Scrambling perennial; stems densely hairy, sharply angled, but not winged. Lvs finely hairy; tendrils branched in upper lvs, often reduced and simple in lower lvs; leaflets in 1-(3) pairs, elliptic to obovate, acute to obtuse, (15)-25-40 mm long; veins only weakly parallel; stipules narrowly triangular, sagittate or often with only 1 basal lobe, narrower than stem, 3-8 mm long. Infl. much > lvs, 1-4-flowered; pedicels 6-8 mm long. Calyx ± glabrous or hairy, slightly gibbous at base; calyx teeth ± equal, triangular, < tube. Corolla 25-35 mm long, with violet standard, purple to crimson wings and pink keel. Pod glabrous, brown, 15-20-seeded, 60-90 mm long; seeds smooth; hilum ⅙ of circumference.