Astragalus detritalis
Author: M.E. Jones

Debris milkvetch

Fabaceae (Pea Family)

Close up of Astragalus detritalis by Larry Alison.
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Close up of Astragalus detritalis by Larry Alison.
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Ranks and Status

Global rank: G3
State rank: S2
Federal protection status: BLM Sensitive
State protection status: None

[+] Description and Phenology

Please see 1997 profile.

General description: Stemless, erect, cushion-shaped perennial from 2 to 6 cm in height. Leaves with 3 to 5 narrowly oblanceolate to linear spinulose-tipped leaflets from 3 to 30 mm in length, with dolabriform hairs. Three to eight vivid pink-purple flowers produced in racemes; erect, sessile pods form in a close terminal cluster. The dark-colored, laterally-compressed pods are more than twice as long as wide, are not inflated and are unilocular. Pods are also slightly incurved, mottled, and sparsely strigose (Spackman et al. 1997, Ackerfield 2015).

Look Alikes: A. calycosus var. scaposus has oval leaflets and smaller, densely strigose pods. A. spatulatus has smaller flowers and much shorter pods (Spackman et al. 1997). 

Phenology: Flowering late April to early June with a peak in mid-May; fruiting late May to late June (Neese and Smith 1982, Colorado Natural Heritage Program 2012).

[+] Habitat

Habitat of Astragalus detritalis courtesy of the Colorado Natural Areas Program.
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Found in barren habitats in pinyon-juniper and mixed desert shrub communities, often in rocky soils ranging from sandy clays to sandy loams, and on alluvial terraces with cobbles (Spackman et al. 1997). Associated with Artemisia, Stipa, Phlox, Trifolium, and cactus species. 

Elevation Range: 5,384 - 7,205 feet (1,641 - 2,196 meters)

[+] Distribution

Distribution of Astragalus detritalis in Colorado according to mapped land ownership/management boundaries (CNHP 2015, COMaP v9).
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Distribution of Astragalus detritalis in Colorado.
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Colorado endemic: No
Global range: This species is found within the Uinta Basin in Duchesne and Uintah Counties, Utah, and Rio Blanco (Barneby 1964) and Moffat Counties, Colorado. It is a Uintah Basin endemic (Welsh et al. 1993).
State range: Known from Rio Blanco and Moffat counties in Colorado.

[+] Threats and Management Issues

Overgrazing, exotic species, gravel pit development and road disturbance are threatening this species.

[+] References

    • Ackerfield, J. 2015. Flora of Colorado. Brit Press, Botanical Research Institute of Texas, Fort Worth, TX. 818 pp.
    • Barneby, R.C. 1964. Atlas of North American Astragalus. 2 Vols. New York Botanical Garden, Bronx, New York. 1188 pp.
    • Goodrich, S., and E. Neese. 1986. Uinta Basin flora. U.S. Forest Service, Intermountain Region, Ogden, Utah. 320 pp.
    • Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
    • Neese, E., and F. Smith. 1982. Final Report: Threatened and endangered plant inventory for the Oil Shale RMP, Bookcliffs Resource Area, Utah Bureau of Land Management, Vernal District. Volume 1 - Text. Pp 1-88 + appendices.
    • Spackman, S., B. Jennings, J. Coles, C. Dawson, M. Minton, A. Kratz, and C. Spurrier. 1997. Colorado rare plant field guide. Prepared for Bureau of Land Management, U.S. Forest Service and U.S. Fish and Wildlife Service by Colorado Natural Heritage Program.
    • USDA, NRCS. 2013. The PLANTS Database. National Plant Data Team, Greensboro, NC 27401-4901 USA.
    • Weber, W. A. and R. C. Wittmann. 2012. Colorado Flora, Western Slope, A Field Guide to the Vascular Plants, Fourth Edition. Boulder, Colorado. 532 pp.
    • Welsh, S.L., N.D. Atwood, S. Goodrich and L.C. Higgins. (Eds.) 2003. A Utah Flora. 3rd edition. Brigham Young University, Provo, Utah, U.S.A. 912 pp.
    • Welsh, S.L., N.D. Atwood, S. Goodrich, and L.C. Higgins (eds.) 1993. A Utah flora. 2nd edition. Brigham Young Univ., Provo, Utah. 986 pp.

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