CONFERENCE
Rh. pachytrichum Franch.
Shrub 1-6 m high; branchlets rather densely with long shaggy, curly, branched, brownish hairs, eglandular.
Leaves oblanceolate, oblong, lanceiolate or oblong-lanceolate; lamina 6-13,6 cm long, 2-4 cm broad; upper surface bright green, glabrous; underside pale green, shiny glabrous, midrib rather densely or moderately hairy with long, shaggy, curly, branched browny hairs.
Petiole rather densely hairy with long curly hairs, eglandular.
Inflorescence in trusses of 6-15 flowers.
Pedicel densely hairy.
Corolla campanulate, 2,8-4,2 cm long, white, pale rose, deep purple or red, with or without a deep purple blotch.
W Sichuan. 2,300-3,600 m.
Epithet: With thick hairs.
Rh. parvifolium Adams
sin. Rh. lapponicum ssp. parvifolium (Adams) T. Yamaz.
Rh. pentandrum (Maxim.) Craven
Piecputekšņlapu rododendrs
sin. Menziesia pentandra Maxim.
Rh. periclymenoides (Michx.) Shinners
sin. Rh. nudiflorum (L.) Torr.
Shrub 0,6-3 m high, occasionally stoloniferous; young shoots glabrous or sparsely pubescent, strigose, eglandular.
Leaves deciduous, elliptic, obovate or oblong; lamina chartaceous, 3-9 cm long, 1,3-3 cm broad; upper surface bright green, strigose or not strigose, midrib densely pubescent; margin strigose; underside green, strigose or not strigose, midrib strigose or not strigose..
Inflorescence 6-12 flowers, flowers opening before or with the leaves, fragrant.
Corolla tubular-funnel-shaped, 2,6-3,5 cm long, white, pale pink, pink or pinkish-purple, without blotch, outside pubescent, eglandular.
On the Appalachian Mountains, and extends from Massachusetts to N Carolina, W to Central New York, Pennsylvania, S Ohio, E Kentucky, E. Tennessee, N Georgia, N Alabama. Up to 1,150 m.
Epithet: Like honeysuckle.
Rh. pilosum (Michx.) Craven
sin. Menziesia pilosa (Michx.) Juss.
Rh. ponticum L.
Shrub 1-4,6 m or tree up to 7,6 m high; branchlets glabrous.
Leaves lanceolate, oblong-lanceolate, oblanceolate or oblong; lamina 6,5-21 cm long, 2,1-6 cm broad; upper surface dark green, shiny, glabrous; underside pale green, glabrous.
Petiole glabrous.
Inflorescence a candelabroid umbel; 6-19 flowers.
Calyx 1-2 mm long, glabrous.
Corolla widely funnel-shaped, 3-5 cm long, pinkish-purple, purple, pink, lilac-purple, lavender or mauve, with greenish-yellow spots.
Pontic ranges of North Anatolia, Turkey, Caucasus, Lebanon, SE Bulgaria, Portugal, Spain. Sea-level up to 1,200-1,800 m.
Epithet: From the Pontus, Asia Minor.
Rh. praevernum Hutch.
Agrais rododendrs
Rh. prinophyllum (Small) Millais
sin. Rh. roseum (Lois.) Rehder et E.H.Wilson
Shrub 0,6-4,5 m high, rarely stoloniferous; young shoots rather densely finely pubescent, strigose or not strigose.
Leaves deciduous, elliptic, obovate or oblong-obovate; lamina 3-7 cm long, 1,3-3 cm broad, upper surface bluish-green, villous; margin strigose; underside pale green, rather densely villous, strigose.
Petiole densely pubescent, strigose.
Inflorescence 5-9 flowers, flowers opening with the leaves, clove-scented.
Pedicel villous, glandular.
Corolla tubular-funnel-shaped, 2,8-3,5 cm long, pink or purplish-pink, rarely white, with or without brown-red blotch, flowers opening with the leaves, clove-scented; glandular.
Stamens about twice as long as the corolla-tube.
Extends from SW Quebec, through Massachusetts, Pennsylvania, SE Missouri and Tennessee to Virginia.
Epithet: With leaves like prinos.
Rh. prunifolium (Small) Millais
Plūmjlapu rododendrs
Rh. pumilum Hook.f.
Rh. purdomii Rehder et E.H. Wilson
Rh. quinquefolium Bisset et S.Moore
Shrub or small tree, 1,2-7,6 m high; branchlets glabrous, eglandular.
Leaves deciduous, in pseudowhorls of 4 or 5 at the end of the branchlets, broadly obovate, oval or broadly elliptic; lamina 3-5 cm long, 1,8-3 cm broad, upper surface pale green, often with a red-purple margin, glabrous; midrib pubescent; margin ciliate; underside pubescent towards the base or glabrous.
Petiole pubescent.
Inflorescence 1-3 flowers, flowers produced with the leaves from the same terminal bud.
Corolla rotate-campanulate, 2,3-2,8 cm long, 3-4,3 cm across, pure white with green spots.
Honshu and Shikoku (Japan). 700-1,500 m.
Epithet: Leaves in fives.
Rh. racemosum Franch.
Shrub 0,15-4,6 m high; branchlets glabrous or minutely puberulous, scaly.
Leaves elliptic, oblong-elliptic, obovate, oval, oblong or oblong-lanceolate; lamina 1-5,4 cm long, 0,4-2,6 cm broad; upper surface glabrous, scaly or not scaly; underside glaucous, scaly, scales 0,5-2 times their own diameter apart.
Inflorescence axillary in the uppermost few leaves, flowers usually in several clusters forming a raceme along the branchlet, 1-4 flowers.
Calyx minute, 0,5 mm long.
Corolla widely funnel-shaped, 0,8-2,3 cm long, white, pink, deep rose or reddish-pink, outside scaly.
Mid-W and NW Yunnan, SW Sichuan. 1,850-4,250 m.
Epithet: Flowers in racemes.
Rh. reticulatum D. Don ex G.Don
sin. Rh. rhombicum Miq.
Shrub or tree, 1-3 m high; young shoots densely adpressed-pilose, later glabrous, eglandular.
Leaves deciduous in whorls 2 or 3 at the end of the branchlets, broadly ovate or ovate or rhombic; lamina generally 3-7 cm long, 2-5 cm broad; upper surface dark green, later glabrous or almost glabrous; underside somewhat reticulate, pubescent or nearly glabrous.
Petiole pilose.
Inflorescence 1-2 rarely 3-4 flowers, flowers opening before the leaves.
Calyx minute, 0,5-1 mm long, pilose.
Corolla rotate-funnel-shaped, 2-2,8 cm long, 3,5-5 cm across, purple, rose-purple or reddish-purple, unspotted or with dark purple blotaches.
Stamens 10.
Honshu, Kyushu, Shikoku in Japan. 300-1,000 m.
Epithet: Netted, referring to the venation.
Rh. rex H. Lev.
Rh. rubiginosum Franch.
Shrub or tree 0,6-9 m high; branchlets scaly.
Leaves ovate-lanceolate, elliptic-lanceolate, lanceolate or oblong-lanceolate, not aromatic; lamina 3-9 cm long, 1,3-4,2 cm broad; upper surface pale green or dark green, somewhat matt, scaly or not scaly; underside densely scaly, scales rust-coloured or brown, overlapping or contiguous, with or without widely scattered larger darker scales.
Inflorescence 4-8 flowers.
Corolla tubular-funnel-shaped, or funnel-shaped 1,6-3,1 cm long, pink, pale rose, pinkish-purple, lavender-purple or white, with crimson spots, outside scaly.
W and NW Yunnan, SE Tibet, SW Sichuan. 2,450-4,250 m.
Epithet: Reddish-brown.
Rh. russatum Balf. f. et Forrest
Shrub 0,35-1,5 m high; branchlets densely scaly.
Leaves oblong-elliptic, oblong-oval, oval, oblong or oblong-lanceolate; lamina 0,8-6,5 cm long, 0,4-2,3 cm broad; upper surface dark or pale green, densely scaly, scales nearly contiguous or overlapping; underside densely scaly, the scales large, dark brown and yellow, or unicolorous, cinnamon-red, dark brown or brown, overlapping or one-half their own diameter apart.
Inflorescence 3-10 or rarely 14 flowers.
Calyx 3-6 mm long.
Corolla widely funnel-shaped, 1,3-2 cm long, white, deep purple-blue, rose-purple, deep violet-purple, light purple or violet, outside not scaly.
NW and mid-W Yunnan, NE Upper Burma, SW Sichuan. 3,350-4,300 m.
Epithet: Reddened.
Rh. saluenense ssp. chameunum (Balf. f. et Forrest) Cullen
sin. Rh. prostratum W.W.Smith
Small shrub 5-60 cm high; branchlets densely scaly, moderately or densely bristly.
Leaves oblong-oval, oval, elliptic or obovate; lamina 0,5-2 cm long, 0,4-1,1 cm broad; upper surface dark green, shiny, not scaly or sometimes scaly; underside densely scaly, scales overlapping crenulate.
Petiole bristly.
Inflorescence 1-6 flowers.
Pedicels bristly.
Corolla widely funnel-shaped, 1,7-2,9 cm long, deep purplish-rose or purple-crimson, with crimson spots.
W and NW Yunnan, NE Upper Burma, SW Sichuan, SE Tibet. 3,350-4,575 m.
Epithet: Lying on the ground.
Rh. sanguineum var. haemaleum (Balf. f. & Forrest) D.F.Chamb
Rh. schlippenbachii Maxim.
Shrub 1-5 m high; young shoots glandular with long-stalked glands, later eglandular.
Leaves deciduous in pseudowhorls of 5 at the end of the branchlets, obovate; lamina 5-8,8 cm long, 3-6,8 cm broad, upper surface dark green, glabrous; underside pale green, glabrous, midrib pubescent.
Petiole flattened, glandular, glands long-stalked.
Inflorescence 3-6 flowers, flowers opening with or immediately before the leaves.
Pedicel rather densely glandular.
Corolla broadly rotate-funnel-shaped, 3-4 cm long, 5,6-8 cm across, pale to rose-pink or white, spotted red-brown.
Korea and the Korean archipelago, bordering parts of Russia and Japan. 400-1,800 m.
Epithet: After Baron A. von Schlippenbach, Russian naval officer and traveller.
Rh. searsiae Rehd. et E.H.Wilson
Shrub 1,5-5 m high; branchlets scaly.
Leaves lanceolate, oblong-lanceolate or oblanceolate; lamina 2,5-8 cm long, 1-2,6 cm broad, apex acuminate, acutely acuminate or acute; upper surface dark green or pale green, scaly; underside bluish-glaucous, densely scaly, scales yellowish or pale brown, one-half their own diameter apart, with larger dark brown scattered scales.
Inflorescence 3-8 flowers.
Corolla widely funnel-shaped, 2-3,4 cm long, white or pale rose-purple, with light green spots, not scaly outside.
W Sichuan. 2,300-3,000 m.
Epithet: After Sarah C. Sears, American artist.
Rh. selense ssp. jucundum (Balf.f. et W.W.Sm) D.F.Chamb.
sin. Rh. jucundum Balf.f. & W.W.Sm.
Shrub 60 cm-3 m high or tree up to 6,10 m high; branchlets not glandular, not setulose-glandular or sometimes setulose-glandular, often warty.
Leaves elliptic, oblong or oblong-elliptic; lamina 3,8-7,4 cm long, 2-4 cm broad; upper surface dark green, glabrous; underside markedly glaucous, glabrous or minutely hairy.
Petiole not glandular, not setulose-glandular.
Inflorescence 5-8 flowers.
Pedicel glandular.
Calyx 1-6 mm long, margin glandular.
Corolla funnel-campanulate, 3-4 cm long, pale rose, rose, pink or white suffused with rose, with or without crimson blotch.
Ovary densely glandular.
W Yunnan. 3,000-3,700 m.
Epithet: Pleasant.
Rh. sichotense Pojark.
Rh. smirnowii Trautvetter
Shrub or tree, 0,5-6 m high; branchlets rather densely woolly with whitish of fawn wool, glandular.
Leaves oblong-obovate or oblanceolate; lamina 6,5-16 cm long, 1,8-4,2 cm broad; upper surface olive-green or dark green, shiny, glabrous (in young leaves, densely whitish woolly); underside covered with a thick, woolly, fawn or brown, continuous bistrate indumentum of hairs.
Petiole densely whitish or fawn woolly, glandular.
Inflorescence a cendelabroid umbel of 6-12 flowers.
Pedicel floccose, glandular.
Corolla funnel-campanulate, 3,1-4,8 cm long, pink, deep pink, rose-red or rose-purple, with or without spots.
NE Turkey, Caucasus, Georgia, Russia. 800-2,800 m.
Epithet: After M. Smirnow, a friend of its discoverer, Baron Ungern-Sternberg.
Rh. sutchuenense Franch.
Shrub or tree 2-6 m high, branchlets with a thin, white tomentum, eglandular.
Leaves oblong-obovate, oblanceolate or oblong-oval; lamina 9-28 cm long, 3-7,5 cm broad; upper surface dark green or pale green, matt, glabrous; underside pale green, glabrous, midrib moderately or densely woolly or hairy in its entire length.
Petiole flat above, margins with very narrow wings or ridges.
Inflorescence in trusses of 8-20 flowers.
Pedicel stout, 1-3,6 cm long.
Calyx eglandular.
Corolla widely campanulate, 5-7,5 cm long, white suffused with pink, rose-pink or deep rose, with crimson spots, without a blotch at the base.
Stamens 13-17 or rarely 22.
W Hubei, E Sichuan. 1,400-2,500 m.
Epithet: From Sichuan.
Rh. tomentosum Harmaja
sin. Ledum palustre L.
Dwarf shrub of thin habit, 0,3-1,2 m high; branchlets rusty tomentose, glandular.
Leaves 1-5 cm long, 0,2-0,8 cm wide, linear, margin strongly revolute; upper surface matt dark green; underside with a bistrate indumentum, upper layer thick woolly, ferrugineous, lower layer of short setulose hairs and/or reddish glands, always scaly.
Inflorescence many flowers.
Calyx minute.
Corolla 1,2 cm across white, rotate.
Stamens 7-10.
Ovary glandular.
Style glabrous.
N & Central Europe, Russia (to S Siberia). 0-2,000 m.
Epithet: Tomentose.
Rh. traillianum Forrest et W.W.Sm.
Shrub or tree, 1-9 m high; branchlets with a thin tomentum.
Leaves oblong, oblong-obovate or oblong-lanceolate; lamina 5,2-17 cm long, 2-6,8 cm broad; upper surface pale green or dark green, glabrous; underside covered with a thin, continuous, powdery or sometimes suede-like, brown, rust or sometimes cinnamon-coloured, or yellowish, unistrate indumentum of radiate hairs with somewhat pear-shaped arms (pyriform).
Petiole with a thin tomentum.
Inflorescence in trusses of 9-15 flowers.
Corolla funnel-campanulate, 2,6-4 cm long, white, white suffused with rose, pink or rose.
NW, W and mid-W Yunnan, SW Sichuan, SE Tibet. 3,000-4,600 m.
Epithet: After G.W. Traill (1836-1897), botanist and father-in-law of George Forrest.
Rh. tschonoskii Maxim.
Rh. ungernii Trautv. ex Regel
Shrub or tree 1-6 m high; branchlets with whitish tomentum, glandular.
Leaves oblong-obovate, oblanceolate or oblong-oblanceolate; lamina 9-25,5 cm long, 2,8-7,5 cm broad; upper surface dark green, glabrous; underside covered wth a thick, woolly, whitish or fawn, continuous, bistrate indumentum of hairs.
Inflorescence a candelabroid unmel of 12-30 flowers.
Pedicel moderately or rather densely glandular.
Calyx outside glandular.
Corolla campanulate, 3-4,5 cm long, pale rose, pink or white, with or without pale green spots, outside of tube pubescent, glandular.
Ovary densely glandular.
NE Turkey, Georgia, Russia. 850-2,000 m.
Epithet: After Baron F. von Ungern-Sternberg (1800-1868), Professor at Dorpat.
Rh. vaseyi A. Gray
Shrub 1,5-4,6 m high; young shoots at first sparsely pilose, afterwards glabrous or glabrescent.
Leaves deciduous, scattered, elliptic, elliptic-lanceolate or oblong-lanceolate; lamina 5-12,5 cm long, 1,3-4,3 cm broad, apex acuminate; upper surface dark green, glabrous; margin strigose; underside light green, not setulose except midrib setulose.
Inflorescence 4-8 flowers, flowers opening before the leaves.
Pedicel glandular.
Corolla rotate-campanulate, 2,5-3 cm long, 3,5-3,8 cm across, 2-lipped, upper lip of 3 lobes, lower lip of 2 lobes, light rose or pale pink, with orange or reddish-brown spots.
Stamens 7.
N and S Carolina. 900-1,830 m.
Epithet: After G.R. Vasey (1822-1893), who discovered it in N Carolina in 1878.
Rh. vaseyi A. Gray (tumšāk rozā)
Rh. vernicosum Franch.
Shrub or tree 1-7,6 m high; branchlets glabrous.
Leaves oblong-elliptic, elliptic, oblong-oval or oval; lamina 4-13,5 cm long, 2-5,6 cm broad; upper surface olive-green or dark green, matt, wax-covered becoming glossy when rubbed or heated, glabrous; underside pale glaucous green, glabrous.
Inflorescence in trusses of 5-10 flowers.
Pedicel moderately or rather densely glandular.
Calyx densely glandular.
Corolla widely funnel-campanulate, 3,8-5,4 cm long, white, deep or pale rose, rose-lavender or purplish-red, with or without crimson spots; lobes 7.
Stamens 12-14.
Style glandular throughout to the tip with dark red or crimson glands.
W and SW Sichuan, NW and mid-W Yunnan, SE Tibet. 2,750-4,500 m.
Epithet: Varnished.
Rh. viscosum (L.) Torr.
Shrub 1-4,5 m high, stoloniferous; young shoots setulose or strigose, eglandular.
Leaves deciduous, obovate, oblong-obovate or oblanceolate; lamina 1,5-7,3 cm long, 0,5-3,5 cm broad; upper surface dark green, usually glabrous; margin strigose; underside pale green or glaucescent, usually glabrous except midrib strigose.
Petiole setulose or strigose.
Inflorescence 3-9 flowers, flowers opening after the leaves are developed, spicy fragrance.
Pedicel setulose-glandular.
Calyx setulose-glandular or setulose.
Corolla slender, narrowly tubular-funnel-shaped, 3-4,5 cm long, white or sometimes white suffused with pink, tube setulose-glandular outside, lobes glandular along the middle.
Maine, Massachusetts, Connecticut to N Carolina, south eastern S Carolina, west to Ohio, SE Tennessee, Louisiana.
Epithet: Sticky.
Rh. wardii var. puralbum (Balf. f. et W.W.Sm.) D.F. Chamb.
sin. Rh. puralbum Balf. f. et W.W. Sm.
Shrub 1,5-4,6 m high; branchlets sparsely glandular or eglandular.
Leaves ovate, ovate-oblong or oblong; lamina 5-12 cm long, 2,4-5 cm broad; upper surface dark green, glabrous; underside pale glaucous green, glabrous.
Inflorescence 5-8-flowered.
Pedicel glandular.
Corolla bowl- or saucer-shaped, 2-4 cm long, pure white or rarely ivory-white.
Ovary densely glandular; style glandular throughout to the tip.
NW Yunnan, SE Tibet. 3,400-4,300 m.
Epithet: Pure white.
Rh. wightii Hook.f.
Shrub or small tree 2-6 m; branchlets greenish-brown to brown; leaf and flower buds sticky.
Leaves 5-10 cm long, 5-7 cm broad, broadly elliptic to obovate; upper surface dark green and glabrous, underside with a compacted pale fawn to brown indumentum of radiate hairs.
Inflorescence 12-20 flowers.
Corolla campanulate, 3-4 cm long, white, cream or pale yellow.
Ovary with a dense red-brown tomentum.
Bhutan, Arunachal Pradesh, S Tibet. 3,400-4,500 m.
Epithet: After R. Wight (1796-1872), a former superintendent, Madras Botanic Gardens.
Rh. williamsianum Rehd. et Wils.
Compact, rounded od dome-shaped or spreading shrub, 0,6-1,5 m or rerely up to 2,4 m high or more; branchlets slender, setulose-glandular.
Leaves ovate or orbicular; lamina 1,5-4,2 cm long, 1,3-4 cm broad, base cordate or truncate; upper surface bright green (in young leaves, bronzy), glabrous; underside glaucous, papillate, glabrous or punctulate with vestiges of hairs.
Petiole often setulose-glandular.
Inflorescence in trusses of 2-3 (rarely up to 5) flowers.
Pedicel glandular.
Corolla campanulate, 3-4 cm long, rose or pink, with or without spots.
Style glandular throughout to the top.
W Sichuan. 2,800 m.
Epithet: After J.C. Williams (1861-1939) of Caerhays, Cornwall.
Rh. degronianum ssp. yakushimanum Hara
sin. Rh. yakushimanum Nakai
Very compact or lax shrub, 0,3-2,5 m high; branchlets densely or moderately whitish woolly.
Leaves lanceolate, oblanceolate or oblong-obovate; lamina 5-10 cm long, 3-8 cm broad; upper surface dark green, markedly convex or flat, glabrous (in young leaves, densely whitish woolly), margin recurved or flat; underside covered with a thick, woolly, fawn, continuous, bistrate indumentum of hairs.
Petiole densely whitish woolly.
Inflorescence a candelabroid umbel of 8-12 flowers.
Corolla campanulate, 3,2-3,6 cm long, flower-buds rich pink, rose, finally corolla pure white or very pale pink.
Yakushima Island, Japan. 500-2,000 m.
Epithet: From Yakushima Island, Japan.
Rh. yedoense f. poukhanense (H. Lev.) Sugim. Ex T.Yamaz
Shrub 0,6-1,8 m high, sometimes low or prostrate; shoots densely brown or grey-strigose, eglandular.
Leaves dimorphic, deciduous or semi-deciduous; spring leaves chartaceous, oblanceolate, lanceolate, oblong-lanceolate or ovate-lanceolate; lamina 2,8-7,8 cm long, 0,5-2 cm broad; upper surface dark green, grey or brown strigose, margin strigose, underside paler, grey or brown-strigose; summer leaves thicker, oblanceolate or lanceolate, smaller, 0,4-1 cm long; upper surface soon glabrescent, otherwise same as spring leaves.
Petiole densely brown-strigose.
Inflorescence 2-4 flowers, flowers expanding with or shortly before the leaves.
Pedicel brown-strigose.
Calyx outside brown-strigose.
Corolla widely funnel-shaped, large, 3,2-4,2 cm long, 3,2-5 cm across, rose, rosy-purple or pale lilac-purple, with purple-brown spots, fragrant.
Korea, and Tsushima (Japan). Sea-level up to 1,800 m.
Epithet: From Mt Poukhan-san, Korea.