Brazilian waterweed, Brazilian elodea: Egeria densa (Hydrocharitales: Hydrocharitaceae): Invasive Plant Atlas of the United States

Brazilian waterweed, Brazilian elodea	USDA PLANTS Symbol: EGDE U.S. Nativity: Exotic Habit: Aquatic Plants
Egeria densa Planch.

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Taxonomic Rank: Liliopsida: Hydrocharitales: Hydrocharitaceae
Synonym(s): Brazilian waterweed, Brazilian elodea, South American waterweed
Native Range: S. America (BAIL);
Appearance Egeria densa is a submersed aquatic plant that invades freshwater systems throughout much of the United States. Often confused with hydrilla, Egeria densa has a smooth midrib on the underside of the leaf, whereas hydrilla has small teeth. Foliage The finely serrated leaves are usually less than 1 in. (2.5 cm) long and occur in whorls of 3-6. Flowers The flowers, which bloom above the surface of the water, are white with three petals. Fruit Outside of its native habitat, Egeria densa only reproduces vegetatively. Special double nodal regions can produce lateral buds, branches and roots. Only a double node can produce a new plant when it breaks off from the parent plant. Ecological Threat Egeria densa invades both still and flowing water ecosystems including lakes, ponds, ditches, and rivers. It can form dense stands that crowd out native vegetation and reduce the area's value as fish habitat. It can also interfere with recreational activities such as fishing and swimming. This plant was first introduced into the United States in the late 1800s as an aquarium plant.

Identification, Biology, Control and Management Resources

Fact Sheet - Ontarios Invading Species Awareness Program
Global Invasive Species Database - Invasive Species Specialist Group

Selected Images from Invasive.org

View All Images at Invasive.org

Plant(s); Virginia Tech Weed Identification Guide , Virginia Polytechnic Institute and State University, Bugwood.org Additional Resolutions & Image Usage	Flower(s); Leslie J. Mehrhoff, University of Connecticut, Bugwood.org Additional Resolutions & Image Usage	Infestation; combination of Egeria densa and Egeria najas; predominantly Egeria densa William T. Haller, University of Florida, Bugwood.org Additional Resolutions & Image Usage	Feature(s); Ann Murray, University of Florida, Bugwood.org Additional Resolutions & Image Usage
Plant(s); leaf Robert Vidéki, Doronicum Kft., Bugwood.org Additional Resolutions & Image Usage	Structure; leaf Robert Vidéki, Doronicum Kft., Bugwood.org Additional Resolutions & Image Usage	Foliage; Robert Vidéki, Doronicum Kft., Bugwood.org Additional Resolutions & Image Usage

EDDMapS Distribution:
This map is incomplete and is based only on current site and county level reports made by experts and records obtained from USDA Plants Database. For more information, visit www.eddmaps.org