6. Desmodium scorpiurus (Swartz) Desvaux, J. Bot. Agric. 1: 122. 1813.
蝎尾山蚂蝗 xie wei shan ma huang
Hedysarum scorpiurus Swartz, Prodr. 107. 1788; Desmodium akoense Hayata.
Herbs, perennial. Stems ascending or diffuse, hooked hairy. Leaves 3-foliolate; petiole 1.5-3 cm, minutely hooked hairy; terminal leaflet blade ovate or broadly elliptic to obovate, 1-4 × 0.7-2.5 cm, lateral ones slightly smaller, both surfaces adpressed hairy, lateral veins 4 or 5, base obtuse, apex obtuse-rounded or emarginate. Racemes terminal or axillary; rachis slender, minutely hooked hairy, laxly flowered, 1- or 2-flowered at each node. Pedicel 3-7 mm, with hooked hairs, sometimes intermixed with straight hairs. Calyx campanulate, ca. 2.5 mm; upper lobes slightly 2-toothed. Corolla pink, ca. 4 mm; standard obovate; wings oblong, clawed; keel obliquely obovate, long clawed. Ovary linear, ca. 3.5 mm; style curved. Legume linear, slender, 2-5 × ca. 0.25 cm, 3-8-jointed, constricted between articles; articles 4-6 mm, 3-4 × as long as wide, hooked hairy. Fl. and fr. Aug-Oct. 2n = 22*.
Open dry places; low and middle elevations (sea level to 500 m). Introduced and naturalized in S Taiwan [introduced in Australia, New Guinea, Pacific islands, and Philippines; native to tropical America].