Statiotes aloides, commonly known as the water soldiers or water pineapple, is a submerged aquatic plant native to Europe and northwestern Asia. In Britain it was once common in East Anglia and still is in many places, particularly wet ditches and healthy ponds. It is the only species in the genus Stratiotes.
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. Only the female plant occurs naturally in Britain, though plants with hermaphrodite flowers are also found occasionally. Seed is never set in Britain, the plants increasing mainly by offsets. 
The herb has had a high reputation for treating wounds, especially when these are made by an iron implement. It is applied externally. The plant is also said to be of use in the treatment of St. Anthony's Fire and also of bruised kidneys. 
- "Stratiotes aloides". Natural Resources Conservation Service PLANTS Database. USDA. Retrieved 3 December 2015.
- http://www.bqrap.ca/cms_lib/watersoldierPosterLOWRES.PDF[dead link]
- Clapham, Tootin and Warburg
- Grieve, A Modern Herbal. Penguin (1984)
- Clapham, Tootin and Warburg. Flora of the British Isles. Cambridge University Press 1962