Cyperus iriaL.

ricefield flatsedge

WFO wfo-0000375442 Accepted WFO 2026-06 8 photographs CC BY / CC BY-SA

Plate 1 figs. a–h · 8 separate observations

Cyperus iria, photographed by Augustin Soulard
fig. a Augustin Soulard, CC BY 4.0 / 2022-05-17 / obs. 199303383
Cyperus iria, photographed by Augustin Soulard
fig. b Augustin Soulard, CC BY 4.0 / obs. 198815094
Cyperus iria, photographed by Greg Tasney
fig. c Greg Tasney, CC BY-SA 4.0 / obs. 185714097
Cyperus iria, photographed by Greg Tasney
fig. d Greg Tasney, CC BY-SA 4.0 / obs. 184004291
Cyperus iria, photographed by Greg Tasney
fig. e Greg Tasney, CC BY-SA 4.0 / obs. 178782877
Cyperus iria, photographed by 高山田鼠
fig. f 高山田鼠, CC BY 4.0 / obs. 177325110
Cyperus iria, photographed by Greg Tasney
fig. g Greg Tasney, CC BY-SA 4.0 / obs. 176563194
Cyperus iria, photographed by Augustin Soulard
fig. h Augustin Soulard, CC BY 4.0 / obs. 183079297

Every figure is a research-grade observation under CC0, CC BY or CC BY-SA, rehosted with the photographer’s name, the licence and the observation it came from. Photographs under a NonCommercial licence are excluded from this site and are never stored, which costs us a great many pictures and is not negotiable.

Native range 81 botanical countries

Regions where Cyperus iria is native: Benin, Botswana, Burkina, Chad, Comoros, DR Congo, Eritrea, Eswatini, Ethiopia, Gabon, Gambia, Ghana, Guinea, Ivory Coast, Kenya, Madagascar, Malawi, Mali, Mauritania, Mozambique, Namibia, Niger, Nigeria, Northern Provinces, Senegal, Somalia, Sudan-South Sudan, Tanzania, Uganda, Zambia, Zimbabwe, Afghanistan, China North-Central, China South-Central, China Southeast, Hainan, Iran, Iraq, Japan, Kazan-retto, Korea, Manchuria, Nansei-shoto, Ogasawara-shoto, Oman, Tadzhikistan, Taiwan, Tibet, Turkmenistan, Uzbekistan, Xinjiang, Assam, Bangladesh, Borneo, Cambodia, East Himalaya, India, Jawa, Laos, Lesser Sunda Is., Malaya, Maluku, Myanmar, Nepal, New Guinea, Pakistan, Philippines, South China Sea, Sri Lanka, Sulawesi, Sumatera, Thailand, Vietnam, West Himalaya, New South Wales, Northern Territory, Queensland, South Australia, Western Australia, Caroline Is., Marianas BeninBotswanaBurkinaChadDR CongoEritreaEswatiniEthiopiaGabonGambiaGhanaGuineaIvory CoastKenyaMadagascarMalawiMaliMauritaniaMozambiqueNamibiaNigerNigeriaNorthern ProvincesSenegalSomaliaSudan-South SudanTanzaniaUgandaZambiaZimbabweAfghanistanChina North-CentralChina South-CentralChina SoutheastHainanIranIraqJapanManchuriaOmanTadzhikistanTaiwanTibetTurkmenistanUzbekistanXinjiangAssamBangladeshBorneoCambodiaEast HimalayaIndiaJawaLaosLesser Sunda Is.MalayaMalukuMyanmarNepalNew GuineaPakistanPhilippinesSri LankaSulawesiSumateraThailandVietnamWest HimalayaNew South WalesNorthern TerritoryQueenslandSouth AustraliaWestern Australia ComorosKoreaNansei-shotoSouth China SeaCaroline Is.Marianas
Native distribution of Cyperus iria, after Kew’s World Checklist of Vascular Plants. Introduced, extinct and doubtful records are excluded, so this is where the plant is from, not everywhere it now grows. Regions too small to draw at this scale are marked with a dot.
RegionTDWG codeContinent
Benin BEN AFRICA
Botswana BOT
Burkina BKN
Chad CHA
Comoros COM
DR Congo ZAI
Eritrea ERI
Eswatini SWZ
Ethiopia ETH
Gabon GAB
Gambia GAM
Ghana GHA
Guinea GUI
Ivory Coast IVO
Kenya KEN
Madagascar MDG
Malawi MLW
Mali MLI
Mauritania MTN
Mozambique MOZ
Namibia NAM
Niger NGR
Nigeria NGA
Northern Provinces TVL
Senegal SEN
Somalia SOM
Sudan-South Sudan SUD
Tanzania TAN
Uganda UGA
Zambia ZAM
Zimbabwe ZIM
Assam ASS ASIA-TROPICAL
Bangladesh BAN
Borneo BOR
Cambodia CBD
East Himalaya EHM
India IND
Jawa JAW
Laos LAO
Lesser Sunda Is. LSI
Malaya MLY
Maluku MOL
Myanmar MYA
Nepal NEP
New Guinea NWG
Pakistan PAK
Philippines PHI
South China Sea SCS
Sri Lanka SRL
Sulawesi SUL
Sumatera SUM
Thailand THA
Vietnam VIE
West Himalaya WHM
Afghanistan AFG ASIA-TEMPERATE
China North-Central CHN
China South-Central CHC
China Southeast CHS
Hainan CHH
Iran IRN
Iraq IRQ
Japan JAP
Kazan-retto KZN
Korea KOR
Manchuria CHM
Nansei-shoto NNS
Ogasawara-shoto OGA
Oman OMA
Tadzhikistan TZK
Taiwan TAI
Tibet CHT
Turkmenistan TKM
Uzbekistan UZB
Xinjiang CHX
New South Wales NSW AUSTRALASIA
Northern Territory NTA
Queensland QLD
South Australia SOA
Western Australia WAU
Caroline Is. CRL PACIFIC
Marianas MRN

Not drawn on the map: Kazan-retto, Ogasawara-shoto. We hold no public-domain boundary for these regions, so they are listed rather than guessed at.

Region boundaries approximated from Natural Earth (public domain) and mapped to TDWG World Geographical Scheme for Recording Plant Distributions (WGSRPD) level-3 botanical countries (Brummitt 2001). Indicative, not the official WGSRPD geometry.

Flowering 46 in flower of 92 examined

Peak flowering in Nov. Each bar is the share of Cyperus iria observations in which someone actually recorded the reproductive state and found the plant in flower, not the raw number of flowering records. That distinction matters: people observe plants far more in spring than in winter, so a bare count of flowering records partly measures when people go outside. Dividing by the number examined removes that. 46 of 92 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 4 months have fewer than 5 examined observations, so no proportion is drawn for them. This is still a global aggregate and not a forecast for your garden: the same species flowers on different dates in different hemispheres. Where a species has fewer than 30 flowering records we do not draw this chart at all. Computed from 10.15468/dl.cgje2x.

Also published as 19 synonyms

A synonym is not an error. It is a record of botanists disagreeing, in print, about where this plant belongs. Each of these was somebody’s considered answer.

  • Carex nangtciangensis Pamp.
  • Chlorocyperus iria (L.) Rikli
  • Cyperus chrysomelinus Link
  • Cyperus diaphaniria Steud.
  • Cyperus iria f. chrysomelinus (Link) Kük.
  • Cyperus iria f. diaphaniria (Steud.) Miq.
  • Cyperus iria f. flavescens (Benth.) Domin
  • Cyperus iria f. multiflora Domin
  • Cyperus iria var. flavescens Benth.
  • Cyperus iria var. paniciformis (Franch. & Sav.) C.B.Clarke
  • Cyperus iria var. santonici (Rottb.) Fernald & Griscom
  • Cyperus iria var. typicus Domin
  • Cyperus microlepis Baker
  • Cyperus nangtciangensis Pamp.
  • Cyperus paniciformis Franch. & Sav.
  • Cyperus panicoides Lam.
  • Cyperus resinosus Hochst. ex Steud.
  • Cyperus resinosus Hochst.
  • Cyperus santonici Rottb.

Sourcesevery claim on this page

  1. World Flora Online Plant List. accepted name, authority, classification. CC0. Retrieved 2026-07-12.
  2. iNaturalist. photographs and flowering annotations, CC0 / CC BY / CC BY-SA only. per photograph. Retrieved 2026-06-27.
  3. Wikidata. common name (P1843), joined on the World Flora Online identifier (P7715). CC0. Retrieved 2026-07-13.
  4. Kew, World Checklist of Vascular Plants (WCVP v16). native distribution by TDWG level-3 botanical country, and life form. CC BY 3.0. Retrieved 2026-06-04.

We publish what we can source and we say so when we cannot. This page has no care advice and no toxicity claim, because we do not yet have those from a source we can cite.