Description
Small, broad, rosette-forming, floating aquatic annual (H up to 5 cm, W 15-30 cm). Stem submerged, free floating, up to 2 m long, with several nodes. Leaves in a floating rosette, deltoid (2-3 cm), smooth, dark green. Flowers not remarkable, in leaf axils, floating, star-shaped, white. Flowering period: June-September. Fruit hard, 4-angled nut (2 cm), with 4 thorns, black-grey. Eventually self-seeding, grows in still water, at least 70 cm deep.