1	Leaf blade thickly papery to subleathery, margin of larger leaves with 0–19(–31 in C. fabri) teeth per side; plants evergreen (C. fabri apparently deciduous in SE portion of range).		(2)
+	Leaf blade papery, margin of larger leaves with 22–60 or more teeth per side; plants deciduous.		(4)
2 (1)	Rachis of racemes and pedicels strigose with simple hairs; racemes 1 per branchlet; filaments hirsute; anthers 2.1–2.8 mm; style 5–7 mm at anthesis.		1 Clethra bodinieri
+	Rachis of racemes and pedicels stellate-hirsute; racemes (1 or)2–7 per branchlet; filaments glabrous; anthers 1.0–1.8 mm; style 1.5–5 mm at anthesis.		(3)
3 (2)	Leaf blade abaxially often pubescent along midvein and in axils of secondary veins, otherwise glabrous; sepals suborbicular to ovate, 2.5–3 × 1.5–1.8 mm, midvein abaxially indistinct at anthesis; stamens slightly exserted or ± equal in length to petals.		2 Clethra fabri
+	Leaf blade abaxially densely grayish white appressed stellate-tomentose throughout; sepals ovate-deltoid, 1.5–2.5 × 0.8–1.2 mm, midvein usually abaxially distinct or sepals keeled at anthesis; stamens included.		3 Clethra petelotii
4 (1)	Racemes 1(–4) per branchlet; petal margins neither thickened nor apically distinctly fimbriate; persistent style 7–11 mm; petals (4–)5–12 mm.		4 Clethra delavayi
+	Racemes (1–)3–8(–11) per branchlet; petal margins thickened and apically fimbriate; persistent style 3–6 mm; petals 3–5 mm.		(5)
5 (4)	Racemes stellate-hirsute or stellate-subvillous; thickest rachis on each branchlet basally 1.6–2.8 mm in diam.		5 Clethra kaipoensis
+	Racemes stellate-tomentose but sometimes sparsely so; thickest rachis on each branchlet basally 0.8–1.7(–1.8) mm in diam.		(6)
6 (5)	Leaf blade secondary veins (8–)11–14 on each side of midvein; sepals ovate, outside surface (visible through pubescence) usually medially blackened, midvein usually indistinct at anthesis, apex obtuse; filaments glabrous or occasionally sparsely pilose; ovary and capsule apically hirsute with longer hairs 0.7–1.1 mm.		6 Clethra barbinervis
+	Leaf blade secondary veins (11–)15–21 on each side of midvein; sepals ovate-deltoid to rarely ovate, outside surface (when visible) not medially blackened, midvein usually distinct at anthesis, apex acuminate-mucronate to rarely obtuse-mucronate; filaments basally pilose or occasionally glabrous; ovary and capsule apically hirsutulous with longer hairs 0.2–0.7 mm.		7 Clethra fargesii