Vines woody. Branches shallowly 5-or 6-grooved, appressed puberulous. Leaves usually (1 or)2-pinnate; petiole 3--5 cm; leaflet blades ovate to broadly ovate, 1.5--6 × 0.8--5.5 cm, thin papery, both surfaces sparsely appressed puberulous, base broadly cuneate, rounded, or subcordate, margin serrate, apex acute to acuminate; basal veins flat. Cymes arising from axils of leaves on current year’s branches, 1--3(or 4)-flowered; peduncle 5.5--15 cm; bracts ternate or simple, 3-lobed. Flowers 3--7 cm in diam. Pedicel 3--9.8 cm, appressed puberulous. Sepals 5 or 6(or 7), white, cuneate-obovate to narrowly obovate, 1.8--3.8 × 0.8--2.4 cm, abaxially densely appressed puberulous, adaxially glabrous, apex rounded and apiculate. Stamens 0.7--1.8 cm, glabrous; anthers narrowly oblong, 2--3 mm, apex obtuse. Ovaries pubescent. Style 7--11 mm, densely villous. Achenes obovate to elliptic, 3--4.5 × 2--2.8 mm, glabrous; persistent style 2.5--3.2 cm, plumose. Fl. Jun--Aug, fr. Aug--Oct.