Herbs perennial, aquatic. Stems slender, branched, rhizomatous, repent; internodes at first elongate and apically floating, later erect, foliate, and shortened. Leaves dimorphic. Submersed leaves (Cabomba only), opposite or sometimes whorled, palmately dissected. Floating leaves alternate, peltate, entire. Flowers solitary, axillary from distal nodes, short to long pedunculate, bisexual, hypogynous, actinomorphic, borne at or above water surface; perianth persistent. Sepals 3, separate or nearly so. Petals 3, distinct, alternating with sepals. Stamens 3--36(--51), anthers dehiscent by longitudinal slits. Pistils 3--18, simple, obclavate or ventricose. Ovary 1-loculed; ovules 1--3, pendulous. Styles short. Stigmas capitate or linear-decurrent. Fruit achenelike or folliclelike, coriaceous, indehiscent. Seed endosperm little, perisperm abundant; embryo minute; cotyledons 2, fleshy.
Herbs , perennial, aquatic, rhizomatous; roots adventitious; air chambers conspicuous in vegetative portions of plant. Rhizomes branched, repent, slender. Leaves arising from erect stems with shortened internodes, submersed and floating; stipules absent. Leaf blade: laticifers commonly present. Submersed leaves ( Cabomba only) opposite [whorled], short-petioled; leaf blade palmately dissected. Floating leaves alternate; petiole short to long; leaf blade peltate, linear to broadly elliptic, sometimes with basal sinus (some Cabomba ), margins entire. Inflorescences axillary, solitary flowers. Flowers bisexual, protogynous, diurnal, borne at or above water surface (occasionally submersed); peduncle long; involucre absent; perianth persistent in fruit, hypogynous; sepals usually 3, distinct or nearly so; petals usually 3, alternate with sepals; stamens 3--36, rarely more; filaments slender; anthers dehiscing by longitudinal slits, without connective appendage; pistils [1--]2--18, 1-carpellate, inversely club-shaped or swollen on one side; ovary 1-locular; placentation laminar; ovules [1--]2--3[--5]; style short; stigma capitate or linear-decurrent. Fruits achenelike or folliclelike, leathery, indehiscent. Seeds 1--3, aril absent; endosperm sparse; perisperm abundant; embryo minute; cotyledons 2, fleshy.
Carpels 2–18, completely free, with a simple narrow stigma but very reduced style; ovules 1–3, parietal, pendulous, anatropous
Stamens 3–18, with extrorse anthers dehiscing longitudinally
Seeds with fleshy endosperm and perisperm but no aril
Fruiting carpels indehiscent, 1–3-seeded
Flowers rather small, hermaphrodite, axillary, solitary and regular
Leaves alternate, the floating ones peltate, the submerged ones finely divided or absent
Aquatic herbs with perennial sympodial rhizomes; stems long and slender, coated with mucilage
Stamens 3–18; anthers extrorse, opening lengthwise
Seeds 1–3 with a fleshy endosperm
Aquatic herbs with perennial rhizomes; stems coated with mucilage
Carpels 2–18, free; style very short or absent but with an attenuated, entire stigma; ovules 1–3, pendulous, parietal
Flowers axillary, solitary, actinomorphic