Description from Flora of China
Climbing herbs, sparsely hirsute. Leaves 1-foliolate; petiole 1.5-3.5 cm; stipels subulate, as long as petiolules; petiolules 3-4 mm; leaflets papery, narrowly oblong or narrowly lanceolate, 12-19 × 2.3-3 cm, rough on both surfaces, base rounded or slightly cordate, margin slightly revolute, apex acuminate or obtuse; midrib elevated abaxially, prominent adaxially, lateral veins 9-15 pairs, raised on both surfaces, at an angle of 50-60°, veinlets reticulate, slightly prominent on both surfaces. Racemes axillary, 5-15 cm, sometimes forming panicles with 1 or 2 branches. Flowers pedicellate, solitary or paired; bracts small, caducous; bracteoles ovate-lanceolate. Calyx ca. 7 mm; teeth narrowly lanceolate, upper 2 as long as tube, lower 3 slightly longer. Corolla light yellow; standard broadly elliptic, ca. 10.5 × 8 mm, apex emarginate, with 2 inflexed, short basal auricles, claw ca. 2 mm; wings obovate-oblong, ca. 9 × 4 mm, apex obtuse or rounded, with long, acute basal auricle, claw ca. 3 mm; keel falcate, ca. 8 × 2.5 mm, arcuate and ± connate on back, apex slightly acute, base without auricle, claw ca. 4 mm. Anthers broadly oblong, ca. 0.5 mm. Ovary narrowly oblong, slightly compressed, hirsute. Legumes narrowly oblong or linear, compressed, 4.5-5 × 0.5-0.6 cm, base rounded, apex with a 2-3 mm beak, valves sparsely hirsute. Seeds 6-8, blackish brown, shiny, orbicular, ca. 3 mm in diam. Fl. Aug.
● Mountain slopes, thick grass, near roads. E and NW Guangxi (Mengshan, Tian’e), SE Yunnan.