General description:- Monoecious herbs with whorled leaves.

Flowers:- Perianth of 8-12 linear segments, united at the base. Stamens numerous; filaments short or absent; connective prolonged apically. Ovary superior, 1-celled.

Fruit:- A 1-seeded nut.

Genus: CERATOPHYLLUM

General description:- Submerged aquatics, perennating by dormant terminal buds.

Leaves:- In whorls of 3-8, dichotomously divided.

Flowers:- Axillary, sessile, the male and female at different nodes. Perianth green in female flowers, whitish in male. Stamens up to 30.

Fruit:- Nut usually armed with 1 or more spines.

All species inhabit still or slow-moving waters.