Cylindropuntia acanthocarpa(Engelm. & J.M.Bigelow) F.M.Knuth

buck-horn chollabuckhorn cholla

WFO wfo-0000632319 Accepted WFO 2026-06 8 photographs CC BY / CC BY-SA

Plate 1 figs. a–h · 8 separate observations

Cylindropuntia acanthocarpa, photographed by Robert Webster
fig. a Robert Webster, CC BY-SA 4.0 / 2022-05-23 / obs. 200676046

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
832277
Filed as
Cylindropuntia acanthocarpa var. acanthocarpa
Det. by
M. A. Baker 2017-01-01
Collected
A. E. Areces-Mallea 1996-07-01
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 5 botanical countries

Regions where Cylindropuntia acanthocarpa is native: Arizona, California, Mexico Northwest, Nevada, Utah ArizonaCaliforniaMexico NorthwestNevadaUtah
Native distribution of Cylindropuntia acanthocarpa, 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
Arizona ARI NORTHERN AMERICA
California CAL
Mexico Northwest MXN
Nevada NEV
Utah UTA

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 395 in flower of 850 examined

Proportion of examined Cylindropuntia acanthocarpa in flower, by month
Month In flower Examined Share 95% interval
Jan 7 41 17% 9% to 31%
Feb 10 48 21% 12% to 34%
Mar 52 152 34% 27% to 42%
Apr 192 294 65% 60% to 71%
May 89 135 66% 58% to 73%
Jun 9 29 31% 17% to 49%
Jul 2 16 13% 4% to 36%
Aug 2 8 25% 7% to 59%
Sep 0 7 0% 0% to 35%
Oct 5 20 25% 11% to 47%
Nov 10 38 26% 15% to 42%
Dec 17 62 27% 18% to 40%

Peak flowering in May. Each bar is the share of Cylindropuntia acanthocarpa 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. 395 of 850 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 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.

When it blooms, where you are 1 state

StatePeaksObservations in flower
Arizona May 342

Where it actually grows measured, from 1,955 observations

Condition 5th percentile Median 95th percentile
Coldest month, mean daily low -0.5 °C 3.7 °C 6.3 °C
Warmest month, mean daily high 33.3 °C 38.2 °C 40.8 °C
Annual rainfall 151 mm 271 mm 362 mm
Rainfall in the driest quarter 11 mm 20 mm 28 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 1,955 research-grade observations of Cylindropuntia acanthocarpa 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 16 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.

  • Cylindropuntia acanthocarpa subsp. coloradensis (L.D.Benson) U.Guzmán
  • Cylindropuntia acanthocarpa subsp. major (Engelm. & J.M.Bigelow) U.Guzmán
  • Cylindropuntia acanthocarpa var. acanthocarpa
  • Cylindropuntia acanthocarpa var. coloradensis (L.D.Benson) Pinkava
  • Cylindropuntia acanthocarpa var. major (Engelm. & J.M.Bigelow) Pinkava
  • Cylindropuntia acanthocarpa var. ramosa (Peebles) Backeb.
  • Cylindropuntia acanthocarpa var. thornberi (Thornber & Bonker) Backeb.
  • Grusonia acanthocarpa (Engelm. & J.M.Bigelow) G.D.Rowley
  • Opuntia acanthocarpa Engelm. & J.M.Bigelow
  • Opuntia acanthocarpa var. coloradensis L.D.Benson
  • Opuntia acanthocarpa var. major (Engelm. & J.M.Bigelow) L.D.Benson
  • Opuntia acanthocarpa var. ramosa Peebles
  • Opuntia acanthocarpa var. thornberi (Thornber & Bonker) L.D.Benson
  • Opuntia echinocarpa var. major Engelm. & J.M.Bigelow
  • Opuntia echinocarpa var. robustior J.M.Coult.
  • Opuntia thornberi Thornber & Bonker

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.