Plants emergent perennial herbs growing in freshwater, with starch-rich rhizomes or tubers. Leaves basal, usually long-petiolate, with simple blades. inflorescences usually simple or 2-branched spikes, at first enclosed in a thin spathe. Flowers usually bisexual, rarely unisexual, usually bilaterally symmetric; tepals 1-6 or absent, petal-like, free; stamens usually 6, free, filaments narrow; anthers with 2 thecae, longitudinally deshiscent; carpels superior, usually 3-6, free or slightly united at the base, 1-celled; ovules 1-14 per carpel; styles short. Fruits 1-several seeded follicles; seeds with straight embryos, without endosperm.
The family Aponogetonaceae includes only one genus, Aponogeton, which has about 40 species.