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Brazilian Waterweed

Egeria densa

Description: 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. The finely serrated leaves are usually less than 1 in. (2.5 cm) long and occur in whorls of 3-6.  The flowers, which bloom above the surface of the water, are white with three petals. 


Ecological Threat:  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.


Biology & Spread:  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.


In Oklahoma:  First recorded in 1947 in Oklahoma and has been reported from Wichita Mountains NWR, Holdenville Lake, Lake Murray, and Schooler Lake.

ManagementAquatic Weed Management, OSU Extension Factsheet


Leslie J. Mehrhoff, University of Connecticut,

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