Elodea

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iWater weed

Elodea nuttallii

Scientific classification

Kingdom:	Plantae
Division:	Magnoliophyta
Class:	Liliopsida
Order:	Alismatales
Family:	Hydrocharitaceae
Genus:	Elodea

Species

Elodea canadensis
Elodea nuttallii

Elodea is a genus of aquatic plants often called the Water weeds. Elodea is native to North America and it is also widely used as aquarium vegetation. The introduction of some species of Elodea into waterways in parts of Europe, Australia, Africa, Asia, and New Zealand has created a significant problem, and it is now considered a noxious weed in these areas.

Elodea canadensis, sometimes called American or Canadian waterweed/pondweed or Anacharis (a former scientific name) is widely known as the generic water weed. The use of these names causes it to be confused with similar-looking non-native plants, like Brazilian elodea (Egeria densa) or hydrilla (Hydrilla verticillata). American waterweed is an attractive aquarium plant, and is a good substitute for Brazilian elodea.

The American waterweed 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 fall, leafy stalks will detach from the parent plant, float away, root, and start new plants. This is the American waterweed's most important method of spreading, with seed production playing a relatively minor role.

Silty sediments and water rich in nutrients favor the growth of American waterweed in nutrient-rich lakes. However, the plant 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 unrooted, as floating fragments. It is found throughout temperate North America, where it is one of the most common aquatic plants.

American waterweed is an important part of lake ecosystems. It provides good habitat for many aquatic invertebrates and cover for young fish and amphibians. Waterfowl, especially ducks, as well as beaver and muskrat eat this plant. Also, it is of economic importance as an attractive and easy to keep aquarium plant. It was used as a drug by the Iroquois. The first written record of the Elodea in North America was in 1945 in Le Folklore Botanique De Caughnawaga and was written by Jacques Rousseau.

Cells of elodea leaves are known for their vivid exhibition of cyclosis, or cytoplasmic streaming.