Asclepias hallii
Author: Gray

Hall's milkweed



Asclepiadaceae (milkweed family)







Close up of Asclepias hallii by Scott Smith

Close up of Asclepias hallii by Scott Smith

Ranks and Status

Global rank: G3
State rank: S3
Federal protection status: None
State protection status: None

Description and Phenology

Asclepias hallii: by Helen Smithwick. Please also see illustration in Weber and Wittmann 2012.

General description: Plants erect, 2-6 dm tall.  Flower petals dull purple.  Hoods spreading widely, tapering to the top, 5-6 mm long; peduncles 1-4 (6) cm long; leaves petiolate 4-10 (15) mm, (6) 8-14 cm long, uniformly pubescent to glabrate, not densely pubescent along the margins (Ackerfield 2012, Weber and Wittmann 2012).

Look Alikes: Not likely to be confused with other taxa.

Phenology: Flowering June-July (Univeristy of Colorado Herbarium 2012). June-August (Ackerfield 2012).

Habitat

Habitat of Asclepias hallii by Scott Smith

Habitat of Asclepias hallii by Tass Kelso

Habitat of Asclepias hallii by Tass Kelso

Common in sandy and gravelly soil of roadsides and sagebrush, pinyon-juniper, or cottonwood communities (Ackerfield 2012). Sloping creek banks on the plains (Colorado Natural Heritage Program 2013).

Elevation Range: 9,400 - 9,900 feet (2,865 - 3,018 meters)

Distribution

Colorado endemic: No
Global range: Asclepias hallii is known from Colorado, Utah, Nevada, Arizona, and New Mexico (USDA NRCS 2012).
State range: Known from Alamosa, Chaffee, Conejos, Costilla, Custer, Douglas, El Paso, Fremont, Garfield, Gunnison, Mineral, Montezuma, Montrose, Park, Rio Blanco, Saguache, San Miguel, and Weld counties (Colorado herbaria in 2013). Common in the intermountain parks and San Luis Valley, southern counties (Weber and Wittmann 2012).
Please also see county list under state range for Colorado distribution.

Threats and Management Issues

Threats and management issues have not been documented.

References

    • Ackerfield, J. 2012. The Flora of Colorado. Colorado State University Herbarium. 433 pp.
    • Beardsley, M. and D. A. Steingraeber. 2013. Population dynamics, rarity and risk of extirpation for populations of Mimulus gemmiparus (budding monkeyflower) on National Forests of Colorado. A research report submitted to the USFS Forest Service. Arapaho and Roosevelt National Forets and Pawnee National Grassland. pp 17. Accessed online on May 11 at: http://www.r5.fs.fed.us/wildflowers/Rare_Plants/profiles/Critically_Imperiled/mimulus_gemmiparus/ documents/USFS_MimulusStatusReport2013.pdf
    • Harrington, H.D. 1954. Manual of the plants of Colorado. Sage Press, Chicago. 666 pp.
    • Kartesz, J., and the Biota of North America Program (BONAP). 1998. A Synonymized Checklist of the Vascular Flora of the United States, Puerto Rico, and the Virgin Islands. http://plants.usda.gov.
    • 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.
    • Kartesz, J.T. 1996. Species distribution data at state and province level for vascular plant taxa of the United States, Canada, and Greenland (accepted records), from unpublished data files at the North Carolina Botanical Garden, December, 1996.
    • Kearney, T.H., R.H. Peebles, and collaborators. 1951. Arizona flora. 2nd edition with Supplement (1960) by J.T. Howell, E. McClintock, and collaborators. Univ. California Press, Berkeley. 1085 pp.
    • 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, Eastern Slope, A Field Guide to the Vascular Plants, Fourth Edition. Boulder, Colorado. 555 pp.
    • 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.
    • Weber, W.A., and R.C. Wittmann. 1996a. Colorado flora: Eastern slope. Revised edition. Univ. Press of Colorado, Niwot, Colorado. 524 pp.
    • Weber, W.A., and R.C. Wittmann. 1996b. Colorado flora: Western slope. Univ. Press of Colorado, Niwot, Colorado. 496 pp.
    • Weber, W.A., and R.C. Wittmann. 2012a. Colorado Flora, Eastern Slope, a field guide to the vascular plants, fourth edition. University of Colorado Press. Boulder, Colorado. 555 pp.
    • Weber, W.A., and R.C. Wittmann. 2012b. 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

2013-07-09