Woody climbers. Branches blackish when dry, glabrous, apex often twisting and spirally hooked. Leaves 6-7.5 cm; leaflets (3-)5-7; petiolules ca. 1.5 mm, slightly puberulent or subglabrous; blade abaxially glaucous, adaxially dark green, obovate-oblong, 1.5-3 × 1-2 cm, abaxially very sparsely appressed puberulent, adaxially glabrous, base cuneate, sometimes subrounded, apex rounded or obtuse, sometimes emarginate. Panicles axillary, 2.5-5 cm, subsessile or with very short peduncles; branches slightly puberulent; bracts ovate-lanceolate; bracteoles larger than bracts, broadly ovate, embracing lower 1/3 of calyx tube. Calyx broadly campanulate, subglabrous; teeth subequal, broadly triangular to ovate, obtuse, upper pair of teeth subconnate. Corolla white; petals long clawed; standard reflexed, oblong; wings obovate-oblong, sagittate on upper side; keel oblong, united above, auriculate on upper side below. Stamens 9(or 10), monadelphous. Ovary stipitate, oblong, glabrous, 1(or 2)-ovuled; style subulate, slender; stigma small. Legume shortly stipitate, half-moon-shaped, compressed, 2-2.4 cm when 1-seeded, 3.5-4 cm when 2-seeded, 1-1.2 cm wide, firmly leathery, ventral suture straight, dorsal suture arcuate, faintly reticulate throughout, not prominent opposite seeds. Seeds reniform, compressed, ca. 6 × 3 mm. Fl. May-Aug, fr. Jun-Nov.
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