Hydrocharitaceae is a flowering plant family including 16 known genera with a total of ca 135 known species (Christenhusz & Byng 2016[2]), that including a number of species of aquatic plant, for instance the tape-grasses, the well known Canadian waterweed, and frogbit.

The species are annual or perennial, with a creeping monopodial rhizome with the leaves arranged in two vertical rows, or an erect main shoot with roots at the base and spirally arranged or whorled leaves.

As with many aquatics they can be quite variable in shape – from linear to orbicular, with or without a petiole, and with or without a sheathing base.

Fruits are globular to linear, dry or pulpy, dehiscent or more usually indehiscent and opening by decay of the pericarp.

[3] Enhalus Thalassia Halophila Vallisneria Nechamandra Hydrilla Najas Limnobium Hydrocharis Elodea Egeria Appertiella Ottelia Blyxa Lagarosiphon Stratiotes Some species have become established ornamental plants, and subsequently serious weeds in the wild (especially Egeria, Elodea and Hydrilla).