Description from Flora of China
Herbs twining. Stems slender, 1-3 m, pubescent when young. Stipules small, lanceolate, 1-2 mm; petiole 0.2-2.6 cm; stipels small, setiform; petiolules slender, extremely short, absent on uppermost leaves, glabrous or pubescent; leaflets membranous, almost cordate to reniform, 1-3 × 1.2-2.8 cm, abaxially glabrous or sparsely pubescent on midrib, reticulate veins slender, ± visible, base truncate or very shallowly cordate, apex subrounded or slightly concave, usually mucronate. Raceme axillary, slender, 2-7 cm, sparsely hairy or glabrous, 2- to many flowered; pedicels slender. Calyx ca. 5 mm, glabrous. Corolla light yellow, stipitate; standard obovate, auricles obtuse; wings and keels subequal. Ovary stipitate, glabrous; style enlarged, compressed; stigma capitate. Legume oblanceolate to oblong, slightly curved, ca. 3 × 0.4-0.6 cm, shortly stipitate. Seeds 3-5, brown-black, reniform, ca. 3 mm. Fl. Aug-Sep, fr. Oct-Dec. 2n = 22.
Sunny mountain slopes; 1200-2800 m. Sichuan, Xizang, Yunnan [E India].