''Eleocharis'' is a virtually

cosmopolitan Cosmopolitan may refer to: Internationalism * World citizen, one who eschews traditional geopolitical divisions derived from national citizenship * Cosmopolitanism, the idea that all of humanity belongs to a single moral community * Cosmopolitan ...

genus of 250 or more species of

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

s in the sedge family,

Cyperaceae The Cyperaceae () are a family of graminoid (grass-like), monocotyledonous flowering plants known as wikt:sedge, sedges. The family (biology), family is large; botanists have species description, described some 5,500 known species in about 90 ...

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

Greek Greek may refer to: 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 of all kno ...

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, a cosmopolitan distribution is the range of a taxon that extends across most or all of the surface of the Earth, in appropriate habitats; most cosmopolitan species are known to be highly adaptable to a range of climatic and en ...

, with centers of diversity in the

Amazon Rainforest The Amazon rainforest, also called the Amazon jungle or Amazonia, is a Tropical and subtropical moist broadleaf forests, moist broadleaf tropical rainforest in the Amazon biome that covers most of the Amazon basin of South America. This basin ...

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 considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

Andes The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the List of longest mountain chains on Earth, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range ...

, northern

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

, eastern

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

Southern Africa Southern Africa is the southernmost region of Africa. No definition is agreed upon, but some groupings include the United Nations geoscheme for Africa, United Nations geoscheme, the intergovernmental Southern African Development Community, and ...

, and subtropical

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

. 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 semi-aquatic ecosystem whose groundcovers are flooded or saturated in water, either permanently, for years or decades, or only seasonally. Flooding results in oxygen-poor ( anoxic) processes taking place, especially ...

s, while many others are small

caespitose This glossary of botanical terms is a list of definitions of terms and concepts relevant to botany and plants in general. Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary ...

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 Cyperaceae, sedge native to Asia, tropical Africa, and Oceania. It is grown in many countries for its edible corms, but if eaten uncooked, the surface of the ...

''. These plants bear tubers on their rhizomes which may be peeled and eaten raw or boiled. In Australia, magpie geese 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'' 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'' 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 ''Eleocharis plana'', the flat spike-sedge, is a flat perennial sedge (in the family Cyperaceae) with creeping rhizomes, which grows up to 80 cm high in moist situations. It is widespread in inland New South Wales, and is also found in Queenslan ...

'' 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 ''Eleocharis triquetra'' is a sedge of the family Cyperaceae that is native to the Kimberley region of Western Australia Western Australia (WA) is the westernmost state of Australia. It is bounded by the Indian Ocean to the north and west, th ...

'' K.L.Wilson *'' Eleocharis tuberculosa '' (Michx.) Roem. & Schult. *'' Eleocharis uniglumis'' (Link) (Link) Schult., 1824 *'' Eleocharis vivipara'' Link – umbrella hairgrass *'' Eleocharis wadoodii'' S.R.Yadav, Lekhak & Chandore * '' Eleocharis welwitschii'' Nelmes * '' Eleocharis wichurae'' Boeckeler * '' Eleocharis wilkensii'' Schuyler * '' Eleocharis wolfii'' (A.Gray) A.Gray ex Britton

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. {{Authority control Cyperaceae genera Aquatic plants Freshwater plants