Shrubs climbing. Branchlets brownish to purplish black, tomentose-villous, nearly unarmed or with sparse, curved minute prickles. Leaves simple; petiole 3–5 cm, tomentose-villous, with sparse, minute prickles; stipules caducous, narrower, margin deeply laciniate, lobes linear, hairy; blade narrowly ovate, 7–11 × 4–7 cm, lateral veins 6 or 7 pairs, abaxially densely pilose, adaxially less densely so, base cordate, margin undivided or 3–5-lobed, irregularly thinly serrate, apex acute to shortly acuminate. Inflorescences usually terminal, cymose panicles, lax, to 20 cm; rachis and pedicels tomentose-villous; bracts caducous, margin laciniate, lobes lanceolate or linear, hairy. Pedicel 1–2 cm. Flowers ca. 1 cm in diam. Calyx abaxially tomentose-villous; sepals ovate or ovate-triangular, 4–6 mm and nearly as broad, apex acute to shortly acuminate; outer sepals pinnately laciniate, lobes linear to lanceolate, inner sepals usually entire. Petals white, obovate to elliptic, slightly longer than sepals, base slightly pubescent and shortly clawed. Stamens many, slightly shorter than petals; filaments linear, hairy in basal part. Pistils to 50, somewhat shorter than stamens; ovary glabrous. Aggregate fruit small, enclosed in persistent calyx. Fl. Jul–Aug, fr. Sep–Oct.

Montane valleys, slopes, sparse forests; 800--1800 m. Yunnan.