''Eleocharis'' is a virtually

cosmopolitan Cosmopolitan may refer to: Food and drink * Cosmopolitan (cocktail), also known as a "Cosmo" History * Rootless cosmopolitan, a Soviet derogatory epithet during Joseph Stalin's anti-Semitic campaign of 1949–1953 Hotels and resorts * Cosmopoli ...

genus of 250 or more species of

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants t ...

s in the sedge family,

Cyperaceae The Cyperaceae are a family of graminoid (grass-like), monocotyledonous flowering plants known as sedges. The family is large, with some 5,500 known species described in about 90 genera, the largest being the "true sedges" genus '' Carex'' ...

.Kew World Checklist of Selected Plant Families
/ref> The name is derived from the

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

words ἕλειος (''heleios''), meaning "marsh dweller," and χάρις (''charis''), meaning "grace." Members of the genus are known commonly as spikerushes or spikesedges. The genus has a geographically

cosmopolitan distribution In biogeography, cosmopolitan distribution is the term for the range of a taxon that extends across all or most of the world in appropriate habitats. Such a taxon, usually a species, is said to exhibit cosmopolitanism or cosmopolitism. The extr ...

, with centers of diversity in the

Amazon Rainforest The Amazon rainforest, Amazon jungle or ; es, Selva amazónica, , or usually ; french: Forêt amazonienne; nl, Amazoneregenwoud. In English, the names are sometimes capitalized further, as Amazon Rainforest, Amazon Forest, or Amazon Jungle. ...

and adjacent eastern slopes of the

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sou ...

Andes The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S ...

, northern

Australia Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. With an area of , Australia is the largest country by ...

, eastern

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and th ...

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...

Southern Africa Southern Africa is the southernmost subregion of the African continent, south of the Congo and Tanzania. The physical location is the large part of Africa to the south of the extensive Congo River basin. Southern Africa is home to a number o ...

, and subtropical

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an are ...

. The vast majority of ''Eleocharis'' species grow in aquatic or mesic habitats from sea level to higher than 5,000 meters in elevation (in the tropical Andes). The genus itself is relatively easy to recognize; all ''Eleocharis'' species have photosynthetic stems but no green leaves (the leaves have been reduced to sheaths surrounding the base of the stems). Many species are robust, rhizomatously-spreading plants of lowland tropical

wetland A wetland is a distinct ecosystem that is flooded or saturated by water, either permanently (for years or decades) or seasonally (for weeks or months). Flooding results in oxygen-free (Anoxic waters, anoxic) processes prevailing, especially in t ...

s, while many others are small caespitose annual or perennial herbs growing near streams, and still others are intermediate. There are also a number of species that are obligate aquatic species, which usually have submerged, branching stems and often exhibit interesting photosynthetic adaptations, such as the ability to switch between C₃ and C₄ carbon fixation in response to different environmental stimuli. In all ''Eleocharis'' species, the flowers are borne on unbranched terminal spikelets at the apices of stems.Biota of North America Program, 2013 county distribution maps for US and Canadian species
/ref> In spite of the diversity of the genus itself, taxonomic characters useful for delimiting species within it are few, and many species are very difficult to tell apart. Many currently recognized species with very wide geographic ranges are highly polymorphic. Some of these species probably contain multiple independently evolving lineages. Because of their difficult nature, it is suggested that many botanists avoid collecting these plants and so many species are under-represented in the botanical record. One of the best known species is the Chinese water chestnut, ''

Eleocharis dulcis ''Eleocharis dulcis'', the Chinese water chestnut or water chestnut, is a grass-like sedge native to Asia, tropical Africa, and Oceania. It is grown in many countries for its edible corms. The water chestnut is not a nut, but an aquatic v ...

''. These plants bear tubers on their rhizomes which may be peeled and eaten raw or boiled. In Australia,

magpie geese The magpie goose (''Anseranas semipalmata'') is the sole living representative species of the family Anseranatidae. This common waterbird is found in northern Australia and southern New Guinea. As the species is prone to wandering, especially ...

rely almost exclusively on these tubers for sustenance for a significant portion of the year.

Selected species

*'' Eleocharis acicularis'' (L.) Roem. & Schult. – needle spikerush; dwarf hairgrass *'' Eleocharis acuta'' R.Br. *'' Eleocharis acutangula'' (Roxb.) Schult. *'' Eleocharis afflata'' Steud. *'' Eleocharis atropurpurea'' (Retz.) J.Presl & C.Presl – purple spikerush *'' Eleocharis baldwinii'' (Torr.) Chapm. *'' Eleocharis bella'' (Piper) Svenson – beautiful spikerush *''

Eleocharis bifida ''Eleocharis bifida'' is a species of spikesedge known by the common name glade spikerush. It is native to the Eastern United States, where it is endemic to the Interior Low Plateau and very small part of the Ridge and Valley ecoregions. This ...

'' S.G. Smith glade spikerush *'' Eleocharis bolanderi'' A.Gray – Bolander's spikerush *'' Eleocharis brassii'' S.T.Blake *'' Eleocharis brittonii'' Svenson ex Small *'' Eleocharis caespitosissima'' Baker *'' Eleocharis cellulosa'' Torr. – coastal spikerush, Gulf Coast spikerush *''

Eleocharis compressa ''Eleocharis'' is a virtually cosmopolitan genus of 250 or more species of flowering plants in the sedge family, Cyperaceae. The name is derived from the Greek words ἕλειος (''heleios''), meaning "marsh dweller," and χάρις (''charis'' ...

'' Sull. – flatstem spikerush *'' Eleocharis confervoides'' (Poir.) Steud. *'' Eleocharis congesta'' D.Don *'' Eleocharis cylindrostachys'' Boeckler *'' Eleocharis dietrichiana'' Boeckler *''

'' (Burm.f.) Trin. ex Hensch. – Chinese water chestnut *'' Eleocharis elegans'' (Kunth) Roem. & Schult. *'' Eleocharis equisetoides'' (Elliott) Torr. *'' Eleocharis erythropoda'' Steud. – Red-stemmed spikerush *'' Eleocharis filiculmis'' Kunth *'' Eleocharis geniculata'' (L.) Roem. & Schult. – Canada spikesedge *'' Eleocharis gracilis'' R.Br. *'' Eleocharis halophila'' Fernald & Brackett – saltmarsh spikerush *'' Eleocharis jacobsiana'' K.L.Wilson *'' Eleocharis keigheryi'' K.L.Wilson *'' Eleocharis kuroguwai'' Ohwi *'' Eleocharis macrostachya'' Britton – pale spikerush *'' Eleocharis montana'' (Kunth) Roem. & Schult. *'' Eleocharis montevidensis'' Kunth – sand spikerush *'' Eleocharis mutata'' (L.) Roem. & Schult. – scallion grass *'' Eleocharis nitida'' Fernald – neat spikerush *'' Eleocharis nodulosa'' Schult. *'' Eleocharis obtusa'' (Willd.) Schult. – blunt spikerush *'' Eleocharis ochrostachys'' Steud. *'' Eleocharis pachycarpa'' Desv. – black sand spikerush *'' Eleocharis pachystyla'' (C.Wright) C.B.Clarke – false junco *'' Eleocharis pallens'' S.T.Blake – pale spikerush *'' Eleocharis palustris'' (L.) Roem. & Schult. – common spikerush *'' Eleocharis papillosa'' Latz *'' Eleocharis parishii'' Britton – Parish's spikerush *'' Eleocharis parvula'' (Roem. & Schult.) Link ex Bluff et al. – dwarf spikerush, hairgrass *'' Eleocharis pellucida'' J.Presl & C.Presl *'' Eleocharis philippinensis'' Svenson *'' Eleocharis plana'' S.T.Blake *'' Eleocharis pusilla'' R.Br. *'' Eleocharis quadrangulata'' (Michx.) Roem. – squarestem spikerush *'' Eleocharis quinqueflora'' (Hartmann) O.Schwarz – fewflower spikerush *'' Eleocharis radicans'' (A.Dietr.) Kunth – rooted spikerush *'' Eleocharis rivalis'' K.L.Wilson *'' Eleocharis rostellata'' (Torr.) Torr. – beaked spikerush *'' Eleocharis sanguinolenta'' K.L.Wilson *'' Eleocharis sellowiana'' Kunth *'' Eleocharis sphacelata'' R.Br. – tall spikerush *'' Eleocharis spiralis'' (Rottb.) Schult. *'' Eleocharis sundaica'' J.Kern *'' Eleocharis tenuis'' (Willd.) Schult. – slender spikerush *'' Eleocharis torticulmis'' S.G.Sm. – twist-stem spikerush *'' Eleocharis tortilis'' (Link) Schult. – twisted spikerush *'' Eleocharis triquetra'' K.L.Wilson *'' Eleocharis tuberculosa '' (Michx.) Roem. & Schult. *'' Eleocharis uniglumis'' (Link) (Link) Schult., 1824 *'' Eleocharis vivipara'' Link – umbrella hairgrass

References

External links

USDA Plants Profile: North American SpecieseFloras ProfileBaksh & Richards (2006) An architectural model for ''Eleocharis'': morphology and development of ''Eleocharis cellulosa'' (Cyperaceae). ''Am J Botany'' 93:707-15.

*Rataj, Karel. 1977. Aquarium plants; hair grass. TFH 12/77. {{Taxonbar, from=Q161871 Cyperaceae genera Aquatic plants Freshwater plants