Ageratina mairetiana(DC.) R.M.King & H.Rob.

WFO wfo-0000031764 Accepted WFO 2026-06 8 photographs CC BY / CC BY-SA

Plate 1 figs. a–h · 8 separate observations

Ageratina mairetiana, photographed by Neptalí Ramírez Marcial
fig. a Neptalí Ramírez Marcial, CC BY 4.0 / 2015-03-31 / obs. 4320738
Ageratina mairetiana, photographed by Neptalí Ramírez Marcial
fig. b Neptalí Ramírez Marcial, CC BY 4.0 / obs. 60494043
Ageratina mairetiana, photographed by Neptalí Ramírez Marcial
fig. c Neptalí Ramírez Marcial, CC BY 4.0 / obs. 13743887
Ageratina mairetiana, photographed by Neptalí Ramírez Marcial
fig. d Neptalí Ramírez Marcial, CC BY 4.0 / obs. 13120043
Ageratina mairetiana, photographed by Neptalí Ramírez Marcial
fig. e Neptalí Ramírez Marcial, CC BY 4.0 / obs. 6092248
Ageratina mairetiana, photographed by Neptalí Ramírez Marcial
fig. f Neptalí Ramírez Marcial, CC BY 4.0 / obs. 199788085
Ageratina mairetiana, photographed by Eugenio Padilla
fig. g Eugenio Padilla, CC BY-SA 4.0 / obs. 61801882
Ageratina mairetiana, photographed by Eugenio Padilla
fig. h Eugenio Padilla, CC BY-SA 4.0 / obs. 115219756

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
367573
Filed as
Ageratina mairetiana var. mairetiana
Det. by
B. L. Turner 1987-01-01
Collected
F. R. Barrie 1985-03-28
Origin
MX
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 8 botanical countries

Regions where Ageratina mairetiana is native: Mexico Central, Mexico Gulf, Mexico Northeast, Mexico Northwest, Mexico Southeast, Mexico Southwest, El Salvador, Guatemala Mexico CentralMexico GulfMexico NortheastMexico NorthwestMexico SoutheastMexico SouthwestEl SalvadorGuatemala
Native distribution of Ageratina mairetiana, 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
Mexico Central MXC NORTHERN AMERICA
Mexico Gulf MXG
Mexico Northeast MXE
Mexico Northwest MXN
Mexico Southeast MXT
Mexico Southwest MXS
El Salvador ELS SOUTHERN AMERICA
Guatemala GUA

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 38 observations

Condition 5th percentile Median 95th percentile
Coldest month, mean daily low -0.9 °C 3.9 °C 7.3 °C
Warmest month, mean daily high 19.5 °C 21.7 °C 25.2 °C
Annual rainfall 718 mm 1,312 mm 1,683 mm
Rainfall in the driest quarter 27 mm 48 mm 63 mm

It is found where winters bring light 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 38 research-grade observations of Ageratina mairetiana 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.

  • Ageratina rafaelensis (J.M.Coult.) R.M.King & H.Rob.
  • Eupatorium cognatum Kunth & C.D.Bouché
  • Eupatorium glandulosum Hort.Berol. ex Kunth
  • Eupatorium mairetianum DC.
  • Eupatorium mairetianum f. elucens McVaugh
  • Eupatorium mairetianum f. mairetianum
  • Eupatorium mairetianum var. adenopodum B.L.Rob.
  • Eupatorium mairetianum var. mairetianum
  • Eupatorium rafaelense J.M.Coult.
  • Eupatorium rafaelense Coulter

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. 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.