合萌 he meng

Shrublets or annual herbs, (15-)30-100(-150) cm tall. Stems erect, many branched, cylindric, hollow, glabrous, corky at base, often with nodule-bearing adventitious roots. Stipules elliptic to lanceolate, 4-11 × 1-2 cm, membranous, caducous, base auriculate, apex acuminate. Leaves 20-60-foliolate, often sensitive; petiole 2-4 mm; rachis with tuberculate-based tri­chomes; leaflet blades linear-oblong, 3-13 × 1-3 mm, papery, base oblique, apex obtuse and mucronate. Inflorescences axil­lary, racemose, sometimes short or reduced to a solitary flower; peduncle 4-7 mm, with tuberculate-based trichomes; bracts ovate, caducous, margin often denticulate. Bracteoles ovate-lanceolate, persistent. Calyx 3-4 mm, membranous, glabrous. Corolla pale yellow with purplish longitudinal striations. Leg­ume linear-oblong, 2.2-3.4 cm × 3-5 mm, straight, herbaceous to leathery, abaxial suture straight, slightly indented; articles 2-8, quadrate, slightly muricate and with tuberculate-based tri­chomes. Seeds blackish brown, reniform, ca. 2 mm. Fl. Jul-Sep, fr. Jul-Oct. 2n = 40.

Field margins, ditches, grasslands, trailsides and river margins in sunny places; 100-1300 m. Anhui, Fujian, Guangdong, Guangxi, Gui­zhou, Hainan, Hebei, Henan, Hubei, Hunan, Jiangsu, Jiangxi, S Jilin, Liaoning, Shaanxi, Shandong, Shanxi, Sichuan, Taiwan, Yunnan, Zhe­jiang [Bhutan, India, Japan, Kashmir, Korea, Laos, Malaysia, Myanmar, Nepal, Pakistan, Sri Lanka, Thailand, Vietnam; tropical Africa, SW Asia, Australia, Pacific islands, South America].

This species is used for green fertilizer, medicinal purposes, and as an industrial raw material.