Herbs annual. Leaves opposite or alternate, petiolate; leaf blade flattened, slightly succulent, with unicellular, inflated trichomes, margin serrate. Flowers unisexual (plants monoecious). Male flowers in interrupted, ebracteate spikes at apex of branchlets; perianth 5-parted; segments membranous, slightly succulent abaxially near apex, veinless; stamens 5, inserted on disk. Female flowers borne below male inflorescences, attached to base and petiole of bracts; bracts leaflike, shortly petiolate or subsessile, smaller than leaves; perianth 3- or 4-parted; segments with midvein, slightly enlarged in fruit; ovary obovoid, smooth; style inconspicuous; stigmas 2. Fruit a utricle, slightly compressed, papillate; pericarp membranous, adnate to seed. Seed laterally compressed, lenticular; testa crustaceous; embryo annular; radicle inferior; perisperm copious.