Alopecurus geniculatusL.

marsh foxtailwater foxtail

WFO wfo-0000845537 Accepted WFO 2026-06 8 photographs CC0 / CC BY / CC BY-SA

Plate 1 figs. a–h · 8 separate observations

Alopecurus geniculatus, photographed by Grzegorz Grzejszczak
fig. a Grzegorz Grzejszczak, CC BY-SA 4.0 / 2022-06-03 / obs. 203788568

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.

The specimen a real sheet, in a real collection

Herbarium
The New York Botanical Garden
Accession
1637970
Filed as
Alopecurus geniculatus L.
Det. by
D. E. Atha 2015-01-01
Collected
Hooker
Origin
US
The sheet
View the digitised specimen (CC BY 4.0)

A real pressed plant, in a real collection, under the accession number above. Not an illustration of one. The holding institution does not serve this sheet’s image to third parties, so there is no photograph here. The record is real and the link goes to it. Where we hold no openly licensed sheet for a species this section is simply absent, and where a sheet never recorded who determined it, that field stays empty rather than being filled in. Roughly half of all herbarium sheets never recorded a determiner, which is ordinary.

Native range 39 botanical countries

Regions where Alopecurus geniculatus is native: Algeria, Afghanistan, Kirgizstan, North Caucasus, Türkiye, Uzbekistan, Nepal, West Himalaya, Austria, Baltic States, Belarus, Belgium, Bulgaria, Central European Russia, Czechia-Slovakia, Denmark, East European Russia, Finland, Føroyar, France, Germany, Great Britain, Greece, Iceland, Ireland, Italy, Netherlands, North European Russia, Northwest European Russia, Norway, NW. Balkan Pen., Poland, Portugal, Romania, Sicilia, Spain, Sweden, Switzerland, Ukraine AlgeriaAfghanistanKirgizstanNorth CaucasusTürkiyeUzbekistanNepalWest HimalayaAustriaBaltic StatesBelarusBelgiumBulgariaCentral European RussiaCzechia-SlovakiaDenmarkEast European RussiaFinlandFranceGermanyGreeceIcelandIrelandItalyNetherlandsNorth European RussiaNorthwest European RussiaNorwayNW. Balkan Pen.PolandPortugalRomaniaSiciliaSpainSwedenSwitzerlandUkraine Føroyar
Native distribution of Alopecurus geniculatus, 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
Austria AUT EUROPE
Baltic States BLT
Belarus BLR
Belgium BGM
Bulgaria BUL
Central European Russia RUC
Czechia-Slovakia CZE
Denmark DEN
East European Russia RUE
Finland FIN
Føroyar FOR
France FRA
Germany GER
Great Britain GRB
Greece GRC
Iceland ICE
Ireland IRE
Italy ITA
Netherlands NET
North European Russia RUN
Northwest European Russia RUW
Norway NOR
NW. Balkan Pen. YUG
Poland POL
Portugal POR
Romania ROM
Sicilia SIC
Spain SPA
Sweden SWE
Switzerland SWI
Ukraine UKR
Afghanistan AFG ASIA-TEMPERATE
Kirgizstan KGZ
North Caucasus NCS
Türkiye TUR
Uzbekistan UZB
Nepal NEP ASIA-TROPICAL
West Himalaya WHM
Algeria ALG AFRICA

Not drawn on the map: Great Britain. We hold no public-domain boundary for this region, so it is 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 52 in flower of 56 examined

Proportion of examined Alopecurus geniculatus in flower, by month
Month In flower Examined Share 95% interval
Jan 4 4 too few examined
Feb 0 1 too few examined
Mar 1 1 too few examined
Apr 3 3 too few examined
May 13 15 87% 62% to 96%
Jun 12 13 92% 67% to 99%
Jul 5 5 100% 57% to 100%
Aug 5 5 100% 57% to 100%
Sep 1 1 too few examined
Oct 0 0 too few examined
Nov 4 4 too few examined
Dec 4 4 too few examined

Peak flowering in Jul. Each bar is the share of Alopecurus geniculatus 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. 52 of 56 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 8 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.

Where it actually grows measured, from 717 observations

Condition 5th percentile Median 95th percentile
Coldest month, mean daily low -12.3 °C -2.8 °C 4.3 °C
Warmest month, mean daily high 16.8 °C 21.8 °C 27.0 °C
Annual rainfall 566 mm 733 mm 1,496 mm
Rainfall in the driest quarter 83 mm 137 mm 272 mm

It is found where winters bring hard frost. This is not care advice and it is not a forecast. It is a measurement: we sampled the climate at every one of the 717 research-grade observations of Alopecurus geniculatus 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. Climate from CHELSA V2.1 (Karger et al. 2017); occurrences from 10.15468/dl.cgje2x.

Also published as 20 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.

  • Alopecurus aristulosus Desv.
  • Alopecurus australis Nees
  • Alopecurus bulbosus With.
  • Alopecurus geniculatus f. normanii Neuman
  • Alopecurus geniculatus var. aquaticus Schltdl.
  • Alopecurus geniculatus var. bulbosus Gray
  • Alopecurus geniculatus var. geniculatus
  • Alopecurus geniculatus var. patagonicus Parodi
  • Alopecurus geniculatus var. pumila Vasey
  • Alopecurus geniculatus var. salinus Blytt
  • Alopecurus geniculatus var. strictus Andersson
  • Alopecurus geniculatus var. vinealis Neilr.
  • Alopecurus geniculatus var. virens Peterm.
  • Alopecurus geniculatus var. viridis Neilr.
  • Alopecurus nothus R.Arndt
  • Alopecurus pallescens Piper
  • Alopecurus palustris Syme
  • Alopecurus palustris subsp. geniculatus (L.) Syme
  • Alopecurus subaristatus Pursh
  • Tozzettia geniculata (L.) Bubani

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.