Citation: Rich., Mém. Cl. Sci. Math. Inst. Natl. France 12, 2:9, 61, 76 (1814).

Derivation: A diminutive of Hydra, the water serpent slain by Hercules.

Synonymy: Not Applicable

Common name: None

Description:
Fresh water; leaves in whorls of usually 4-6, mostly well-spaced along the stem, sessile, glabrous.

Flowers usually dioecious, arising from spathes in the leaf axils; male flowers released as a bud and opening as a free-floating flower on the water surface, with 3 sepals, 3 petals and 3 stamens; female flowers pedicellate, with 3 sepals, 3 petals, 3 placentas and a single style with 3 stigmas.

Fruit more or less cylindrical, seeds 2-6.

Distribution:  1 species from Europe, Africa, Asia and Australia.

Biology: No text

Author: Prepared by J.P. Jessop