29. Desmodium stenophyllum Pampanini, Nuovo Giorn. Bot. Ital., n.s. 17: 15. 1910.
狭叶山蚂蝗 xia ye shan ma huang
Desmodium elegans Candolle subsp. stenophyllum (Pampanini) H. Ohashi; D. tiliifolium (D. Don) Wallich var. stenophyllum (Pampanini) Schindler.
Shrubs, 1-2 m tall, glabrous except for hairy petiolules. Leaves 3-foliolate; petiole 2-5 cm; leaflet blade lanceolate or lanceolate-linear, 6-13 × 1.2-3 cm, base broadly cuneate or nearly rounded, apex acuminate. Racemes terminal or at lower parts 2- or 3-branched in terminal panicles, ca. 20 cm, 1-3-flowered at each node. Pedicel 1-1.2 cm, filiform. Calyx ca. 4 mm, 4-lobed; upper lobes connate, longer than lower ones. Corolla purple or purple-red, 1.2-1.3 cm; standard elliptic or broadly elliptic, base shortly clawed, apex emarginate; wings oblong-falcate, equal to keel, auriculate and clawed. Stamens ca. 1.2 cm. Pistil ca. 1.2 cm. Legume flat, slightly curved, slightly falcate, 4.5-6.5 × ca. 0.5 cm, glabrous, lower suture constricted and crenate between articles, upper suture slightly straight, 6- or 7-jointed; articles ca. 1 cm, slightly reticulate veined. Fl. and fr. Aug-Sep.
● Mountain slopes, thickets, riversides; 2300-2700 m. Yunnan.
One of us (Ohashi, J. Jap. Bot. 70: 115. 1995) recognizes this species as a rheophyte found along streams and supposedly having evolved from Desmodium elegans.