1	Ovary tapering into style.		(2)
+	Ovary apex truncate.		(7)
2 (1)	Abaxial leaf surface glabrous.		427 Rhododendron neriiflorum
+	Abaxial leaf surface with continuous or discontinuous indumentum.		(3)
3 (2)	Abaxial leaf surface with 2-layered indumentum at maturity.		(4)
+	Abaxial leaf surface with 1-layered indumentum at maturity.		(5)
4 (3)	Young shoots, pedicels, petiole and ovary eglandular, densely floccose; upper layer of leaf indumentum lax, lanate.		426 Rhododendron albertsenianum
+	Young shoots, pedicels, petiole and ovary stipitate-glandular and tomentose; upper layer of leaf indumentum spongy.		429 Rhododendron euchroum
5 (3)	Young shoots, pedicels and ovary glandular-setose, tomentose; abaxial leaf surface with continuous white to cinnamon indumentum.		430 Rhododendron sperabile
+	Young shoots and ovary usually eglandular, abaxial leaf surface with discontinuous reddish brown indumentum.		(6)
6 (5)	Leaf blade narrowly elliptic to oblong or elliptic, glaucous, abaxial epidermis papillate; filaments glabrous.		431 Rhododendron floccigerum
+	Leaf blade oblong-elliptic to oblanceolate, 4.5–8.5 cm, abaxial epidermis epapillate; filaments pubescent at base.		432 Rhododendron sperabiloides
7 (1)	Abaxial leaf surface with a continuous, thick, 1- or 2-layered rufous or brown to cinnamon (rarely whitish) indumentum.		(8)
+	Abaxial leaf surface glabrous or with discontinuous or continuous indumentum.		(16)
8 (7)	Adaxial leaf surface markedly rugose.		(9)
+	Adaxial leaf surface smooth.		(11)
9 (8)	Leaf blade elliptic to oblong, abaxial surface with 2-layered appressed tomentose indumentum, upper layer fulvous.		419 Rhododendron piercei
+	Leaf blade broadly obovate to obovate or obovate to elliptic, abaxial surface with 1-layered rufous indumentum.		(10)
10 (9)	Young shoots and petiole densely tomentose; leaf blade 4–7.5 cm wide; shrubs or small trees 3–6(–8) m tall.		417 Rhododendron mallotum
+	Young shoots stellate-setose and glandular-hairy; leaf blade 2–4 cm wide; small, upright shrubs, 2–3 m tall.		418 Rhododendron beanianum
11 (8)	Young shoots densely setulose-glandular; ovary densely stipitate-glandular.		(12)
+	Young shoots eglandular; ovary tomentose, eglandular.		(13)
12 (11)	Leaf blade oblong to ovate; petiole tomentose and setulose-glandular; calyx 6–10 mm.		420 Rhododendron pocophorum
+	Leaf blade obovate; petiole glandular; calyx 3(–7) mm.		421 Rhododendron coelicum
13 (11)	Young shoots glabrous; corolla yellow or orange to red		424 Rhododendron citriniflorum
+	Young shoots setulose or tomentose, with or without sparse setulae; corolla white, pink, crimson or purple.		(14)
14 (13)	Young shoots setulose; corolla white.		422 Rhododendron chionanthum
+	Young shoots tomentose; corolla pink, crimson or purple.		(15)
15 (14)	Calyx 13–20 mm; pedicel pale brown tomentose.		425 Rhododendron catacosmum
+	Calyx 3–7 mm; pedicel ferruginous tomentose.		423 Rhododendron haematodes
16 (7)	Creeping shrubs, 0.2–0.9(–1.5) m; inflorescence 1(or 2)-flowered; leaves obovate to orbicular, 1.3–2.5 × 1.2–1.7 cm.		436 Rhododendron forrestii
+	Upright or creeping shrubs, 0.1–2 m; inflorescence, (1–)2–6-flowered; leaf shape various.		(17)
17 (16)	Shrubs 1–2.5 m, abaxial leaf surface with whitish to cinnamon appressed indumentum.		(18)
+	Shrubs often dwarf, 0.2–2 m tall; abaxial leaf surface glabrous or with a discontinuous indumentum.		(20)
18 (17)	Abaxial leaf surface with buff to cinnamon indumentum; ovary floccose or stipitate-glandular; filaments puberulent at base.		433 Rhododendron microgynum
+	Abaxial leaf surface with whitish to gray appressed thin indumentum; ovary eglandular.		(19)
19 (18)	Filaments pubescent at base; corolla orange to red; leaves narrowly elliptic, oblanceolate or obovate.		434 Rhododendron dichroanthum
+	Filaments glabrous; corolla yellow, pink, or red to deep crimson, sometimes bicolored; leaves obovate, broadly elliptic to narrowly oblong.		435 Rhododendron sanguineum
20 (17)	Branchlets with persistent bud-scales; abaxial leaf surface glabrous.		(21)
+	Branchlets without bud-scales or, if with bud-scales, then abaxial leaf surface puberulent.		(22)
21 (20)	Pedicels 1.3–3 cm, glandular and with dendroid hairs; leaves obovate to oblanceolate; petiole wide, eglandular.		437 Rhododendron aperantum
+	Pedicels 0.8–1.3 cm, glandular or eglandular; leaves obovate to oblong-obovate; petiole narrow, sometimes glandular and tomentose.		438 Rhododendron chamaethomsonii
22 (20)	Corolla pale yellow, white or pink; ovary glabrous or glandular.		(23)
+	Corolla purple, crimson or pale rose; ovary glandular-hairy, often also tomentose.		(24)
23 (22)	Leaf blade 5.2–6.4 cm; pedicel 0.6–2 cm; corolla white, rose, or pale yellow, with conspicuous flecks; ovary glandular.		439 Rhododendron parmulatum
+	Leaf blade 1–3.2 cm; pedicel 2–3 cm; corolla pale yellow, without flecks; ovary glabrous.		440 Rhododendron trilectorum
24 (22)	Leaf blade narrowly lanceolate, 7–10 cm; corolla purple.		428 Rhododendron bijiangense
+	Leaf blade elliptic to oblong-obovate, 1.5–6 cm; corolla pink to crimson.		(25)
25 (24)	Leaf blade oblong or oblong-elliptic, 3–6 × 1.3–2.3 cm, abaxial epidermis pale gray-green, papillate; calyx 3–4 mm.		441 Rhododendron temenium
+	Leaf blade elliptic to oblong-obovate, 1.5–4(–6.2) × 0.5–1.4(–2) cm, abaxial epidermis green, epapillate; calyx ca. 1.5 mm.		(26)
26 (25)	Filaments puberulent at base; creeping shrubs, 0.05–0.5 m tall; leaf blade elliptic to oblong- obovate, abaxial surface puberulent.		442 Rhododendron erastum
+	Filaments glabrous; shrubs 0.3–1.2(–1.8) m tall; leaf blade long-elliptic or oblong-obovate, abaxial surface with discontinuous indumentum.		443 Rhododendron eudoxum