Vicia tridentata Bunge, Enum. Pl. China Bor. 19. 1833, not Gaterau (1789), nor Schweinitz (1824); V. americana Muhl­enberg ex Willdenow var. bungei (Ohwi) Stankevicz; V. ameri­cana var. sinensis C. R. Gunn.

Herbs annual or short-lived perennial, 15-50 cm tall. Stem climbing or trailing, much branched, glabrescent. Leaves pari­pinnate; stipules semihastate, 3-7 mm, margin toothed; leaflets 3-5-paired, linear-oblong, oblong, or narrowly oblong-oblan­ceolate to oblong-obovate, 10-25 × 2-8 mm, abaxially pilose, apex usually emarginate and mucronate, thereby often ap­pearing 3-toothed, sometimes truncate or rounded, rarely distal margin also toothed; tendril branched. Raceme subequaling or longer than leaf, 2-4(or 5)-flowered. Calyx campanulate, pi­lose. Corolla red-purple, blue-purple, or pale violet, sometimes white on keel; standard obovate-lanceolate, longer than wings. Ovary long stalked, sericeous along sutures. Legume oblong, 25-35 mm, glabrous. Seeds 2-8, spheroid. Fl. Apr-Jul, fr. May-Aug. 2n = 24, 26, 42.

Forests, mountain and hill slopes, valleys, grasslands, meadows, banks above lakes, streamsides, steep rocky sides of river gorges, walls, fields and field margins, wastelands, roadsides, sandy and rocky sea­shores; sea level to 4200 m. Anhui, Gansu, Hebei, Henan, Jiangsu, Liaoning, Nei Mongol, Qinghai, Shaanxi, Shandong, Shanxi, Sichuan, Xizang, Yunnan [Korea].