Eleocharis

{{Short description|Genus of grass-like plants}} {{Automatic taxobox |image = Starr 081230-0543 Eleocharis calva.jpg |image_caption = ''Eleocharis calva'' |display_parents = 2 |taxon = Eleocharis |authority = R.Br.<ref name="GRIN">{{cite web |url=http://www.ars-grin.gov/cgi-bin/npgs/html/genus.pl?4164 |title=Genus: ''Eleocharis'' R. Br. |work=Germplasm Resources Information Network |publisher=United States Department of Agriculture |date=2010-03-03 |access-date=2013-05-03 |archive-url=https://web.archive.org/web/20131203124206/http://www.ars-grin.gov/cgi-bin/npgs/html/genus.pl?4164 |archive-date=2013-12-03 |url-status=dead }}</ref> |synonyms_ref = <ref name=olga/> |synonyms = *''Heleocharis'' T.Lestib *''Limnochloa'' P.Beauv. ex Lestib *''Megadenus'' Raf. *''Clavula'' Dumort. *''Heliocharis'' Lindl. *''Baeothryon'' Ehrh. ex A.Dietr. *''Chaetocyperus'' Nees *''Eleogenus'' Nees *''Scirpidium'' Nees *''Elaeocharis'' Brongn. *''Websteria'' S.H.Wright *''Chlorocharis'' Rikli *''Chillania'' Roiv. *''Chamaegyne'' Suess. *''Helonema'' Suess. *''Egleria'' L.T.Eiten }}

'''''Eleocharis''''' is a virtually cosmopolitan genus of 250 or more species of flowering plants in the sedge family, Cyperaceae.<ref name=olga>[http://apps.kew.org/wcsp/namedetail.do?name_id=242252 Kew World Checklist of Selected Plant Families]</ref> The name is derived from the Greek words ἕλειος (''heleios''), meaning "marsh dweller," and χάρις (''charis''), meaning "grace."<ref name="eFloras">{{cite web |url=http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=111420 |first1=S. Galen |last1=Smith |first2=Jeremy J. |last2=Bruhl |first3=M. Socorro |last3=González-Elizondo |first4=Francis J. |last4=Menapace |title='''ELEOCHARIS''' R. Brown, Prodr. 224. 1810. |work=Flora of North America |publisher=eFloras.org |access-date=2013-05-03}}</ref> Members of the genus are known commonly as '''spikerushes''' or '''spikesedges'''. The genus has a geographically cosmopolitan distribution, with centers of diversity in the Amazon rainforest and adjacent eastern slopes of the South American Andes, northern Australia, eastern North America, California, Southern Africa, and subtropical Asia. 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).<ref>Govaerts, R. & Simpson, D.A. (2007). World Checklist of Cyperaceae. Sedges: 1-765. The Board of Trustees of the Royal Botanic Gardens, Kew.</ref>

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 wetlands, 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.<ref>[http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=111420 Flora of North America, Vol. 23 Page 4, 6, 7, 29, 60, ''Eleocharis'' R. Brown, Prodr. 224. 1810. ]</ref><ref>[http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=111420 Flora of China, Vol. 23 Page 188, <big>荸荠属</big> bi qi shu, ''Eleocharis'' R. Brown, Prodr. 224. 1810. ]</ref><ref>[http://luirig.altervista.org/flora/taxa/index1.php?scientific-name=eleocharis+atropurpurea Altervista Flora Italiana, genere Eleocharis ] includes photos plus distribution maps for Europe and sometimes for North America</ref><ref>[http://bonap.net/NAPA/TaxonMaps/Genus/County/Eleocharis 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.{{citation needed|date=September 2022}}

One of the best known species is the Chinese water chestnut, ''Eleocharis dulcis''. 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 carniolica'' W.D.J.Koch *''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 *''Eleocharis dulcis'' (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<ref name="ITIS">{{ITIS |id=40010 |taxon=''Eleocharis'' |access-date=2013-05-03}}</ref><ref name="GRINSpecies">{{cite web |url=http://www.ars-grin.gov/cgi-bin/npgs/html/splist.pl?4164 |archive-url=https://archive.today/20130626171143/http://www.ars-grin.gov/cgi-bin/npgs/html/splist.pl?4164 |url-status=dead |archive-date=2013-06-26 |title=GRIN Species Records of ''Eleocharis'' |work=Germplasm Resources Information Network |publisher=United States Department of Agriculture |access-date=2013-05-03 }}</ref> *''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== {{Reflist}}

==External links== {{Commons category}} {{Wikispecies}} *[https://plants.usda.gov/java/profile?symbol=ELEOC USDA Plants Profile: North American Species] *[http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=111420 eFloras Profile] *[https://web.archive.org/web/20060927195550/http://www.amjbot.org/cgi/content/full/93/5/707 Baksh & Richards (2006) An architectural model for ''Eleocharis'': morphology and development of ''Eleocharis cellulosa'' (Cyperaceae). ''Am J Botany'' 93:707-15.] *[http://www.wetwebmedia.com/plantedtkssubwebindex/eleocharis.htm Hairgrass] {{Webarchive|url=https://web.archive.org/web/20140222163128/http://www.wetwebmedia.com/plantedtkssubwebindex/eleocharis.htm |date=2014-02-22 }} *[http://www.botany.com/eleocharis.html Botany.com] {{Webarchive|url=https://web.archive.org/web/20130617024616/http://www.botany.com/eleocharis.html |date=2013-06-17 }} *Rataj, Karel. 1977. Aquarium plants; hair grass. TFH 12/77.

Category:Eleocharis Category:Cyperaceae genera Category:Aquatic plants Category:Freshwater plants