美花山蚂蝗 mei hua shan ma huang

Desmodium elegans Candolle subsp. callianthum (Fran­chet) H. Ohashi; D. elegans var. callianthum (Franchet) P. C. Li.

Shrubs, to 2 m tall, much branched, glabrescent. Leaves 3-foliolate; petiole 1-3 cm, sparsely pubescent or nearly glabrous; leaflet blade ovate-rhombic or ovate, 1.3-4 × 1-3 cm, base broadly cuneate, slightly oblique, apex obtuse-acute, mucro­nate. Racemes terminal or branched in panicles, 15-22 cm, 2-4-flowered at each node, internodes ca. 1 cm. Pedicel filiform, glabrous or nearly so. Calyx ca. 3 mm, 4-lobed; lobes tri­angular. Corolla purple or pink to white, 8-10 mm; standard elliptic, base clawed, apex rounded; wings auriculate, clawed; keel with base auriculate and clawed, apex mucronate. Stamens 7-8 mm. Pistil 8-9 mm. Legume 3-5 × ca. 0.5 cm, flat, slightly curved, nearly glabrous or puberulent, lower suture constricted and crenate, upper suture slightly constricted between articles, 5- or 6-jointed, reticulate veined. Fl. Jun-Aug, fr. Aug-Oct.

● Mountain slopes, roadsides, thickets, forests, ditches, rocky places in river valleys; 1700-3300 m. SW and W Sichuan, SE Xizang, NW Yunnan.

One of us (Ohashi, Bull. Univ. Mus. Univ. Tokyo 2: 291. 1971; J. Jap. Bot. 70: 113. 1995) recognizes this species as a subspecies of Des­modium elegans due to continuous ranges of variation in morphology, including the shape of the floral petals.