water hyacinth

Tropical aquatic plant belonging to the pickerelweed family. In one growing season 25 plants can produce 2 million new plants. It is liable to choke waterways, removing nutrients from the water and blocking out the sunlight, but it can be used to purify sewage-polluted water as well as in making methane gas, compost, concentrated protein, paper, and baskets. Originating in South America, it now grows in more than 50 countries. (Genus Eichhornia crassipes, family Pontederiaceae.)