> Egeria densa
Egeria densa (Brazilian waterweed)
Synonyms: Anacharis densa; Elodea canadensis gigantea; Elodea densa; Elodea densa longifolia; Philotria densa; Udora densa
Egeria densa (syn. Anacharis densa Vict. , Elodea densa Casp. ; Large-flowered Waterweed or Brazilian Waterweed) is a species of Egeria native to warm temperate South America in southeastern Brazil, Argentina, and Uruguay. It is an aquatic plant growing in water up to 4 m deep, with trailings stems to 2 m or more long, producing roots at intervals along the stem. The leaves are produced in whorls of four to eight, 1–4 cm long and 2–5 mm broad, with an acute apex.
Egeria densa is a submersed, freshwater perennial herb that forms dense monospecific stands that restrict water movement, trap sediment, and cause fluctuations in water quality. It has also affected the status of certain threatened species. It has been introduced worldwide through the aquarium trade, and even in its native range can become a nuisance species causing local economic impacts. Chemical control is the most effective option for management of E. densa. Mechanical control is not recommended because fragments of the plant left behind can readily re-colonize and move downstream. The introduction of grass carp offers biological control of this species, but care must be taken because carp can introduce their own negative effects on the environment.
SE. & S. Brazil to NE. Argentina, introduced elsewere;
|Lifespan  ||Perennial|
|Structure  ||Herb|
Species recognized by Govaerts R., 25-Jan-2005, WCSP: World Checklist of Selected Plant Families in