Annual, prostrate, silky herb; leaves opposite, usually unequal, one leaf of each pair usually smaller or wanting, pinnately compound, leaflets 5-7 pairs, ovate-lanceolate, mucronate or acuminate, serrate, pubescent on both surfaces; stipules linear-lanceolate, persistent, spiny or hairy; flower pedicellate, white or yellow,1 cm across, solitary or on short, pseudo-axillary peduncles shorter than leaves; sepals-5, lanceolate, acute, scarious, minutely ciliate; petals 5, free, shorter than sepals, golden yellow, obovate, imbricate; stamens 10, inserted on the base of 10 lobed disc, filaments filiform, unequal, 5 longer, opposite to petals, alternating with 5 shorter, with a gland outside; ovary superior, sessile, hirsute, 5-12 celled, style short, filiform, stigmas 5-12, pyramidal; fruit of 5-12 indehiscent cocci, woody, globose, each with 2 pairs of hard, sharp spines, one pair usually longer than other; seeds 1 or 2 in each cocci, obliquely pendulous, exalbuminous.