Aquatic herbs. Leaves sagittate at base, erect. Inflorescence a pyramidal panicle, composed of 4-7 whorls; lower whorls bearing female or bisexual flowers; upper bearing mostly male flowers. Sepals boat-shaped, deflexed after flowering. Petals, white, circular, clawed. Stamens 6. Carpels numerous.
Worldwide: 4 species in Old World tropics.
Botswana: 2 taxa.