Herbs annual, erect, glabrous. Leaves alternate, petiolate; leaf blade flattened, triangular-ovate or hastate, margin entire or lobed-serrate. Flowers unisexual (plants dioecious), forming glomerules, male ones usually arranged in terminal, interrupted panicles, female ones axillary. Male flowers: perianth 4- or 5-parted; segments oblong, apex obtuse; stamens 4 or 5, inserted at base of perianth; filaments capillary; anthers exserted. Female flowers borne within 2 united, leathery, and hardening bractlets; perianth absent; ovary subglabrous; ovule subsessile; stigmas 4 or 5, filiform. Utricle compressed globose; pericarp membranous, adnate to seed. Seed vertical; embryo annular; perisperm copious, farinaceous.

Three species: Mediterranean region; one species (introduced) in China.