Annual to perennial, prostrate to decumbent, pubescent to glabrescent herbs. Leaves opposite or alternate due to abortion of one leaf, abruptly paripinnate; stipules lanceolate to subulate; leaflets 3-10 pairs, opposite, shortly petiolulate to sessile, oblique, oblong to ovate or elliptical. Flowers solitary, axillary or pseudoaxillary, pedicellate, actinomorphic, yellow, rarely white; disc annular, fleshy, 10-lobed. Sepals 5, free, pubescent, caducous or persistent. Petals 5, free, spreading, obovate, fugaceous. Stamens 10 in 2 whorls, rarely 5, inserted at the base of the disc, 5 antisepalous ones shorter, filaments unappendaged, anthers oblong. Carpels 5; ovary sessile, ovoid or globose, beset with long silky hairs, 5-loculed, each locule with 2-5(-10) obliquely pendulous superposed ovules in axile placentation; style stout, 5-ridged, stigma 5-rayed. Fruit Schizocarpic, winged or spinous, pubescent, septicidally dehiscent into 5, triangular, indehiscent indurated, trans¬versely locellate 1-seeded mericarps. Seeds exalbuminous.