Erect, ± glabrous, annual herb, usually dioecious. Stems ribbed, much-branched, up to c. 50 cm high. Lvs ovate or narrowly elliptic, acute, (1)-2-6-(8) cm long; margins crenate and finely ciliate; petiole < lf blade; stipules 4 per node, subulate or triangular, 1-2 mm long. Fls shortly pedicellate; ♂ fls clustered on long pendulous spikes; ♀ fls solitary or clustered on short spikes (spikes of some plants monoecious); perianth segments ovate-triangular, acute. Capsule hispid, smooth, deeply grooved between cells. Seeds ovoid, rounded, rugulose or smooth, brown, c. 2 mm long.