Pterocactus tuberosus

Plate 1 figs. a–h · 8 separate observations

Pterocactus tuberosus, photographed by aacocucci — fig. d aacocucci, CC BY 4.0 / obs. 165450962

Pterocactus tuberosus, photographed by Nicolas Olejnik — fig. g Nicolas Olejnik, CC BY 4.0 / obs. 60251864

Pterocactus tuberosus, photographed by Luciano Massa — fig. h Luciano Massa, CC BY 4.0 / obs. 74758116

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: 03890215
Filed as: Pterocactus tuberosus (Pfeiff.) Britton & Rose
Det. by: not recorded on this sheet
Collected: not recorded
Origin: not recorded
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 3 botanical countries

Native distribution of Pterocactus tuberosus, 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.

Region	TDWG code	Continent
Argentina Northeast	AGE	SOUTHERN AMERICA
Argentina Northwest	AGW
Argentina South	AGS

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 54 in flower of 85 examined

76%

84%

38%

Proportion of examined Pterocactus tuberosus in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	0	6	0%	0% to 39%
Feb	0	2	too few examined
Mar	0	0	too few examined
Apr	0	2	too few examined
May	0	1	too few examined
Jun	0	0	too few examined
Jul	0	0	too few examined
Aug	1	1	too few examined
Sep	1	2	too few examined
Oct	16	21	76%	55% to 89%
Nov	31	37	84%	69% to 92%
Dec	5	13	38%	18% to 64%

Peak flowering in Nov. Each bar is the share of Pterocactus tuberosus 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. 54 of 85 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 151 observations

Condition	5th percentile	Median	95th percentile
Coldest month, mean daily low	-2.4 °C	2.5 °C	6.3 °C
Warmest month, mean daily high	23.6 °C	30.2 °C	32.6 °C
Annual rainfall	198 mm	286 mm	516 mm
Rainfall in the driest quarter	15 mm	45 mm	72 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 151 research-grade observations of Pterocactus tuberosus 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 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.

Opuntia kuntzei (K.Schum.) Kiessling
Opuntia skottsbergii Britton & Rose
Opuntia tuberosa Pfeiff.
Opuntia tuberosa var. spinosa Pfeiff.
Pterocactus decipiens Gürke
Pterocactus kuntzei K.Schum.
Pterocactus kuntzei f. lelongii Ruiz Leal ex R.Kiesling
Pterocactus kurtzei K.Schum.
Pterocactus skottsbergii (Britton & Rose) Backeb.
Pterocactus tuberosus f. lelongii (Ruiz Leal ex R.Kiesling) R.Kiesling

Sourcesevery claim on this page

World Flora Online Plant List. accepted name, authority, classification. CC0. Retrieved 2026-07-12.
iNaturalist. photographs and flowering annotations, CC0 / CC BY / CC BY-SA only. per photograph. Retrieved 2026-06-27.
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.