mm, pale brown. Ovary 3–4 x 2–3mm, shortly cylindrical, densely covered with semi-appressed white hairs and white scales, abruptly contracted distally; style 16–18mm, glabrous; stigma disc-shaped. Fruit 11–15 x 5–7mm, broadly ellipsoid, the valves spreading to 45° or weakly curving back; placentae adhering to the central column or weakly spreading from the base. Seeds c.2.5mm, without tails 0.8–0.9mm, the longest tail to 1mm.
Habitat: In mossy montane forest on ridges where it is predominantly terrestrial but it may also grow epiphytically.
Distribution: Malaysia (Borneo), Sarawak, Mt Mulu, Mt Tamacu, (Mulu Nat. Park), Mt Murud. Sabah, Crocker Range, Mt Alab, (not yet recorded from Mt Kinabalu); Mt Lumarku and Long Pa Sia area.
Named in honour of Joseph Yong, former director of the Forest Department, Sarawak, who facilitated the expedition on which this species was collected.
Vegetatively this species is very similar to R. praetervisum from Mt Kinabalu and the Crocker Range (Sabah) but the flowers are smaller, different in colour and disposition and hairy outside. Some earlier collections of this species were ascribed to R. x keditii but that taxon is larger with more pointed leaves, longer pedicels, anthers and ovary and much broader pink flowers. Amongst the red-flowered Bornean species this appears to be distinctive in having the stamens tightly clustered on the upper side of the mouth of the flower as is much more common in New Guinea.
Type: Argent et al. 826, 24 Nov. 1977. Malaysia (Borneo), Sarawak, 4th Div., G. Mulu Nat. Park, G. Mulu W ridge, c.2000m (E, SAR).
Occurs in Countries: MY Subgenus: Vireya Habit: Epiphyte, Non-Tree Fl. Colour: white
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:265
Free-growing shrub, to 1-3 m. Young growth loriform-setose, the setae variably persistent. Leaves narrowly elliptic to narrowly obovate, tapered to the base and to the rather obtuse apex, 70-100 x 28-38 mm, upper surface dark brownish green, glabrous, elepidote, margin loriform-ciliate when young, glabrous later, lower surface light greyish green, papillose, with a lax covering of unequal, golden scales; petioles lepidote and loriform-setose. Inflorescence (l-)2-4-flowered, pedicels sparsely lepidote. Calyx conspicuous, 5-lobed, the lobes oblong, c. 7 mm, conspicuously and evenly loriform-ciliate, the surface sparsely lepidote. Corolla 60 mm, tube 32 mm, white faintly flushed pink, funnel-campanulate, glabrous and elepidote outside. Stamens 10, filaments pubescent towards the base. Ovary lepidote, tapering into the style which is elepidote except for a few scattered scales near the base. Capsule oblong-cylindric, lepidote, 12—16 mm.
Habitat: Cliffs
Distribution: China. (W Yunnan)
Altitude: 2100-2450m
Known only from the type and its re-collection in fruit (Forrest 25772). Very distinctly and easily recognised by the elepidote style and glabrous and eiepidote corolla. Material under cultivation as Forrest 25446 is R. chrysodoron (see p. 135), and has no connection with R. yungchangense.
Type: China, Yunnan, ranges N of Yungchang fu, 7-8000 ft, Forrest 25446 (holo. E)
Occurs in Countries: CN Altitude Ranges: 2,000 - 3,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: pink, white
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):53
Erect shrub, 1(-1 *3) m. Leaves (6-)8-20 x (2-)4-8 mm, elliptic to broadly elliptic or oblong, apex acute or obtuse, clearly or obscurely mucronate, base cuneate, undersurface fawn to ferrugineous, sometimes with slight darker spotting, with ± contiguous scales. Inflorescence 3-4(-6)-flowered, pedicels lepidote, 2-3 mm. Calyx lobes irregular, usually 2-3 mm, deltoid to strap-shaped or irregularly lobed, variably lepidote and ciliate. Corolla deep purplish blue, rose-lavender or rarely white, broadly funnel-shaped, 11—14(—16-5) mm, tube 5-6 mm, pubescent in the throat and rarely so on the outside. Stamens (8-)10, filaments pubescent towards the base. Ovary lepidote, style short (3.5-6 mm) or long (10-15 mm), glabrous. Capsule ovoid, c. 5 mm, lepidote.
Habitat: Open alpine slopes
Distribution: China (N & NW Yunnan, SW Sichuan)
Altitude: 3200-4300m
The Philipsons (1975, p. 27) record the occurrence of a natural hybrid with R. rupicola var. rupicola.
Type: China, SW Szechuan, mountains east of Yungning, 4260 m, Forrest 20463 (holo. E)
Synonymy: R. glomerulatum Hutchinson, Gard. Chron. 91:428 (1932). Type: a cultivated specimen (holo. K).
Occurs in Countries: CN Altitude Ranges: 3,000 - 4,000m: 4,000 - 5,000m Subgenus: Rhododendron Fl. Colour: blue, lavender, purple
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):99
Shrub, (0.3—)1—6 m. Young growth lepidote and sometimes loriform-setose, the setae quickly deciduous. Leaves evergreen, subdeciduous or completely deciduous, narrowly elliptic to elliptic, (30-)35-70 x 12-20 mm, apex acute, base cuneate, usually elepidote above, beneath with flat scales 3-5 x their own diameter apart; petiole and upper surface of midrib usually puberulent; petiole, leaf margin and also the leaf upper surface densely to sparsely loriform-setose, at least when young, the setae variably deciduous. Inflorescence loose, pedicels (8-) 11-18 mm. Calyx minute, disc-like, lepidote, ciliate with loriform and/or filiform-acicular hairs, rarely glabrous. Corolla (21-)25-31 mm, white, pink or lavender, usually densely spotted with red or yellow, ± elepidote outside. Capsule 12-17 mm.
Habitat: Scrub, thickets, and forests, also on forest margins and sometimes on cliffs and in meadows
Distribution: NE Burma, China (N, NW & W Yunnan, SW & NW Sichuan, Guizhou)
Altitude: 2100-3950m
Illustrations:
A variable, widely distributed and common species; the most characteristic variant, with long, narrow, very setose leaves is found along the Burmese-Chinese border, between 25° 30'and 27° N; similar plants, though with somewhat broader, less setose leaves are found scattered over Yunnan, from Tali as far as the Yangtze, and extend into Sichuan near Muli, and also into Guizhou. Both this species and the next are very variable as to leaf persistence; there is no justification for the separation of the deciduous variants of both as R. hormophorum.
Type: China, Yunnan, les bois au dessus de Mow kou Tchang, au dessus de Ta pin tze, a 2000 m, 23 iv 1886, Delavay (holo. P—n.v., iso. E)
Synonymy: R. chartophyllum Franchet, Journ. de Bot. 9:398 (1895). Type: China, Yunnan, sur le mont Hee-chan-men, Delavay 4393 (holo. P—n.v., iso. E). R, chartophyllum forma praecox Diels, Notes R.B.G. Edinb. 5:217 (1912). Type: China, Yunnan, ascent of Sung kwei pass from Lankong valley, 9000 ft, iv 1906, Forrest 2030 (holo. E). R. hormophorum Balfour f. & Forrest, Notes R.B.G. Edinb. 12:117 (1920). Type: China, SW Szechuan, Muli mountains, valley of the Litang, 11000 ft, Forrest 16265 (holo. E). R. aechmophyllum Balfour f. & Forrest, ibid. 13:226 (1926). Type: China, SW Szechuan, Muli mountains, 13-12000 ft, viii 1918, Forrest 16790 (holo. E). R. suberosum Balfour f. & Forrest, op. cit. 301. Type: China, W Yunnan, E flank of the N'Maikha/Salween Divide, 12-13000 ft, Forrest 18000 (holo. E)
Occurs in Countries: CN, MM Altitude Ranges: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: lavender, pink, red, white, yellow
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):67
Shrub (0-6-)2-8(-ll)m. Leaves (38-)44-62(-88) x (16-)20-25(-28) mm, lanceolate to oblong-lanceolate, rarely elliptic, acute to acuminate at the apex,, cuneate-rounded at base, upper surface usually elepidote, midrib usually puberulous; margins with loriform cilia, at least when young; lower surface shining, white-papillose with distant, flat, large, rimless golden scales. Inflorescences 1-4-fIowered, pedicels lepidote, (8-)12-15(-19) mm. Calyx very small, scarcely lobed to undulate, often loriform- and/or filiform-acicular-ciliate. Corolla white, white flushed pink or lavender, (27-)30-40(-44) mm, tube (14-)18-23 mm, sparsely lepidote and usually puberulous, at least at the base of the tube outside, pubescent inside. Capsule lepidote, oblcfhg-cylindric, 10 mm or more.
Habitat: Scrub, thickets and forest margins, 1800-3000(-3500) m
Distribution: N Burma, China (NW, W Si SW Yunnan)
Illustrations:
A distinct species with a rather southerly and low altitude distribution, in many ways (size of leaves and flowers, corolla indumentum) a link with subsection Maddenia. A few specimens collected at Wei hsi (to the north and east of the main distribution area) appear to be intermediate to R, oreotrephes (p. 69) in the possession of opaque scales, smallish flowers and much less conspicuous white leaf undersurface; they may well be natural hybrids.
Type: China, W Yunnan, western flank of the Shweli/Salween Divide, 10-11000 ft, viii 1912, Forrest 8923 (holo. E)
Synonymy: R. erileucum Balfour f. & Forrest, Notes R.B.G. Edinb. 12:108 (1920). Type: China, W Yunnan, Shweli/Salween Divide, 9-10000 ft, v-vi 1918, Forrest 17593 (holo. E)
Occurs in Countries: CN, MM Subgenus: Rhododendron Habit: Non-Tree Fl. Colour: lavender, pink, white
Cullen, J. (1980) A Revision of Rhododendron 1: Subgenus Rhododendron sections Rhododendron & Pogonanthum. Notes from the Royal Botanic Garden Edinburgh 39(1):63
Shrub to 3m or tree to 10m, with a 15cm diameter trunk. Twigs rounded, 3–5mm in diameter, laxly scaly when young, glabrescent below; internodes 3–14cm. Leaves 3–6 in tight pseudowhorls. Blade 70–160 x 40–80mm, broadly elliptic to elliptic, rarely sub-ovate-elliptic or ovate-oblong; apex broadly acute to acute, often deflexed; margin flat, but the sides often curved upwards; base broadly tapering to rounded, the two sides often slightly unequal; glabrescent above at maturity; laxly brown-scaly beneath, remaining punctate when the scales disappear in old leaves. Scales small, marginal zone sub-stellately lobed; centre minute and shallowly impressed. Mid-vein narrowly grooved above in the proximal ½, as wide as the petiole and obtusely prominent for most of its length beneath; lateral veins 6–14 per side, diverging at c.45°, irregular, often running down the mid-vein, curved upwards and anastomosing before the margin, slightly raised above, smooth or distinctly prominent beneath, reticulation lax, mostly distinct, but smooth on both sides. Petiole 10–16 x c.3mm, flattened and shallowly grooved above in the distal ½, scaly initially. Flower buds to 65 x 26mm, narrowly ovoid, imbricate, smooth, acute. Bracts to 40 x 15mm; outer bracts ovate-triangular, inner ones ovate to obovate or spathulate, all appressed, obtuse and covered by minute appressed hairs, amongst which are pale brown scales; margin fringed with small fragile scales. Bracteoles to 30mm, linear-sub-spathulate, shortly hairy. Inflorescence a complete or slightly open umbel of 4–8 flowers. Pedicels 15–40 x 1–1.5mm, laxly to sub-densely stellate-scaly, and sparsely shortly hairy in the distal part, sometimes throughout. Calyx c.5mm in diameter, obliquely disc-shaped, laxly scaly and hairy outside, obtusely 5-lobed. Corolla 60 x 90mm, enlarging with age, funnel-shaped, lobed to almost halfway, usually with a yellow tube and broad orange margins to the lobes so that the flower appears with a yellow ‘star’ in the throat; tube 30–45 x 5–8 x 20–27mm, deeply grooved in the proximal ½, and with 5 distinct, translucent veins which run lengthwise to the lobes, sometimes with some hairs at the base within the furrows, otherwise sparsely and indistinctly scaly outside, laxly hairy in the proximal ½ of the tube inside, tube straight or nearly so; lobes 42 x 30mm, the distal ½ reflexed to perpendicular, broadly obovate-spathulate, overlapping to halfway. Stamens loosely arranged in the lower ½–2⁄3 of the mouth, exserted 10–15mm; filaments linear, densely to laxly covered with spreading hairs in the proximal 1⁄3–½, glabrous and filiform distally; anthers 4–8 x 1.5–2mm, oblong, curved; base obtuse or rarely obscurely apiculate. Disc prominent, densely hairy at least on the upper margin. Ovary 9–12 x c.3mm, sub-cylindrical, white with stiff distally directed hairs which cover scales, tapering distally; style lying on the lower side of the tube at first, rising to a central position later; equalling the stamens, densely to laxly hairy in the lower 2⁄3–¾, glabrous distally, with some scattered scales mostly in the proximal ½; stigma c.2mm in diameter, green, rounded. Fruit 50–90 x 5–8mm, cylindrical, tapering at both ends, slightly curved, densely hairy and scaly. Seeds 8–10mm including the tails at both ends.
Habitat: Epiphytic or terrestrial, often in high forest, terrestrial in lighter mountain forest with Castanopsis. Also in secondary forest and common in anthropogenic grassland which is not burnt too frequently, sometimes hanging from precipices. Growing from sea level to 2000m, often abundant, on poor sandy or clayey soil, but also recorded from limestone areas.
Distribution: Indonesia and Papua New Guinea. Throughout the mainland of New Guinea, Maluku, W Seram in the Ora Mts.
Altitude: 0-2000m
Named after Hugo Zöller, a German journalist, who led the first expedition to the Finisterre Mountains in New Guinea in 1891.
Sleumer noted a form with smaller anthers (3–4mm) apparently limited to SE New Guinea in the Central and Milne Bay Districts. A specimen from Seram which keys to this species also has small anthers only 3mm long; it is smaller in most other flower parts and could be a distinct species.
Van Leeuwen (1926) observed the flowers of R. zoelleri were visited during the daytime by butterflies of the genera Ornithopthera and Papilio.
Flower colour is reported to be variable, usually with yellow at least at the base of the tube but with the upper tube and lobes orange or reddish, and reported (Sleumer 1966) as very rarely white or greenish white and sweet-scented. This he regarded as a hybrid with R. konori var. phaeopeplum. It also forms hybrid swarms with R. macgregoriae in some of the open grassland areas in the Eastern Highlands of Papua New Guinea. Van Royen (1984) reported this species ‘growing on a slope about 3ft (1m) above sea level, regularly sprayed by seawater’, whereas Cruttwell (1971) says that in the Daga country it only grows above 3000ft (900m) and is the second rhododendron to come into the altitudinal zonation after R. christianae. It has been confused with R. baenitzianum which was unsatisfactorily keyed in Sleumer (1966). It differs in having much larger leaves on shorter petioles than R. zoelleri.
Type: Hellwig 339. Finisterre Mts (B†). Neotype: Schlechter 18017, 16 July 1908. Finisterre Mts, c.1000m (P, E, K, L, NY).
Synonymy: R. asparagoides Wernham, Trans. Linn. Soc. London, II, Bot. 1916. 9: 94. R. moszkowskii Schltr., Bot. Jahr. 1918. 55: 161. R. oranum J.J.Sm., Fedde Rep. 1932. 30: 167. R. doctersii J.J.Sm., Nova Guinea 1936. 18: 98, t.21, 1. R. laetum (non J.J.Sm. 1914) J.J.Sm., Nova Guinea 1936. 18: 98.
Occurs in Countries: ID, PG Altitude Ranges: 0 - 1,000m: 1,000 - 2,000m: 2,000 - 3,000m Subgenus: Vireya Habit: Epiphyte, Tree Fl. Colour: orange, yellow
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:322
Much-branched, erect shrub or tree, to 4m. Twigs slender, rounded, densely reddish scaly when young; internodes 2–10cm. Leaves 4–6 together in tight pseudowhorls but commonly with an odd leaf inserted apart from the others. Blade 30–70 x 10–22mm, narrowly ovate to obovate or elliptic or narrowly elliptic; apex shortly acuminate, sub-acute or sometimes obtuse, often apiculate with a small protruding gland; margin flat and entire, or slightly revolute when dry; base broadly to narrowly tapering; initially scaly on both sides, glabrescent above at maturity, the scales leaving small pits; persistently scaly beneath. Scales small, dense to overlapping, pale yellowish-brown, rounded or lobed, marginal zone broad, the centre small and impressed, with occasional much larger scales distributed irregularly. Mid-vein impressed above, prominent beneath, reddish in fresh specimens; lateral veins 5–7 per side, the lower ones steeply ascending, upper ones more spreading, curved, indistinctly anastomosing, faintly impressed above, minutely, but visibly raised beneath. Petiole 2.5–5 x 1–1.5mm, semi-rounded, grooved above, scaly. Bracts to 8 x 4mm, ovate to obovate, obtuse, thin, scaly outside towards the apex, glabrous otherwise. Bracteoles to 6mm, filiform, glabrous. Inflorescence terminal but often with some axillary, a 3–8-flowered open umbel, the flowers horizontal to half-hanging. Pedicels 10–15mm, slender, densely scaly. Calyx c.3mm in diameter, cup-shaped, oblique, irregularly 5-lobed, often with 2 narrowly triangular acute lobes, up to 2mm, the other ones smaller, all densely scaly. Corolla 14–15 x 9mm, tubular, red or orange; tube c.10 x 3–6 x 3–5mm, sub-densely scaly outside, glabrous inside, variable in shape, cylindrical or sometimes contracted distally; lobes c.4 x 4mm, sub-circular, scaly outside except near the margins, erect and overlapping to c.¾. Stamens nearly as long as the corolla tube; filaments linear, glabrous; anthers c.1 x 1mm, broadly obtusely obovate. Disc glabrous. Ovary 3–4 x 2–2.5mm, conical, 5-ribbed, densely brown-scaly, abruptly contracted distally; style 4–5mm, glabrous, with a 5-lobed stigma. Fruit 15–18 x 5–6mm, thick-fusiform or sub-cylindrical, sometimes slightly curved in the upper part, densely scaly, the style persistent. Seeds 2.7–3mm, without tails c.0.8mm, the longest tail c.1mm.
Habitat: Bare open slopes or ridges, exposed summits, volcanic rocks or crater walls, in fern-grass – and scrub-vegetation or open forest, in Casuarina forest, on dry places, on sandy, stony or ashy soil, also near solfataras, common locally
Distribution: Indonesia, C and E Java; Kedu, Besuki, Madiun, Lesser Sunda Is. (Bali, Flores, Lombok), C and SW Sulawesi. Philippines, Luzon, Prov. Benguet: Mt Bandschan, Mountain Province Banaue to Bontoc.
Altitude: 1200-3090m
Named after the collector of this species, Heinrich Zollinger (1818–1859), a Swiss botanist who made extensive collections in Java and other Indonesian islands.
Type: Zollinger 1684, 16 June 1845. Java, Besuki, Hijang (Jang) plateau, Argopuro (BO, lectotype, BM, FI, L, fragment, P).
Synonymy: R. tubiflorum (non Blume) Mor., Syst. Verz. 1846. 42. R. album (non Blume) Zoll., Syst. Verz. 1854. 2: 137. R. malayanum (non Jack) Koord., Junghuhn Gedenkb. 1910. 185.
Occurs in Countries: ID, PH Altitude Ranges: 1,000 - 2,000m: 2,000 - 3,000m: 3,000 - 4,000m Subgenus: Vireya Habit: Tree Fl. Colour: orange, red
Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:131