Plants perennial freshwater herbs, floating or rooted. Roots adventitious. Leaves submeredd or floating; petioles sheathing at the base. Flowers bisexual, in racemes or spikes, subtended by a spathe-like leaf sheath; perianth segments 6, free or united; stamens (1-3)6, epitepalous, filaments often unequal, anthers equal or unequal; ovaries superior, with 1-3 cells, and 1 style, styles simple or lobed, placentation parietal, axile, or pendulous, ovules 1-numerous. Fruits 3-valved capsules or nuts; seeds ribbed.
The family Pontederiaceae includes 6 genera and about 30 species. It is mostly tropical in distribution, bering particularly abundant in Africa and the Americas.