Description from Flora of China
Herbs. Stems twining or climbing, densely pubescent or sometimes sparsely villous. Leaves pinnately 3-foliolate; stipules small, ovate, ca. 4 mm, sparsely pubescent, deciduous; petiole 4-10 cm, densely pubescent; stipels bristlelike; petiolules ca. 3 mm, densely pubescent; leaflets thinly leathery; terminal leaflet lanceolate to ovate-lanceolate, 9-15 × 3.5-8 cm, sparsely pubescent, abaxial surface with yellow-brown sessile glands, basal veins 3, lateral veins 3-5 pairs, base broadly cuneate or rounded, margin slightly sinuate, apex caudate-acuminate; lateral leaflet smaller, obliquely ovate. Raceme axillary, branched, up to 27 cm; bracts ovate, ca. 4 mm, deciduous; peduncle 1-3 cm, densely pubescent. Flowers small, ca. 1.1 cm, sparse; pedicels slender, 4-7 mm, pubescent. Calyx campanulate, ca. 5 mm, 5-lobed; lobes triangular, shorter than tube, sparsely hairy or almost glabrous. Corolla yellow, petals obviously stipitate, almost glabrous; standard ovate-orbicular or almost orbicular, ca. 1 cm, base with 2 slender auricles and accessory callosity; wings extremely narrow, apex acute, base with 2 auricles, one longer; keels slightly curved, with long beak. Ovary sparsely hairy; style linear, glabrous; stigma capitate. Legume reddish purple, oblong, ca. 1.5 × 1 cm, compressed, glabrous or almost glabrous, slightly constricted between seeds, with small beak. Seeds blackish purple, suborbicular, ca. 4 mm in diam. Fl. and fr. summer and autumn. Fr. Sep.
● Mountains; ca. 600 m. Guangdong, Guangxi, Guizhou, Jiangxi.