Procumbent, annual herb; stems ± glabrous. Lvs almost glabrous or sparsely hairy on petioles and undersurface of leaflets, glabrous above; petioles c. 5-40 mm long; leaflets mostly obovate, acute to obtuse or emarginate, obtuse to cuneate at base, serrate in upper 1/2, uniform in colour, c. 5-15 mm long; terminal petiolule (1.5)-3-7 mm long; lateral petiolules < 1.5 mm long; stipules ovate, acuminate, laciniate. Infl. 1-5-flowered; peduncles ± glabrous, <, = or > petioles; pedicels < calyx tube. Calyx usually sparsely hairy; calyx teeth triangular, acuminate, ± =, or > tube. Corolla yellow, 3-5 mm long. Pod ± glabrous, coiled in 11/2-6 turns, without a hole in the centre, distinctly reticulately veined and with a double row of spines at the margin (spines sometimes reduced to tubercles only), 4-8 mm diam. (excluding spines), few-seeded; seeds yellow to brown, c. 3 mm long.