Cyperus difformis

Population Trend:

Growing

Taxonomy

Notes:

Name Status: Accepted Name. Latest taxonomic scrutiny: 15-Mar-2000

Place of publication: Cent. pl. II:6. 1756 (Amoen. acad. 4:302. 1759)

Name verified on 19-Jan-2001 by ARS Systematic Botanists. Last updated: 25-Mar-2003

Physical Description

Family Cyperaceae:

Herbs, annual or perennial, cespitose or not, rhizomatous or not, stoloniferous or not. Roots fibrous, 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 forming cylindric sheaths enclosing stem, margins usually fused; junction of sheaths and blades often with adaxial flaps of tissue or fringes 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, venation parallel. Primary inflorescences (spikelets) a shortened axis; glumaceous bracts (scales) 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; anthers basifixed; 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) .^[1]

Genus Cyperus:

Herbs, perennial or less often annual, cespitose or not, rhizomatous, stoloniferous, rarely tuberous. Culms solitary or not, trigonous or round, glabrous or scabridulous with extrorse or antrorse (rarely retrorse) prickles. Leaves usually basal; ligules absent; blades keeled abaxially, flat, V-, or inversely W-shaped in cross section. Inflorescences terminal, rarely pseudolateral, 1st order subumbellate to capitate, 2d order with spicate or digitately arranged spikelets, rarely a solitary spikelet; spikelets 1-150; 1st order rays unequal (rarely equal) in length, produced singly from the axils of inflorescence bracts; involucral bracts 1-22, spirally arranged at culm apex, spreading to erect, leaflike. Spikelets: scales to 76, distichous, each subtending flower, cylindric to compressed, borne spicately or digitately at ends of rays (occasionally proliferous) . Flowers bisexual [rarely unisexual], in axils of distichous floral scales, bases often decurrent onto rachilla as ± hyaline wings; perianth absent; stamens 1-3; styles linear, 2-3-fid, base deciduous or persistent; stigmas 2-3. Achenes biconvex, flattened, or trigonous.

Species ca. 600: pantemperate and tropical.^[2]

Habit: Graminoid

Images:

Distribution

Range and Population

Caribbean

Native: Honshu, Kyushu, Natal, Northern Territory, Queensland, Ryukyu Islands, South Australia, Victoria.

Reproduction

Duration: Annual

Similar Species

Members of the genus Cyperus:

There are approximately 2,376 species, subspecies, varieties, forms, and cultivars in this genus. Here are just 100 of them: C. alatus ascolepidioides · C. brevifolius intricatus · C. brevifolius luridus · C. comosipes decolorans · C. compressus micranthus · C. conglomeratus jeminicus · C. cristatus ascolepidioides · C. diffusus macrostachyus · C. diffusus tolucensis · C. dubius coloratus · C. erectus jubensis · C. ferax engelmannii · C. ferax speciosus · C. flavescens fallaciosus · C. flavescens intermedius · C. flavescens microglumis · C. flavescens tanaensis · C. flavus redolens · C. imbricatus elongatus · C. laxus macrostachyus · C. longus tenuiflorus · C. malaccensis monophyllus · C. melanospermus elatus · C. niger elegantulus · C. nutans subprolixus · C. oblongus flavus · C. oblongus jubensis · C. polystachyos holosericeus · C. polystachyos laxiflorus · C. rigens arechavaleta · C. rotundus brevibracteatus · C. sanguinolentus nairobiensis · C. vaginatus gymnocaulos · C. vaginatus vaginatus · C. 'Chira' · C. 'Zumila' · C. aberdarensis · C. abyssinicus · C. actinostachys · C. acuminatus (Short-Point Flatsedge) · C. acuminatus var. cyrtolepis · C. acutangulus · C. acuticarinatus · C. acutiusculus · C. acutus · C. adami · C. adansonii · C. adenophorus · C. adoensis · C. adustus · C. aegyptiacus · C. aequalis · C. aethiops · C. affinis · C. afroalpinus · C. afrodunensis · C. afroechinatus · C. afromontanus · C. afropumilus · C. afrovaricus · C. afzelii · C. aggregatus (Inflated Scale Flatsedge) · C. aggregatus var. gigas · C. agregatus · C. agrestis · C. ajax · C. alatus · C. alba-purpureus · C. albiceps · C. albidus · C. albiflorus · C. albo-marginatus · C. albo-sanguineus · C. albogracilis · C. albopilosus · C. albopurpureus · C. albostriatus (Dwarf Umbrella Grass) · C. albostriatus 'Nanus' · C. albus · C. alleizettei · C. almensis · C. alopecuroides (Foxtail Flatsedge) · C. alpestris · C. alpinus · C. alterniflorus · C. alternifolia (Umbrella Plant) · C. alternifolius 'Compactus' · C. alternifolius 'Variegatus' · C. alternifolius flabelliformis · C. alternifolius non · C. alternifolius subsp. flabelliformis · C. alternifolius var. Gracilis (Dwarf Umbrella Plant) · C. altochrysocephalus · C. altomicroglumis · C. altsonii · C. altus · C. alulatus · C. amabalis · C. amabilis (Foothill Flatsedge) · C. amauropus

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Notes

Contributors:

• Bisby, F.A., Y.R. Roskov, M.A. Ruggiero, T.M. Orrell, L.E. Paglinawan, P.W. Brewer, N. Bailly, J. van Hertum, eds (2007). Species 2000 & ITIS Catalogue of Life: 2007 Annual Checklist. Species 2000: Reading, U.K.
• Global Biodiversity Information Facility. Accessed November 13, 2007. http://www.gbif.org Mediated distribution data from 27 providers.
• USDA, ARS, National Genetic Resources Program. Germplasm Resources Information Network - (GRIN) [Online Database]. National Germplasm Resources Laboratory, Beltsville, Maryland. URL (April 27, 2008)
• World Checklist of Selected Plant Families

Data Sources:

Accessed through GBIF Data Portal November 13, 2007:

• Australian National Herbarium
• , Australian National Herbarium
• Berkeley Natural History Museums, University and Jepson Herbaria DiGIR provider
• Bernice Pauahi Bishop Museum, Bishop Museum Natural History Specimen Data
• Fairchild Tropical Botanic Garden, Fairchild Tropical Botanic Garden Virtual Herbarium Darwin Core format
• GBIF-Spain, Dirección General de Investigación, Desarrollo Tecnológico e Innovación de la Junta de Extremadura(DGIDTI): HSS
• GBIF-Spain, Herbario de la Universidad de Sevilla, SEV
• GBIF-Spain, Real Jardin Botanico
• , Vascular Plant Herbarium
• GBIF-Spain, Universidad de Oviedo. Departamento de Biología de Organismos y Sistemas: FCO
• Herbarium of the University of Aarhus, The AAU Herbarium Database
• Missouri Botanical Garden, Missouri Botanical Garden
• National Herbarium of New South Wales, NSW herbarium collection
• National Herbarium of New South Wales, Plants of Papua New Guinea
• National Institute of Genetics, ROIS, Herbarium Specimens of Museum of Nature and Human Activities, Hyogo Pref., Japan
• School of Life Sciences, Arizona State University, Arizona State University Vascular Plant Herbarium
• School of Life Sciences, Arizona State University, The Deaver Herbarium, Northern Arizona University
• Taiwan Biodiversity Information Facility, Magnoliophyta
• The Swedish Museum of Natural History
• , Lund Botanical Museum
• USDA PLANTS, USDA PLANTS Database
• University of Alabama Biodiversity and Systematics, Herbarium
• University of Washington Burke Museum, Vascular Plant Collection - University of Washington Herbarium

Identifiers:

• Integrated Taxonomic Information System (ITIS) Taxonomic Serial Number (TSN): 39915
• Global Biodiversity Information Facility Taxonkey: 13752920
• Globally Unique Identifier: urn:lsid:ipni.org:names:304311-1
• Natural Heritage Network Species Identifier: PMCYP060Q0
• U.S.D.A. Plant Symbol: CYDI4
• Zipcode Zoo Species Identifier: 33909

Footnotes:

1. 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.
2. Gordon C. Tucker, Brian G. Marcks & J. Richard Carter "Cyperus". in Flora of North America Vol. 23 Page 7, 141, 154, 162, 163, 164, 168, 170, 184,. Oxford University Press. Online at EFloras.org.