Annual; stems moderately to densely clothed in appressed hairs, erect or ascending, not rooting at nodes. Lvs glabrous to moderately hairy on petioles and undersurface of leaflets; petioles c. 3-12 mm long; leaflets obovate, obtuse or emarginate, occasionally mucronate, cuneate at base, finely serrate, c. 4-15 mm long; lateral veins thin and straight to leaflet margin; petiolules distinctly unequal in most lvs; lateral petiolules < 1 mm long; terminal petiolule up to 3 mm long; stipules ovate, acute. Infls axillary, racemose, cylindric, pedunculate, much > lvs; fls 20-40; pedicels c. 0.5-1 mm long; bracts subtending fls reduced to glandular hairs. Calyx glabrous or somewhat hairy about teeth, 5-veined, not inflated at fruiting; throat open, glabrous; calyx teeth unequal, erect at fruiting; 3 lower teeth longer, lanceolate, < corolla, much > tube; 2 upper teeth triangular, < tube; sinuses obtuse. Corolla yellow, persistent, 3.5-5 mm long. Pod glabrous, straight, ± = or > calyx, c. 2 mm long, usually 1-seeded; seeds c. 1 mm diam.