Cyperus melanostachyusKunth

black flatsedge

WFO wfo-0000377636 Accepted WFO 2026-06 8 photographs CC0 / CC BY

Plate 1 figs. a–h · 4 observations

This species has been photographed under an open licence only 4 times, so some figures below are different views of the same plant, taken on the same day, rather than different individuals. They are usually different parts of it: the leaf, the flower, the bark.

Cyperus melanostachyus, photographed by Ken-ichi Ueda
fig. a Ken-ichi Ueda, CC BY 4.0 / 2022-05-14 / obs. 198300310

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 24 botanical countries

Regions where Cyperus melanostachyus is native: Arizona, California, Mexico Central, Mexico Gulf, Mexico Northeast, Mexico Northwest, Mexico Southeast, Mexico Southwest, New Mexico, Oklahoma, Texas, Argentina Northeast, Argentina Northwest, Bolivia, Brazil South, Colombia, Costa Rica, Ecuador, Guatemala, Honduras, Nicaragua, Panamá, Peru, Venezuela ArizonaCaliforniaMexico CentralMexico GulfMexico NortheastMexico NorthwestMexico SoutheastMexico SouthwestNew MexicoOklahomaTexasArgentina NortheastArgentina NorthwestBoliviaBrazil SouthColombiaCosta RicaEcuadorGuatemalaHondurasNicaraguaPanamáPeruVenezuela
Native distribution of Cyperus melanostachyus, 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.
RegionTDWG codeContinent
Argentina Northeast AGE SOUTHERN AMERICA
Argentina Northwest AGW
Bolivia BOL
Brazil South BZS
Colombia CLM
Costa Rica COS
Ecuador ECU
Guatemala GUA
Honduras HON
Nicaragua NIC
Panamá PAN
Peru PER
Venezuela VEN
Arizona ARI NORTHERN AMERICA
California CAL
Mexico Central MXC
Mexico Gulf MXG
Mexico Northeast MXE
Mexico Northwest MXN
Mexico Southeast MXT
Mexico Southwest MXS
New Mexico NWM
Oklahoma OKL
Texas TEX

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.

Where it actually grows measured, from 44 observations

Condition 5th percentile Median 95th percentile
Coldest month, mean daily low 1.2 °C 4.6 °C 10.4 °C
Warmest month, mean daily high 19.5 °C 28.0 °C 34.2 °C
Annual rainfall 305 mm 671 mm 2,044 mm
Rainfall in the driest quarter 5 mm 28 mm 185 mm

It is found where winters are cool but frost is light or absent. This is not care advice and it is not a forecast. It is a measurement: we sampled the climate at every one of the 44 research-grade observations of Cyperus melanostachyus that carry a coordinate, and this is the range those places actually span. The 5th and 95th percentiles are used rather than the minimum and maximum, because a single cultivated specimen in a heated conservatory should not widen a tropical plant's range to the Arctic.

This is not a hardiness zone. A USDA zone is the average annual extreme minimum temperature. The figure above is the mean daily minimum of the coldest month, which is a different quantity and is typically far warmer. Reading one as the other would place a plant several zones too warm, so we do not publish a hardiness zone, because we do not have one.

Also published as 32 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.

  • Chlorocyperus cimicinus (J.Presl & C.Presl) Rikli
  • Chlorocyperus melanostachyus (Kunth) Rikli
  • Cyperus adustus J.Presl & C.Presl
  • Cyperus biradiatus Boeckeler
  • Cyperus cimicinus J.Presl & C.Presl
  • Cyperus diandrus var. capitatus Britton
  • Cyperus flavescens subvar. capitatus (Britton) Farw.
  • Cyperus intricatoramosus Boeckeler
  • Cyperus longicruris Boeckeler
  • Cyperus lorentzianus Boeckeler
  • Cyperus lorentzianus var. compressus Kük.
  • Cyperus lorentzianus var. elatus Kük.
  • Cyperus melanostachyus var. caespitosus Boeckeler
  • Cyperus melanostachyus var. capitatus (Britton) G.C.Tucker & Gandhi
  • Cyperus melanostachyus var. gracilis Liebm.
  • Cyperus melanostachyus var. lorentzianus (Boeckeler) G.C.Tucker & Gandhi
  • Cyperus melanostachyus var. robustus Liebm.
  • Cyperus niger Ruiz & Pav.
  • Cyperus niger var. capitatus (Britton) O'Neill
  • Cyperus niger var. castaneus Kük.
  • Cyperus niger var. intricatoramosus (Boeckeler) Kük.
  • Cyperus niger var. lorentzianus (Boeckeler) Kük.
  • Cyperus niger var. pseudoelegantulus Kük.
  • Cyperus niger var. robustus (Liebm.) Kük.

and 8 more.

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. USDA PLANTS Database. common name, checklist symbol CYNI2. public domain. 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.