The genus was formerly included in the related genus Elodea, from which it differs in having the leaves in whorls of four or more, not three, and in having more conspicuous flowers with larger (particularly broader) petals.
Egeria is found in many temperate and subtropical regions throughout the world as an introduced, or "alien", species, meaning a species that does not originate from the area in which it is found. In many places, particularly in Europe, fast-growing, adaptable plants such as Egeria can spread quickly and cause major damage to native plants and wildlife.
- Egeria densa Planch. - S + SE Brazil, NE Argentina, Paraguay, Uruguay; naturalized in scattered locales in Europe, Africa, China, New Zealand, Hawaii, USA, Mesoamerica, West Indies
- Egeria heterostemon S.Koehler & C.P.Bove - Brazil
- Egeria najas Planch. - S + SE + E Brazil, NE Argentina, Paraguay, Uruguay
- lectotype designated by Oostroom & Reichgelt, Fl. Neerl. 1(6): 27 (1964)
- Tropicos, Egeria Planch.
- Planchon, Jules Émile. 1849. Annales des Sciences Naturelles; Botanique, sér. 3 11: 79
- Kew World Checklist of Selected Plant Families
- Flora of North America: Egeria
- Huxley, A., ed. (1992). New RHS Dictionary of Gardening. Macmillan ISBN 0-333-47494-5.
- Hisock, Peter. (2005). Aquarium Plants (Mini Encyclopedia), p. 146. NY: Barrons. ISBN 0-7641-2989-9.
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