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Home / Aquatic Invasives / Aquatic Plants / Alligatorweed

Alligatorweed

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Alligatorweed
Alligatorweed, flower - Photo by Chris Evans; University of Illinois
Scientific Name: 

Alternanthera philoxeroides (Mart.) Griseb. (ITIS)

Synonym: 

Achyranthes philoxeroides (ITIS)

Common Name: 

Alligatorweed, alligator weed, pig weed

Native To: 

South America (Spencer and Coulson 1976)

Date of U.S. Introduction: 

First reported in Alabama in 1897 (Buckingham 1996)

Means of Introduction: 

Possibly introduced through ballast water (Buckingham 1996)

Impact: 

Forms dense mats that crowd out native species and impede recreational activities such as boating, swimming, and fishing (Texas Invasives 2007)

Current U.S. Distribution: 
Southeastern U.S., California

Distribution / Maps / Survey Status

University of Georgia. Center for Invasive Species and Ecosystem Health.
Provides state, county, point and GIS data. Maps can be downloaded and shared.
DOI. USGS. Wetland and Aquatic Research Center.
Provides detailed collection information as well as animated map.

Images

University of Georgia. Center for Invasive Species and Ecosystem Health.

Videos

Google. YouTube; University of Florida. IFAS. Center for Aquatic and Invasive Plants.

Selected Resources

The section below contains highly relevant resources for this species, organized by source. Or, to display all related content view all resources for Alligatorweed.

Partnership
European and Mediterranean Plant Protection Organization.
IUCN. Species Survival Commission. Invasive Species Specialist Group.
University of Georgia. Center for Invasive Species and Ecosystem Health.
USDA. FS. Institute of Pacific Islands Forestry.

Texas Commission on Environmental Quality, Galveston Bay Estuary Program; Houston Advanced Research Center (HARC).

Centre for Invasive Species Solutions; Atlas of Living Australia; Australian Government. Department of Agriculture, Water and the Environment.

Designated Weed of National Significance

Federal Government

Smithsonian Institution. Smithsonian Marine Station at Fort Pierce.

Smithsonian Institution. Smithsonian Environmental Research Center. Marine Invasions Research Lab.

DOI. USGS. Wetland and Aquatic Research Center.
Provides distribution maps and collection information (State and County).
USDA. NRCS. National Plant Data Center.

USDA. ARS. National Genetic Resources Program. GRIN-Global.

International Government
New South Wales Department of Primary Industries (Australia).
State and Local Government
California Department of Food and Agriculture.
See also: Included on California's noxious weed list; see Encycloweedia: Program Details for additional resources
South Carolina Department of Natural Resources. Aquatic Nuisance Species Program.
Academic
Texas A&M University. AgriLife Extension Service. Department of Wildlife and Fisheries Sciences.

Mississippi State University. Geosystems Research Institute.

See also: Species Factsheets for more fact sheets

University of Florida. IFAS. Center for Aquatic and Invasive Plants.

Citations