In the Summer this plant floats on the water surface with the leaves just above the surface. In the Autumn they become covered with a slimy secretion (calcium carbonate) and the whole plant sinks to the bottom to rise again in the Spring. Fossils have been found of this plant. Plants are dioecious, male and female plants must be grown if seed is required. Most suitable for the cool aquarium or pond. Propagation from runners which form from the centre of the rosette of leaves. The herb has had a high reputation for treating wounds, especially when these are made by an iron implement. It is applied externally.
Found in Europe and NW Asia, particularly wet ditches and healthy ponds.