Description

Perennial, glabrous aquatic herbs. Roots 1 at each node with prominent root-hairs. Leaves floating, with a spongy layer of tissue on the underside; petioles long. Inflorescences unisexual. Male inflorescences sessile or pedunculate with flowers projecting above the water; sepals 3, greenish-white to yellowish; petals 3; stamens in 1-6 whorls of 3 with filaments united in a column. Female inflorescences usually sessile with fewer flowers; sepals and petals similar to those of male flowers; staminodes 2-6; ovary with 3-9 united carpels. Fruit ellipsoid to spherical, beaked.