All Floras      Advanced Search
FOC Vol. 14 Page 275 Login | eFloras Home | Help
FOC | Family List | FOC Vol. 14 | Ericaceae

5. Rhododendron subsect. Triflora (Hutchinson) Sleumer, Bot. Jahrb. Syst. 74: 536. 1949.

三花杜鹃亚组 san hua du juan ya zu

Fang Ruizheng (方瑞征 Fang Rhui-cheng); David F. Chamberlain

Rhododendron ser. Triflora Hutchinson in J. B. Stevenson, Sp. Rhodod. 758. 1930 ["Triflorum"].

Shrubs, rarely small trees, usually evergreen, rarely deciduous or semievergreen, 0.6–10 m tall; young shoots scaly or glandular-scaly or sometimes glabrous, rarely pubescent, or hispid. Leaf blade leathery, less often papery; abaxial surface scales dense, yellow to brown, large, unequal or all similar, often without hairs, sometimes pubescent along midrib; adaxial surface sparsely or densely scaly, scales unequal, often absent by maturity, hairs usually absent, rarely pubescent along midrib. Inflorescence terminal or subterminal, umbellate or shortly racemose, (1–)2–5(–10)-flowered; rachis 0.5–8 mm. Calyx undeveloped, 0.5–5 mm; corolla broadly funnelform-campanulate, lobed to middle, red to purple, white or yellow, rarely pale green or blue, sometimes with darker spots, with or without scales on outer surface, rarely hairy; stamens 10, unequal; ovary 5-locular, usually densely scaly, rarely also pubescent; style often longer than corolla, usually glabrous, rarely pubescent at base, not scaly. Capsule cylindric, 6–20 mm. Seed wingless.

Twenty-five species: Bhutan, China, India, Japan, Myanmar, Nepal, Sikkim; 24 species (20 endemic) in China.

1 Leaf blade ± hairy on both sides, or at least midrib pubescent or hispid abaxially and pubescent adaxially.   (2)
+ Leaf blade glabrous on both surfaces, or at most pubescent along midrib adaxially.   (7)
2 (1) Corolla pale yellow; abaxial leaf surface with scales 3–5 × their own diameter apart.   44 Rhododendron shimianense
+ Corolla white, pale green, purple or rosy red; abaxial leaf surface densely or sparsely scaly.   (3)
3 (2) Young shoots, petiole, leaf adaxial surface, corolla tube, and ovary hispid.   45 Rhododendron trichanthum
+ Young shoots, petiole, leaf adaxial surface, corolla tube, and ovary pubescent or glabrous, not hispid.   (4)
4 (3) Corolla 1.5–2 cm.   (5)
+ Corolla 2.5–3.5 cm.   (6)
5 (4) Leaf obovate or elliptic; apex obtuse or rounded; corolla rosy red; leaf abaxial surface densely scaly, scales at most 1 × their own diameter apart; pedicel 7–10 mm.   46 Rhododendron bivelatum
+ Leaf ovate; apex apiculate; corolla white; leaf abaxial surface sparsely scaly, scales 1–3 × their own diameter apart; pedicel 3–6 mm.   47 Rhododendron guangnanense
6 (4) Leaf blade 3–7 cm; corolla purple, red, or white.   48 Rhododendron augustinii
+ Leaf blade 7–10 cm; corolla pale green.   49 Rhododendron brachypodum
7 (1) Corolla yellow, creamy yellow or pale green.   (8)
+ Corolla white, pale red or purple, never yellow.   (11)
8 (7) Leaf blade papery, abaxial surface sparsely scaly, scales 0.5–6 × their own diameter apart; leaf apex acuminate or caudate; corolla densely pubescent outside.   50 Rhododendron lutescens
+ Leaf blade leathery, abaxial surface densely scaly, scales ± contiguous to their own diameter apart; leaf apex acute, acuminate or obtuse; corolla glabrous or pubescent outside.   (9)
9 (8) Corolla outer surface not scaly, 1.6–2.2 cm.   51 Rhododendron wongii
+ Corolla outer surface scaly, 2–3.5 cm.   (10)
10 (9) Corolla with yellowish green markings inside; scales on abaxial leaf surface dimorphic, the larger deep brown, the smaller yellowish brown; leaf midrib adaxially hairy.   52 Rhododendron ambiguum
+ Corolla with brown spots inside; scales on abaxial leaf surface uniform; leaf midrib adaxially glabrous.   53 Rhododendron triflorum
11 (7) Scales on abaxial leaf surface scattered, (1–)2–4(–8) × their own diameter apart.   (12)
+ Scales on abaxial leaf surface dense, ± contiguous to 1 × their own diameter apart.   (15)
12 (11) Mature leaves with abaxial surface pinkish white, scales 0.5–4 × their own diameter apart; corolla white to lavender pink, densely glandular-scaly outside, sometimes pubescent on tube.   54 Rhododendron zaleucum
+ Mature leaves with abaxial surface pale green or pale brown; corolla pale red, pale purple or white, sparsely scaly or not outside, without hairs.   (13)
13 (12) Leaf blade V-shaped in cross section; scales on abaxial surface contiguous to 4 × their own diameter apart; adaxial surface and petioles glabrous.   55 Rhododendron davidsonianum
+ Leaf blade flat; scales on abaxial surface 2–8 × their own diameter apart; adaxial surface and petioles sometimes hairy.   (14)
14 (13) Evergreen; young shoots, leaf adaxially along midrib, leaf margin and petioles glabrous or pubescent; corolla pale purple in bud.   56 Rhododendron rigidum
+ Evergreen or semievergreen; young shoots, leaf adaxial surface, leaf margin and petioles glabrous or pubescent or sparsely hispid; corolla white in bud (see also 58. R. pleistanthum)   57 Rhododendron yunnanense
15 (11) Leaves 1.6–2.6 × 0.5–1.2 cm; corolla 1.3–1.6 cm, not scaly outside.   59 Rhododendron gemmiferum
+ Leaves 2–11 × 1–3.5 cm; corolla 1.5–4 cm, scaly or not outside.   (16)
16 (15) Calyx lobes irregular, to 4–6 mm.   (17)
+ Calyx often undeveloped, rimlike or undulate, lobes 0.5–2 mm.   (18)
17 (16) Leaf blade base cuneate, rarely rounded, abaxial surface with scattered large scales; calyx with long hairs; corolla white or pale reddish purple, inside with deep green spots.   60 Rhododendron searsiae
+ Leaf blade base rounded, rarely broadly cuneate, abaxial surface scales all similar; calyx scaly along margin; corolla pale or deep purplish red, inside with or without brownish red spots.   61 Rhododendron concinnum
18 (16) Leaf blade base rounded or broadly cuneate.   (19)
+ Leaf base narrower, cuneate to rounded.   (21)
19 (18) Petiole hispid; corolla purple or deep red, 3–4 cm.   62 Rhododendron amesiae
+ Petiole glabrous; corolla pale yellow, pale red or rosy red, 1.2–3 cm.   (20)
20 (19) Leaf blade apex rounded, scales on abaxial surface flat, veins inconspicuous on both sides; corolla not scaly outside.   63 Rhododendron oreotrephes
+ Leaf blade apex obtuse to acute, apiculate; scales on abaxial surface concave, veins conspicuous on both sides; corolla scaly outside.   64 Rhododendron tatsienense
21 (18) Leaf blade elliptic, 2.5–5 × 0.8–1.8 cm; corolla 1.5–1.8 cm.   65 Rhododendron xichangense
+ Leaf blade elliptic, elliptic-lanceolate or oblong-lanceolate, 3–11 × 1.2–3.5 cm; corolla 1.6–3.5 cm.   (22)
22 (21) Leaf blade oblong or oblong-lanceolate; abaxial leaf surface with scales thin, gray-brown, contiguous or overlapping, to 0.5 × their own diameter apart.   66 Rhododendron polylepis
+ Leaf blade elliptic or elliptic-lanceolate; abaxial leaf surface with scales rusty brown, 0.5–1(–2) × their own diameter apart.   67 Rhododendron siderophyllum

  • List of lower taxa


  • Flora of China @
    Browse by
    Advanced Search

    Flora of China Home




     |  eFlora Home |  People Search  |  Help  |  ActKey  |  Hu Cards  |  Glossary  |