Equisetum myriochaetumSchltdl. & Cham.

Mexican giant horsetail

WFO wfo-0001113267 Accepted WFO 2026-06 8 photographs CC BY / CC BY-SA

Plate 1 figs. a–h · 6 observations

This species has been photographed under an open licence only 6 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.

Equisetum myriochaetum, photographed by Alexis López Hernández
fig. a Alexis López Hernández, CC BY 4.0 / 2021-01-05 / obs. 111695235
Equisetum myriochaetum, photographed by ELOYJIMENEZ13
fig. b ELOYJIMENEZ13, CC BY-SA 4.0 / obs. 49595794
Equisetum myriochaetum, photographed by Neptalí Ramírez Marcial
fig. c Neptalí Ramírez Marcial, CC BY 4.0 / obs. 9946884
Equisetum myriochaetum, photographed by Neptalí Ramírez Marcial
fig. d Neptalí Ramírez Marcial, CC BY 4.0 / obs. 4321230
Equisetum myriochaetum, photographed by vientoro
fig. e vientoro, CC BY-SA 4.0 / obs. 84430208
Equisetum myriochaetum, photographed by Alan Rockefeller
fig. f Alan Rockefeller, CC BY 4.0 / obs. 155036923
Equisetum myriochaetum, photographed by Alan Rockefeller
fig. g Alan Rockefeller, CC BY 4.0 / obs. 155036941
Equisetum myriochaetum, photographed by vientoro
fig. h vientoro, CC BY-SA 4.0 / obs. 84429276

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 15 botanical countries

Regions where Equisetum myriochaetum is native: Mexico Central, Mexico Gulf, Mexico Northeast, Mexico Northwest, Mexico Southeast, Mexico Southwest, Colombia, Costa Rica, Ecuador, El Salvador, Guatemala, Honduras, Nicaragua, Peru, Venezuela Mexico CentralMexico GulfMexico NortheastMexico NorthwestMexico SoutheastMexico SouthwestColombiaCosta RicaEcuadorEl SalvadorGuatemalaHondurasNicaraguaPeruVenezuela
Native distribution of Equisetum myriochaetum, 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
Colombia CLM SOUTHERN AMERICA
Costa Rica COS
Ecuador ECU
El Salvador ELS
Guatemala GUA
Honduras HON
Nicaragua NIC
Peru PER
Venezuela VEN
Mexico Central MXC NORTHERN AMERICA
Mexico Gulf MXG
Mexico Northeast MXE
Mexico Northwest MXN
Mexico Southeast MXT
Mexico Southwest MXS

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 223 observations

Condition 5th percentile Median 95th percentile
Coldest month, mean daily low 6.1 °C 9.6 °C 14.5 °C
Warmest month, mean daily high 18.7 °C 25.3 °C 30.5 °C
Annual rainfall 673 mm 1,460 mm 2,873 mm
Rainfall in the driest quarter 21 mm 72 mm 290 mm

It is barely found anywhere that freezes. This is not care advice and it is not a forecast. It is a measurement: we sampled the climate at every one of the 223 research-grade observations of Equisetum myriochaetum 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 10 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.

  • Equisetum elongatum var. muelleri Milde
  • Equisetum mexicanum Gand.
  • Equisetum mexicanum Milde
  • Equisetum myriochaetum var. densum Milde
  • Equisetum myriochaetum var. laxum Milde
  • Equisetum ramosissimum f. muelleri Milde
  • Equisetum ramosissimum f. sprucei Milde
  • Equisetum ramosissimum var. muelleri (Milde) Milde
  • Equisetum ramosissimum var. sprucei
  • Hippochaete myriochaeta (Schldl. & Cham.) Holub

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 EQMY. 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.