Common Names in English:
, cespitose or not, rhizomatous
or not, stoloniferous
or not. Roots
, principally adventitious. Stems (culms
) usually trigonous
, occasionally terete
, rarely compressed
, usually solid, rarely hollow or septate
. Leaves basal and/or cauline, alternate, usually 3-ranked, rarely 2-ranked or multi-ranked, bases
enclosing stem, margins
usually fused; junction of sheaths and blades
often with adaxial
flaps of tissue
of hair (ligules) ; blades frequently absent from some basal leaves
, rarely from cauline leaves, when present divergent or ascending
, flat, folded, plicate
, rolled, or terete, linear
) a shortened axis; glumaceous
) 1-many, spirally arranged
, sometimes 2-ranked, usually appressed
or ascending; scales usually all fertile
, each subtending
a single flower, sometimes proximal
and/or distal scales empty; lateral
spikes often with basal, usually empty, usually 2-keeled scale (prophyll) ; occasionally prophyll subtending and enclosing rachilla, bearing 1 pistillate
, sometimes (0-) 3 staminate flowers
and empty scales (Carex, Cymophyllus, and Kobresia) . Secondary inflorescences panicles, often modified to corymb, pseudoumbel, cyme (anthela), raceme
, spike, or capitulum (head
), rarely single spike, usually subtended by foliaceous
or, less frequently, glumaceous bracts; secondary inflorescences sometimes simulating spikelets (Carex, Cymophyllus, and Kobresia) . Flowers hypogynous, bisexual
in most genera, unisexual
in Scleria, Carex, Cymophyllus, and Kobresia; perianth absent or with (1-) 3-6(-30) bristles
and/or scales, usually falling off with fruit; stamens usually (1-) 3, rarely more, usually distinct
; pistils 1, 2-3(-4) -carpellate, fused, locule 1; style undivided or branches 2-3(-4) ; stigma sometimes papillate
. Fruits achenes, usually trigonous or biconvex
; pericarps thin (except in Scleria) . Seeds 1; testa thin, free
from pericarp; embryo basal; endosperm abundant. x
= 5-ca. 100.
Genera ca. 100, species ca. 5000 (27 genera, 843 species in the flora ) : worldwide.
No consensus exists regarding the number of genera and the overall relationships of genera within Cyperaceae. The most recent account of the family (P. Goetghebeur 1998) recognized 104 genera distributed among 4 subfamilies and 14 tribes . That arrangement differs somewhat from that of J. Bruhl (1995) . With one minor exception the arrangement of the family here follows that of Goetghebeur.
The family is characterized by the occurrence of a number of unusual cytological features including: (1) chromosomes with diffuse centromeres , (2) post-reductional meiosis, and (3) pollen grains formed from tetrads in which 3 of the 4 microspores fail to develop. The first two features are found in at least some Juncaceae and are unique to the two families. Juncaceae also have pollen in tetrads, but in that family all four microspores produce pollen grains. Some species in some genera of Cyperaceae (particularly Eleocharis) possess chromosomes with localized centromeres (S. S. Bir et al. 1993) . The wide range of chromosome numbers found in Cyperaceae is largely because of agmatoploidy; polyploidy has been hypothesized for some genera, especially Eleocharis, although polyploidy has not been demonstrated unequivocally.
Because of morphologic similarities in vegetative and inflorescence characters, the family has commonly been associated with Poaceae. Cytological features discussed above clearly indicate that to be a superficial similarity . Data from rbcL studies also support the view that Cyperaceae and Poaceae are not closely related (M. R. Duvall et al. 1993b; G. M. Plunkett et al. 1995) ; they do support the concept of close relationship between Cyperaceae and Juncaceae.
For most families of flowering plants the phenological data given are flowering times. Because most Cyperaceae cannot be reliably identified when in flower, in this volume fruiting time is given for all species by season , sometimes qualified by early, mid, or late, or by months. The fruiting time has been interpreted broadly to include the period when the fruit is more or less fully formed but not yet ripe . The fruiting period provided covers the entire range of the taxon . Quite a difference between fruiting periods in different parts of the range of the species may well occur, especially for widespread species and species with extensive elevation range.
For a recent, comprehensive review of the economic importance of Cyperaceae, see D. A. Simpson and C. A. Inglis (2001) .
, usually cespitose, often rhizomatous
, sometimes stoloniferous
; rhizomes rarely with terminal
tubers or bulbs, horizontal and long or ascending
and caudexlike. Culms
sometimes solitary, terete
, 3-5-angled or more, or strongly compressed
with internal air
cavities and incomplete
septa or sometimes hollow with complete
transverse septa. Leaves basal, 2 per culm; ligules absent; blades
absent or a mucro
) at apex of sheath
, very rarely flattened, to 6 cm. Inflorescences terminal; spikelet
1; involucral bracts
absent, rarely a proximal
scale of spikelet resembling short bract. Spikelets: scales
4-500 or more, spirally or rarely distichously arranged, each subtending
flower or proximal 1-2(-3) empty, stramineous
(straw-brown) to medium brown or red brown or blackish brown. Flowers bisexual
; perianth of (0-) 3-6(-10) bristles
, straight or curved
, shorter than to 2 times longer
than achene, retrorsely (to antrorsely) spinulose
or sometimes smooth
; stamens 1-3; styles linear
, 2-3-fid, base
(tubercle) usually persistent
, usually enlarged, usually different in appearance
from achene. Achenes biconvex
, or trigonous
Species ca. 200: worldwide.
The name of the genus has sometimes been given as Heleocharis Lestibudois; this is now regarded as an orthographic variant of Eleocharis.
Eleocharis dulcis (Burman f.) Trinius ex Henschel is sometimes cultivated for its edible tubers. Some species are weeds in rice fields , mostly extraterritorially. Almost all species are restricted to wetlands, often emergent, and sometimes submerged aquatic .
No recent comprehensive worldwide taxonomic treatment of Eleocharis is available. The treatment herein is based mostly on the extensive studies by H. K . Svenson (1929, 1932, 1934, 1937, 1939, 1947, 1957), which were mostly restricted to species of North America. Classification of Eleocharis is unusually difficult because relatively few macroscopic characters are provided by the simple structure characteristic of the genus (only two leaves, basal, without blades or with only rudimentary blades, and unbranched aerial stems, each with a single terminal spikelet and without an involucral bract). Undoubtedly much evolutionary convergence has occurred in most vegetative and reproductive structures (M. S. González-E. and J. A. Tena-F. 2000; E. H. Roalson and E. A. Friar 2000).
North American Eleocharis includes some extremely difficult species complexes that need taxonomic revision: (1) The E. palustris complex (species 17) is discussed under 1. E. palustris. (2) The E. tenuis complex (species 1621) is discussed under 21. E. tenuis. (3) The four species (species 5760) of 8c. Eleocharis subg. Zinserlingia that occur in North America belong to the E. quinqueflora (= E. pauciflora) complex, discussed under subg. Zinserlingia. (4) All six species of 8a2b. E. ser. Ovatae (species 4247) constitute a complex discussed under ser. Ovatae.
The supraspecific classification of Eleocharis used here is that of M. S. González-E. and P. M. Peterson (1997), which was based on a study of most species worldwide. Other recent classifications are based on more or less regional studies (H. K. Svenson 1957; T. V. Egorova 1981; I. Kukkonen 1990). A study using limited DNA data from 30 species (E. H. Roalson and E. A. Friar 2000), mostly from North America, indicates that the following supraspecific taxa are probably monophyletic: 8a2a. ser. Maculosae, 8a2b. ser. Ovatae, and 8d. subg. Limnochloa, whereas the following taxa are probably para- or polyphyletic: 8a1. sect. Eleocharis, 8a1a. ser. Eleocharis, 8a1d. ser. Tenuissimae, and 8a2. sect. Eleogenus.
Users of this treatment should be aware of the following: culms that are smooth when fresh are often ridged when dry; culms of pressed specimens are often flattened and must be carefully rehydrated and sectioned to determine the original cross-section shape ; culm widths given here are usually for culms pressed flat; floral scale widths are measured on flattened scales or by doubling the width measured on scales folded along the midrib ; and achene length does not include the tubercle, which is often included in descriptions published elsewhere. In this treatment, I describe the tubercle (style base) after the achene in consecutive sentences to stress the separate nature of the two structures.
Some species, mostly of 8a1d. Eleocharis ser. Tenuissimae, often proliferate from spikelets, often on arching or horizontal culms, especially when growing as submerged or floating aquatics. Because many such plants reproduce entirely asexually and have no normal spikelets or achenes, it is often impossible to identify them to species. The invalid name E. prolifera Torrey has sometimes been used for these plants. Species of ser. Tenuissimae in which the spikelets may be proliferous and which are easily confused with each other are E. baldwinii, E. brittonii, E. microcarpa, E. nana, E. retroflexa, and E. vivipara. Aquatic forms of at least some of those species are very hard to distinguish from Websteria confervoides (Poiret) S. S. Hooper. Other species in which the spikelets often poliferate or the culm tips root are E. pachycarpa of ser. Tenuissimae, E. melanocarpa of 8a1b. ser. Melanocarpae, and E. rostellata of 8a1c. ser. Rostellatae. When submersed , plants of E. acicularis of 8b. subg. Scirpidium and E. elongata and E. robbinsii of 8d. subg. Limnochloa may be entirely vegetative, the latter two species sometimes forming whorls of flaccid stems without spikelets.
Species Eleocharis torticulmis
; rhizomes 1.5–2 mm thick, scales
7–9 mm, thinly papery
, sometimes fibrous
; resting buds unknown;
caudices present, hard, 3 mm thick. Culms
, markedly spirally
twisted, markedly obliquely contracted
, when dry often
with to 6 broad, rounded
on each side, greatly compressed
3–4 times as wide as thick, 20–40 cm × 1.5–2.5
mm, firm; culm tufts not proximally bulbous. Leaves: distal leaf
to medium (or dark) brown, papery, apex often
dark brown to reddish, broadly obtuse
. Spikelets 6–8 × 2–3
scale empty, 3–4 mm, shorter than to equaling
scales 8–10 per spikelet, 3.5–5 × 2
0–5, unequal, rudimentary
achene, the shorter stout, smooth
or nearly so, the longer
1.8 –3 mm. Achenes stramineous to
medium brown, thickly trigonous
, 1.75–2.75 × 1–1.25 mm;
0.3–0.6 mm. Tubercles
0.25–0.6 × 0.3–0.55
Flowers: Bloom Period: May, June, July.
Fruiting summer (Jun–Jul). Fens , wet meadows, vernal ponds ; of conservation concern; 1100 m .
- Whittaker & Margulis,1978
- Haeckel, 1866
- Cavalier-Smith, 1981
- Sinnott, 1935 ex Cavalier-Smith, 1998
- Vascular Plants
- Kenrick & Crane, 1997
- Brongniart, 1843
- Takhtajan, 1967
- Takhtajan, 1967
- Small, 1903
- A.L. de Jussieu, 1789, nom. cons.
- Sedge Family
- R. Brown, 1810
- Spike-rush, spikesedge [Greek heleios, dwelling in a marsh, and charis, grace]
- Specific epithet:
- S. G. Smith, Novon. 11: 250, figs. 2, 4E–I. 2001.
- Botanical name: - Eleocharis torticulmis S.G.Sm. S. G. Smith, Novon. 11: 250, figs. 2, 4E–I. 2001.
- Specific epithet: torticulmis - S. G. Smith, Novon. 11: 250, figs. 2, 4E–I. 2001.
- Genus: Eleocharis () - R. Brown, 1810 - Spike-rush, spikesedge [Greek heleios, dwelling in a marsh, and charis, grace]
- Tribe: Eleocharideae ()
- Subfamily: Cyperoideae ()
- Family: Cyperaceae () - A.L. de Jussieu, 1789, nom. cons. - Sedge Family
- Order: Poales () - Small, 1903
- Superorder: Juncanae () - Takhtajan, 1967
- Subclass: Commelinidae () - Takhtajan, 1967
- Class: Spermatopsida () - Brongniart, 1843
- Infraphylum: Radiatopses () - Kenrick & Crane, 1997
- Subphylum: Euphyllophytina ()
- Phylum: Tracheophyta () - Sinnott, 1935 ex Cavalier-Smith, 1998 - Vascular Plants
- Subkingdom: Viridaeplantae () - Cavalier-Smith, 1981
- Kingdom: Plantae () - Haeckel, 1866 - Plants
Status: Accepted Name
Last scrutiny: 21-Jun-2005
Members of the genus Eleocharis
ZipcodeZoo has pages for 92 species, subspecies, varieties, forms, and cultivars in this genus:
E. acicularis (Least Spike-Rush) · E. acicularis f. occidentalis (Needle Spike-Rush) · E. acicularis var. acicularis (Needle Spike-Rush) · E. acicularis var. gracilescens (Needle Spikerush) · E. acicularis var. porcata (Needle Spikerush) · E. acicularis var. submersa (Needle Spikerush) · E. acuta (Common Spike-Rush) · E. acutangula (Acute Spikerush) · E. acutisquamata (Sharp-Scale Spikerush) · E. albida (White Spikerush) · E. atropurpurea (Purple Spikerush) · E. austrotexana (Rio Grande Spikerush) · E. baldwinii (Baldwin's Spikerush) · E. bella (Beautiful Spikerush) · E. bolanderi (Bolander's Spikerush) · E. brachycarpa (Short-Fruited Spikerush) · E. brittonii (Britton's Spikerush) · E. cancellata (Arizona Spike-Rush) · E. cellulosa (Carolina Spike-Rush) · E. compressa (Flat-Stem Spike-Rush) · E. compressa var. acutisquamata (Sharpscale Spikerush) · E. congesta (Spikerush) · E. cylindrica (Cylinder Spike-Rush) · E. decumbens (Decumbent Spikerush) · E. dulcis (Chinese Waterchestnut) · E. dulcis var. tuberosa (Chinese Water-Chestnut) · E. dulcis var. Variegata (Chinese Water Chestnut) · E. elegans (Elegant Spikerush) · E. elliptica (Elliptic Spikerush) · E. elongata (Slim Spike-Rush) · E. engelmannii (Engelmann Spike-Rush) · E. equisetoides (Horsetail Spikerush) · E. erythropoda (Bald Spike-Rush) · E. fallax (Creeping Spikerush) · E. flavescens (Pale Spikerush) · E. flavescens var. flavescens (Leafy Fleabane) · E. flavescens var. thermalis (Yellow Spikerush) · E. geniculata (Canada Spikesedge) · E. halophila (Salt-Marsh Spike-Rush) · E. intermedia (Matted Spikerush) · E. interstincta (Knotted Spikerush) · E. kamtschatica (Kamchatka Spike-Rush) · E. kuroguwai (Spikerush) · E. lanceolata (Daggerleaf Spikerush) · E. melanocarpa (Black-Fruited Spike-Rush) · E. microcarpa (Small-Fruited Spike-Rush) · E. minima (Small Spikerush) · E. montana (Dombey's Spike-Rush) · E. montevidensis (Hairgrass) · E. mutata (Angled Spikerush) · E. nana (Hair-Like Spikerush) · E. nigrescens (Black Spikerush) · E. nitida (Quill Spikerush) · E. obtusa (Blunt Spikerush) · E. occulata (Limestone Spikerush) · E. ochrostachys (Spikerush) · E. oligantha (Fewflowered Spikerush) · E. olivacea (Bright Green Spikerush) · E. olivacea Torr. var. olivacea Torr. (Bright Green Spikerush) · E. olivacea var. olivacea (Bright Green Spikerush) · E. olivacea var. reductiseta (Bright Green Spikerush) · E. ovata (Ovate Spikerush) · E. pachycarpa (Black Sand Spikerush) · E. pachystyla (False Junco) · E. palmeri (Palmer's Spikerush) · E. palustris (Common Spike-Rush) · E. palustris palustris (Common Spikerush) · E. palustris uniglumis (Common Spikerush) · E. palustris var. calva (Creeping Spike-Rush) · E. parishii (Parish Spikerush) · E. parvula (Dwarf Spikerush) · E. quadrangulata (Square Stemmed Spike Rush) · E. quinqueflora (Few-Flower Spike-Rush) · E. radicans (Rooted Spike-Rush) · E. retroflexa chaetaria (Coastal Plain Spikerush) · E. robbinsii (Robbins Spikerush) · E. rostellata (Beaked Spike-Rush) · E. schaffneri (Schaffner's Spikerush) · E. setifolia (Smallflower Spikerush) · E. sintenisii (Sintenis' Spikerush) · E. tenuis (Slender Spikerush) · E. tenuis (Willd.) J.A.Schultes var. tenuis (Willd.) J.A.Schultes (Slender Spikerush) · E. tenuis var. pseudoptera (Slender Spikerush) · E. tenuis var. tenuis (Slender Spikerush) · E. tenuis var. verrucosa (Slender Spikerush) · E. torticulmis (Twisted Spikerush) · E. tortilis (Twisted Spike-Rush) · E. tricostata (Three-Angle Spikerush) · E. tuberculosa (Cone-Cup Spikerush) · E. uniglumis (Creeping Spike-Rush) · E. vivipara (Viviparous Spike-Rush) · E. wolfii (Wolf Spikerush)
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- Bruhl, J. 1995. Sedge genera of the world: Relationships and a new classification of the Cyperaceae. Austral. Syst. Bot. 8: 125-305.
- Goetghebeur, P. 1998. Cyperaceae. In: K. Kubitzki et al., eds. 1990+. The Families and Genera of Vascular Plants. 4+ vols. Berlin etc. Vol. 4, pp. 141-190.
- Mackenzie, K. K. 1931-1935. Cyperaceae [in part]. In: N. L. Britton et al., eds. 1905+. North American Floraâ¦. 47+ vols. New York. Vol. 18, parts 1-7, pp. 1-478.
- Simpson, D. A. and C. A. Inglis. 2001. Cyperaceae of economic, ethnobotanical and horticultural importance: A checklist. Kew Bull. 56: 257-360.
- Svenson, H. K. 1957. Cyperaceae. Tribe 2, Scirpeae. In: N. L. Britton et al., eds. 1905+. North American Flora.... 47+ vols. New York. Vol. 18, pp. 505-556.
- Tucker, G. C. 1987. The genera of Cyperaceae in the southeastern United States. J. Arnold Arbor. 68: 361-445.
- Egorova, T. V. 1981. Generis Eleocharis (Cyperaceae) florae URSS systema et conspectus. Novosti Sist. Vyssh. Rast. 18: 95124.
- González-E., M. S. and J. A. Tena-F. 2000. Eleocharis (Cyperaceae) in the New World. In: K. L. Wilson and D. A. Morrison, eds. 2000. Monocots: Systematics and Evolution. Melbourne. Pp. 637643.
- González-E., M. S. and P. M. Peterson. 1997. A classification of and key to the supraspecific taxa in Eleocharis (Cyperaceae). Taxon 46: 433449.
- González-E., M. S., P. M. Peterson, and I. Granzow-de la C. 1997. A cladistic and phenetic analysis of the Pauciflorae group of Eleocharis (Cyperaceae). BioLlania, Ed. Esp. 6: 341368.
- Kukkonen, I. 1990. On the genus Eleocharis (Cyperaceae) in the Flora Iranica area, with revised infrageneric classification and nomenclature. Ann. Bot. Fenn. 27: 109117.
- Roalson, E. H. and E. A. Friar. 2000. Infrageneric classification of Eleocharis (Cyperaceae) revisited: Evidence from internal transcribed spacer (ITS) region of nuclear ribosomal DNA. Syst. Bot. 25: 323336.
- Smith, S. G. 2001. Taxonomic innovations in North American Eleocharis (Cyperaceae). Novon 11: 241257.
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- Svenson, H. K. 1934. Monographic studies in the genus Eleocharis. III. Rhodora 35: 377389.
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- Svenson, H. K. 1929. Monographic studies in the genus Eleocharis. I. Rhodora 31: 121135, 152163, 167191, 199219, 224242.
- Svenson, H. K. 1932. Monographic studies in the genus Eleocharis. II. Rhodora 34: 193203, 215227.
- Svenson, H. K. 1937. Monographic studies in the genus Eleocharis. IV. Rhodora 39: 210231, 236273.
- Brands, S.J. (comp.) 1989-present. The Taxonomicon. Universal Taxonomic Services, Zwaag, The Netherlands. Accessed January 31, 2012.
- "Eleocharis". in Flora of North America Vol. 23 Page 112, 113, 115. Published by Oxford University Press. Online at EFloras.org.
- Global Biodiversity Information Facility. Accessed February 29, 2008. http://www.gbif.org Mediated distribution data from 2 providers.
- Ruggiero M., Gordon D., Bailly N., Kirk P., Nicolson D. (2011). The Catalogue of Life Taxonomic Classification, Edition 2, Part A. In: Species 2000 & ITIS Catalogue of Life: 2011 Annual Checklist (Bisby F.A., Roskov Y.R., Orrell T.M., Nicolson D., Paglinawan L.E., Bailly N., Kirk P.M., Bourgoin T., Baillargeon G., Ouvrard D., eds). DVD; Species 2000: Reading, UK.
- World Checklist of Selected Plant Families. Release date: November 27, 2009
Accessed through GBIF Data Portal February 29, 2008:
- Berkeley Natural History Museums: University and Jepson Herbaria DiGIR provider
- The New York Botanical Garden: Vascular Plant Type Specimens
- Biodiversity Heritage Library NamebankID: 8287787
- Catalogue of Life Accepted Name Code: Kew-242930
- Globally Unique Identifier: urn:lsid:ipni.org:names:321530-2
- MoBot NameID: 50183046
- Natural Heritage Network Species Identifier: PMCYP092E0
- Zipcode Zoo Species Identifier: 170086
- Peter W. Ball, A. A. Reznicek, David F. Murray "Cyperaceae". in Flora of North America Vol. 23 Page 3, 4, 192, 243, 252. Oxford University Press. Online at EFloras.org. [back]
- S. Galen Smith, Jeremy J. Bruhl, M. Socorro González-Elizondo & Francis J. Menapace "Eleocharis". in Flora of North America Vol. 23 Page 4, 6, 7, 29, 60, 61, 121. Oxford University Press. Online at EFloras.org. [back]
- "Eleocharis". in Flora of North America Vol. 23 Page 112, 113, 115. Oxford University Press. Online at EFloras.org. [back]