Echinocactus horizonthaloniusLem.

Devilshead

WFO wfo-0000660527 Accepted WFO 2026-06 4 photographs CC0 / CC BY

Plate 1 figs. a–d

Echinocactus horizonthalonius, photographed by amantedarmanin
fig. a amantedarmanin, CC BY 4.0 / 2011-01-19 / obs. 153976450
Echinocactus horizonthalonius, photographed by Leticia Jiménez Hernández
fig. b Leticia Jiménez Hernández, CC BY-SA 4.0 / obs. 113201848
Echinocactus horizonthalonius, photographed by CK2AZ
fig. c CK2AZ, CC BY 4.0 / obs. 59213409
Echinocactus horizonthalonius, photographed by Michelle Cloud-Hughes
fig. d Michelle Cloud-Hughes, CC BY-SA 4.0 / obs. 177719164

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.

Confused withby our own model

These are not lookalikes we guessed at. Each one is a species our identification model genuinely mistook for this plant, and how many times. The error rate is published.

Flowering n = 514 observations

Peak flowering in May, from 514 community-annotated observations worldwide. This is a global aggregate, not a forecast for your garden: the same species flowers on different dates in different hemispheres, and citizen-science records cluster near cities, at weekends, and in spring. Where a species has fewer than 30 annotated records we do not draw this chart at all.

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.

  • Echinocactus equitans Scheidw.
  • Echinocactus horizontalis C.F.Först.
  • Echinocactus horizonthalonius f. centrispinus (Engelm.) Schelle
  • Echinocactus horizonthalonius f. curvispinus (Salm-Dyck) Schelle
  • Echinocactus horizonthalonius f. obscurispinus (Rud.Mey.) Schelle
  • Echinocactus horizonthalonius subsp. diabolicus Halda, L.Vacek & Vaško
  • Echinocactus horizonthalonius subsp. horizonthalonius
  • Echinocactus horizonthalonius subsp. jarmilae Halda & Horáček
  • Echinocactus horizonthalonius subsp. nicholii (L.D.Benson) U.Guzmán
  • Echinocactus horizonthalonius var. centrispinus Engelm.
  • Echinocactus horizonthalonius var. curvispinus Salm-Dyck
  • Echinocactus horizonthalonius var. equitans Schmoll
  • Echinocactus horizonthalonius var. laticostatus Schmoll
  • Echinocactus horizonthalonius var. obscurispinus Rud.Mey.
  • Echinocactus horizonthalonius var. subikii Staník & Dráb
  • Echinocactus laticostatus Engelm. & J.M.Bigelow
  • Echinocactus pachycornis Muehlenpf.
  • Meyerocactus horizonthalonius (Lem.) Doweld
  • Meyerocactus horizonthalonius subsp. nicholii (L.D.Benson) Doweld

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.

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