Brazilian waterweed, Brazilian elodea

Egeria densa Planch.

Description from Invasive.org

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.

Resources


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

Distribution