Pistia
(probably from pistos, watery; in reference to the habitat). SYNS. Apiospermum, Limnonesis, Zara. ORD. Aroideae (Araceoe). A monotypic genus. The species is an ornamental, stove aquatic, requiring plenty of heat. It increases rapidly, and often completely coats tropical ponds and water-tanks with verdure, keeping the water beneath fresh and cool. The plant floats on the water, and sends down many long, feathery roots. Each plant sends out several runners, and upon the ends of these other similar plants are formed, which again send out runners.
P. Stratiotes (Stratiotes).* Tropical Dockweed; Water Lettuce. fl. greenish, very small, borne in little spathes at the end of the leaves, each spathe containing one male and one female flower attached to an adnate spadix. l. wedge-shaped, slightly concave, notched or round topped, 2in. to 5in. long, of a delicate pale pea-green, covered with fine hairs. Tropics, 1843. (B. M. 4564; F. d. S. 625; L. J. F. 137.)