Vines perennial, herbaceous. Branches deeply to sometimes shallowly 4--6-grooved, often 4--6-angulate, glabrous or sometimes sparsely puberulous, nodes swollen. Leaves usually 2-pinnate or 2-ternate, sometimes 1-pinnate or 1-ternate; petiole 2--6(--9) cm, base dilated and connate to opposite petiole, basally often with a few hairs but elsewhere glabrous or sparsely puberulous; leaflet blades narrowly ovate, ovate-lanceolate, ovate, or ovate-elliptic, 2--6.5(--8) × 1.4--3(--4.5) cm, herbaceous to thinly papery, undivided or 3-lobed, abaxially usually glabrous, sometimes sparsely puberulous, adaxially usually sparsely appressed puberulous, base broadly cuneate to rounded, margin serrate, denticulate, or dentate, apex acuminate to long acuminate; basal veins abaxially ± prominent. Cymes axillary or terminal, 1--9-flowered; peduncle (0.3--)1--6 cm; bracts ternate or simple, lanceolate to narrowly ovate, to 4 cm. Flowers 1--2 cm in diam. Pedicel 1.5--3.5 cm, sparsely puberulous or glabrous. Sepals 4, purple red, erect, oblong to ovate-oblong, 1--1.7 × 0.5--0.8 cm, papery, abaxially glabrous except for velutinous margin, adaxially sparsely puberulous only near apex or also near base, apex ± acute and recurved. Stamens 0.9--1.8 cm; filaments basally pubescent, apically densely villous; anthers narrowly oblong, 2--3 mm, glabrous, apex obtuse. Ovaries puberulous. Style 5--6 mm, densely villous. Achenes narrowly elliptic to narrowly rhombic-obovate, ca. 3 × 1.8 mm, puberulous; persistent style 2--3 cm, plumose. Fl. Aug--Oct, fr. Nov.

Slopes, scrub, along streams; 500--2800 m. S Anhui, S Gansu, N Guangdong, N Guangxi, Guizhou, SW Henan, Hubei, Hunan, W Jiangxi, S Shaanxi, Sichuan, Taiwan, Yunnan, Zhejiang [Japan].