Vines perennial, herbaceous. Stems shallowly longitudinally 5-grooved, sparsely pubescent, often glabrescent; nodes swollen. Leaves 1- or 2-ternate, or pinnate; petiole 3--7 cm, base ± dilated; leaflet blades elliptic, narrowly ovate, or ovate, 3--6.5 × 1.4--2 cm, papery, undivided or sometimes 3-lobed, both surfaces sparsely pubescent on veins, abaxially ± reticulate, base broadly cuneate, rounded, or truncate, margin entire, apex acuminate to acute; basal veins abaxially prominent. Cyme axillary, 1-flowered; peduncle 2.5--7 cm; bracts shortly petiolate, ovate to broadly ovate, 3.4--6.2 cm, margin entire. Flowers 5--9.5 cm in diam. Pedicel 3.4--6.8 cm, densely puberulous. Sepals 6, white or tinged purplish, long elliptic to elliptic, 2.7--5 × 1--2.3 cm, abaxially sparsely pubescent along central vein and velutinous along lateral veins, adaxially glabrous, margin glabrous, apex acute. Stamens 0.8--1.7 cm, glabrous; anthers linear, 4.5--6 mm, apex minutely apiculate or ± obtuse. Ovaries pubescent. Style ca. 4 mm, densely yellowish villous. Achenes obovate, 3.5--4.5 × 2--4 mm, sparsely pubescent; persistent style 1.2--3 cm, yellow plumose. Fl. May--Jun, fr. Jun--Jul.

* Forests, slopes, along streams; 200--500 m. Anhui, SE Henan, E Hubei, E Hunan, S Jiangsu, N Zhejiang.