Aquatic herbs, free floating or rooting, with stolons. Stem short. Leaves rosulate or alternate, petiolate. Inflorescence terminal, panicle or spike. Perianth gamophyllous, 6-partite. Stamens unequal, usually 3 longer, hairy or not, anthers equal. Ovary 3-locular; style filiform. Capsule ovoid to linear.