1. Cyperaceae Juss.

    1. This family is accepted.

[NTK]

Prata, A.P.N. & Simpson, D.A. (2009). Neotropical Cyperaceae.

Morphology
Description

Perennial or annual herbs, terrestrial, rarely submerged aquatics, or scandent; perennial species rhizomatous, stoloniferous, bulbous, or subbulbous; annual species generally caespitose. Some genera have a caudex (e.g. Bulbostylis). Culms usually trigonous to triquetrous, less often terete , flattened or irregular, formed by prominent ribs. Leaves basal or basal and cauline, generally tristichous with a closed sheath ; blade usually linear , glabrous , scabrous , hairy, hispid , with central midrib prominent , sometimes with an expanded, 3-veined blade (Hypolytrum, Mapania); ligules usually absent (but present in Scleria, Fimbristylis, Fuirena and Carex).  Involucral bracts usually present, leaf-like or glume-like. Inflorescence simple to compound , lax to condensed and usually highly branched, paniculate, corymbose, spicate, or capitate , comprising 1 to many ultimate inflorescence units, these either indeterminate (= spikelets) or, in a few genera, determinate (= spicoids). Spikelets few to many, sometimes reduced to a single spikelet (Eleocharis), terminal or lateral comprising 1-many scales, usually spirally arranged, or sometimes distichous ; flowers bisexual , unisexual, or both types present; spicoids few to many, terminal , with 2-12 membranous scales on a much reduced axis , the lowest 2 scales opposite, keeled , the spicoid subtended and usually hidden by a larger scale-like bract ; flowers unisexual. Perianth absent or of 1-many bristles or scales. Stamens 1-3. Ovary superior , carpels usually 2-3, locule 1, ovule 1; style short to elongate, base thickened and sometimes persistent ; stigma usually 2-3-branched. Fruit a nutlet, nutlet-like or a nutlet protected by a utricle.

Distribution
Distribution in the Neotropics
  • Cyperaceae have high species diversity in the Neotropics. Of the 5,400 species described in 106 genera (Govaerts et al. 2007), 43 genera and approximately 1,000 species occur in the Neotropics. Brazil has 622 species in 43 genera (Alves et al. 2007).
Diagnostic
Key differences from similar families

Cyperaceae are sometimes confused with Poaceae and Juncaceae.  These, however, differ from Cyperaceae in the following characters:

  • Poaceae - leaves alternate, distichous, with open sheath and a ligule present at the blade insertion; flowers with perianth reduced to 2 scales (lodicules), protected by a series of bracts (glumes, lemma, palea); fruit a caryopsis.
  • Juncaceae - leaves spirally arranged, sheath open or closed; flowers trimerous; perianth of tepals; fruit capsular.
Useful tips for generic identification
  • Rhynchospora - Style-base persistent on the nutlet, often forming a beak; scales spirally arranged.
  • Carex - Spikes unisexual or with staminate and pistillate flowers; pistillate flowers enclosed  by a utricle.
  • Cyperus - Inflorescence terminal; spikelets several to many per inflorescence; scales distichous; flowers bisexual; nutlet lenticular or trigonous; stigmas 2-3.
  • Bulbostylis - Trichomes in the leaf sheath apex and stylopodium thickened and persistent in the nutlet apex.
  • Eleocharis - Leaves reduced to sheath, scales generally imbricate, inflorescence  unispicate, bisexual flowers with perianth reduced to bristles or absent and the style base persistent, dilated and articulated with ovary.
  • Scleria - Spikelets unisexual, nutlet usually globose with hypogynium adnate to the base.
Distinguishing characters (always present)
  • Herbs.
  • Flowers grouped in spikelets.
  • Ovarysuperior, 2-3-carpellate, locule 1, ovule 1.
  • Fruit a nutlet.
Other important characters
  • Tristichous leaves.
  • Ligule.
  • Silica.
  • Persistentstyle base (stylopodium) in some genera (Bulbostylis, Eleocharis, Rhynchospora).
General Description
General notes
  • Cosmopolitan, occupying diverse habitats, with a preference for open and wetland environments. The third largest family of monocotyledons and the seventh largest in the Angiosperms.
Number of genera

43 genera and approximately 1,000 species.  Larger genera in Neotropics: Rhynchospora (250 spp.), Carex (200 spp.), Cyperus (150 spp.), Bulbostylis (70 spp.), Eleocharis (60 spp.) and Scleria (60 spp.).

  • Abildgaardia Vahl
  • Androtrichum (Brongn.) Brongn.
  • Ascolepis Nees ex Steud.
  • Becquerelia Brongn.
  • Bisboeckelera Kuntze
  • Bolboschoenus (Asch.) Palla
  • Bulbostylis Kunth
  • Calyptrocarya Nees
  • Carex L.
  • Cephalocarpus Nees
  • Cladium P. Browne
  • Cryptangium Schrad. ex. Nees
  • Cyperus L.
  • Diplacrum R. Br.
  • Diplasia Rich.
  • Egleria Eiten
  • Eleocharis R. Br.
  • Everardia Ridl. ex Thurn.
  • Exochogyne C.B. Clarke
  • Fimbristylis Vahl
  • Fuirena Rottb.
  • Hypolytrum Rich.
  • Isolepis R. Br.
  • Koyamaea W. Thomas & Davidse.
  • Kyllinga Rottb.
  • Lagenocarpus Nees
  • Lipocarpha R. Br.
  • Mapania Aubl.
  • Machaerina Vahl.
  • Oreobolus R. Br
  • Oxycaryum Nees
  • Pleurostachys Brongn.
  • Pycreus P. Beauv.
  • Remirea Aubl.
  • Rhynchocladium T. Koyama
  • Rhynchospora Vahl
  • Schoenoplectus (Reichb.) Palla
  • Schoenus L.
  • Scirpus L.
  • Scleria P. Bergius
  • Trilepis Nees
  • Uncinia Pers.
  • Websteria S.H. Wright
Status

Native.

Notes on delimitation
  • Because of their great morphological similarity, Cyperaceae and Poaceae were, for a long time, considered to be closely related families. DNA studies have shown that Juncaceae (along with Thurniaceae) are the sister group of Cyperaceae, rather than Poaceae.
  • Cyperaceae are divided into two subfamilies (Simpson et al. 2007): Cyperoideae and Mapanioideae: Cyperoideae - the most diverse subfamily.  Members of this subfamily have spikelet-type inflorescence units with unisexual or biesexual flowers (Androtrichum, Ascolepis, Becquerelia, Bisboeckelera, Bulbostylis, Calyptrocarya, Carex, Cephalocarpus, Cladium, Cyperus, Didimiandrum, Diplacrum, Egleria, Eleocharis, Everardia, Exochogyne, Fimbristylis, Fuirena, Kyllinga, Lagenocarpus, Lipocarpha, Oreobolus, Pleurostachys, Remirea, Rhynchospora, Scirpus, Scleria, Trilepis, Uncinia); and Mapanioideae - members of this subfamily have spicoid-type inflorescence units with unisexual flowers. Many species occur in the herb layer of tropical rainforests (e.g. the Amazonian and Atlantic coastal forests) (Diplasia, Hypolytrum and Mapania).
Literature
Important literature

Alves, M., Araújo, A.C, Prata, A.P, Vitta, F., Hefler, S., Trevisan, R., Gil, A.B., Martins & S.,Thomas, W.W. 2007. Diversidade de Cyperaceae no Brasil. In: A Botânica no Brasil: pesquisa, ensino e políticas públicas ambientais (L. Barbosa & N. Santos Junior, orgs.). SBB, São Paulo, pp. 286-290.

Bruhl, J.J. 1995. Sedge genera of the world: relationships and a new classification of the Cyperaceae. Australian Systematic Botany 8(2): 125-305.

Govaerts, R., Simpson, D.A., Bruhl, J., Egorova, T., Goetghebeur, P., & Wilson, K. 2007. Word checklist of Cyperaceae Sedges. Royal Botanic Gardens, Kew.

Kearns, D.M., Thomas, W.W., Tucker, G., Kral, R., Camelbeke, K., Simpson, D.A., Reznicek, A., González-Elizondo, M., Strong, M. & Goetghebeur, P. 1998. Cyperaceae In: Berry, P.E., Yatskievych, K. and Holst, B.K. (eds.), Flora of the Venezuelan Guayana vol. 4, pp. 486-663. Missouri Botanical Garden, Press, St. Louis.

Simpson, D.A., Muasya, A.M., Alves, M., Bruhl, J.J., Dhooge, S., Chase, M.W., Furness, C.A., Ghamkhar, K., Goetghebeur, P., Hodkinson, T.R., Marchant, A.D., Reznicek, A.A., Nieuwborg, R., Roalson, E.A., Smets, E., Starr, J.R., Thomas, W.W., Wilson, K.L., Zhang, X. 2007. Phylogeny of Cyperaceae based on DNA sequence data - a new rbcL analysis. Aliso 23: 72-83.

Thomas, W.W. 2004. Cyperaceae. In: Smith, N., Mori, S.A., Henderson, A., Stevenson, D.W. & Heald, S.V. (eds.), Flowering Plants of the Neotropics, pp. 434-436. Princeton Univ. Press, Princeton.

[FWTA]

Cyperaceae, Miss S.S. Hooper. Flora of West Tropical Africa 3:2. 1972

Habit
Annuals or caespitose (tufted), rhizomatous, occasionally tuberiferous perennials (Microdracoides is pseudo-arborescent); underground stems bearing scales which grade into the culm leaves; culms generally leafy only at, or towards the base and generally unbranched below the inflorescence, solid, triquetrous, round, flattened or 5-angled; leaves with a distinct cylindrical sheath, closed (except in Coleochloa), generally without a ligule, prolonged at the apex on the side opposite the blade (antiligule) in species of Scleria and Afrotrilepis, and a generally linear blade (reduced to an apiculus in Eleocharis and elsewhere), not articulated with the sheath as in grasses, though deciduous in Coleochloa
Flowers
Flowers small, simple, often consisting only of stamens or pistil or both within a subtending glume, sometimes with accompanying hypogynous bristles, hairs or squamellae, arranged in bisexual or unisexual (Microdracoides, Carex, some Sclerieae) spikelets
Inflorescences
Spikelets sometimes solitary (always so in Eleocharis), more often aggregated into capitula, spikes or glomerules which in turn may be solitary or variously arranged, often in 1–3 times compound, unequally rayed umbels, subtended by 1-several, more or less leaf-like, bracts
Androecium
Stamens 1-numerous, often 3, anthers basifixed with two pollen sacs often with sterile tips and crest, opening lengthwise by a slit, often protandrous
Gynoecium
Ovary superior with one erect anatropous ovule, and generally 2–3 branched style
Fruits
Fruit indehiscent, nut-like (achene) generally lenticular or trigonous
Seeds
Seed erect with a small embryo and abundant mealy or fleshy endosperm
[FTEA]

Cyperaceae, K Hoenselaar, B. Verdcourt & H. Beentje. Hypolytrum, D Simpson. Fuirena, M Muasya. Flora of Tropical East Africa. 2010

Habit
Herbs, often tufted and with rhizomes or stolons, sometimes at base with very short internodes forming a tuber or corm
Stem
Stems solid or hollow, triangular or less often rounded or 4–6-angular or flattened, sometimes with transverse septa
Leaves
Leaves (sub)basal or with a few cauline, usually in 3 ranks, with a usually closed sheath and a linear blade, the lowermost often reduced to a sheath
Inflorescences
Inflorescence terminal (rarely pseudolateral), paniculate, spicate, anthelate or capitate or combinations thereof, with few to many spikelets, sometimes much reduced; often subtended by leafy involucral bracts
Spikelets
Spikelets with few to many flowers, each subtended by a glume (bract).
Glume
Glumes spirally arranged or distichous.
Flowers
Flowers unisexual or bisexual
Stamens
Stamens 1–3(–6).
Anthers
Anthers basifixed, introrse
Ovary
Ovary solitary and superior, 1-locular, of (2–)3 joined carpels; hypogynous scales or bristles absent or 3–6.
Style
Style most often with 2–3 branches
Fruits
Fruit a 1-seeded nutlet, sessile or nearly so, sometimes (in Carex, Schoenoxiphium) surrounded by a sac-like utricle.
Ecology
Often in moist conditions, and can be the dominant plants in wetlands.

Images

Cyperaceae Juss. appears in other Kew resources:

First published in Gen. Pl. [Jussieu] 26. 1789 [4 Aug 1789] (1789)

Accepted by

  • APG IV (2016) http://dx.doi.org/10.1111/boj.12385

Sources

Flora of Tropical East Africa
Flora of Tropical East Africa
http://creativecommons.org/licenses/by-nc-sa/3.0

Flora of West Tropical Africa
Flora of West Tropical Africa
http://creativecommons.org/licenses/by-nc-sa/3.0

Kew Names and Taxonomic Backbone
The International Plant Names Index and World Checklist of Selected Plant Families 2019. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
© Copyright 2017 International Plant Names Index and World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0

Neotropikey
Milliken, W., Klitgard, B. and Baracat, A. (2009 onwards), Neotropikey - Interactive key and information resources for flowering plants of the Neotropics.
http://creativecommons.org/licenses/by/3.0