Astragalus eastwoodiae
Author: M.E. Jones


Eastwood milk-vetch


Fabaceae (Pea Family)

Close up of Astragalus eastwoodiae by Peggy Lyon.
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Close up of Astragalus eastwoodiae by Terry Bridgman.
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Close up of Astragalus eastwoodiae by Terry Bridgman.
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Taxonomic Comments

The white-flowered Astragalus debequaeus may be a color form of purple-flowered A. eastwoodiae (Weber and Wittmann 2012).

Ranks and Status

Global rank: G3
State rank: S2S3
Federal protection status: None
State protection status: None

[+] Description and Phenology

No artwork available.

General description: Caulescent perennials, forming neat rounded mounds, 3-20 cm tall. Leaves are light green, 3-13 cm long, and are pinnately compound with numerous small leaflets, 1-15 mm long. Inflorescence included or shortly exserted, 4-8 flowered. Flowers pink-purple. Pods are ovoid to oblong-ellipsoid, subterete or slightly obcompressed, glabrate or minutely hairy. Foliage, pods, and corolla are glabrous; calyx has very short, sharp, appressed hairs (Ackerfield 2015, Schneider 2017).
 

Look Alikes: Astragalus debequaeus flowers are white or yellowish-white, mostly 7-9 (11) per raceme, and calyx tubes are 5-6 mm; A. eastwoodiae flowers are pink-purple, mostly 4-8 flowers per raceme, and the calyx tube is (6) 8-9 mm long.

Phenology: Flowering April-May (Ackerfield 2015).  Fruiting May-June (Colorado Natural Heritage Program 2016).

[+] Herbarium Photos

Images of Astragalus eastwoodiae housed at the Colorado State University Herbarium.

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[+] Habitat

Habitat of Astragalus eastwoodiae by Peggy Lyon.
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Habitat of Astragalus eastwoodiae by Peggy Lyon.
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Dry slopes and in dry creek beds, often on clay soil, usually with pinyon-juniper (Ackerfield 2015). Desert gulches (Weber and Wittmann 2012).  Sparsely vegetated, rocky hillsides, dominated by pinyon-juniper; assocated species also include Atriplex confertifolia, Platyschkuhria integrifolia, Astragalus rafaelensis, Gutierrezia sarothrae, Tetraneuris ivesiana, Gilia haydenii, Pediomelum megalanthum, Cercocarpus montanus, Artemisia nova, Astragalus linifolius, Astragalus lonchocarpusChrysothamnus nauseosus, Opuntia fragilis, Oryzopsis hymenoides, and Erigeron flagellaris

Elevation Range: 4,800 - 7,044 feet (1,463 - 2,147 meters)

[+] Distribution

Distribution of Astragalus eastwoodiae in Colorado according to mapped land ownership/management boundaries (CNHP 2017, COMaP).
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Distribution of Astragalus eastwoodiae in Colorado.
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Colorado endemic: No
Global range: Known from Utah and Western Colorado (Delta, Mesa, Montrose and San Miguel counties).
State range: In Colorado, known from Delta, Mesa, Montrose and San Miguel counties.  Also known from Utah.

[+] Threats and Management Issues

Predominant land uses: grazing, recreation. Exotic species: Bromus tectorum.  Occurrences are found in at least one BLM ACEC, and one NCA. Colorado climate scenarios for 2050 suggest temperature will increase by 3-7 F and precipitation may decrease or increase. The impact to any given rare plant habitat is likely to vary. Long-term monitoring that includes weather and soil moisture data is critical to understanding climate impacts.

[+] References

    • Ackerfield, J. 2015. Flora of Colorado. Brit Press, Botanical Research Institute of Texas, Fort Worth, TX. 818 pp.
    • Colorado Natural Heritage Program and the Geospatial Centroid. 2017. The Colorado Ownership and Protection Map (COMaP). Colorado State University, Ft. Collins, CO.
    • Heil, K.D, S.L. O'Kane Jr., L.M. Reeves, and A. Clifford. 2013. Flora of the Four Corners Region. Vascular Plants of the San Juan River Drainage: Arizona, Colorado, New Mexico, and Utah. Monographs in systematic botany from the Missouri Botanical Garden, Vol. 124, Missouri Botanical Garden Press, St. Louis, MO. xvi + 1098 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.
    • Schneider, A. 2017. Wildflowers, ferns, and trees of the Four Corners regions of Colorado, New Mexico, Arizona, and Utah. Online: http://www.swcoloradowildflowers.com.
    • 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.) 1993. A Utah flora. 2nd edition. Brigham Young Univ., Provo, Utah. 986 pp.

Last Updated

2017-04-10