''Elodea'' is a genus of 6 species of

aquatic plant Aquatic plants are plants that have adapted to living in aquatic environments (saltwater or freshwater). They are also referred to as hydrophytes or macrophytes to distinguish them from algae and other microphytes. A macrophyte is a plant that ...

s often called the waterweeds described as a genus in 1803. Classified in the frog’s-bit family ( Hydrocharitaceae), ''Elodea'' is native to the

Americas The Americas, which are sometimes collectively called America, are a landmass comprising the totality of North and South America. The Americas make up most of the land in Earth's Western Hemisphere and comprise the New World. Along with th ...

and is also widely used as

aquarium An aquarium (plural: ''aquariums'' or ''aquaria'') is a vivarium of any size having at least one transparent side in which aquatic plants or animals are kept and displayed. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, aq ...

vegetation and laboratory demonstrations of cellular activities. It lives in fresh water. An older name for this genus is ''Anacharis'', which serves as a common name in North America. The introduction of some species of ''Elodea'' into waterways in parts of Europe,

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

, Africa, Asia, and New Zealand has created a significant problem and it is now considered a noxious weed in these areas. ''

Elodea canadensis ''Elodea canadensis'' (American waterweed or Canadian waterweed or pondweed) is a perennial aquatic plant, or submergent macrophyte, native to most of North America.Flora of North America''Elodea canadensis''/ref>Plants of British Columbia''Elod ...

'', sometimes called American or Canadian water weed or pond weed, is widely known as the generic water weed. The use of these names causes it to be confused with similar-looking plants, like Brazilian elodea ('' Egeria densa'') or hydrilla (''

Hydrilla verticillata ''Hydrilla'' (waterthyme) is a genus of aquatic plant, usually treated as containing just one species, ''Hydrilla verticillata'', though some botanists divide it into several species. It is native to the cool and warm waters of the Old World in ...

''). American water weed is an attractive aquarium plant and is a good substitute for Brazilian elodea. It can be used for science experiments in classrooms demonstrating how plants use carbon dioxide with the usage of bromothymol blue. The American water weed lives entirely underwater with the exception of small white flowers which bloom at the surface and are attached to the plant by delicate stalks. It produces winter buds from the stem tips that overwinter on the lake bottom. It also often overwinters as an evergreen plant in mild climates. In the Autumn, leafy stalks will detach from the parent plant, float away, root, and start new plants. This is the American water weed's most important method of spreading, while seed production plays a relatively minor role. Silty sediments and water rich in nutrients favor the growth of American water weed in nutrient-rich lakes. However, the plants will grow in a wide range of conditions, from very shallow to deep water, and in many sediment types. It can even continue to grow uprooted, as floating fragments. It is found throughout temperate North America, where it is one of the most common aquatic plants. American water weed is an important part of lake ecosystems. It provides good habitat for many aquatic invertebrates and cover for young fish and

amphibian Amphibians are tetrapod, four-limbed and ectothermic vertebrates of the Class (biology), class Amphibia. All living amphibians belong to the group Lissamphibia. They inhabit a wide variety of habitats, with most species living within terres ...

s. Waterfowl, especially ducks, as well as

beaver Beavers are large, semiaquatic rodents in the genus ''Castor'' native to the temperate Northern Hemisphere. There are two extant species: the North American beaver (''Castor canadensis'') and the Eurasian beaver (''C. fiber''). Beavers ar ...

muskrat The muskrat (''Ondatra zibethicus'') is a medium-sized semiaquatic rodent native to North America and an introduced species in parts of Europe, Asia, and South America. The muskrat is found in wetlands over a wide range of climates and habitat ...

and aquatic turtles eat this plant. It is also of economic importance as an attractive and easy to keep aquarium plant, although in the states of Alabama, New Hampshire, New York, South Carolina, and Washington it has been deemed an invasive species and is illegal to sell. ;Species # '' Elodea bifoliata'' H.St.John - Canada ( AB, SK), W United States ( OR + CA to NM + MN) # '' Elodea callitrichoides'' (Rich.) Casp. - Argentina, Uruguay # ''

'' Michx. - most of United States + Canada # ''

Elodea granatensis ''Elodea'' is a genus of 6 species of aquatic plants often called the waterweeds described as a genus in 1803. Classified in the frog’s-bit family ( Hydrocharitaceae), ''Elodea'' is native to the Americas and is also widely used as aquarium veg ...

'' Humb. & Bonpl. - much of South America # '' Elodea nuttallii'' (Planch.) H.St.John - much of United States + Canada # '' Elodea potamogeton'' (Bertero) Espinosa - Chile, Peru,

Bolivia , image_flag = Bandera de Bolivia (Estado).svg , flag_alt = Horizontal tricolor (red, yellow, and green from top to bottom) with the coat of arms of Bolivia in the center , flag_alt2 = 7 × 7 square p ...

, Ecuador

Chemical control

Chemical methods are ineffective in eradicating Elodea – at best they only slow growth for a season or two. As Elodea spreads into new ecosystems, it experiences rapid growth for 5–6 years and then slows as soil nutrients are used up. Elodea is threatening aquatic environments across Europe. Chemicals may be used in places that cause undue economic concerns, but very few aquatic herbicides are registered for aquatic use in the EU. Fluridone, the most commonly used aquatic herbicide is highly effective against Hydrilla, but only marginally effective against Elodea, especially at lower use rates.

Mechanical control

An aquatic weed harvester collecting ''Elodea'' from a lake The plants can also be removed from lakes and rivers mechanically. They are extracted either by hand or by using rakes, chains, mowing boats or weed buckets. The problem is that through vegetative reproduction via fragments, mechanical removal methods can contribute to the spread of the plant. Torn fragments can be transported downstream or are introduced to new environments via attachment to boats and anchor chains.

References

External links

*
Jepson Manual Treatment
{{Taxonbar, from=Q21129 Hydrocharitaceae Hydrocharitaceae genera Freshwater plants Aquarium plants

Chemical control

Mechanical control

See also

References

External links