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Asclepias hallii

Gray

Hall's Milkweed

G3Vulnerable Found in 10 roadless areas NatureServe Explorer →
G3VulnerableGlobal Rank
Identity
Unique IDELEMENT_GLOBAL.2.157728
Element CodePDASC020Q0
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
Endemicendemic to a single nation
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderGentianales
FamilyApocynaceae
GenusAsclepias
Other Common Names
Hall's milkweed (EN)
Concept Reference
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.
Conservation Status
Review Date1999-05-18
Change Date1999-12-27
Edition Date1999-05-18
Edition AuthorsFayette, Kim and Susan Spackman (1999)
Rank Reasons
There are approximately 30 locations known from 5 out of the 6 states reported to support this species.
Range Extent Comments
Asclepias hallii is known from Colorado, Utah, Nevada, Arizona, and New Mexico (USDA NRCS 2012).
Occurrences Comments
There are 3 historical records in Wyoming (pers. comm. Walt Fertig WYNDD 1999 to Kim Fayette). There are 15 specimens at the Colorado State University Herbarium from Saguache, Rio Blanco, Montezuma, Gunnison, Garfield, Fremont, El Paso, Douglas, Conejos, Alamosa, and Weld counties, Colorado and White Pine County, Nevada (CSU Herbarium 1999). There is one disjunct location in the San Franciso Peaks near Flagstaff, Coconino County, Arizona (pers. comm. Sabra Schwartz AZHDMS 1999; Kearney et al. 1951). Welsh et al. (1993) report 9 collections from 7 counties in Utah. There is no locational information for New Mexico.
Ecology & Habitat

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).

Habitat

This species is supported by rocky slopes in sagebrush, mountain brush, pinyon-juniper, ponderosa pine and aspen communities at 1900-3070 m (Welsh et al. 1993).
Other Nations (1)
United StatesN3
ProvinceRankNative
NevadaS1Yes
ArizonaSNRYes
WyomingS1Yes
New MexicoSNRYes
UtahS2Yes
ColoradoS3Yes
Plant Characteristics
Economic Value (Genus)Yes
Roadless Areas (10)
Colorado (2)
AreaForestAcres
Bristol HeadRio Grande NF46,087
Pole Mountain / Finger MesaRio Grande NF43,863
Nevada (5)
AreaForestAcres
Bunker HillHumboldt-Toiyabe National Forest27,569
ButlerHumboldt-Toiyabe National Forest39,470
Table Mtn. - Barley Ck.Humboldt-Toiyabe National Forest5,424
Table Mtn. - EastHumboldt-Toiyabe National Forest87,789
Toiyabe RangeHumboldt-Toiyabe National Forest99,225
Utah (3)
AreaForestAcres
Casto BluffDixie National Forest87,466
Deer CreekDixie National Forest39,818
Lava BedsDixie National Forest14,944
References (9)
  1. Ackerfield, J. 2015. Flora of Colorado. Botanical Research Institute of Texas, Fort Worth, TX. 818 pp.
  2. 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.
  3. 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.
  4. 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.
  5. Weber, W.A., and R.C. Wittmann. 1996a. Colorado flora: Eastern slope. Revised edition. Univ. Press of Colorado, Niwot, Colorado. 524 pp.
  6. Weber, W.A., and R.C. Wittmann. 1996b. Colorado flora: Western slope. Univ. Press of Colorado, Niwot, Colorado. 496 pp.
  7. 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.
  8. 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.
  9. 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.