Herbs, aquatic, perennial, rhizomatous. Leaves all basal, aerial, floating, or submerged, ovate to elliptic; floating leaves deep green, large; aerial leaves subleathery, with erect petiole; submerged leaves usually smaller. Inflorescences paniculate or racemose, much branched; branches whorled, each whorl with 3-6 branches; bracts lanceolate. Flowers pedicellate, verticillate, bisexual. Petals usually larger than sepals. Stamens 6-12. Carpels few to numerous in a single whorl, free, each with 1 ovule. Fruitlets drupaceous, with woody endocarp and spongy exocarp, swollen or slightly compressed, with a short beak.
Peduncle longer than the leaves; inflorescence compound, pyramidal, consisting of whorls of 3 branches or 3 flowers subtended by 3 lanceolate bracts, and 2 or 3 smaller bracteoles
Sepals 3, spreading or reflexed
Perennial or annual aquatic and marsh herbs
Leaves floating; leaf-blade broadly elliptic to broadly ovate; apex rounded to obtuse; base truncate to deeply cordate
Achenes swollen, smooth, ridged or warty; style persistent, ventral.
Carpels 2–9(–20), free, crowded on a small receptacle; style ventral; ovules solitary, basal