National Collection of Imperiled Plants

CPC National Collection Plant Profile

Photographer:

Joyce Maschinski

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CPC National Collection Plant Profile

Asclepias welshii

Family:	Asclepiadaceae
Common Name:	Welsh's milkweed
Author:	N. Holmgren & P. Holmgren
Growth Habit:	Forb/herb
CPC Number:	312

Distribution
Protection
Conservation
References

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Photographer: Joyce Maschinski
jmaschinski[at]fairchildgarden.org

Asclepias welshii is Fully Sponsored

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

The Arboretum at Flagstaff

Joyce Maschinski, Ph.D. contributed to this Plant Profile.

Asclepias welshii

Welsh's milkweed is an herbaceous perennial with extremely hairy and broad ovate leaves. Cream-colored flowers with rose-tinged centers are produced in a ball shaped cluster from May to June. Large seeds with rudimentary tufts of hairs develop and are dispersed from July to early September. However, two other growth forms are known to exist. What is designated as the �primary� growth form has narrow linear leaves and looks very similar to A. subverticillata. A second form exhibits intermediate leaf traits of the �primary� form and the first description (referred to as the �mature� form) and is called the �secondary� form. (Palmer & Armstrong 2000) This species grows in coral pink colored sand dunes and was listed as threatened in 1987 in response to increased threats of off-road vehicle (ORV) activity (USFWS 1987).

Distribution & Occurrence

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State Range

Arizona
Utah

Habitat

A. welshii grows on active sand dunes in sagebrush, juniper, and ponderosa pine communities, between 4700 and 6250 ft in elevation. (NatureServe 2001)

Co-occurring species include Wyethia scabra, Calamovilfa gigantea, Chrysothamnus nauseosus and Sophora stenophylla.

Distribution

Kane Co., UT, near Kanab, and adjacent Coconino Co., AZ, near the Utah-Arizona state line.

Number Left

At the time of listing, there were thought to be no more than 11,000 individuals of this species, with populations scattered in a fairly localized area in Utah and on the Utah-Arizona state line. (USFWS 1987)

There are now three Utah populations: Coral Pink Sand Dunes (ca. 10,000 individuals), 2) Sand Hills ( ca. 500 individuals), 3) Sand Cove (ca. 600 individuals). At least two others are known to exist near Page County, Arizona and in the Paria-Vermillion Cliffs Wilderness are near the Utah/Arizona border in Kane County, Utah and Coconino County, Arizona (Palmer & Armstrong 2000).

Protection

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Global Rank:	G1	1/1/1996	Guide to Global Ranks
Federal Status:	LT	10/24/1996	Guide to Federal Status
Recovery Plan:	Yes	9/30/1992

State/Area Protection

State/Area	Rank	Status	Date
Arizona	S1		8/1/2002
Navaho Nation	4	E	3/1/2001
Utah	S1		6/1/1998

Conservation, Ecology & Research

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Ecological Relationships

� This species is adapted to the naturally unstable sand dunes on which it occurs. As a sand dune-adapted species, this plant has a rhizomatous rootstock that is able to hold sand in place, which initiates the stabilization of the sand dune on which it grows. (USFWS 1987)
� Reproduces mainly by rhizomes, but by seed when conditions are right (Palmer & Armstrong 2000).
� While a number of species in the Asclepias genus contain toxins that make them poisonous to grazers (including cattle), this species has been shown to be palatable and non-toxic to range livestock. However, cattle seldom traverse the sand dunes where this species occurs, so grazing is likely not a major threat to this species. (USFWS 1987)

Threats

As stated by the U.S. Fish and Wildlife Service at the time of listing (USFWS 1987), threats include:
� Off-road vehicles
� Drought

Current Research Summary

� Palmer and Armstrong (2000) have monitored two populations for 12 years. The species colonizes shifting dunes and tends to be outcompeted when dunes stabilize. The authors believe that education and enforcement of regulations to protect dune habitat from off-road vehicles has effectively helped to preserve the species.

Current Management Summary

BLM has monitored the species for the past 12 years and has been enforcing ORV regulations to protect dunes. (Palmer & Armstrong 2000)

Research Management Needs

The possibility of creating new dune habitat adjacent to occupied habitat could be explored.

Ex Situ Needs

Seed germination protocol has been determined, but cultivation for more than 2 years has been problematic. Further cultivation trials are needed.

References

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Books (Single Authors)

Rutman, S. 1992. Handbook of Arizona's endangered, threatened, and candidate plants. Phoenix, Arizona: U.S. Fish & Wildlife Service.

Welsh, S.L.; Atwood, N.D.; Goodrich, S.; Higgins, L.C. 1993. A Utah flora. Provo, Utah: Brigham Young Univ. 986p.

Books (Sections)

Kartesz, J.T. 1999. A synonymized checklist of the vascular flora of the U.S., Canada, and Greenland. In: Kartesz, J.T.; Meacham, C.A., editors. Synthesis of the North American Flora, Version 1.0. North Carolina Botanical Garden. Chapel Hill, NC.

Tepedino, V.J. 2002. Section III. Environmental Monitoring. III.5 The Reproductive Biology of Rare Rangeland Plants and Their Vulnerability to Insecticides. Grasshoppers: Their biology, identification and management, User Handbook.

Conference Proceedings

Hughes, L.E. Monitoring Update on Four Listed Plants on the Arizona Strip. Southwestern rare and endangered plants: proceedings of the third conference; September 25-28; Flagstaff, AZ. In: Maschinski, J.; Holter, L., editors. 2000. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. Fort Collins, CO (Proceedings RMRS-P-23). p 78-82.

Palmer, B.C.; Armstrong, L. Demography and Monitoring of Welsh's Milkweed at Coral Pink Sand Dunes. Southwestern rare and endangered plants: proceedings of the third conference; September 25-28; Flagstaff, AZ. In: Maschinski, Joyce; Holter, Louella, editors. 2000. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. Fort Collins, CO (Proceedings RMRS-P-23). p 59-69.

Electronic Sources

(2002). New York Botanical Garden--The Virtual Herbarium. [Searchable Web site] New York Botanical Garden. Fordham Road Bronx, New York. http://scisun.nybg.org:8890/searchdb/owa/wwwspecimen.searchform. Accessed: 2002.

(2002). Rare Plant Profiles. [Searchable Web site] State of Utah Natural Resources, Division of Wildlife Resources. http://www.utahcdc.usu.edu/rsgis2/Search/SearchSelection.asp?Group=PLANT&Species=PLANT. Accessed: 2002.

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

1988. Threatened and Endangered Plants Summary. Sego Lily: Newsletter of the Utah Native Plant Society. 15: 2.

USFWS. 1984. Four Plants Proposed for Listing. Endangered Species Technical Bulletin. 9, 7: 1, 4-5.

USFWS. 1984. Proposal to determine Asclepias welshii (Welsh's milkweed) to be an endangered species. Federal Register. 49, 110: 23399-23401.

USFWS. 1984. Public Hearing and Reopening of Comment Period on Proposed Endangered with Critical Habitat Status for Asclepias welshii (Welsh's milkweed). Federal Register. 49, 172: 34879.

USFWS. 1987. Final rule determining Asclepias welshii (Welsh's milkweed) to be a threatened species with critical habitat. Federal Register. 52, 208: 41435-41441.

Reports

2002. General Species Information. Phoenix, Arizona: Arizona Ecological Services Field Office.

Franklin, M.A. 1993. Survey report on Asclepias welshii. Salt Lake City: Utah Dept. Natural Resources, Utah Natural Heritage Program, U.S. Fish & Wildlife Service Ecological Service. p.6 + appendices. Unpublished report on file Utah Natural Heritage Program.

USFWS. 1992. Welsh's Milkweed (Asclepias welshii) Recovery Plan. Denver, Colorado: U.S. Fish and Wildlife Service. p.19.

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This profile was updated on 9/28/2010