| 1 |
Calyx (3–)5–15 mm. |
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(2) |
| + |
Calyx 0.5–3 mm. |
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(20) |
| |
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|
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| 2 (1) |
Abaxial leaf surface with discontinuous indumentum. |
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(3) |
| + |
Abaxial leaf surface with continuous indumentum. |
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(7) |
| |
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|
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| 3 (2) |
Abaxial leaf surface indumentum loose, woolly, patchy, ± deciduous. |
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(4) |
| + |
Abaxial leaf surface indumentum scattered or only along midrib. |
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(5) |
| |
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|
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| 4 (3) |
Leaf blade 3–6 × 1–2 cm, indumentum red-brown; corolla yellow; style glandular to apex. |
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343 Rhododendron codonanthum |
| + |
Leaf blade 7–10 × 2–4 cm, indumentum pale brown; corolla pink; style glandular in lower 3/4. |
|
344 Rhododendron x detonsum |
| |
|
|
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| 5 (3) |
Leaf blade with abaxial surface loosely woolly-tomentose along midrib only; petioles tomentose and
glandular. |
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340 Rhododendron pubicostatum |
| + |
Leaf blade with abaxial surface sparsely and minutely pubescent. |
|
(6) |
| |
|
|
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| 6 (5) |
Leaf blade 7–9 cm, without punctate glands; petioles glabrous; calyx ca. 5 mm. |
|
341 Rhododendron montiganum |
| + |
Leaf blade 4.5–6.5 cm, punctate; petioles glabrous; calyx 4–6 mm. |
|
342 Rhododendron punctifolium |
| |
|
|
|
| 7 (2) |
Indumentum 2-layered, upper layer usually thick, composed of branched hairs, lower layer thin and
appressed. |
|
(8) |
| + |
Leaf indumentum 1-layered, thin or ± dense and thick. |
|
(11) |
| |
|
|
|
| 8 (7) |
Petiole glabrous; pedicel 2–2.5 cm. |
|
355 Rhododendron x sinosimulans |
| + |
Petiole pubescent, tomentose or floccose, sometimes glabrescent; pedicel 1–2 cm. |
|
(9) |
| |
|
|
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| 9 (8) |
Leaf blade oblong, 4–7 × 1.5–2.5 cm; inflorescence bud-scales ± persistent during flowering; pedicel 1–1.5 cm. |
|
393 Rhododendron x bathyphyllum |
| + |
Leaf blade elliptic to oblong-ovate, 6–17 × 2.5–7 cm; inflorescence bud-scales not persistent; pedicel 1.5–2 cm. |
|
(10) |
| |
|
|
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| 10 (9) |
Young shoots and petiole densely pubescent; calyx 8–12 mm; petiole 1.5–2.5 cm. |
|
354 Rhododendron faberi |
| + |
Young shoots and petiole sparsely floccose, often glabrescent; calyx 3–6 mm; petiole 1–1.5 cm. |
|
356 Rhododendron mimetes |
| |
|
|
|
| 11 (7) |
Leaf indumentum thin. |
|
(12) |
| + |
Leaf indumentum ± dense and thick. |
|
(14) |
| |
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|
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| 12 (11) |
Ovary glandular, style glandular in lower part; leaf blade 5–8 × 2.5–3.5 cm, indumentum pale brown to cinnamon, ± agglutinated; corolla pale pink to pink. |
|
345 Rhododendron balfourianum |
| + |
Ovary hairy, style glabrous, eglandular; leaf blade various; corolla white or pink. |
|
(13) |
| |
|
|
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| 13 (12) |
Leaf blade 8.5–10 × 3.6–4.7 cm, indumentum pale yellow, not agglutinated; corolla pink, 3. 5 cm. |
|
346 Rhododendron pomense |
| + |
Leaf blade 7.5–9.5 × 3.2–4.5 cm, indumentum tawny, ± agglutinated; corolla white, 3–3.5 cm. |
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347 Rhododendron trichogynum |
| |
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| 14 (11) |
Leaf indumentum spongy, cinnamon to tawny; leaf blade 6–12 × 2–4 cm; ovary densely stipitate glandular, style glandular in lower part. |
|
348 Rhododendron adenogynum |
| + |
Indumentum felted or woolly. |
|
(15) |
| |
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|
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| 15 (14) |
Indumentum felted, tawny to fawn, sparsely glandular on midrib. |
|
(16) |
| + |
Leaf indumentum woolly, rust-red or red-brown, eglandular. |
|
(17) |
| |
|
|
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| 16 (15) |
Leaf blade 6.5–7.5 × 3–4 cm; corolla campanulate; ovary glandular, style glabrous. |
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349 Rhododendron dumicola |
| + |
Leaf blade 7–10 × 2.5–3.5 cm; corolla funnel-campanulate, pale red; ovary sparsely pubescent
and glandular, style glandular at base. |
|
350 Rhododendron zhongdianense |
| |
|
|
|
| 17 (15) |
Shoots and petioles densely hairy and glandular. |
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351 Rhododendron bureavii |
| + |
Shoots and petioles densely tomentose, eglandular. |
|
(18) |
| |
|
|
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| 18 (17) |
Leaf blade 8.5–13 × 3.5–5.5 cm; ovary densely villous, style villous, and with few dendroid
branched hairs in lower half. |
|
353 Rhododendron pugeense |
| + |
Leaf blade 3–9 × 1–3 cm; ovary and style with glandular hairs. |
|
(19) |
| |
|
|
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| 19 (18) |
Petiole 3–4 mm; inflorescence 4–8-flowered. |
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362 Rhododendron detersile |
| + |
Petiole 10–15 mm; inflorescence 10–20-flowered. |
|
352 Rhododendron elegantulum |
| |
|
|
|
| 20 (1) |
Abaxial leaf surface glabrous or with discontinuous indumentum. |
|
(21) |
| + |
Abaxial leaf surface with continuous indumentum. |
|
(25) |
| |
|
|
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| 21 (20) |
Leaf indumentum absent; corolla pink; ovary sparsely pubescent. |
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361 Rhododendron purdomii |
| + |
Leaf indumentum discontinuous, scattered; ovary tomentose and sometimes glandular. |
|
(22) |
| |
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|
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| 22 (21) |
Ovary tomentose and glandular; leaf blade abaxial surface with glands; corolla rose or pale yellow,
with fine spots and crimson basal blotch. |
|
360 Rhododendron dignabile |
| + |
Ovary tomentose but not glandular; leaf blade not glandular; corolla white or creamy white. |
|
(23) |
| |
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|
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| 23 (22) |
Abaxial leaf surface densely hairy only on lower half of midrib. |
|
359 Rhododendron potaninii |
| + |
Abaxial leaf surface sparsely fawn tomentose, hairs ± peeling off. |
|
(24) |
| |
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|
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| 24 (23) |
Pedicel tawny tomentose; apex obtuse, ± beaked; corolla obliquely-campanulate, white, ca. 4 cm. |
|
357 Rhododendron x paradoxum |
| + |
Pedicel whitish tomentose; apex acute; corolla funnel-campanulate, creamy white, ca. 2.5 cm. |
|
358 Rhododendron x inopinum |
| |
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| 25 (20) |
Adaxial leaf surface bullate. |
|
(26) |
| + |
Adaxial leaf surface smooth, not bullate. |
|
(27) |
| |
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| 26 (25) |
Leaf blade obovate-oblong to lanceolate; abaxial surface with 1-layered indumentum; corolla white to
pink, 3–4 cm. |
|
363 Rhododendron wiltonii |
| + |
Leaf blade oblanceolate; abaxial surface with 2-layered indumentum, upper-layer thick, ± peeling
off; corolla pink to pale purple, 4–4.5 cm. |
|
364 Rhododendron coeloneurum |
| |
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| 27 (25) |
Abaxial leaf surface indumentum thick, spongy or woolly, with pellicle. |
|
(28) |
| + |
Abaxial leaf surface without pellicle. |
|
(30) |
| |
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|
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| 28 (27) |
Corolla broadly-campanulate, 6(–7)-lobed; stamens 12(–14); abaxial leaf surface gray-white to pale cinnamon, woolly. |
|
368 Rhododendron clementinae |
| + |
Corolla funnel-campanulate, 5-lobed; stamens 10; indumentum spongy; abaxial leaf surface white
to yellowish or silvery-white to gray-yellow. |
|
(29) |
| |
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| 29 (28) |
Petiole 8–15 mm, glabrous or with a few glands; abaxial leaf surface with 1-layered indumentum;
capsule straight. |
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365 Rhododendron aganniphum |
| + |
Petiole 15–20 mm, white-floccose; abaxial leaf surface with 2-layered indumentum; capsule curved. |
|
366 Rhododendron vellereum |
| |
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|
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| 30 (27) |
Indumentum thin, 1-layered, agglutinated or not. |
|
(31) |
| + |
Indumentum thick, loose or dense, 1- or 2-layered, woolly or felted. |
|
(41) |
| |
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| 31 (30) |
Corolla yellow. |
|
(32) |
| + |
Corolla white to pink. |
|
(36) |
| |
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| 32 (31) |
Ovary glabrous; leaf blade abaxial surface densely pale brown radiate-tomentose, base cordate; corolla pale yellow with purple spots. |
|
373 Rhododendron barkamense |
| + |
Ovary tomentose or glandular-hairy. |
|
(33) |
| |
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|
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| 33 (32) |
Ovary densely red short glandular-hairy; corolla bright yellow, with crimson spots; calyx 2–4 mm. |
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343 Rhododendron codonanthum |
| + |
Ovary white- or brown-tomentose; corolla paler yellow, often without markings; calyx to 1.5 mm. |
|
(34) |
| |
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| 34 (33) |
Leaf indumentum composed of radiate hairs, leaf blade abaxial surface with dense cinnamon to fawn tomentum, base broadly cuneate; corolla spotted. |
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376 Rhododendron wightii |
| + |
Leaf indumentum composed of branched hairs, leaf blade broadly-elliptic, base auriculate-cordate or slightly cordate; corolla unspotted. |
|
(35) |
| |
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| 35 (34) |
Leaf blade abaxial surface densely yellowish green to pale brown tomentose, base auriculate-cordate; corolla pale yellow. |
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374 Rhododendron heizhugouense |
| + |
Leaf blade abaxial surface densely fawn to gray-tawny tomentose; base rounded, slightly cordate; corolla pure yellow. |
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375 Rhododendron lacteum |
| |
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| 36 (31) |
Indumentum not agglutinated, compacted. |
|
(37) |
| + |
Indumentum ± agglutinated. |
|
(38) |
| |
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|
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| 37 (36) |
Leaf blade oblanceolate, 10–25 × 3–7 cm, abaxial surface fawn to cinnamon, with compacted indumentum, not powdery; corolla broadly campanulate, with few or no spots; ovary tomentose. |
|
377 Rhododendron beesianum |
| + |
Leaf blade oblong-lanceolate, 6.5–10 × 2.5–3.5 cm, abaxial surface pale brown to tawny with powdery indumentum; corolla funnel-campanulate, spotted; ovary glabrous or sometimes sparsely floccose. |
|
378 Rhododendron traillianum |
| |
|
|
|
| 38 (36) |
Petiole 2–2.5 cm; ovary with glandular hairs. |
|
372 Rhododendron lulangense |
| + |
Petiole 0.6–1.5 cm; ovary without glandular hairs, usually glabrous. |
|
(39) |
| |
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|
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| 39 (38) |
Petiole flattened, 6–8 × ca. 5 mm; pedicel 2–2.5 cm; base of leaf blade cuneate, abaxial indumentum white. |
|
371 Rhododendron torquescens |
| + |
Petiole 10–15 mm; pedicel 1–1.5 cm; base of leaf blade rounded or sub-cordate. |
|
(40) |
| |
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| 40 (39) |
Young shoots and petioles white-floccose, glabrescent; abaxial leaf surface usually with
long-rayed stellate hairs (with branched hairs in subsp. yushuense), indumentum sometimes deciduous. |
|
369 Rhododendron przewalskii |
| + |
Young shoots and petioles glabrous; abaxial leaf surface with branched hairs, indumentum persistent. |
|
370 Rhododendron phaeochrysum |
| |
|
|
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| 41 (30) |
Abaxial leaf surface with 1-layered indumentum. |
|
(42) |
| + |
Abaxial leaf surface with 2-layered indumentum. |
|
(45) |
| |
|
|
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| 42 (41) |
Ovary hairy or glabrous. |
|
(43) |
| + |
Ovary hairy and glandular. |
|
(44) |
| |
|
|
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| 43 (42) |
Shoots, petioles and ovaries hairy; leaf blade ovate-lanceolate, 2.5–4 cm wide, abaxial surface red-brown to rust-brown; corolla white to pink or yellow. |
|
379 Rhododendron wasonii |
| + |
Shoots, petioles and ovaries glabrous; leaf blade elliptic, 4–6.5 cm wide; abaxial surface yellow initially, later deep brown; corolla pale purple. |
|
380 Rhododendron shanii |
| |
|
|
|
| 44 (42) |
Shoots and petioles densely branched-hairy, eglandular; leaf blade oblong-elliptic, 9–12 cm;
abaxial surface with dense, thick indumentum; corolla white. |
|
381 Rhododendron danbaense |
| + |
Shoots and petioles densely tomentose and glandular; leaf blade lanceolate, 12–17 cm; abaxial surface with loose woolly indumentum; corolla initially deep pink, later yellowish pink. |
|
382 Rhododendron nigroglandulosum |
| |
|
|
|
| 45 (41) |
Dwarf shrubs; bud-scales persistent, leaves usually narrower; margin conspicuously revolute. |
|
(46) |
| + |
Erect shrubs, bud-scales deciduous (except in R. balangense and R. dachengense); leaves larger;
margin flattened or inconspicuously revolute. |
|
(50) |
| |
|
|
|
| 46 (45) |
Leaf blade oblanceolate or narrowly-oblanceolate, at least 3–4 × as long as broad. |
|
(47) |
| + |
Leaf blade oblong, oblong-elliptic, oblanceolate or narrowly-elliptic, rarely as much as 3 × as long as broad. |
|
(48) |
| |
|
|
|
| 47 (46) |
Leaf blade 6–10 cm; pedicels tomentose and glandular; corolla white tinged pink, 3–4 cm, style glabrous. |
|
389 Rhododendron roxieanum |
| + |
Leaf blade 5.5–7.5 cm; pedicels tomentose, eglandular; corolla deep pink, 2.5–3.5 cm, style glandular in lower half. |
|
390 Rhododendron roxieoides |
| |
|
|
|
| 48 (46) |
Plants procumbent, 0.1–0.5 m tall; ovary and filaments glabrous. |
|
392 Rhododendron pronum |
| + |
Plants erect, 0.6–1.5 m tall; ovary and filaments hairy. |
|
(49) |
| |
|
|
|
| 49 (48) |
Leaf blade 0.5–1 cm wide; pedicel ca. 1 cm; corolla white to pale yellow, ca. 3 cm. |
|
394 Rhododendron proteoides |
| + |
Leaf blade 1–1.5 cm wide; pedicel ca. 2 cm; corolla deep rose, ca. 3.5 cm. |
|
395 Rhododendron comisteum |
| |
|
|
|
| 50 (45) |
Ovary hairy or glandular. |
|
(51) |
| + |
Ovary glabrous. |
|
(54) |
| |
|
|
|
| 51 (50) |
Inflorescence 4–7-flowered; pedicel 0.5–1 cm, densely velutinous; leaf bud-scales persistent. |
|
391 Rhododendron dachengense |
| + |
Inflorescence 6–15-flowered; pedicel 1–2 cm, floccose; leaf bud-scales deciduous. |
|
(52) |
| |
|
|
|
| 52 (51) |
Abaxial leaf surface with long-rayed stellate hairs; calyx glabrous except for sparsely ciliate margin. |
|
386 Rhododendron nakotiltum |
| + |
Abaxial leaf surface with branched hairs; calyx floccose or sparsely ciliate with glandular-
ciliate margin. |
|
(53) |
| |
|
|
|
| 53 (52) |
Inflorescence 6–11-flowered, rachis ca. 5 mm; corolla 2–3 cm. |
|
387 Rhododendron rufum |
| + |
Inflorescence 10–15-flowered, rachis 10–18 mm; corolla 3.5–4 cm. |
|
388 Rhododendron alutaceum |
| |
|
|
|
| 54 (50) |
Shoots and petioles glabrous. |
|
(55) |
| + |
Shoots and petioles hairy. |
|
(56) |
| |
|
|
|
| 55 (54) |
Leaf blade obovate, 6–10 × 2. 5–5 cm, upper-layer of indumentum loose, whitish to pale yellow; corolla white; bud-scales persistent. |
|
383 Rhododendron balangense |
| + |
Leaf blade oblong-ovate, 7.5–15 × 4–6.5 cm, upper-layer of indumentum dense, rust-red to cinnamon; corolla 2.5–3 cm, white to pink; bud-scales deciduous. |
|
384 Rhododendron sphaeroblastum |
| |
|
|
|
| 56 (54) |
Leaf blade oblong-ovate; corolla 3–3.5 cm, creamy white or yellow to pale pink. |
|
385 Rhododendron taliense |
| + |
Leaf blade oblong-elliptic; corolla white to pink. |
|
367 Rhododendron principis |
