1 |
Young branches and petioles generally setose or with stipitate to setose glands. |
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(2) |
+ |
Young branches glabrous, rarely pilose or with glands, without bristles, never setose. |
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(11) |
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2 (1) |
Corolla 7-lobed; stamens 14–16. |
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2 Rhododendron subsect. Auriculata |
+ |
Corolla 5–6-lobed; stamens 10–14. |
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(3) |
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3 (2) |
Corolla tube densely hairy outside. |
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18 Rhododendron subsect. Griersoniana |
+ |
Corolla tube glabrous outside. |
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(4) |
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4 (3) |
Corolla campanulate or funnelform, yellow or white to red or purplish red, without basal nectar
pouches. |
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(5) |
+ |
Corolla tubular, often deep red, with nectar pouches at base. |
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(7) |
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5 (4) |
Leaf apex acute; abaxial surface stipitate-glandular, lanate or strigose. |
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9 Rhododendron subsect. Glischra |
+ |
Leaf apex rounded; abaxial surface glabrous. |
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(6) |
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6 (5) |
Corolla broadly campanulate, style with glands throughout. |
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5 Rhododendron subsect. Williamsiana |
+ |
Corolla funnelform, narrow; style glabrous. |
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8 Rhododendron subsect. Selensia |
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7 (4) |
Peduncle to 4 cm; style glandular or stellate-hairy. |
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19 Rhododendron subsect. Parishia |
+ |
Peduncle to 1 cm; style glabrous or glandular only at base. |
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(8) |
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8 (7) |
Inflorescence 2–8(–12)-flowered; leaf apex acute or rounded. |
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21 Rhododendron subsect. Neriiflora |
+ |
Inflorescence usually 7–20-flowered; leaf apex cuspidate. |
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(9) |
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9 (8) |
Leaves lanceolate to elliptic; capsule curved. |
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10 Rhododendron subsect. Irrorata |
+ |
Leaves ovate to elliptic; capsule straight. |
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(10) |
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10 (9) |
Leaf apex cuspidate. |
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7 Rhododendron subsect. Maculifera |
+ |
Leaf apex acute to rounded at apex. |
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20 Rhododendron subsect. Barbata |
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11 (1) |
Corolla campanulate or tubular-campanulate, with well-marked nectar pouches, 5-lobed; stamens 10. |
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(12) |
+ |
Corolla (5–)6–10-lobed, with or without nectar pouches; stamens (10–)12–18. |
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(17) |
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12 (11) |
Corolla white or yellow to pinkish red. |
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(13) |
+ |
Corolla deep red. |
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(14) |
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13 (12) |
Leaves elliptic to obovate, abaxial surface with persistent soft or stiff hairs along central
veins. |
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7 Rhododendron subsect. Maculifera |
+ |
Leaves elliptic to lanceolate, abaxial surface glabrous or with simple hairs |
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10 Rhododendron subsect. Irrorata |
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14 (12) |
Corolla fleshy, without spots; ovary densely hairy. |
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(15) |
+ |
Corolla thin or fleshy, with or without spots; ovary often glabrous. |
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(16) |
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15 (14) |
Small shrubs, rarely creeping; inflorescence often 1–12-flowered. |
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21 Rhododendron subsect. Neriiflora |
+ |
Small trees; inflorescence dense, often 20–25-flowered. |
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13 Rhododendron subsect. Arborea |
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16 (14) |
Leaf blade orbicular to elliptic, abaxial surface glabrous or hairy; calyx 2–15 mm. |
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23 Rhododendron subsect. Thomsonia |
+ |
Leaf blade elliptic, abaxial surface densely pilose or lanate; calyx 0.5–1 mm. |
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22 Rhododendron subsect. Fulgensia |
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17 (11) |
Corolla (5–)7–8(–10)-lobed; leaves large, elliptic. |
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(18) |
+ |
Corolla 5-lobed; leaves small, ovate-elliptic or lanceolate. |
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(23) |
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18 (17) |
Abaxial surface of leaves conspicuously hairy when mature. |
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(19) |
+ |
Abaxial surface of mature leaves glabrous or with a thin agglutinated indumentum. |
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(21) |
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19 (18) |
Abaxial surface of leaves generally with 2 layers of hairs, outer layer cupular. |
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4 Rhododendron subsect. Falconera |
+ |
Abaxial surface of leaves with 1 or 2 layers of hairs, hairs never cupular. |
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(20) |
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20 (19) |
Ovary pilose, rarely glandular, or if glabrous then with abaxial surface of leaves viscid-hairy. |
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3 Rhododendron subsect. Grandia |
+ |
Ovary glabrous, rarely glandular or pilose, abaxial surface of leaves often pannose. |
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14 Rhododendron subsect. Taliensia |
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21 (18) |
Leaves (9–)20–70 cm; ovary densely tomentose, rarely glandular or glabrous. |
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3 Rhododendron subsect. Grandia |
+ |
Leaves less than 20 cm; ovary glabrous or glandular. |
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(22) |
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22 (21) |
Corolla broadly campanulate, without basal nectar pouches; ovary glabrous or glandular. |
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1 Rhododendron subsect. Fortunea |
+ |
Corolla campanulate or tubular-campanulate, with basal nectar pouches; ovary glandular, with or without a thin indumentum. |
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10 Rhododendron subsect. Irrorata |
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23 (17) |
Abaxial leaf surface glabrous; peduncle 5–60 mm. |
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(24) |
+ |
Abaxial leaf surface hairy (rarely glabrous in subsect. Taliensia). |
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(26) |
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24 (23) |
Leaves ovate to orbicular; peduncle 2–5 mm. |
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6 Rhododendron subsect. Campylocarpa |
+ |
Leaves lanceolate to elliptic; peduncle 5–25(–60) mm. |
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(25) |
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25 (24) |
Peduncles 10–25 mm; corolla campanulate to funnelform. |
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11 Rhododendron subsect. Pontica |
+ |
Peduncles 5–10 mm; corolla broadly campanulate. |
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10 Rhododendron subsect. Irrorata |
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26 (23) |
Leaf blade ovate to obovate, sometimes narrow; corolla funnelform or campanulate, generally
with deeply colored spots. |
|
(27) |
+ |
Leaf blade ovate to obovate or orbicular; corolla campanulate, broadly campanulate, rarely
funnelform, with or without deeply colored spots. |
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(29) |
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27 (26) |
Peduncle short; pedicels short; flowers densely arranged; calyx 0.5–1.5 mm. |
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14 Rhododendron subsect. Taliensia |
+ |
Peduncle long; pedicels slender, long; flowers loosely arranged; calyx 1–3(–5) mm. |
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(28) |
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28 (27) |
Abaxial surface of leaves with silvery white, pale yellow or yellowish-brown hairs; capsule cylindric, straight. |
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12 Rhododendron subsect. Argyrophylla |
+ |
Abaxial surface of leaves with gray-white to rufous-brown hairs; capsule slender, curved. |
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15 Rhododendron subsect. Fulva |
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29 (26) |
Ovary glabrous; peduncles 10–25 mm; leaves ovate to broadly elliptic. |
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17 Rhododendron subsect. Campanulata |
+ |
Ovary densely hairy; peduncles 2–20 mm. |
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(30) |
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30 (29) |
Ovary densely pilose to stipitate-glandular; peduncle 10–20 mm. |
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7 Rhododendron subsect. Maculifera |
+ |
Ovary pilose to thinly glandular; peduncle 3–10 mm. |
|
(31) |
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31 (30) |
Abaxial leaf surface with one layer of hairs; ovary densely pilose or tomentose and glandular; young shoots always tomentose; calyx 1–2 mm. |
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16 Rhododendron subsect. Lanata |
+ |
Abaxial leaf surface with one or two layers of thin to dense hairs; ovary thinly or densely
pilose and glandular; if young shoots tomentose then calyx often more than 2 mm. |
|
14 Rhododendron subsect. Taliensia |