National Collection of Imperiled Plants

CPC National Collection Plant Profile

Photographer:

Linda Stoneman

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CPC National Collection Plant Profile

Sclerocactus glaucus

Family:	Cactaceae
Common Name:	Uinta Basin Hookless Cactus
Author:	(J.A. Purpus ex K. Schum.) L. Benson
Growth Habit:	Shrub
CPC Number:	3883

Distribution
Protection
Conservation
References

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Photographer: Linda Stoneman
Image Owner: Denver Botanic Gardens

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Photographer: Jennifer Ramp Neale
nealejr[at]botanicgardens.org
Image Owner: Denver Botanic Gardens

Sclerocactus glaucus is Not Sponsored

Primary custodian for this plant in the CPC National Collection of Endangered Plants is:

Denver Botanic Gardens

Laura Smith and Jennifer Neale contributed to this Plant Profile.

Sclerocactus glaucus

Sclerocactus glaucus, the Uinta Basin hookless cactus flowers from April to May, and after blooming may shrink below the ground. Thus plants are often only visible while blooming, when they have bright pink flowers. S. glaucus and S. parviflorus look similar, but S. parviflorus has a hooked central spine and is larger than S. glaucus.

Since listing, the taxonomic status of Sclerocactus glaucus has been through many iterations ranging from one to three species. Hochst�tter (1993) split the species into two distinct species, S. glaucus and S. wetlandicus var. ilseae Hochst�tter (later termed S. brevispinus). Hochst�tter (1997) later divided the species further into three distinct taxonomic units, S. glaucus, S. brevispinus Heil & Porter, and S. wetlandicus, a split which represents the currently accepted taxonomy (FNA 2004, USFWS 2007).

Taxonomy within the genus Scelerocactus is notoriously difficult due to shifts in the morphology of a species throughout its lifetime (i.e. juvenile vs. reproductive, primary stem vs. secondary stems). All parts of the stems, spines, and flowers express great variation throughout the life cycle making species-level identification difficult (Heil & Porter, 1994). In general the genus is characterized by perennial stems which may shrink into the soil during the winter, confounding species identification when not in flower. Hybridization is very common in the genus, further complicating species identification in areas of sympatric populations (Heil & Porter 1994).

Distribution & Occurrence

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State Range

Colorado
Utah

Habitat

Populations of S. glaucus occur on alluvial benches and lower mesa slopes along the Green, Colorado, and Gunnison Rivers. Soils are usually coarse, gravelly river alluvium above the river flood plains. Mancos shale with volcanic cobbles and pebbles form surface material. Elevations range from 1200-2000 m. Associated vegetation is typically desert scrub dominated by Atriplex confertifolia, Hilaria jamesii, Artemesia nova, and Stipa hymenoides. Other important species include Echinocereus triglochidiatus var. melanacanthus, Pediocacus simpsonii, Opuntia polycantha, Krascheninnikovia lanata, Yucca harrimaniae, Gutierrezia sarothrae, Crysothamnus viscidiflorus, Sporobolus cryptandrus, and Elymus salinus.

Distribution

Sclerocactus glaucus is a regional endemic to western Colorado and eastern Utah. There are 90-100 element occurrences in Colorado and 36 in Utah, but many of these occurrences have very few individuals. In Colorado S. glaucus is known from Delta, Garfield, Mesa, and Montrose Counties; in Utah it is known from Carbon, Duchesne, and Uintah Counties.

Number Left

There are an estimated 19,000 individuals of Sclerocactus glaucus, 7600 of them in Colorado, as of 1998. Although no complete inventory data is available, it appears from available information that population numbers are declining in Colorado.

Protection

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Global Rank:	G3	10/4/2006	Guide to Global Ranks
Federal Status:	LT	10/11/1979	Guide to Federal Status
Recovery Plan:	Yes	9/27/1990

State/Area Protection

State/Area	Rank	Status	Date
Colorado	S3	Vulnerable
Utah	S3	Vulnerable

Conservation, Ecology & Research

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Ecological Relationships

Ants and gravity appear to be the primary dispersal mechanisms for S. glaucus seeds.

Threats

Nearly all populations are threatened with habitat destruction or modification from development of energy extraction, water storage projects, transportation, and residential facilities. Other ongoing threats include impacts from moss-rock and rip-rap collecting operations, illegal collection and damage by recreational use or livestock trampling. The threat of habitat destruction or modification is wide-ranging, increasing, and less amenable to mitigation than are the other ongoing threats.

Current Research Summary

Denver Botanic Gardens� Research staff established permanent macroplots in two populations of S. glaucus in the Escalante Canyon area in 2007, and established two additional macroplots in 2008, one in the Escalante Canyon area and one near Debeque. The goal of the monitoring is to record demographic trends in populations of S. glaucus.

Current Management Summary

In 2007 the US Fish and Wildlife Service proposed to change the taxonomy of the Sclerocactus glaucus �complex� into three distinct species: S. brevispinus, S. glaucus, and S. wetlandicus. The Sclerocactus glaucus �complex� is listed as threatened by the US Fish and Wildlife Service, and currently all three distinct species maintain the threatened status.

Research Management Needs

Not Available

Monitoring Efforts

Sclerocactus glaucus is a Colorado Natural Heritage Program tracked species. Several populations are being monitored annually by Denver Botanic Gardens� Research Department. They are also conducting counts throughout the entire range to establish trends of the species.

Ex Situ Needs

Seed collection and storage.

References

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Electronic Sources

Colorado Natural Heritage Program. (2008). -. [Website]. http://www.cnhp.colostate.edu. Accessed: 2008.

NatureServe. (2008). NatureServe Explorer: An online encyclopedia of life [web application]. [Internet].Version 7.0. NatureServe, Arlington, Virginia. http://www.natureserve.org/explorer. Accessed: (June 17, 2008).

Journal Articles

Heil, K.; Porter, J.M. 1994. Sclerocactus (Cactaceae): A Revision. Haseltonia. 2: 20-46.

Hochstatter, F. 1993a. Revision Sclerocactus I. Succulenta. 71: 247-262.

Hochstatter, F. 1993b. Revision Sclerocactus II. Succulenta. 72: 19-34.

Hochstatter, F. 1993c. Revision Sclerocactus III. Succulenta. 72: 82-92.

Hochstatter, F. 1993d. Revision Sclerocactus IV. Succulenta. 72: 187-191.

United States Fish and Wildlife Service. 2007. Endangered and threatened wildlife and plants; 12-month finding on a petition to list Sclerocactus brevispinus (Pariette cactus) as an endangered or threatened species; taxonomic change from Sclerocactus glaucus to Sclerocactus brevispinus, S. glaucus, and S. wetlandicus. Federal Register. 72, 180: 53211-53222.

Reports

Hochstatter, F. 1993e. The genus Sclerocactus revised (magnificent, fascinating natural wonder). Mannheim, Germany.

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This profile was updated on 3/4/2010