Annual herb with opposite or alternate branches and leaves. Leaves entire. Flowers small, hermaphrodite, solitary in the axils of scarious bracts, sessile in dense, solitary or clustered spikes. Perianth segments 3-4 (-5), hyaline, perianth subtended by two very small bracteoles. Stamens 1 or 2, the filaments filiform, intermediate teeth absent. Style short, stigma capitate. Ovary with a single pendulous ovule, radicle ascending. Capsule delicate, irregularly rupturing. Seed round, laterally compressed, endosperm copious.