- Trapa natans is a rooted, floating plant that invades shallow to deep, fresh water habitats in the northeastern United States. It can grow in 12-15 ft. (3.6-4.6 m) of water and forms dense, floating mats, often three layers deep.
- The rosette of leaves on the surface of the water are alternate, triangular in shape, strongly dentate (toothed) and connected to the stem by an inflated petiole. Submerged leaves are feathery and either opposite or alternate.
- Trapa natans has small, four-petaled flowers that bloom from July to frost.
- The nut-like fruit has two to four, 0.5 in. (1.3 cm) long, sharp, barbed spines. They ripen in about a month and can remain viable as long as 12 years. Each seed can produce 1-15 rosettes and each rosette can produce as many as 20 seeds. The spines can penetrate shoes.
- Ecological Threat
- The dense, floating mats of Trapa natans restrict light availability, reduce the oxygen content, and displace other emergent and floating vegetation. It also limits boating, fishing, swimming and other recreational activities. Trapa natans is native to Europe and Asia and was first observed in the United States in Massachusetts in the late 1800s.
- Biological Control of Invasive Plants in the Eastern United States - USDA Forest Service
- Invasive Plant Atlas of New England - University of Connecticut
- Global Invasive Species Database - Invasive Species Specialist Group
- Plant Invaders of Mid-Atlantic Natural Areas - National Park Service and U.S. Fish and Wildlife Service
- Fact Sheet - Ontarios Invading Species Awareness Program
Image Sets View other image sets:
EDDMapS Distribution - This map is incomplete and is based only on current site and county level reports made by experts, herbaria, and literature. For more information, visit www.eddmaps.org
State Invasive List - This map identifies those states that list this species on their invasive species list. For more information, visit Invasive.org
Invasive Listing Sources
- Alabama Noxious Weeds - Class C Noxious Weed
- Arizona Noxious Weeds
- Commonwealth of Pennsylvania, Department of Conservation and Natural Resources, 1994.
- Connecticut Invasive Plant List
- Connecticut Invasive Plant Working Group
- Delaware Natural Resources and Environmental Control, 2004
- EDDMapS Ontario
- Faith Campbell, 1998
- Hoffman, R. & K. Kearns, Eds. 1997. Wisconsin manual of control recommendations for ecologically invasive plants. Wisconsin Dept. Natural Resources, Bureau of Endangered Resources. Madison, Wisconsin. 102pp.
- Idaho Noxious Weeds
- Invasive Plant Council of New York State
- Jil M. Swearingen, Survey of invasive plants occurring on National Park Service lands, 2000-2007
- John Randall, The Nature Conservancy, Survey of TNC Preserves, 1995.
- Maine Noxious Weeds
- Maryland Department of Natural Resources, 1994
- Massachusetts Noxious Weeds
- Mid-Atlantic Exotic Pest Plant Council, 2005
- National Wildlife Refuge Association, Silent Invasion: A Call to Action from the National Wildlife Refuge Association, 2002. Washington DC. 17 pp.
- New Hampshire Invasive Species Committee. 2005. Guide to Invasive Upland Plant Species in New Hampshire. New Hampshire Department of Agriculture, Markets and Food Plant Industry Division and New Hampshire Invasive Species Committee.
- New Hampshire Prohibited Aquatic Species
- Nonnative Invasive Species in Southern Forest and Grassland Ecosystems
- Oregon Noxious Weeds
- South Carolina Noxious Weeds
- Tennessee Exotic Pest Plant Council
- Vermont Department of Environmental Conservation
- Vermont Noxious Weeds
- Virginia Invasive Plant Species List
- WeedUS - Database of Plants Invading Natural Areas in the United States
- Wisconsin's Invasive Species Identification, Classification and Control Rule
|Common Name Reference:|| Weed Science Society of America Common Names List|
|Scientific Name Reference:||USDA, NRCS. 2010. The PLANTS Database. National Plant Data Center, Baton Rouge, LA, USA.|