Elodea | |
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Elodea canadensis foliage detail | |
Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Monocots |
Order: | Alismatales |
Family: | Hydrocharitaceae |
Subfamily: | Anacharioideae |
Genus: | Elodea Michx. |
Synonyms [1] | |
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 [2] and is also widely used as aquarium vegetation and laboratory demonstrations of cellular activities. It lives in fresh water. [3] An older name for this genus is Anacharis, which serves as a common name in North America. [4]
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 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 ). 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. [5]
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. [5]
American water weed 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, muskrat 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. [6]
Chemical methods are ineffective in eradicating Elodea – at best they only slow growth for a season or two. [8] As Elodea spreads into new ecosystems, it experiences rapid growth for 5–6 years and then slows as soil nutrients are used up. [9] Elodea is threatening aquatic environments across Europe. [10] 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. [11] [12] [13]
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. [14]
Aquatic plants are plants that have adapted to living in aquatic environments. They are also referred to as hydrophytes or macrophytes to distinguish them from algae and other microphytes. A macrophyte is a plant that grows in or near water and is either emergent, submergent, or floating. In lakes and rivers, macrophytes provide cover for fish, substrate for aquatic invertebrates, produce oxygen, and act as food for some fish and wildlife.
Hydrocharitaceae is a flowering plant family including 16 known genera with a total of ca 135 known species, that including a number of species of aquatic plant, for instance the tape-grasses, the well known Canadian waterweed, and frogbit.
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 Asia, Africa and Australia, with a sparse, scattered distribution; in Australia from Northern Territory, Queensland, and New South Wales.
Vallisneria is a genus of freshwater aquatic plant, commonly called eelgrass, tape grass or vallis. The genus is widely distributed in tropical and subtropical regions of Asia, Africa, Australia, Europe, and North America.
Alternanthera philoxeroides, commonly referred to as alligator weed, is a native species to the temperate regions of South America, which includes Argentina, Brazil, Paraguay and Uruguay. Argentina alone hosts around 27 species that fall within the range of the genus Alternanthera. Its geographic range once covered only the Parana River region of South America, but it has since expanded, having been introduced to over 30 countries, such as the United States, Japan, China, Australia, New Zealand and many more. This invasive species is believed to have been accidentally introduced to these non-native regions through sediments trapped by, or attached to, tanks and cargo of ships travelling from South America to these various areas.
Elodea canadensis is a perennial aquatic plant, or submergent macrophyte, native to most of North America. It has been introduced widely to regions outside its native range and was first recorded from the British Isles in about 1836.
Myriophyllum aquaticum is a flowering plant, a vascular dicot, commonly called parrot's-feather and parrot feather watermilfoil.
Pontederia crassipes, commonly known as common water hyacinth, is an aquatic plant native to South America, naturalized throughout the world, and often invasive outside its native range. It is the sole species of the subgenus Oshunae within the genus Pontederia. Anecdotally, it is known as the "terror of Bengal" due to its invasive growth tendencies.
Egeria densa, the large-flowered waterweed or Brazilian waterweed, is a species of Egeria native to warm temperate South America in southeastern Brazil, Argentina, Chile and Uruguay. It is considered a problematic invasive species due to its use in home aquariums and subsequent release into non-native ecosystems.
Hygrophila polysperma, commonly known as dwarf hygrophila, dwarf hygro, Miramar weed, Indian swampweed or Indian waterweed, is an aquatic plant in the family Acanthaceae. It is native to Bangladesh, India, China and Malaysia, and has also been introduced to the US states of Florida, Texas and possibly Virginia. It is listed on the Federal Noxious Weed List in the US and is illegal to import and sell in a number of states including Kansas and South Carolina.
Elodea nuttallii is a species of waterweed known by the common name western waterweed or Nuttall's waterweed. This is a perennial aquatic plant which is native to North America where it grows submersed in lakes, rivers, and other shallow water bodies. It is also found in Eurasia, where it is commonly weedy; it is not known as a weed species in its native range. It is sometimes used as an aquarium plant.
Lagarosiphon major is a monocotic aquatic plant native to Southern Africa. Common names include African elodea, curly waterweed, oxygen weed and South African oxygen weed. It is used as freshwater aquarium plant.
Limnocharis flava is a species of aquatic flowering plant which is native to Mexico, Central America, South America, Cuba, Haiti and the Dominican Republic but widely naturalized in southern and southeastern Asia: India, Sri Lanka, Cambodia, Burma, Thailand, Vietnam, Indonesia, Malaysia, Brunei and southern China.
Limnobium laevigatum is a floating aquatic plant, and is a member of the family Hydrocharitaceae. Common names include West Indian spongeplant, South American spongeplant and Amazon or smooth frogbit. This plant was introduced to North American waterways through use in aquariums and aquascapes.
An aquatic weed harvester, also known as a water mower, mowing boat and weed cutting boat, is an aquatic machine specifically designed for inland watercourse management to cut and harvest underwater weeds, reeds and other aquatic plant life. The action of removing aquatic plant life in such a manner has been referred to as "aquatic harvesting".
Fluridone is an organic compound that is used as aquatic herbicide often used to control invasive plants. It is used in the United States to control hydrilla and Eurasian watermilfoil among other species. Fluridone is sold as a solution and as a slow release solid because the herbicide level must be maintained for several weeks. The compound is a colorless solid.
Mayaca fluviatilis, also known as bog moss, is a perennial herbaceous submerged plant in the monogeneric family Mayacaceae. It is native to Central and South America, the Caribbean, and the United States where it is often sold as an aquarium plant. Through the aquatic plant trade, it has recently become naturalized in Sri Lanka, Singapore, and China. It has been identified in three locations in Australia but more populations are likely in other parts of Australia as well.