Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Datasheet

Cyperus difformis
(small-flowered nutsedge)

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Datasheet

Cyperus difformis (small-flowered nutsedge)

Summary

  • Last modified
  • 08 November 2018
  • Datasheet Type(s)
  • Invasive Species
  • Pest
  • Host Plant
  • Preferred Scientific Name
  • Cyperus difformis
  • Preferred Common Name
  • small-flowered nutsedge
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Plantae
  •     Phylum: Spermatophyta
  •       Subphylum: Angiospermae
  •         Class: Monocotyledonae
  • Summary of Invasiveness
  • C. difformis  is a sedge which is listed in Holm's list of the world's worst weeds, being a problem especially in rice, sugarcane, tea and maize. It is a dominant weed in direct-seeded rice when it occurs in hi...

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Pictures

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PictureTitleCaptionCopyright
Growth habit: 6-80 cm in height, stems smooth, triangular, slightly winged, 0.7-3.0 mm thick. Leaves smooth, flat, linear, 5-25 cm long or often two-thirds of plant height, 2-6 mm wide, sometimes reduced to sheaths.
TitleGrowth habit
CaptionGrowth habit: 6-80 cm in height, stems smooth, triangular, slightly winged, 0.7-3.0 mm thick. Leaves smooth, flat, linear, 5-25 cm long or often two-thirds of plant height, 2-6 mm wide, sometimes reduced to sheaths.
CopyrightNOVARTIS
Growth habit: 6-80 cm in height, stems smooth, triangular, slightly winged, 0.7-3.0 mm thick. Leaves smooth, flat, linear, 5-25 cm long or often two-thirds of plant height, 2-6 mm wide, sometimes reduced to sheaths.
Growth habitGrowth habit: 6-80 cm in height, stems smooth, triangular, slightly winged, 0.7-3.0 mm thick. Leaves smooth, flat, linear, 5-25 cm long or often two-thirds of plant height, 2-6 mm wide, sometimes reduced to sheaths.NOVARTIS
Close-up of C. difformis plant with inflorescences. 
The inflorescence consists of dense, globose, umbellate heads, simple or compound, 5-15 mm in diameter, with 10-60 stellately spreading spikelets.
TitleInflorescence
CaptionClose-up of C. difformis plant with inflorescences. The inflorescence consists of dense, globose, umbellate heads, simple or compound, 5-15 mm in diameter, with 10-60 stellately spreading spikelets.
CopyrightTomas Marquez/DuPont-Spain
Close-up of C. difformis plant with inflorescences. 
The inflorescence consists of dense, globose, umbellate heads, simple or compound, 5-15 mm in diameter, with 10-60 stellately spreading spikelets.
InflorescenceClose-up of C. difformis plant with inflorescences. The inflorescence consists of dense, globose, umbellate heads, simple or compound, 5-15 mm in diameter, with 10-60 stellately spreading spikelets.Tomas Marquez/DuPont-Spain
Young C. difformis plants.
TitleYoung plants
CaptionYoung C. difformis plants.
CopyrightTomas Marquez/DuPont-Spain
Young C. difformis plants.
Young plantsYoung C. difformis plants.Tomas Marquez/DuPont-Spain
Young C. difformis plants.
TitleYoung plants
CaptionYoung C. difformis plants.
CopyrightTomas Marquez/DuPont-Spain
Young C. difformis plants.
Young plantsYoung C. difformis plants.Tomas Marquez/DuPont-Spain
C. difformis seedlings.
TitleSeedlings
CaptionC. difformis seedlings.
CopyrightTomas Marquez/DuPont-Spain
C. difformis seedlings.
SeedlingsC. difformis seedlings.Tomas Marquez/DuPont-Spain
C. difformis seeds. The achenes are 0.6-0.8 mm long and 0.3-0.4 mm wide, triangular, obovate-elliptic, yellowish-brown or pale-brown, and minutely papillose.
TitleSeeds
CaptionC. difformis seeds. The achenes are 0.6-0.8 mm long and 0.3-0.4 mm wide, triangular, obovate-elliptic, yellowish-brown or pale-brown, and minutely papillose.
CopyrightTomas Marquez/DuPont-Spain
C. difformis seeds. The achenes are 0.6-0.8 mm long and 0.3-0.4 mm wide, triangular, obovate-elliptic, yellowish-brown or pale-brown, and minutely papillose.
SeedsC. difformis seeds. The achenes are 0.6-0.8 mm long and 0.3-0.4 mm wide, triangular, obovate-elliptic, yellowish-brown or pale-brown, and minutely papillose.Tomas Marquez/DuPont-Spain

Identity

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Preferred Scientific Name

  • Cyperus difformis L.

Preferred Common Name

  • small-flowered nutsedge

Other Scientific Names

  • Cyperus goeringii Steud
  • Cyperus holoschoenoides Jan ex Schult
  • Cyperus oryzetorum Steud.
  • Cyperus subrotundus Llanos

International Common Names

  • English: dirty-Dora; one-arm sedge; rice sedge; smallflower flat sedge; small-flower umbrella plant; variable flatsedge
  • Spanish: cortadera; estoquillo (Colombia); juncia de agua; lleivun; tiña; varita de San Jose (Bolivia)
  • French: souchet à petites fleurs; souchet difforme
  • Portuguese: negrinha

Local Common Names

  • : jinquillo; junco de agua
  • Albania: Truska dyformash
  • Australia: Dirty Dora; variable flat sedge
  • Brazil: junquinho
  • Czechoslovakia (former): Sachorec nepravidelny
  • Hungary: Rizspalka
  • Indonesia: Jebungan; Jukut pendul; Ramon brendelan
  • Italy: cipero globoso
  • Japan: Tamagayatsuri
  • Korea, DPR: Albang dong sani
  • Malaysia: Rumput air
  • Nepal: Chow; Guchen; Mothey; Ochumani
  • Nigeria: Imeremere
  • Philippines: Baki-baki; Ballayang; Bankoan; Baong-baong; Gilhamon; Sirau-sirau; Ubod-ubod
  • Romania: Parul porcului de balta
  • Saint Lucia: umbrella sedge
  • Sierra Leone: A-kek-a-pot
  • Taiwan: Chyou-hwa-hau-tsau
  • Thailand: Kok ka-narg; Kok khanaak
  • USA: Small-flowered umbrella plant

EPPO code

  • CYPDI (Cyperus difformis)

Summary of Invasiveness

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C. difformis  is a sedge which is listed in Holm's list of the world's worst weeds, being a problem especially in rice, sugarcane, tea and maize. It is a dominant weed in direct-seeded rice when it occurs in high plant densities; forms dense mats of vegetation in the young crop and can cause rice yield losses of 12-50%. It is native to the tropics of the Old World, but is spreading well outside its native range. It has a relatively short generation period of as little as 4 to 6 weeks from seed to seed. It can spread along waterways and grow in disturbed sites, lake margins and on river banks.

Taxonomic Tree

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  • Domain: Eukaryota
  •     Kingdom: Plantae
  •         Phylum: Spermatophyta
  •             Subphylum: Angiospermae
  •                 Class: Monocotyledonae
  •                     Order: Cyperales
  •                         Family: Cyperaceae
  •                             Genus: Cyperus
  •                                 Species: Cyperus difformis

Notes on Taxonomy and Nomenclature

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Cyperaceae (the sedge family) has a cosmopolitan distribution and plays a dominant role in wetland vegetation. Based on recent molecular phylogenetic studies, the family Cyperaceae consists of two main clades, corresponding to the subfamilies Cyperoideae and Mapanioideae (Simpson et al., 2003; Muasya et al., 2009). In the Cyperoideae, two clades stand out because of their extraordinary species diversity: (1) the clade corresponding to the predominantly temperate tribe Cariceae (approximately 1950 species); and (2) the clade corresponding to the mainly tropical tribe Cypereae (approximately 1120 species). Together, they cover nearly three-fifths of the species diversity in Cyperaceae (Larridon et al., 2013). Cyperus difformis was first described by Linnaeus (1756). It originated in the Old World tropics and is one of approximately 950 species in the genus Cyperus (Stevens, 2012).

Description

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C. difformis varies in height from 6 to 80 cm. The stems are smooth, triangular, slightly winged and 0.7-3.0 mm thick. The roots are numerous, fibrous and reddish. The leaves are smooth (or slightly scabrid on the midrib and margin), flat, linear, 5-25 cm long or often two-thirds of the plant height, 2-6 mm wide, sometimes reduced to sheaths. Sheaths are tubular, united, green to reddish-brown and without leaf blades at the base.

The inflorescence consists of dense, globose, umbellate heads, simple or compound, 5-15 mm in diameter, with 10-60 stellately spreading spikelets. The inflorescence is rather loose, simple or compound, subtended by 1-4 leaf-like bracts, one of which can be up to 25 cm long. The umbel rays are 1-5 cm long, some long and some long peduncled.

Spikelets are linear to oblong-linear, compressed but slightly swollen, obtuse, 2.5-8 mm long, 0.8-1.25 mm wide, 6-30 flowered. Glumes are 0.6-0.8 mm long, obovate, pale-yellowish to dark reddish-brown with yellow or white margins and a green midrib ending in a short mucro. Stamens 1-2. Style 3-branched. Achenes are 0.6-0.8 mm long and 0.3-0.4 mm wide, triangular, obovate-elliptic, yellowish-brown or pale-brown, minutely papillose. These descriptions are based on Haines and Lye (1983) and Holm et al. (1977).

Plant Type

Top of page Annual
Grass / sedge
Perennial

Distribution

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C. difformis is native to the Old World (subtropical and tropical areas). Currently it is widespread throughout southern Europe, Asia, Central America, North America, South America, Africa and the islands of the Indian and Pacific oceans. It is mainly a weed of the tropics and subtropics but can be found from latitudes 45°N to 35°S (Holm et al., 1977).






 

Distribution Table

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The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

Continent/Country/RegionDistributionLast ReportedOriginFirst ReportedInvasiveReferenceNotes

Asia

AfghanistanPresentNativeMoody et al., 1984; Govaerts, 2014
ArmeniaPresentNativeGovaerts, 2014
AzerbaijanPresentNativeGovaerts, 2014
BangladeshPresentNativeGovaerts, 2014
BhutanPresentNativeFlora of China Editorial Committee, 2014
Brunei DarussalamPresentWaterhouse, 1993
CambodiaPresentMoody, 1989
Chagos ArchipelagoPresentIntroduced Invasive Whistler, 1996
ChinaWidespreadHolm et al., 1979
-AnhuiPresentNativeFlora of China Editorial Committee, 2014
-ChongqingPresentNativeFlora of China Editorial Committee, 2014
-FujianPresentNativeLi, 1987; Flora of China Editorial Committee, 2014
-GansuPresentNativeFlora of China Editorial Committee, 2014
-GuangdongPresentNativeWang et al., 1990; Flora of China Editorial Committee, 2014
-GuangxiPresentNativeFlora of China Editorial Committee, 2014
-GuizhouPresentNativeFlora of China Editorial Committee, 2014
-HainanPresentNativeFlora of China Editorial Committee, 2014
-HebeiPresentNativeWang et al., 1990; Flora of China Editorial Committee, 2014
-HeilongjiangPresentNativeFlora of China Editorial Committee, 2014
-HenanPresentNativeFang and Wang, 1990; Flora of China Editorial Committee, 2014
-HubeiPresentNativeFlora of China Editorial Committee, 2014
-HunanPresentNativeFlora of China Editorial Committee, 2014
-JiangsuPresentNativeFlora of China Editorial Committee, 2014
-JiangxiPresentNativeFlora of China Editorial Committee, 2014
-JilinPresentNativeFlora of China Editorial Committee, 2014
-LiaoningPresentNativeFlora of China Editorial Committee, 2014
-Nei MengguPresentNativeFlora of China Editorial Committee, 2014
-NingxiaPresentNativeFlora of China Editorial Committee, 2014
-ShaanxiPresentNativeWang, 1990; Flora of China Editorial Committee, 2014
-ShandongPresentNativeFlora of China Editorial Committee, 2014
-ShanxiPresentNativeWang et al., 1990; Flora of China Editorial Committee, 2014
-SichuanPresentNativeFlora of China Editorial Committee, 2014
-XinjiangPresentNativeFlora of China Editorial Committee, 2014
-YunnanPresentNativeWang et al., 1990; Flora of China Editorial Committee, 2014
-ZhejiangPresentNativeZhang et al., 1989; Flora of China Editorial Committee, 2014
IndiaWidespreadMoody, 1989
-Andaman and Nicobar IslandsPresentSingh and Gangwar, 1987; Govaerts, 2014
-Andhra PradeshPresentIntroduced Invasive Raju and Reddy, 1992; Reddy, 2008
-Arunachal PradeshPresentIntroduced Invasive Chandra, 2012
-AssamPresentIntroduced Invasive Kurmi and Das, 1993; Chandra, 2012
-BiharPresentIntroduced Invasive Reddy, 2008
-ChandigarhPresentIntroduced Invasive Reddy, 2008
-ChhattisgarhPresentIntroduced Invasive Reddy, 2008
-Dadra and Nagar HaveliPresentIntroduced Invasive Reddy, 2008
-DamanPresentIntroduced Invasive
-DelhiPresentIntroduced Invasive Reddy, 2008
-DiuPresentIntroduced Invasive Reddy, 2008
-GoaPresentIntroduced Invasive Reddy, 2008
-GujaratPresentIntroduced Invasive Patel et al., 1985; Reddy, 2008
-HaryanaPresentIntroduced Invasive Reddy, 2008
-Himachal PradeshPresentIntroduced Invasive Chandra, 2012
-Indian PunjabPresentIntroduced Invasive Bir et al., 1992; Reddy, 2008
-Jammu and KashmirPresentIntroduced Invasive Chandra, 2012
-JharkhandPresentIntroduced Invasive Reddy, 2008
-KarnatakaPresentIntroduced Invasive Sastry et al., 1980; Reddy, 2008
-KeralaPresentIntroduced Invasive Joseph, 1986; Reddy, 2008
-Madhya PradeshPresentIntroduced Invasive Chandrakar et al., 1993; Reddy, 2008
-MaharashtraPresentIntroduced Invasive Reddy, 2008
-ManipurPresentIntroduced Invasive Chandra, 2012
-MeghalayaPresentIntroduced Invasive Chandra, 2012
-MizoramPresentIntroduced Invasive Chandra, 2012
-NagalandPresentIntroduced Invasive Chandra, 2012
-OdishaPresentIntroduced Invasive Jena and Patro, 1990; Reddy, 2008
-RajasthanPresentIntroduced Invasive Reddy, 2008
-SikkimPresentIntroduced Invasive Chandra, 2012
-Tamil NaduPresentIntroduced Invasive Srinivasan and Subbian, 1991; Reddy, 2008
-TripuraPresentIntroduced Invasive Chandra, 2012
-Uttar PradeshPresentIntroducedSingh et al., 1989; Khanna, 2009
-UttarakhandPresentIntroduced Invasive Chandra, 2012
-West BengalPresentIntroduced Invasive Singh, 1993; Chandra, 2012
IndonesiaWidespreadMoody, 1989
-JavaPresentNativeGovaerts, 2014
-Nusa TenggaraPresentNativeGovaerts, 2014
-SulawesiPresentNativeGovaerts, 2014
-SumatraPresentNativeMangoensoekardjo and Pancho, 1975; Govaerts, 2014
IranPresentNativeDastgheib and Beigi, 1988; Govaerts, 2014
IraqPresentNativeGovaerts, 2014
IsraelPresentNativeGovaerts, 2014
JapanWidespreadNumata et al., 1975; Govaerts, 2014
-HonshuPresentNativeUSDA-ARS, 2014
-KyushuPresentNativeUSDA-ARS, 2014
-Ryukyu ArchipelagoPresentNativeUSDA-ARS, 2014
-ShikokuPresentNativeUSDA-ARS, 2014
KazakhstanPresentNativeGovaerts, 2014
Korea, DPRPresentNativeUl'yanova, 1988; Govaerts, 2014
Korea, Republic ofPresentNativeKim et al., 1982; Govaerts, 2014
KyrgyzstanPresentNativeFlora of China Editorial Committee, 2014
LaosPresentMoody, 1989
MalaysiaWidespreadBarnes and Chan, 1990
-Peninsular MalaysiaPresentNativeGovaerts, 2014
MyanmarPresentNativeMoody, 1989; Govaerts, 2014
NepalPresentNativeRanjit and Bhattarai, 1988; Govaerts, 2014
PakistanPresentNativeFarrukh-Hussain et al., 1984; Govaerts, 2014
PhilippinesWidespreadMoody et al., 1984; Govaerts, 2014
SingaporePresentWaterhouse, 1993
Sri LankaPresentNative
SyriaPresentNativeUSDA-ARS, 2014
TaiwanWidespreadHorng, 1976; Flora of China Editorial Committee, 2014
TajikistanPresentNativeGovaerts, 2014
ThailandWidespreadNoda et al., 1985; Govaerts, 2014
TurkeyPresentNativeHolm et al., 1979; Govaerts, 2014
UzbekistanPresentNativeGovaerts, 2014
VietnamPresentNativeMinh-Si, 1969; Govaerts, 2014
YemenPresentNativeGovaerts, 2014

Africa

AngolaPresentNativeGovaerts, 2014
BeninPresentNativeClayton, 1972; Govaerts, 2014
BotswanaPresentNativeGovaerts, 2014
Burkina FasoPresentNativeClayton, 1972; Govaerts, 2014
BurundiPresentNativeGovaerts, 2014
CameroonWidespreadDeuse et al., 1983; Govaerts, 2014
Central African RepublicPresentNativeGovaerts, 2014
ChadPresentNativeGovaerts, 2014
ComorosPresentNativeGovaerts, 2014
CongoPresentNativeGovaerts, 2014
Congo Democratic RepublicPresentNativeGovaerts, 2014
Côte d'IvoirePresentNativeMerlier, 1975; Govaerts, 2014
EgyptPresentIntroducedBoulos and el-Hadidi, 1984; Govaerts, 2014
Equatorial GuineaNativeGovaerts, 2014
EthiopiaPresentNativeGovaerts, 2014
GabonPresentNativeGovaerts, 2014
GambiaWidespreadTerry, 1981; Govaerts, 2014
GhanaWidespreadHolm et al., 1979; Govaerts, 2014
GuineaPresentNativeClayton, 1972; Govaerts, 2014
Guinea-BissauPresentNativeGovaerts, 2014
KenyaPresentNativeHaines and Lye, 1983; Govaerts, 2014
LesothoPresentNativeGovaerts, 2014
LiberiaPresentNativeGovaerts, 2014
LibyaPresentIntroducedGovaerts, 2014
MadagascarWidespreadElliott et al., 1993; Govaerts, 2014
MalawiPresentNativeBinns, 1968; Govaerts, 2014
MaliPresentNativeClayton, 1972; Govaerts, 2014
MauritaniaPresentNativeGovaerts, 2014
MauritiusPresentNativeHolm et al., 1979; Govaerts, 2014
MoroccoPresentIntroducedTanji and Taleb, 1997; Govaerts, 2014
NamibiaPresentNativeGovaerts, 2014
NigerPresentNativeClayton, 1972; Govaerts, 2014
NigeriaWidespreadImeokparia, 1989; Govaerts, 2014
RéunionPresentNativeGovaerts, 2014
RwandaPresentNativeGovaerts, 2014
Saint HelenaPresentIntroducedGovaerts, 2014
SenegalPresentNativeClayton, 1972; Govaerts, 2014
SeychellesPresentNativeRobertson, 1989; Govaerts, 2014
Sierra LeonePresentNativeClayton, 1972; Govaerts, 2014
SomaliaPresentNativeGovaerts, 2014
South AfricaPresentNativeHolm et al., 1979; Govaerts, 2014Noxious weed
SudanPresentBebawi & Neugebohrn, 1991
SwazilandPresentNativeHolm et al., 1979; Govaerts, 2014
TanzaniaWidespreadTerry, 1978; Govaerts, 2014
TogoPresentNativeClayton, 1972; Govaerts, 2014
UgandaPresentNativeHaines and Lye, 1983; Govaerts, 2014
ZimbabwePresentDrummond, 1984

North America

MexicoPresentIntroduced Invasive Villaseñor and Espinosa-Garcia, 2004Weed
USAPresentPresent based on regional distribution.
-AlabamaPresentIntroducedUSDA-NRCS, 2014Weed and potentially invasive
-ArizonaPresentIntroducedUSDA-NRCS, 2014Weed and potentially invasive
-CaliforniaPresentRejmaneck, 1987; Barrett and Seaman, 1980; USDA-NRCS, 2014
-DelawarePresentIntroducedUSDA-NRCS, 2014Weed and potentially invasive
-FloridaPresentIntroducedUSDA-NRCS, 2014Weed and potentially invasive
-GeorgiaPresentIntroducedUSDA-NRCS, 2014Weed and potentially invasive
-HawaiiPresentIntroduced Invasive Holm et al., 1979; Wagner et al., 1999
-IdahoPresentIntroducedUSDA-NRCS, 2014Weed and potentially invasive
-KentuckyPresentIntroducedUSDA-NRCS, 2014Weed and potentially invasive
-LouisianaPresentIntroducedUSDA-NRCS, 2014Weed and potentially invasive
-MarylandPresentIntroducedUSDA-NRCS, 2014Weed and potentially invasive
-MississippiPresentIntroducedUSDA-NRCS, 2014Weed and potentially invasive
-NebraskaPresentIntroducedUSDA-NRCS, 2014Weed and potentially invasive
-New JerseyPresentIntroducedUSDA-NRCS, 2014Weed and potentially invasive
-North CarolinaPresentIntroducedUSDA-NRCS, 2014Weed and potentially invasive
-OhioPresentIntroducedUSDA-NRCS, 2014Weed and potentially invasive
-OklahomaPresentIntroducedUSDA-NRCS, 2014Weed and potentially invasive
-OregonPresentIntroducedUSDA-NRCS, 2014Weed and potentially invasive
-PennsylvaniaPresentIntroducedUSDA-NRCS, 2014Weed and potentially invasive
-South CarolinaPresentIntroducedUSDA-NRCS, 2014Weed and potentially invasive
-TennesseePresentIntroducedUSDA-NRCS, 2014Weed and potentially invasive
-TexasPresentIntroduced Invasive USDA-NRCS, 2014
-VirginiaPresentIntroducedUSDA-NRCS, 2014Weed and potentially invasive
-WashingtonPresentIntroducedUSDA-NRCS, 2014Weed and potentially invasive

Central America and Caribbean

Costa RicaPresentIntroducedGómez-Laurito, 2003
Dominican RepublicPresentIntroducedAcevedo-Rodriguez and Strong, 2012
HaitiPresentIntroducedAcevedo-Rodriguez and Strong, 2012
JamaicaPresentIntroducedUSDA-ARS, 2014
NicaraguaPresentIntroducedUSDA-ARS, 2014
PanamaPresentIntroduced Invasive USDA-ARS, 2014
Puerto RicoPresentIntroduced Invasive Acevedo-Rodriguez and Strong, 2012

South America

BoliviaPresentIntroducedGonzales and Webb, 1989; Gómez-Laurito, 2003
BrazilPresentAbud, 1986
ChilePresentIntroduced Invasive Belov, 2013
ColombiaPresentFischer et al., 1993
EcuadorPresentIntroduced Invasive Gómez-Laurito, 2003
GuyanaPresentIntroducedUSDA-ARS, 2014
ParaguayPresentIntroducedGómez-Laurito, 2003
PeruPresentIntroduced Invasive Diaz, 1976; USDA-ARS, 2014
VenezuelaPresentIntroducedGómez-Laurito, 2003

Europe

AlbaniaPresentNativeWilliams and Hunyadi, 1987; Govaerts, 2014
AustriaPresentHolm et al., 1979
BelgiumPresentIntroduced Invasive DAISIE, 2014
Bosnia-HercegovinaPresentNativeGovaerts, 2014
BulgariaPresentNativeWilliams and Hunyadi, 1987; Govaerts, 2014
CroatiaPresentNativeGovaerts, 2014
FrancePresentNativeJauzein, 1991; Govaerts, 2014
-CorsicaPresentNativeGovaerts, 2014
GermanyPresentWilliams and Hunyadi, 1987
GreecePresentNativeHolm et al., 1979; Govaerts, 2014
HungaryPresentIntroduced Invasive Williams and Hunyadi, 1987; Balogh et al., 2004
ItalyPresentHolm et al., 1979; DAISIE, 2014; Govaerts, 2014
MacedoniaPresentNativeGovaerts, 2014
PortugalPresentNativeHolm et al., 1979; Govaerts, 2014
-AzoresPresentIntroduced Invasive DAISIE, 2014
-MadeiraPresentIntroduced Invasive DAISIE, 2014
RomaniaPresentNativeWilliams and Hunyadi, 1987; Govaerts, 2014
Russian FederationPresentWilliams and Hunyadi, 1987
-Russian Far EastPresentNativeGovaerts, 2014Prymorye
SerbiaPresentNativeGovaerts, 2014
SlovakiaPresentWilliams and Hunyadi, 1987
SloveniaPresentNativeGovaerts, 2014
SpainPresentIntroduced Invasive Pamplona and Evangelista, 1981; DAISIE, 2014
UkrainePresentIntroducedDAISIE, 2014
Yugoslavia (former)PresentNativeGovaerts, 2014

Oceania

AustraliaRestricted distributionAuld and Medd, 1987
-Australian Northern TerritoryPresentNativeGovaerts, 2014
-New South WalesPresentNativeMcIntyre et al., 1991; Govaerts, 2014
-QueenslandPresentNativeGovaerts, 2014
-South AustraliaPresentNativeGovaerts, 2014
-VictoriaPresentNativeGovaerts, 2014
-Western AustraliaPresentNativeGovaerts, 2014; Govaerts, 2014
FijiPresentIntroduced Invasive Parham, 1958; Smith, 1979
French PolynesiaPresentIntroduced Invasive Florence et al., 2013
GuamPresentIntroduced Invasive Fosberg et al., 1987
Marshall IslandsPresentIntroduced Invasive Vander, 2003
Micronesia, Federated states ofPresentIntroduced Invasive Space et al., 2000Invasive on Kosrae Island
Norfolk IslandPresentNativeGovaerts, 2014
Northern Mariana IslandsPresentRaulerson, 2006Listed as introduced on Saipan Island
PalauPresentIntroducedFosberg et al., 1987
Papua New GuineaPresentNativeGovaerts, 2014
Solomon IslandsPresentHancock et al., 1988

History of Introduction and Spread

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The history of introduction of C. difformis in the New World is not well known. Because this species behaves as an agricultural weed, it is highly probable that it was introduced as a contaminant of crop seeds (Holm et al., 1979; USDA-ARS, 2014). In the Caribbean, it was collected in the 1960s in Puerto Rico and the Dominican Republic (US National Herbarium).  

Risk of Introduction

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The risk of introduction of C. difformis is high. This species has been listed as one of the world's worst weeds, being a problem especially in rice, sugarcane, tea and maize (Holm et al., 1979). It can grow in swamps, lake margins, and along the edges of rivers and canals. Because the species spreads along major waterways and in rice production areas, its likelihood to invade new habitats remains high.

Habitat

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C. difformis is usually found on flooded or very wet soils, open soggy grasslands, pools (but not in deep water) and riverbanks, often associated with C. halpan and C. iria, where it is usually scattered but often becoming dominant. It prefers fertile soils but can also grow on poor sandy or clay soils (Kostermans et al., 1987). It is one of the commonest weeds of paddy or flooded rice but it has also been reported as a weed of upland rice and crops such as bananas, sugarcane, tea and maize (Holm et al., 1977). In general, C. difformis can be found growing in grasslands on mountain slopes, in shallow water, water margins, lake margins, riversides, swamps, wet places in grasslands, along trails, and in rice paddy fields. 

Habitat List

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CategorySub-CategoryHabitatPresenceStatus
Terrestrial
 
Terrestrial – ManagedCultivated / agricultural land Present, no further details Harmful (pest or invasive)
Cultivated / agricultural land Present, no further details Natural
Managed forests, plantations and orchards Present, no further details Harmful (pest or invasive)
Managed forests, plantations and orchards Present, no further details Natural
Managed grasslands (grazing systems) Present, no further details Harmful (pest or invasive)
Managed grasslands (grazing systems) Present, no further details Natural
Disturbed areas Present, no further details Harmful (pest or invasive)
Disturbed areas Present, no further details Natural
Rail / roadsides Present, no further details Harmful (pest or invasive)
Rail / roadsides Present, no further details Natural
Urban / peri-urban areas Present, no further details Harmful (pest or invasive)
Urban / peri-urban areas Present, no further details Natural
Urban / peri-urban areas Present, no further details Productive/non-natural
Terrestrial ‑ Natural / Semi-naturalNatural grasslands Present, no further details Harmful (pest or invasive)
Natural grasslands Present, no further details Natural
Riverbanks Present, no further details Harmful (pest or invasive)
Riverbanks Present, no further details Natural
Wetlands Present, no further details Harmful (pest or invasive)
Wetlands Present, no further details Natural
Littoral
Mangroves Present, no further details Harmful (pest or invasive)
Mangroves Present, no further details Natural
Mud flats Present, no further details Harmful (pest or invasive)
Mud flats Present, no further details Natural
Freshwater
 
Irrigation channels Present, no further details Harmful (pest or invasive)
Irrigation channels Present, no further details Natural
Lakes Present, no further details Harmful (pest or invasive)
Lakes Present, no further details Natural
Rivers / streams Present, no further details Harmful (pest or invasive)
Rivers / streams Present, no further details Natural
Ponds Present, no further details Harmful (pest or invasive)
Ponds Present, no further details Natural

Host Plants and Other Plants Affected

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Plant nameFamilyContext
Camellia sinensis (tea)TheaceaeMain
Musa x paradisiaca (plantain)MusaceaeMain
Oryza sativa (rice)PoaceaeMain
Saccharum officinarum (sugarcane)PoaceaeMain
Zea mays (maize)PoaceaeMain

Growth Stages

Top of page Vegetative growing stage

Biology and Ecology

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C. difformis is an annual sedge, sometimes behaving as a perennial. It propagates from seeds (achenes or nutlets) which are produced in large quantities. In Italy, Jacometi (1912) reported that one plant could produce 50,000 seeds, with about 60% germination. Such fecundity enables C. difformis seedlings to become established at high densities, enabling it to rapidly cover the ground and become the dominant vegetation. In tropical climates, the plant can flower and produce seeds throughout the year, provided that sufficient moisture is present.

C. difformis is a weed of flooded rice, even where there is good water control, being capable of germinating under water. Civico and Moody (1979) note that this species has exceptional tolerance of flooding, greater than that of C. iria.

Studies in India have shown that chromosome numbers in C. difformis (n=16) do not vary but the plant exhibits marked phenotypic plasticity which is characteristic of individuals belonging to different populations/clones (Bir et al., 1992).

The ability of C. difformis to complete its vegetative and reproductive life cycle within one month makes it a very competitive weed. It is a not a particularly tall plant but it can have a high biomass per hectare. It competes with crops mostly for nutrients and water, rather than for light.

Like rice, C. difformis has the C3 photosynthetic pathway, a condition which favours growth in submerged soils.

Climate

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ClimateStatusDescriptionRemark
Af - Tropical rainforest climate Preferred > 60mm precipitation per month
Am - Tropical monsoon climate Preferred Tropical monsoon climate ( < 60mm precipitation driest month but > (100 - [total annual precipitation(mm}/25]))
As - Tropical savanna climate with dry summer Preferred < 60mm precipitation driest month (in summer) and < (100 - [total annual precipitation{mm}/25])
Aw - Tropical wet and dry savanna climate Preferred < 60mm precipitation driest month (in winter) and < (100 - [total annual precipitation{mm}/25])
BS - Steppe climate Tolerated > 430mm and < 860mm annual precipitation
BW - Desert climate Tolerated < 430mm annual precipitation
Cf - Warm temperate climate, wet all year Preferred Warm average temp. > 10°C, Cold average temp. > 0°C, wet all year
Cs - Warm temperate climate with dry summer Preferred Warm average temp. > 10°C, Cold average temp. > 0°C, dry summers
Cw - Warm temperate climate with dry winter Preferred Warm temperate climate with dry winter (Warm average temp. > 10°C, Cold average temp. > 0°C, dry winters)

Soil Tolerances

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Soil drainage

  • seasonally waterlogged

Soil reaction

  • acid
  • neutral

Soil texture

  • heavy
  • light
  • medium

Notes on Natural Enemies

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There are no known natural enemies of C. difformis other than those pests and diseases of rice for which it is an alternative host. For further information, see Economic Impact.

Pathway Causes

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CauseNotesLong DistanceLocalReferences
Crop productionAs a contaminant Yes Yes Holm et al., 1979
DisturbanceGrows as a weed in disturbed areas Yes Yes Holm et al., 1979

Pathway Vectors

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VectorNotesLong DistanceLocalReferences
Debris and waste associated with human activities Yes Yes Holm et al., 1979
Machinery and equipmentAs a contaminant Yes Yes Holm et al., 1979
Soil, sand and gravelAs a contaminant of soils Yes Yes Holm et al., 1979
WaterSeeds Yes Yes Holm et al., 1979

Impact Summary

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CategoryImpact
Economic/livelihood Negative
Environment (generally) Negative

Economic Impact

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C. difformis is rated by Holm et al. (1977) to be a serious weed of rice in the United States, Australia, Italy, Japan, Madagascar, Taiwan and the Philippines, and a principal weed of rice in several European and African countries. In California, this plant has become resistant to rice-field herbicides. In Asian rice production, where herbicides are not used, this weed may account for 60-70% of the total biomass of the rice field. It is difficult to separate the competitive effects of C. difformis from those of other components of the weed flora, but 12-50% reductions in rice grain yields have been caused by this weed (Ampong-Nyarko and DeDatta, 1991). The rate of appearance of C. difformis and tiller number are the main factors causing yield loss in early rice (Yu, 1992). The costs of controlling C. difformis, whether manual, mechanical or chemical, are significant.

C. difformis is a host for several pests of rice. Meloidogyne incognita, a major root-knot nematode in southern Nigeria, can grow and reproduce on C. difformis (Atu et al., 1988). Eggs of the rice stem borer, Diopsis macrophthalma, have also been found on this weed in southern Nigeria (Alghali, 1979). The node-feeding black bug, Scotinophara latiuscula, an occasional pest of wetland rice fields in the Philippines, can develop on C. difformis (Barrion and Litsinger, 1987). The brown planthopper, Nilaparvata lugens can use C. difformis as a temporary food plant (Chu and Yang, 1984). Larvae of the rice leaf-folder, Marasmia patnalis, can survive for a short period on C. difformis before migrating to the rice crop (Joshi et al., 1985). Pathogens of rice that have been reported on C. difformis include Puccinia conclusa (Dube et al., 1979), Sarocladium oryzae (cause of sheath rot) (Balakrishnan and Nair, 1981) and Thanatephorus sasakii (cause of sheath blight) (Bandara and Nadaraja, 1979).

Environmental Impact

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C. difformis can impact natural wetlands and native vegetation swamps and flooded areas. Having heavy seed production and massive seedling densities, this rapid growing weed can quickly form dense colonies smothering native vegetation (Holm et al., 1979; USDA-NRCS, 2014). 

Risk and Impact Factors

Top of page Invasiveness
  • Invasive in its native range
  • Proved invasive outside its native range
  • Has a broad native range
  • Abundant in its native range
  • Highly adaptable to different environments
  • Is a habitat generalist
  • Tolerates, or benefits from, cultivation, browsing pressure, mutilation, fire etc
  • Pioneering in disturbed areas
  • Highly mobile locally
  • Benefits from human association (i.e. it is a human commensal)
  • Fast growing
  • Has high reproductive potential
Impact outcomes
  • Damaged ecosystem services
  • Monoculture formation
  • Negatively impacts agriculture
  • Negatively impacts livelihoods
  • Reduced amenity values
  • Reduced native biodiversity
  • Threat to/ loss of native species
  • Transportation disruption
Impact mechanisms
  • Competition - monopolizing resources
  • Competition - smothering
  • Rapid growth
Likelihood of entry/control
  • Highly likely to be transported internationally accidentally
  • Difficult to identify/detect as a commodity contaminant
  • Difficult to identify/detect in the field
  • Difficult/costly to control

Detection and Inspection

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The experienced eye can detect the seeds of C. difformis as a contaminant of crop seed

Similarities to Other Species/Conditions

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C. difformis is readily distinguished by its dense, globose heads composed of many radiating spikelets. However, as a seedling or non-flowering plant, it closely resembles many immature, annual Cyperus spp. In a key to seedling Cyperaceae, Kostermans et al. (1987) use the coleoptile, seed, first leaf blade and first leaf sheath as diagnostic characters. Unlike C. iria, C. difformis releases no aroma when crushed.

Prevention and Control

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The principles of good weed management in rice, such as those advocated by Ampong-Nyarko and DeDatta (1992), are applicable to C. difformis in rice and in other crops. These include the need to prepare clean seedbeds, prevent seed production, establish a healthy and vigorous crop and avoid contamination of crop seed at harvest.

C. difformis is susceptible to many of the usual methods of weed control in rice and other crops. These include hand-pulling, manual and mechanical tillage and trampling in puddled fields. Flooding of rice fields to a depth of 20 cm strongly suppresses the growth of C. difformis (Williams et al., 1990) but with the continuous use of the more usual shallower flooding, C3 weeds, including C. difformis, become dominant (Ampong-Nyarko and DeDatta, 1992).

Biological Control

At present there appears to be little scope for biological control of C. difformis, but good suppression of growth is possible where a thick mat of Azolla pinnata is established on the water surface of irrigated ricefields (Janiya and Moody, 1984).

Chemical Control

Many herbicides are approved for use in rice but their use is dictated by the conditions used to grow the crop, e.g. irrigated, rainfed lowland, upland and deepwater. C. difformis is susceptible to the following herbicides commonly used in rice: bensulfuron, bentazon, bifenox + 2,4-D, butachlor, butralin, 2,4-D, MCPA, oxyfluorfen, pendimethalin, piperophos + dimethametryn, pretilachlor + safener (e.g. fenclorim), propanil, thiobencarb and thiobencarb + 2,4-D.

Other rice herbicides active against C. difformis are cinmethylin and chlomethoxyfen (Ampong-Nyarko and DeDatta, 1991). Pyributicarb is reported to have excellent activity against C. difformis (Tsuzuki, 1990). Paraquat and glyphosate can both be used as non-selective, post-emergence herbicides against C. difformis, such as for land preparation using zero tillage. Resistance to bensulfuron has been reported in the USA and Australia (Heap, 1997).

Integrated Weed Management

Integrated weed management is recommended for cost-effective weed control.

References

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Abud JK, 1986. Effects of herbicides on control of red rice (Oryza sativa L.), (Echinochloa crus-galli L.) Beauv. and (Cyperus difformis L.) in irrigated rice. Lavoura Arrozeira, 39(363):8-10

Acevedo-Rodríguez P; Strong MT, 2012. Catalogue of the Seed Plants of the West Indies. Smithsonian Contributions to Botany, 98:1192 pp. Washington DC, USA: Smithsonian Institution. http://botany.si.edu/Antilles/WestIndies/catalog.htm

Alghali AM, 1979. Weed hosts of Diopsid (Diptera) rice stem borers in southern Nigeria. International Rice Research Newsletter, 4(4):21

Ampong-Nyarko K; DeDatta SK, 1991. A Handbook for Weed Control in Rice. Manila, Philippines: International Rice Research Institute.

Atu UG; Enyinnia T; Chinaka CC, 1988. Grass and sedge weed hosts of Meloidogyne incognita. Nigerian Journal of Weed Science, 1(1):17-20

Auld BA; Medd RW, 1987. Weeds. An illustrated botanical guide to the weeds of Australia. Melbourne, Australia; Inkata Press, 255 pp.

Balakrishnan B; Nair MC, 1981. Weed hosts of Acrocylindrium oryzae Saw., a sheath rot pathogen of rice. International Rice Research Newsletter, 6(6):13

Balogh L; Dancza I; Kiraly G, 2004. Actual list of neophytes in Hungary and their classification according to their success. In: Biological invasions in Hungary - Invasive plants [ed. by Mihaly, B. \Botta-Dukat, Z.]. 61-92.

Bandara JMRS; Nadaraja V, 1979. Reaction of some common weeds in Sri Lankan rice fields to Corticium sasakii. International Rice Research Newsletter, 4(3):15-16

Barnes DE; Chan LG, 1990. Common Wees of Malaysia and their Control. Malaysia: Ancom Berhad.

Barrett SCH; Seaman DE, 1980. The weed flora of Californian rice fields. Aquatic Botany, 9(4):351-376

Barrion AT; Litsinger JA, 1987. The bionomics, karyology and chemical control of the node-feeding black bug, Scotinophara latiuscula Breddin (Hemiptera: Pentatomidae) in the Philippines. Journal of Plant Protection in the Tropics, 4(1):37-54

Belov M, 2013. ChileFlora. http://www.chileflora.com/index.html

Binns B, 1968. A First Check List of the Herbaceous Flora of Malawi. Zomba, Malawi: The Government Printer.

Bir SS; Chatha GS; Sidhu M, 1992. Intraspecific variation in Cyperaceae from Punjab Plain, India. Willdenowia, 22(1-2):133-142

Boulos L; El-Hadidi MN, 1984. The Weed Flora of Egypt. Cairo, Egypt: The American University in Cairo Press.

Chandra SK, 2012. Invasive Alien Plants of Indian Himalayan Region- Diversity and Implication. American Journal of Plant Sciences, 3:177-184.

Chandrakar BL; Tripathi RS; Tuteja SS; Taunk, 1993. Effect of application timings and formulations of anilofos in broadcast seeded semi dry rice (Oryza sativa). Integrated weed management for sustainable agriculture. Proceedings of an Indian Society of Weed Science International Symposium, Hisar, India, 18-20 November 1993 Hisar, Haryana, India; Indian Society of Weed Science, Vol. III:13-15

Chu YI; Yang PS, 1984. Ecology of the brown planthopper (Nilaparvata lugens (Stal)) during the winter season in Taiwan. Chinese Journal of Entomology, 4(2):23-34

Civico RSA; Moody K, 1979. The effect of the time and depth of submergence on growth and development of some weed species. Philippine Journal of Weed Science, 6:41-49

Clayton WD, 1972. Gramineae. In: Hutchinson J, Dalziel JM, Hepper FN, 1972. Flora of West Tropical Africa. Vol 3. Part 2. London, UK: Crown Agents, 349-512.

DAISIE, 2014. Delivering Alien Invasive Species Inventories for Europe. European Invasive Alien Species Gateway. www.europe-aliens.org/default.do

Dastgheib F; Beigi M, 1988. Weed flora and their effect on rice in Fars Province, Iran. Iran Agricultural Research, 7(2):135-142

Deuse JPL; Birie-Habas J; Jeutong F; Nguimatsa M, 1983. Chemical weed control in irrigated rice in West Cameroon. Proceedings of the Second Biannual Conference, West African Weed Science Society [edited by Deat, M.; Marnotte, P.] Abidjan, Ivory Coast; West African Weed Science Society, 167-171

Diaz CA, 1976. Identificacion y analisis cuantitativo de malezas en arroz, cana de azucar, algodon y garbanzo. Trabajos y Resumenes, III Congreso Asociacion Latinoamericana de Malezas "ALAM" y VIII Reunion Argentina de Malezas y su Control, "ASAM", Mar de Plata. Buenos Aires, Argentina, 1:15-30.

Drummond RB, 1984. Arable Weeds of Zimbabwe. Harare, Zimbabwe: Agricultural Research Trust of Zimbabwe.

Dube VP; Tyagi S; Singhal VP; Charaya MU, 1979. Additions to the host range of Puccinia conclusa and Uromyces viciae-fabae. National Academy Science Letters, 2(12):432

Elliot PC; Clarisse RN; Beby R; Josue HR, 1993. Weeds in rice in Madagascar. International Rice Research Notes, 18(1):53-54.

Fang ZY; Wang SX, 1990. Preliminary study on weed control in dry seeded rice (DSR) after winter wheat. International Rice Research Newsletter, 15(6):26-27

Farrukh Hussain; Nigar MM; Jabeen Akhtar; Najma Abidi, 1984. Distribution of weeds in the fields of Virginia tobacco at Yar Hussain and its out-skirts. Pakistan Journal of Agricultural Research, 5(4):227-235

Fischer AJ; Lozano J; Ramirez A; Sanint LR, 1993. Yield loss prediction for integrated weed management in direct-seeded rice. International Journal of Pest Management, 39(2):175-180

Flora of China Editorial Committee, 2014. Flora of China. St. Louis, Missouri and Cambridge, Massachusetts, USA: Missouri Botanical Garden and Harvard University Herbaria. http://www.efloras.org/flora_page.aspx?flora_id=2

Florence J; Chevillotte H; Ollier C; Meyer J-Y, 2013. Base de données botaniques Nadeaud de l'Herbier de la Polynésie Française (PAP) (Botanical database of the Nadeaud Herbarium of French Polynesia). http://www.herbier-tahiti.pf

Fosberg FR; Sachet M-H; Oliver R, 1987. A geographical checklist of the Micronesian monocotyledonae. Micronesia 20: 1-2, 19-129.

Gómez-Laurito J, 2003. Cyperaceae. Monographs in Systematic Botany from the Missouri Botanical Garden, 92:458-551. [Manual de Plantas de Costa Rica.]

Gonzales G; Webb ME, 1989. Manual para la Identicacion y Control de Malezas. Santa Cruz, Bolivia: CIAT.

Govaerts R, 2014. World Checklist of Cyperaceae. London, UK: Royal Botanic Gardens, Kew. http://apps.kew.org/wcsp/

Graveson R, 2012. Plants of Saint Lucia. http://www.saintlucianplants.com

Graveson R, 2012. The Plants of Saint Lucia (in the Lesser Antilles of the Caribbean). The Plants of Saint Lucia (in the Lesser Antilles of the Caribbean). http://www.saintlucianplants.com

Haines RW; Lye KA, 1983. The Sedges and Rushes of East Africa. Nairobi, Kenya: East African Natural History Society.

Hancock IR; Henderson CP, 1988. Flora of the Solomon Islands. Research Bulletin No. 7. Honiara, Solomon Islands: Dodo Creek Research Station.

Heap IM, 1997. The occurrence of herbicide-resistant weeds worldwide. Pesticide Science, 51:235-243.

Holm LG; Pancho JV; Herberger JP; Plucknett DL, 1979. A geographical atlas of world weeds. New York, USA: John Wiley and Sons, 391 pp.

Holm LG; Plucknett DL; Pancho JV; Herberger JP, 1977. The World's Worst Weeds. Distribution and Biology. Honolulu, Hawaii, USA: University Press of Hawaii.

Horng RT, 1976. Investigation of weed flora on paddy fields in the Taichung District. Plant Protection Bulletin, Taiwan, 18(3):268-275

Imeokparia PO, 1989. Weeds of lowland rice in north-western Nigeria. Nigerian Journal of Weed Science, 2(1-2):9-14

Jacometti G, 1912. Le erbe che infestano le risaie italiane. Atti del Congresso Risicolo Internazionale, Vercelli, 4:57-91.

Janiya JD; Moody K, 1984. Use of azolla to suppress weeds in transplanted rice. Tropical Pest Management, 30(1):1-6

Jauzein P, 1991. Eclipta prostrata (L.) L. a weed of rice fields in the Camargue. Monde des Plantes, 86(440):15-16

Jena SN; Patro GK, 1990. Weed composition in dry seeded wetland rice. International Rice Research Newsletter, 15(3):34

Joseph PA, 1986. Influence of different ecological situations on weed emergence in wetland rice. International Rice Research Newsletter, 11(4):38-39

Joshi RC; Medina EB; Heinrichs EA, 1985. Host plants of rice leaffolder (LF) Marasmia patnalis Bradley. International Rice Research Newsletter, 10(3):29-30

Khanna KK, 2009. Invasive alien angiosperms of Uttar Pradesh. Biological Forum, 1(2):34-39. http://www.researchtrend.net

Kim SC; Lee SK; Park RK, 1982. Ecological aspects and effective control of weeds in rice seedbeds. Research Reports of the Office of Rural Development, Crop, 24:107-113

Kurmi K; Das GR, 1993. Effect of herbicides on weed control in transplanted rice. Integrated weed management for sustainable agriculture. Proceedings of an Indian Society of Weed Science International Symposium, Hisar, India, 18-20 November 1993 Hisar, Haryana, India; Indian Society of Weed Science, 3:27-29

Larridon I; Bauters K; Reynders M; Huygh W; Muasya AM; Simpson DA; Goetghebeur P, 2013. Towards a new classification of the giant paraphyletic genus Cyperus (Cyperaceae): phylogenetic relationships and generic delimitation in C4 Cyperus. Botanical Journal of the Linnean Society [Proceedings of the 5th International Conference on Comparative Biology of Monocotyledons (Monocots V), New York, USA, 7-13 July 2013.], 172(1):106-126. http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1095-8339

Li D, 1987. An investigation on paddy field weeds in Fujian. Journal of Fujian Agricultural College, 16(4):267-277

Linnaeus C, 1756. Centuria II Plantarum. Uppsaliae.

Lye KA, 1981. Studies in African Cyperaceae 18. Two new subgenera of Cyperus. Nordic Journal of Botany, 1:57-61.

Mangoensoekardjo S; Pancho JV, 1975. Weed inventory in plantations in North Sumatra. Biotrop Newsletter, No. 12:12

McCormack G, 2013. Cook Islands Biodiversity Database, Version 2007. Cook Islands Biodiversity Database. Rarotonga, Cook Islands: Cook Islands Natural Heritage Trust. http://cookislands.bishopmuseum.org/search.asp

McIntyre S; Finlayson CM; Ladiges PY; Mitchell DS, 1991. Weed community composition and rice husbandry practices in New South Wales, Australia. Agriculture, Ecosystems & Environment, 35(1):27-45

Merlier H, 1975. Weed flora in "upland" rice in the Ivory Coast. 2e Symposium sur le Desherbage des Cultures Tropicales, Montpellier, 1974; organise par ... COLUMA avec la participation des Instituts membres du ... GERDAT. Comite Francais de Lutte contre les Mauvaises Herbes. 8, av. du President Wilson, 75116 Paris, 127-141

Minh-Si H, 1969. Weeds in South Vietnam. Saigon, Vietnam: Agricultural Research Institute, Ministry of Land Reform and Development of Agriculture and Fisheries.

Moody K, 1989. Weeds reported in Rice in South and Southeast Asia. Manila, Philippines: International Rice Research Institute.

Moody K; Munroe CE; Lubigan RT; Paller EC Jr, 1984. Major Weeds of the Philippines. Los Baños, Philippines: Weed Science Society of the Philippines, University of the Philippines at Los Baños.

Muasya AM; Simpson DA; Verboom GA; Goetghebeur P; Naczi RFC; Chase MW; Smets E, 2009. Phylogeny of Cyperaceae based on DNA sequence data: current progress and future prospects. Botanical Review, 75:2-21.

Noda K; Teerawatsakul M; Prakongvongs C; Chaiwiratnukul L, 1985. Major Weeds in Thailand. Bangkok, Thailand: Department of Agriculture.

Numata M; Yoshizawa N, 1975. Weed flora of Japan. Japan Association for the Advancement of Phyto-Regulators. Tokyo, Japan: Zenkoku Noson Kyoiku Kyokai.

Ormeno N J, 1983. Survey of the principal weeds associated with the cultivation of rice (Oriza sativa L.). Agricultura Tecnica, 43(3):285-287

Pamplona PP; Evangelista CC, 1981. Comparative evaluation of Arosin, Rogue and butachlor for weed control in transplanted dapog and wet-bed raised rice field. SMARC Monitor, 2(4):18

Parham JW, 1958. The Weeds of Fiji. Bulletin Fiji Department of Agriculture, 35. Suava, Fiji: Government Press.

Parker C, 1992. Weeds of Bhutan. Weeds of Bhutan., vi + 236 pp.

Patel CL; Patel ZG; Patel RB; Patel HR, 1985. Herbicides for weed control in rice nurseries. International Rice Research Newsletter, 10(5):26

Raju RA; Reddy KA, 1992. Comparison of application methods for chemical weed control in rice. Plant Protection Quarterly, 7(1): 26-27.

Ranjit JD; Bhattarai AN, 1988. Crop Weeds and their Control in Nepal. Kathmandu, Nepal: Winrock International/USAID.

Raulerson L, 2006. Checklist of Plants of the Mariana Islands. University of Guam Herbarium Contribution, 37. 1-69.

Reddy CS, 2008. Catalogue of invasive alien flora of India. Life Science Journal, 5:84-89.

Rejmanek M, 1987. Systematics and distribution of California Cyperus weedy species. Proceedings, 39th annual California weed conference El Macero, California, USA, 83-86

Robertson SA, 1989. Flowering Plants of Seychelles. Kew, UK: Royal Botanic Gardens.

Sastry KSK; Boraiah G; Govindu HC; Khaleel TF, 1980. Weeds of Karnataka. Weeds of Karnataka. University of Agricultural Sciences Bangalore India, 360pp.

Simpson DA; Furness CA; Hodkinson TR; Muasya AM; Chase MW, 2003. Phylogenetic relationships in Cyperaceae subfamily Mapanioideae inferred from pollen and plastid DNA sequence data. American Journal of Botany, 90:1071-1086.

Singh D; Gangwar B, 1987. Ricefield weeds in South Andaman, India. International Rice Research Newsletter, 12(4):47

Singh G; Singh JN; Tiwari S; Chauhan VS; Singh MP, 1989. Weed control efficacy of fluroxypyr and tridiphane in transplanted rice. Proceedings, 12th Asian-Pacific Weed Science Society Conference Taipei, Taiwan; Asian-Pacific Weed Science Society, No. 1:303-307

Singh SK, 1993. Economics of weed control in transplanted rainfed lowland rice in West Bengal, India. Integrated weed management for sustainable agriculture. Proceedings of an Indian Society of Weed Science International Symposium, Hisar, India, 18-20 November 1993 Hisar, Haryana, India; Indian Society of Weed Science, Vol. III:51-53

Smith AC, 1979. Flora Vitiensis nova: A new flora of Fiji. Volume I. Lawai, Kauai, Hawaii, USA: National Tropical Botanical Garden, 494 pp.

Soerjani M; Kostermans AJGH; Tjitrosoepomo G, 1987. Weeds of Indonesia. Jakarta, Indonesia: Balai Pustaka, 716 pp.

Space JC; Waterhouse B; Denslow J; Nelson D; Waguk EE, 2000. Invasive plant species on Kosrae, Federated States of Micronesia. Honolulu, USA: USDA Forest Service, 43 pp.

Srinivasan G; Subbian P, 1991. Study on weed management in rice pulse cropping system. Journal of Maharashtra Agricultural Universities, 16(3):376-378

Stevens PF, 2012. Angiosperm Phylogeny Website. http://www.mobot.org/MOBOT/research/APweb/

Tanji A; Taleb A, 1997. New weed species recently introduced into Morocco. Weed Research (Oxford), 37(1):27-31; 35 ref.

Terry PJ, 1978. Sedge weeds of East Africa - II.Distribution. Technical Report ARC Weed Research Organization, No. 50:26 pp.

Terry PJ, 1981. Weeds and their control in the Gambia. Tropical Pest Management, 27(1):44-52.

Tsuzuki K, 1990. Pyributicarb (TSH-888). A new herbicide for rice. Japan Pesticide Information, No. 57:30.

Ul'yanova TN, 1988. Weeds of the Korea Democratic People's Republic. Nauchno-Tekhnicheskii Byulleten' Vsesoyuznogo Ordena Lenina i Ordena Druzhby Narodov Nauchno-Issledovatel'skogo Instituta Rastenievodstva Imeni N. I. Vavilova, No. 181:21-25

USDA-ARS, 2014. Germplasm Resources Information Network (GRIN). Online Database. Beltsville, Maryland, USA: National Germplasm Resources Laboratory. https://npgsweb.ars-grin.gov/gringlobal/taxon/taxonomysearch.aspx

USDA-NRCS, 2014. The PLANTS Database. Baton Rouge, USA: National Plant Data Center. http://plants.usda.gov/

Vander N, 2003. The vascular plants of Majuro Atoll, Republic of the Marshall Islands. Smithsonian Institution, Atoll Research Bulletin, 503:1-141.

Villaseñor JL; Espinosa-Garcia FJ, 2004. The alien flowering plants of Mexico. Diversity and Distributions, 10(2):113-123.

Wagner WL; Herbst DR; Sohmer SH, 1999. Manual of the flowering plants of Hawaii. Revised edition. Honolulu, Hawaii, USA: University of Hawaii Press/Bishop Museum Press. [Bernice P. Bishop Museum special publication.]

Wang Z; Xin M; Ma D, 1990. Farmland Weeds in China. Agricultural Publishing House, 506 pp.

Waterhouse DF, 1993. The Major Arthropod Pests and Weeds of Agriculture in Southeast Asia. ACIAR Monograph No. 21. Canberra, Australia: Australian Centre for International Agricultural Research, 141 pp.

Waterhouse DF, 1993. The Major Arthropod Pests and Weeds of Agriculture in South-East Asia. Canberra, Australia: Australian Centre for International Agricultural Research.

Whistler WA, 1996. Botanical survey of Diego Garcia, Chagos Archipelago, British Indian Ocean Territory. Isle Botanica (online), 49 pp. http://www.zianet.com/tedmorris/dg/2005NRMP-Appendixe-botanicalsurvey.pdf

Williams G; Hunyadi K(Compilers), 1987. Dictionary of weeds of Eastern Europe. Amsterdam, Netherlands; Elsevier Science Publishers, 479pp.

Williams JF; Roberts SR; Hill JE; Scardaci SC; Tibbits G, 1990. Managing water for weed control in rice. California Agriculture, 44(5):7-10

Yu R, 1992. A study, using a calculation model, of the effect of small-flower umbrella plant (Cyperus difformis L.) on yield losses of early rice. Acta Agriculturae Shanghai, 8(1):58-62

Zhang RJ; Li ZF; He JH, 1989. Efficiency of delachlor-simetryne granule for the control of weeds in paddy fields and techniques for its application. Zhejiang Agricultural Science, No. 3:131-136; [5 tables].

Contributors

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22/04/14 Updated by:

Julissa Rojas-Sandoval, Department of Botany-Smithsonian NMNH, Washington DC, USA

Pedro Acevedo-Rodríguez, Department of Botany-Smithsonian NMNH, Washington DC, USA

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