Slender, profusely branched, annual, herbaceous climber, greyish green with striate stem; leaves 3-foliolate, leaflets sessile; obovate-oblong, twice as long as broad, sub-coriaceous, mucronate, pubescent, terminal one larger; stipules linear, minute, caducous, downy beneath; flowers 2-6 in short, densely pubescent, axillary racemes; calyx densely silky, grey, teeth linear, lowest twice as long as the tube; corolla little exserted, yellow, keel abruptly incurved at the tip; stamens diadelphous; anthers uniform; ovary sessile or subsessile, style filiform, stigma capitate; pods flat, straight, distinctly lineate, densely pubescent, glandular with deep lines between the seeds; 4-6 seeds, black, clothed with fine, spreading hairs.