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Cyperus rotundus

(Purple Nutsedge Cyperus Rotundus)

Common Names

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Click on the language to view common names.

Common Names in Chinese:

Suo Cao, Xiang Fu Zi

Common Names in English:

Brown Nut Sedge, Chaguan Humatag, Coco-Grass, Cocograss, Galingale, Kili'o'opu, Nut Grass, Nut Sedge, Nut-Grass, Nutgrass, Pakopako, Purple Flatsedge, Purple Nut Sedge, Purple Nut-Sedge, Purple Nutsedge, Purple Nutsedge Cyperus Rotundus, Red Nut Sedge

Common Names in French:

Herbe-à-Oignon, Souchet à Tubercules, Souchet Rond

Common Names in German:

Rundes Zypergras

Common Names in Hawaiian:

Kili'o'opu, Pakopako

Common Names in Italian:

Zigolo Infestante

Common Names in Japanese:

Hamasuge

Common Names in Nepalese:

Mothe

Common Names in Portuguese:

Alho-Bravo, Capim-Alho, Capim-Dandá, Junça, Tiririca, Tiririca-Vermelha

Common Names in Spanish:

Castañuela, Coquito, Juncia

Common Names in Thai:

Ya Haeo Mu (Central Thailand), Ya Khon Mu

Description

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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]

Physical Description

Species Cyperus rotundus

Herbs, perennial , stoloniferous ; stolons (2-) 5-12 cm × 1-2 mm, bearing tubers 3-8(-12) mm diam., wiry, springy when dried, indurate . Culms trigonous , 10-35(-40) cm × 0.7-3.4 mm, basally indurate, glabrous . Leaves V-shaped to flanged V-shaped, 5-30 cm × 2-6 mm. Inflorescences: spikes 1(-3), broadly ellipsoid , (12-) 15-25(-30) × (12-) 20-30(-50) mm; rays (3-) 4-6(-7), 0.2-10 cm; bracts (2-) 3-5, horizontal to ascending at 45°, V-shaped to flanged V-shaped, 0.5-10 cm × 0.5-4 mm; rachilla persistent , wings 0.5-1 mm wide. Spikelets (2-) 3-7(-12), compressed , linear , 4-40 × 1.3-1.8 mm; floral scales persistent, 6-36(-42), spreading or appressed , purple to reddish brown, with narrow clear border and green midrib , 7-9-ribbed, ovate , (1.8-) 2.6-3.4 × 2.2-3 mm, apex obtuse . Flowers: anthers 1-2.5 mm; styles 1.3-3.5 mm; stigmas (1.8-) 2-3.3 mm. Achenes black, sessile, ellipsoid, abaxial face convex , adaxial face concave, 1.4-1.7(-1.9) × 0.8-1 mm, apex obtuse, surfaces puncticulate . Fruiting summer-fall. [source]

Cyperus rotundus is documented in Connecticut, Delaware, New York, and Pennsylvania; there is no evidence of persistent populations. [source]

Cyperus esculentus and C. rotundus are the only two species of subg. Cyperus in the New World that produce tuberiferous stolons. The two species also have persistent floral scales and persistent rachillas, a combination of characteristics not found in any other New World species of Cyperus. [source]

Cyperus rotundus is distinguished from other species of the genus in the New World by its open spikes composed of linear reddish spikelets borne on a conspicuous slender rachis. Cyperus rotundus is usually acknowledged to be the world™s worst weed (cf. G. C. Tucker 1987). In the United States, it does not grow north of the mean 1°C January isotherm . Cyperus esculentus (preceding species) is a serious weed in much of the world, especially in cooler regions where the more tropical C. rotundus does not grow. Cyperus esculentus is able to tolerate lower air temperatures (as low as -18°C). The two species apparently differ also in their thermal optima for growth. [source]

Habit: Graminoid

Size/Age/Growth

Size: under 6" tall.

Habitat

Croplands, disturbed soils usually; 0-400 m [3].

Biology

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Reproduction

Duration: Perennial

Growth

Sunlight: Sun Exposure: Full Sun .

Temperature: Cold Hardiness: 3a, 3b, 4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b, 10a, 10b. (map)

Taxonomy

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Unambiguous Synonyms

  1. Chlorocyperus rotundus (L.) Palla

Notes

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

Place of publication : Sp. pl. 1:45. 1753

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

Similar Species

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Members of the genus Cyperus

ZipcodeZoo has pages for 1515 species, subspecies, varieties, forms, and cultivars in this genus. Here are just 100 of them:

C. aberdarensis · C. abyssinicus · C. acicularis · 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. 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. albomarginatus · C. albopilosus · C. albopurpureus · C. albostriatus (Dwarf Umbrella Grass) · C. albostriatus 'Nanus' · C. albostriatus 'Variegatus' · C. albus · C. almensis · C. alopecuroides (Foxtail Flatsedge) · C. alpestris · C. alpinus · C. alterniflorus · C. alternifolia (Umbrella Plant) · C. alternifolius · C. alternifolius 'Compactus' · C. alternifolius flabelliformis · C. alternifolius subsp. flabelliformis · C. alternifolius var. Gracilis (Dwarf Umbrella Plant) · C. alternifolius 'Variegatus' · C. altochrysocephalus · C. altomicroglumis · C. altsonii · C. alulatus · C. amabilis (Foothill Flatsedge) · C. amauropus · C. ambiguus · C. amblyleptos · C. ambongensis · C. amentaceus · C. americanus · C. amnicola · C. amomodorus · C. amplissimus · C. amplus · C. amuricus (Asian Flatsedge) · C. amuricus var. pterygorrachis · C. anceps · C. andersonianus · C. anderssonii · C. andinus · C. andongensis · C. andreanus · C. andreanus var. capitinduensis · C. andrewsii · C. angolensis · C. angulatus · C. angustatus · C. angustatus var. angustatus · C. angustifolius · C. anisostachyos · C. ankaizinensis · C. ankaratrensis · C. annuus · C. antiquorum · C. aphyllus · C. apiculatus · C. appendiculatus · C. apricus · C. aquatilis · C. arenarius · C. argenteus · C. argyraeus

More Info

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Further Reading

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Notes

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Contributors

Data Sources

Accessed through GBIF Data Portal November 13, 2007:

Identifiers

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. [back]
  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. [back]
  3. "Cyperus". in Flora of North America Vol. 23 Page 146, 168, 169, 170. Oxford University Press. Online at EFloras.org. [back]
Last Revised: 7/1/2009