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You are here: Home / Aquatic Species / Species Profiles / Water Lettuce
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Water Lettuce

Water lettuce - Invasive.orgScientific name: Pistia stratiotes L. Royle (ITIS)

Common names: Water lettuce, tropical duckweed

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Selected Resources

Native To: Unknown, possibly South America, Africa, or the U.S. (Dray et al. 1988)

Date of U.S. Introduction: First described in Florida in 1765; experts disagree as to whether water lettuce is native to the U.S. (Ramey 2001)

Means of Introduction: Unknown (possibly native to the U.S., or it may have arrived in ballast water) (Ramey 2001)

Impact: Grows into dense mats that clog waterways (Ramey 2001)

Current U.S. Distribution: Southern U.S., Eastern U.S.



Selected Resources:


Pacific Island Ecosystems at Risk (PIER) - Pistia stratiotes
USDA. FS. Institute of Pacific Islands Forestry.

Invasive Plant Atlas of New England (IPANE) - Water Lettuce
University of Georgia. Center for Invasive Species and Ecosystem Health.

Invasive Plant Atlas of the United States - Water Lettuce
University of Georgia. Center for Invasive Species and Ecosystem Health.

Texas Invasives Database - Pistia stratiotes

The Quiet Invasion: A Guide to Invasive Species of the Galveston Bay Area - Water Lettuce
Texas Commission on Environmental Quality, Galveston Bay Estuary Program; Houston Advanced Research Center (HARC).

Invasive Species Compendium - Pistia stratiotes
CAB International.

Plantwise Technical Factsheet - Water Lettuce (Pistia stratiotes)
CABI. Plantwise Knowledge Bank.

EPPO Global Database - Pistia stratiotes
European and Mediterranean Plant Protection Organization.

Global Invasive Species Database - Pistia stratiotes (aquatic plant)
IUCN. Species Survival Commission. Invasive Species Specialist Group.

Invaders Factsheet: Water Lettuce
Ontario's Invading Species Awareness Program (Canada).

Keys and Fact Sheets: Pistia stratiotes (Water Lettuce)
East African Network for Taxonomy.

Federal Government

Nonindigenous Aquatic Species Database: Fact Sheet - Water Lettuce
DOI. USGS. Wetland and Aquatic Research Center.
Provides distribution maps and collection information (State and County).

U.S. National Plant Germplasm System - Pistia stratiotes
USDA. ARS. National Genetic Resources Program. GRIN-Global.

PLANTS Database - Water Lettuce
USDA. NRCS. National Plant Data Center.

National Exotic Marine and Estuarine Species Information System (NEMESIS): Chesapeake Bay Introduced Species Database - Pistia stratiotes
Smithsonian Institution. Smithsonian Environmental Research Center. Marine Invasions Research Lab.

International Government

Weeds in Australia - Water Lettuce (Pistia stratiotes)
Australian Government. Department of the Environment and Energy.

NSW WeedWise: Water lettuce
New South Wales Department of Primary Industries (Australia).

Invasive Plants: Restricted Invasive Plants - Water lettuce
Queensland Business and Industry Portal (Australia).

State Government

Weed Alerts: Water-lettuce
Florida Fish and Wildlife Conservation Commission.

Invasive Plants in Pennsylvania: Water Lettuce (PDF | 376 KB)
Pennsylvania Department of Conservation and Natural Resources.
See also: Invasive Plant Fact Sheets for plant species (trees, shrubs, vines, herbs and aquatic plants) that have impacted the state's natural lands

Water Lettuce
Wisconsin Department of Natural Resources.


Plant Profile: Pistia stratiotes
University of Florida. IFAS. Center for Aquatic and Invasive Plants.

AQUAPLANT - Water Lettuce
Texas A&M University. AgriLife Extension Service. Department of Wildlife and Fisheries Sciences.


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 10, 2014].

Ramey, V. 2001. Water lettuce. University of Florida, IFA Extension, Center for Aquatic and Invasive Plants.

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Last Modified: Aug 25, 2018
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