Glabrous, erect or spreading annual. Stems 5-40 cm high, branched or not at base. Lvs alternate, exstipulate, entire, ovate, cuneate at base, subacute to obtuse, 3-20 mm long; petioles 2-5 mm long. Terminal umbel (2)-3-(4)-rayed, with often several to numerous axillary rays arising below; lvs subtending rays similar to stem lvs but usually subsessile; rays sometimes secondarily branched and then forming compound dichasia; lvs subtending ray-branches and cyathia ovate-triangular, sessile, truncate at base, often asymmetric. Glands elliptic-oblong; horns long, slender. Capsule smooth, shallowly grooved; keels with 2 slightly winged ridges. Seeds rounded, grey and brown, c. 1.5 mm long, with 2 long ventral pits and several small circular dorsal pits.