Brazilian waterweed
Egeria densa Planch.


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.
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.
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.


Selected Images


EDDMapS Distribution

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

State Regulated List

State Regulated List - This map identifies those states that list this species on their regulated list. For more information, visit

State Regulated List
   No Data for this state
   Troublesome or Common weed in one or more crops

Most Troublesome / Most Common Agricultural Weed List
This map identifies those states that consider this species either most troublesome or most common in at least one commodity. For more information, visit the MTMC project page.

Invasive Listing Sources

Taxonomic Rank

Kingdom: Plantae
Phylum: Magnoliophyta
Class: Liliopsida
Subclass: Alismatidae
Order: Hydrocharitales
Family: Hydrocharitaceae
Genus: Egeria
Subject: Egeria densa Planch.

Synonyms and Other Names

Other Common Names:
Brazilian waterweed, Brazilian elodea, South American waterweed

Related Scientific Names:
Anacharis densa (Planch.) Victorin (Synonym)
Elodea densa (Planch.) Caspary (Synonym)
Philotria densa (Synonym)


Plants - Aquatic Plants