山豆根 shan dou gen

Euchresta trifoliata Merrill.

Climbing shrubs, nearly not branched. Stems often with adventitious roots. Leaves 3-foliolate; petiole 4-5.5 cm, ap­pressed pubescent, adaxially with a conspicuous groove; ter­minal petiolule 0.5-1.3 cm, lateral petiolule nearly absent; leaflets abaxially pale green, adaxially dark green, elliptic, 8-9.5 × 3-5 cm, thickly papery, abaxially appressed pubescent, adaxially glabrous, corrugated when dried, lateral veins very inconspicuous, base broadly cuneate, apex acuminate to obtuse. Racemes 6-10.5 cm; peduncle 3-5.5 cm; pedicel 0.5-0.7 cm, both surfaces appressed pubescent; bract fine, subulate. Calyx cup-shaped, 3-5 × 4-6 mm, outside and inside appressed pu­bescent; lobes bluntly triangular. Corolla white; standard ellip­tic-oblong, ca. 1 cm × 2-3 mm, abaxially sparsely appressed pubescent at base, apex rounded, stalk linear, slightly reflexed, ca. 2 mm; wings oblong, ca. 9 × 2-3 mm, apex obtuse, stalk linear, ca. 2.5 mm, less than 1 mm wide; keel elliptic, ca. 1 cm × 3.5 mm, with distal margins connate, base with small auricle, stalk ca. 2 mm. Ovary prolate or linear, ca. 5 mm, stipe ca. 4 mm; style ca. 3 mm. Infructescence ca. 8 cm. Legume dark, ellipsoid, 1.2-1.7 × ca. 1.1 cm, glabrous, apex obtuse, mucron­ulate; pedicel ca. 1 cm, with carpopodium ca. 4 cm, glabrous.

Valleys, mountain slopes, dense forests; 800-1400 m. Guangdong, Guangxi, Guizhou, Hunan, Jiangxi, Sichuan, Zhejiang [Japan, Korea].