1	Leaves setose.		171 Rhododendron radendum
+	Leaves not setose.		(2)
2 (1)	Calyx lobes 1–2.5 mm.		(3)
+	Calyx lobes 2–7 mm.		(6)
3 (2)	Leaf blade linear, linear-lanceolate or narrowly oblanceolate; corolla tube not hairy outside.		172 Rhododendron trichostomum
+	Leaf blade oblong or elliptic; corolla tube usually densely hairy outside.		(4)
4 (3)	Leaf blade 0.8–2 cm; adaxial surface densely scaly; corolla narrowly tubular.		169 Rhododendron nyingchiense
+	Leaf blade 1–1.2 cm; adaxial surface glabrous; corolla funnelform or salver-shaped.		(5)
5 (4)	Corolla funnelform; calyx lobes 1–2 mm.		170 Rhododendron tubulosum
+	Corolla salver-shaped; calyx lobes 2–2.5 mm.		159 Rhododendron luhuoense
6 (2)	Leaf blade smaller, 7–20 mm (some forms of R. cephalanthum may key out here).		(7)
+	Leaf blade 20–50 mm.		(16)
7 (6)	Adaxial leaf surface usually pale green, scaly; abaxial surface of leaves with pale yellow-brown or brown scales.		(8)
+	Adaxial leaf surface dark green, with deciduous scales; abaxial surface with dark brown or ferruginous scales.		(11)
8 (7)	Corolla rose, 5.5–7.5 mm; stems ca. 1.5 m.		160 Rhododendron bellissimum
+	Corolla white or (rarely) rose, 9–19 mm; stems 0.3–1(–2.5) m.		(9)
9 (8)	Corolla salver-shaped.		159 Rhododendron luhuoense
+	Corolla narrowly tubular or narrowly funnelform.		(10)
10 (9)	Corolla ca. 10 mm, outer surface of tube pilose.		158 Rhododendron mainlingense
+	Corolla 12–19 mm, outer surface of tube glabrous or pilose.		167 Rhododendron primuliflorum
11 (7)	Calyx lobe margins densely scaly, not ciliate; abaxial leaf surface with dark ferruginous scales.		157 Rhododendron atropunicum
+	Calyx lobe margins long-ciliate, not scaly; abaxial leaf surface with dark brown scales.		(12)
12 (11)	Leaf bud scales deciduous; corolla tube glabrous outside.		(13)
+	Leaf bud scales persistent; corolla tube pilose outside.		(14)
13 (12)	Stamens 5; leaf blade 5–9 mm wide, abaxial surface dark chocolate-brown.		156 Rhododendron rufescens
+	Stamens (5–)6–8(–10); leaf blade 10–16(–25) mm wide, abaxial surface dark reddish or yellow-brown.		164 Rhododendron anthopogon
14 (12)	Scales on abaxial leaf surface with lower tiers lighter than the upper tiers.		155 Rhododendron sargentianum
+	Scales on abaxial leaf surface with lower tiers as dark as or darker than the upper tiers.		(15)
15 (14)	Corolla tube densely pilose outside
+	Corolla tube glabrous outside.		163 Rhododendron hypenanthum
16 (6)	Corolla tube usually hairy or scaly outside.		(17)
+	Corolla tube glabrous outside.		(19)
17 (16)	Corolla 8–11 mm; calyx ca. 1/2 as long as corolla tube; leaf blade shorter than 2.8 cm.		166 Rhododendron kongboense
+	Corolla 12–19 mm; calyx ca. 1/3 as long as corolla tube; leaves up to 3.5 cm.		(18)
18 (17)	Calyx lobes scaly outside, margins usually ciliate; corolla narrowly tubular.		167 Rhododendron primuliflorum
+	Calyx lobes not scaly outside, margins fimbriate-lepidote; corolla hypocrateriform.		168 Rhododendron heteroclitum
19 (16)	Leaf apex acute.		173 Rhododendron hoi
+	Leaf blade apex obtuse or rounded, rarely emarginate.		(20)
20 (19)	Leaf bud scales deciduous.		(21)
+	Leaf bud scales persistent.		(22)
21 (20)	Stamens (5–)6–8(–10); inflorescence 5–9-flowered; calyx scaly outside.		164 Rhododendron anthopogon
+	Stamens 5; inflorescence 10–20-flowered; calyx not scaly outside.		165 Rhododendron anthopogonoides
22 (20)	Leaf blade 3–5 cm; leaf bud scales large, broadly ovate, obovate to rounded, leafy.		161 Rhododendron platyphyllum
+	Leaf blade 2–3.5 cm; leaf bud scales small, linear to lanceolate.		(23)
23 (22)	Corolla white, pink to rose; calyx 4–7 mm.		162 Rhododendron cephalanthum
+	Corolla pale yellow to yellow-green; calyx 2–4 mm.		163 Rhododendron hypenanthum