2. Hylodesmum leptopus (A. Gray ex Bentham) H. Ohashi & R. R. Mill, Edinburgh J. Bot. 57: 179. 2000.
细长柄山蚂蝗 xi chang bing shan ma huang
Desmodium leptopus A. Gray ex Bentham in Miquel, Pl. Jungh. 226. 1852; D. gardneri Bentham; D. laxum Candolle subsp. leptopus (A. Gray ex Bentham) H. Ohashi; D. tashiroi Matsumura; Hylodesmum laxum (Candolle) H. Ohashi & R. R. Mill var. leptopus Y. C. Yang & P. H. Huang; Podocarpium leptopus (A. Gray ex Bentham) Y. C. Yang & P. H. Huang.
Subshrubs, 30-70 cm tall. Young stems pubescent. Leaves caespitose or scattered, 3-foliolate; petiole 5-10 cm, glabrous or sparsely pubescent; leaflet blade ovate to ovate-lanceolate, 10-15 × 3.5-6 cm, abaxially sparsely pubescent, adaxially glabrous except with minute hooked hairs on midvein, base cuneate, orbicular, or oblique, apex long acuminate. Racemes terminal or laxly branched panicles, laxly flowered. Pedicel 3-4 mm, elongated to 1.1-1.3 cm at fruiting, densely hooked pubescent. Calyx 2-3 mm. Corolla pink, ca. 5 mm; standard broadly elliptic, shortly clawed; wings and keel clawed. Ovary long stipitate. Legume flat, slightly curved, minutely hooked pubescent, 2- or 3-jointed; articles obliquely triangular, 1.2-1.4 cm × 4-6 mm; stipe 1-1.2 cm; fruiting pedicel 1.1-1.3 cm. Fl. and fr. Aug-Sep.
Dense valley forests, shaded places along streams; 700-1000 m. Fujian, Guangdong, Guangxi, Hainan, ?Hubei, Hunan, Jiangxi, Sichuan, Taiwan, Yunnan, ?Zhejiang [Indonesia, Japan, Laos, Malaysia, New Guinea, Philippines, Thailand, Vietnam].
At first glance, this species is very similar to Hylodesmum laxum; but, upon detailed examination, they differ in the abaxial leaflet surface, the shape and size of the articles, and the length of the fruiting pedicel and stipe.