Description from Flora of China
Hedysarum heterophyllum Willdenow, Sp. Pl. 3: 1201. 1802.
Herbs, prostrate or ascending, 10-70 cm tall. Young parts spreading pubescent. Leaves 3-foliolate, often intermixed with 1-foliolate leaves on lower part; petiole 0.5-1.5 cm; terminal leaflet blade broadly elliptic or broadly elliptic-obovate, 1-3 × 0.8-1.5 cm, base obtuse, apex rounded or nearly truncate, often emarginate. Flowers solitary or binate in leaf axils or 2 or 3 scattered on rachis. Pedicel 1-2.5 cm. Calyx 5-parted; upper 2 lobes deeply incised near base, villous and minutely hooked hairy. Corolla purple-red to white, ca. 5 mm; standard broadly obovate; wings obovate or narrowly elliptic, shortly auriculate; keel slightly curved, shortly clawed. Stamens diadelphous. Ovary adpressed pubescent. Legume narrowly oblong, straight or curved, 1.2-1.8 cm × ca. 3 mm, lower suture deeply undulate, upper suture straight, 3-5-jointed, flat; articles broadly oblong or quadrate, 3.5-4 mm, glabrescent, reticulate veined. Fl. and fr. Jul-Oct. 2n = 22.
Riversides, roadsides, field margins, grasslands; 200-500 m. Anhui, Fujian, Guangdong, Guangxi, Hainan, Jiangxi, Taiwan, Yunnan [Cambodia, India, Indonesia, Laos, Malaysia, Myanmar, Nepal, Philippines, Sri Lanka, Thailand, Vietnam; Australia, Pacific islands].