Woody climbers, deciduous or subevergreen. Stems grayish brown, verruculose, laxly lenticellate. Petiole 7--11 cm; lateral petiolules 6--12 mm; terminal petiolule 2--4 cm; leaflets 3 (--5), ovate, ovate-oblong, or broadly ovate, 3--8 × 1.5--6 cm, papery, subleathery, or leathery, abaxially pale green, adaxially dark green, base truncate, rounded, cordate, or cuneate, margin sinuate, shallowly lobed, subentire, or entire, apex obtuse to narrowly rounded and slightly emarginate, cuspidate. Racemes axillary on short branches, 6--16 cm; peduncle slender, 3--5 cm. Male flowers: 15--30. Pedicel filiform, 2--5 mm. Sepals 3 or 4, pale purple to purple, broadly elliptic, elliptic, or oblong. Stamens 6; filaments very short; anthers incurved at anthesis. Pistillodes 3, oblong-subulate. Female flowers: pedicel 1.5--3 cm, slightly thicker than in male flower. Sepals 3, purplish brown, dark purple, or purplish black, suborbicular, sublinear, or narrowly oblong. Carpels 4--9, straight, 4--6 mm. Fruit oblong, straight or slightly curved. Seeds ovoid, 5--7 × 4--5 mm. Fl. Apr--May, fr. Jun--Sep.

The roots, stems, and fruits are used medicinally.

Semideciduous forest margins, open forest along valleys, scrub on hillsides, by streams; 200--2100 m. Anhui, Fujian, SE Gansu, Guangdong, Guizhou, Henan, Hubei, Hunan, Jiangsu, Jiangxi, S Shaanxi, Shandong, S Shanxi, Sichuan, Taiwan, Yunnan, Zhejiang [Japan].