Sclerocactus glaucus (K.Schum.) L.D.Benson

Colorado hookless cactus, Uinta Basin hookless cactus, Uintah Basin Hookless Cactus

Climate known 25 photographs Cactus or succulent

Every figure on this page is derived from public data by a stated rule and says its source; nothing here is written by a person or a model, except the Wikipedia passage, which is quoted and marked as such. How it is made.

Summary

Sclerocactus glaucus is a rare species of cactus known by the common name Colorado hookless cactus. It is endemic to Colorado in the United States, where it is known only from the area between Grand Junction and Montrose. It is a federally listed threatened species.

Text from Wikipedia, “Sclerocactus glaucus”, CC BY-SA 4.0, quoted as written. Kept separate from everything derived here.

About the genus · Sclerocactus

Sclerocactus is a genus of cacti. It comprises about 15 species, the exact number depending on the authority. These species are xerophytic. More on Wikipedia ›

The opening of Wikipedia, “Sclerocactus”, CC BY-SA 4.0, quoted as written.

Family

Cactaceae

Described by

(K.Schum.) L.D.Benson

Native to

Colorado

Wild records

110 in range· 29 open

At a glance

Warmest month

31°C

Jul, mean day; nights 15 °C (CHELSA)

Rain

296mm/yr

5 wet months · peak Sep 37 mm (CHELSA)

Light

16–51DLI

mol/m²/day, winter to summer, open sky (CHELSA shortwave)

In short condensed by rule from the cultivation cards · not written by a person

Grouped as a cactus or succulent by Cactaceae, which is usually but not always one kind of plant (archetype table). Rain rule: a summer growing season, March to May and July to October in the northern hemisphere (March to May and July to October at the habitat, northern). Habitat rain 296 mm a year, wettest September at 37 mm, driest January at 15 mm (habitat calendar, northern hemisphere). Open sky over the habitat: 16 to 51 mol/m²/day. Cold floor -14.3 °C (1st-percentile habitat night, NASA POWER).

Each sentence is one card's own one-line form, written by the same rule as the card (Its year, Rain, Light, Temperature); the note cannot say what a card does not. Months are given for the northern hemisphere (set your site in Settings to change this), and the habitat's own alongside. The cards · the figures.

Also known as Echinocactus glaucus K.Schum.; Echinocactus subglacus Rydb.; Echinocactus subglaucus Rydb.; Echinocactus whipplei var. glaucus (K.Schum.) J.A.Purpus; Echinocactus whipplei var. glaucus K.Schum. and 5 more.

Cultivation

Grouped as a cactus or succulent by Cactaceae, which is usually but not always one kind of plant (archetype table). The table holds no figure for this group, which spans too much for one minimum; the cold floor is the habitat's alone, and no prose comes from the table.

Its year Rain rule: a summer growing season, March to May and July to October in the northern hemisphere (March to May and July to October at the habitat, northern).

This species’ habitat figures, and what two fixed rules read from them.

The rain rule reads a summer growing season: 70% of the year's rain (209 mm of 296 mm) falls in March to May and July to October, warmer than the year (wet-season mean 14.5 °C against a yearly mean of 9.9 °C). Months are the habitat's, northern hemisphere; shifted six months for a southern-hemisphere collection: January to April and September to November.

Read from the median year of CHELSA monthly rainfall and mean temperature across the envelope cells: the rain rule takes the smallest set of months carrying 70% of the rain and calls it winter when its mean is more than half a degree below the year's, summer when more than that above, and neither in between; the temperature rule, used only under 120 mm, names the cooler six months when they are at least a degree cooler than the other six. Months are shifted for the other hemisphere only where the temperature curve gives a season to reverse. A reading of the curves, not an observation of the plant.

Rain Habitat rain 296 mm a year, wettest September at 37 mm, driest January at 15 mm (habitat calendar, northern hemisphere).

This species’ habitat figures, with their source.

296 mm a year at the habitat, 209 mm of it March to May and July to October. Wettest month September at 37 mm, driest January at 15 mm. Across the envelope cells the year's total runs 275 mm to 305 mm (10th to 90th percentile of each cell's own year) (median year across the envelope cells, CHELSA; habitat calendar, northern hemisphere).

CHELSA monthly precipitation, median year across the envelope cells. The rain that falls where the species is recorded; nothing about how the plant takes water.

Light Open sky over the habitat: 16 to 51 mol/m²/day.

This species’ habitat figures, with their source.

Open sky over the habitat: 16 to 51 mol/m²/day across the year (daily light integral, median year across the envelope cells, CHELSA).

CHELSA shortwave radiation at each envelope cell, a daily-mean flux taken to a daily total and converted at 2.07 mol of PAR per MJ. The sky over the habitat, measured; what reaches a plant under a rock, a shrub or a shade cloth is not.

Warmth and air Cold floor -14.3 °C (1st-percentile habitat night, NASA POWER).

This species’ habitat figures, with their source.

Temperature

Coldest: the 1st-percentile night over 44 years at the typical cell is -14.3 °C, the absolute minimum -27.0 °C, about 109 frost nights a year (NASA POWER daily minima). Warmest: the 99th-percentile day is 38.5 °C. Monthly means: coldest night -9.1 °C in January (across the envelope cells -9.3 °C to -8.8 °C), warmest day 31.2 °C in July (median year across the envelope cells, CHELSA). Cold floor: -14.3 °C, which is the 1st-percentile night over 44 years at the typical cell (NASA POWER).

NASA POWER daily minima and maxima 1981–2024 at the typical cell, lapse-corrected to its elevation; CHELSA monthly means, median year across the envelope cells, CHELSA. The cold floor is the figure named in its sentence. Not a measured survival limit for any plant in a pot.

Humidity

Relative humidity at the habitat: 43 to 58% across the year (monthly means, median year across the envelope cells, CHELSA). A figure about the air, saying nothing about how the plant takes water.

CHELSA relative humidity, median year across the envelope cells.

The figures the cards read from are in Climate below, and where they came from in Natural habitat.

Climate across the habitat

day night rain 10th–90th percentile across 4 habitat cells cold quarter: the three months around the coldest night extremes over 44 years at the typical cell, marked at the edge: undated DLI, mol/m²/dayRH %each on its own scale

Figures by month

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Day °C	4 / 3–5	6 / 5–7	10 / 10–11	16 / 15–17	22 / 22–23	29 / 28–30	31 / 30–33	29 / 28–31	25 / 24–26	18 / 18–19	10 / 9–11	4 / 3–5
Night °C	-9 / -9–-9	-7 / -7–-6	-3 / -4–-3	1 / 1–2	6 / 6–7	11 / 11–12	15 / 15–16	14 / 14–16	10 / 9–11	4 / 3–5	-2 / -3–-2	-9 / -9–-8
Rain mm	15 / 13–16	17 / 15–17	23 / 20–26	24 / 21–26	27 / 23–28	17 / 16–18	29 / 24–32	36 / 29–39	37 / 35–39	33 / 32–34	21 / 19–23	17 / 16–18
DLI	18 / 18–18	25 / 25–25	34 / 34–34	42 / 42–42	47 / 47–47	51 / 51–51	48 / 48–48	42 / 42–43	36 / 36–36	27 / 27–27	19 / 19–19	16 / 16–16
RH %	58 / 57–59	56 / 56–57	55 / 54–55	51	48 / 47–48	43 / 43–44	46 / 45–47	50 / 48–50	49 / 48–50	51 / 51–52	55 / 54–55	58 / 57–58

Each figure is the median across the 4 grid cells holding the 4 in-range records, with the 10th–90th percentile span across those cells after the slash where it differs. Extremes and elevation were read at the typical cell 1018:1432 (39.075, -108.375). Over 44 years there: absolute minimum -27.0 °C, 1st-percentile night -14.3 °C, 99th-percentile day 38.5 °C. Normals: CHELSA V2.1 1981–2010 climatology, 0.05° cells (each the mean of ~36 1 km pixels). Envelope: median and 10th–90th percentile of each month across the 4 distinct grid cells holding the 4 in-range records; extremes and elevation at the typical cell 1018:1432 (its coldest month's mean night nearest the median across cells); its position is the cell centre. Extremes: NASA POWER (MERRA-2) daily 1981–2024, cell 39.00_-108.125, lapse-corrected -695 m at 6.5 °C/km. Elevation: ETOPO 2022, 1503 m (cell mean).

Natural habitat

Native range as published by WCVP; the marker is where the records are densest and decides nothing: the climate was read across every in-range record's cell, not at the marker.

Openly licensed records inside the range, framed on where they fall.

NativeColorado

Kew's description“succulent subshrub” · “subtropical”· quoted from WCVP, RBG Kew (CC BY 4.0); not derived here

Map marker38.812, -108.348 · in the densest population, 110 records (100% of those in range)

Evidence usedThe map marker and the climate envelope rest on all 110 georeferenced records inside the native range; the map shows only the 29 openly licensed ones, which alone would put the marker 9 km away. 106 in-range records are placed to worse than 10 km and stay on the map but off the climate.

The map markerthe map marker: the openly licensed record nearest the middle of the densest 1° population of the 110 in-range records; it decides nothing.

Photographs

Photographs: no rights reserved · CC0 (2); (c) Anders Hastings, some rights reserved (CC BY) (6).

Photographs: iNaturalist did not answer when this page was built; what is shown came from the sources that did.

Papers naming this species

Works whose title or abstract names Sclerocactus glaucus, most cited first, from OpenAlex (CC0). A mention, not a cultivation source: nothing on this page is drawn from them.

Examining the genetic integrity of a rare endemic Colorado cactus (Sclerocactus glaucus) in the face of hybridization threats from a close and widespread congener (Sclerocactus parviflorus)

Anna L. Schwabe, Jennifer Ramp Neale, Mitchell E. McGlaughlin (2014) · Conservation Genetics

Species Status of Sclerocactus brevispinus, S. wetlandicus, and S. glaucus: Inferences from Morphology, Chloroplast DNA Sequences, and AFLP Markers

Mark Porter, Jennifer M. Cruse‐Sanders, Linda M. Prince, Robert Lauri (2013) · Aliso

A Sampling-Based Approach to Estimating the Minimum Population Size of the Federally Threatened Colorado Hookless Cactus (Sclerocactus glaucus)

Phil P. Krening, Carol Dawson, Kenneth W. Holsinger, John W. Willoughby (2021) · Natural Areas Journal

Annotated Bibliography for the Colorado Hookless Cactus(Sclerocactus glaucus)

Nancy D. Riley (2015) · Haseltonia

Conservation genetics of Sclerocactus in Colorado: the importance of accurate taxonomy to conservation

Mitchell E. McGlaughlin, Samantha K. Naibauer (2023) · Frontiers in Conservation Science

Chipping and Chemical Scarification Effects onSclerocactus glaucus(K.Schum.) L.D.Benson (Cactaceae) Seed Germination

Nancy D. Riley, Terry Z. Riley (2018) · Cactus and Succulent Journal

Analysis of microsatellites from Sclerocactus glaucus and Sclerocactus parviflorus to assess hybridization levels and genetic diversity

Anna L. Schwabe (2012) · Scholarship & Creative Works - Digital UNC a service of University Libraries (University of Northern Colorado)

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