Monoecious annual herbs, with green alternate leaves and stellate hairs. Staminate flowers with 3-5 partite perianth and 2-5 stamens, glomerate, borne above the pistillate flowers, ebracteoleate, the anthers not appendaged. Pistillate flowers in the axils of upper leaves with lateral bracteoles and a perianth of 3 segments; stigmas 2, filiform, usually very long. Fruits vertical; seeds vertical, laterally compressed, albuminous, with horse-shoe-shaped embryo.