Very variable water-plant, very difficult to identify to a species-level even if fruits are present. Usually seen as small bright-green floating rosettes, with variously oval or strap-shaped lees, but may be completely submerged. Male and female flowers borne separately; very small and inconspicuous, in leaf axils. The fruit is a groups of 4 nutlets, each containing a seed.
Identification to species level requires examination of the fruits.