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Pistia stratiotes L. Royle (ITIS)
Water lettuce, tropical duckweed
Unknown, possibly South America, Africa, or the U.S. (Dray et al. 1988)
First described in Florida in 1765; experts disagree as to whether water lettuce is native to the U.S. (Ramey 2001)
Unknown (possibly native to the U.S., or it may have arrived in ballast water) (Ramey 2001)
Grows into dense mats that clog waterways (Ramey 2001)
Southern U.S., Eastern U.S.
Water lettuce, plants
Photo by Troy Evans; Great Smoky Mountains National Park
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Dray, F.A., C.R. Thompson, D.H Habeck, J.K. Balciunas, and T.D. Center. 1988. A survey of the fauna associated with Pistia stratiotes L. (waterlettuce) in Florida (Technical Report A-88-6). Jacksonville, Fla.: U.S. Army Corps of Engineers Aquatic Plant Control Research Program.
Integrated Taxonomic Information System. Pistia stratiotes. [Accessed Sep 28, 2023].
Ramey, V. 2001. Water lettuce. University of Florida, IFAS Extension, Center for Aquatic and Invasive Plants.