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Home/Species/ Bitterroot Milkvetch

Astragalus scaphoides

(M.E. Jones) Rydb.

Bitterroot Milkvetch

G3Vulnerable Found in 3 roadless areas NatureServe Explorer →
G3VulnerableGlobal Rank
Identity
Unique IDELEMENT_GLOBAL.2.148839
Element CodePDFAB0F7V0
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
Endemicendemic to a single nation
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderFabales
FamilyFabaceae
GenusAstragalus
Other Common Names
Bitterroot milkvetch (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 Date1999-12-28
Change Date1990-04-02
Edition Date1987-09-12
Edition AuthorsShelly, J. S., rev. B. Heidel (1999).
Range Extent250-20,000 square km (about 100-8000 square miles)
Number of Occurrences21 - 80
Rank Reasons
Limited geographic distribution and vulnerable under some grazing management practices.
Range Extent Comments
Beaverhead Co., Montana, and Lemhi Co., Idaho.
Occurrences Comments
30 EOs in ID (Lesica and Elliott, 1987); 16 recent and 1 historical EOs in MT (1999).
Threat Impact Comments
Species declines under rotation grazing without rest cycle, or under heavy grazing.
Ecology & Habitat

Description

Bitterroot milkvetch is a stout, herbaceous perennial with several erect stems 2-6 dm in height arising from a branched rootcrown. The pinnately compound leaves (10-25 cm long) have 15-21 narrowly elliptic leaflets, and the foliage is glabrous to sparsely hairy. Crowded clusters of 15-30 spreading yellowing flowers are borne in the axils of upper leaves, becoming less dense as the plant matures. Corollas are about 20 mm long and have a reflexed upper petal and a blackish-hairy calyx (8-10 mm long). Glabrous, green to reddish, oblong pods (15-20 mm long by 4-6 mm wide) are 2-chambered in cross-section, and are borne on a stalk of approximately equal length that spreads out and then arches up, holding the fruit nearly erect.

Diagnostic Characteristics

The long fruit stalks that arch out and up, holding the pods like a candelabra, and pods that are 4-6 mm wide distinguish this from the similar species, A. ATROPUBESCENS and A. TERMINALIS.

Habitat

Sagebrush-grassland communities on dry slopes at mid- elevations (5000-6000 feet).
Terrestrial Habitats
Shrubland/chaparralGrassland/herbaceous
Other Nations (1)
United StatesN3
ProvinceRankNative
MontanaS3Yes
IdahoS3Yes
Plant Characteristics
DurationPERENNIAL
Economic Value (Genus)Yes
Roadless Areas (3)
Montana (3)
AreaForestAcres
Italian PeakBeaverhead-Deerlodge National Forest90,401
Mckenzie CanyonBeaverhead-Deerlodge National Forest33,350
Tash PeakBeaverhead-Deerlodge National Forest61,312
References (12)
  1. Horn, G. 1980. Report on inventory of threatened or endangered, rare, or sensitive plants-Headwaters Resource Area, Butte District, Bureau of Land Management, Montana. Unpublished report. 54 pp.
  2. 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.
  3. Lesica, P. 1984a. Report on the conservation status of <i>Astragalus scaphoides</i>, a candidate for threatened species. Unpublished report to the U.S. Fish and Wildlife Service, Denver, CO. 20 pp. plus appendices.
  4. Lesica, P. 1984b. The distribution and reproduction effort of the rare plant ASTRAGALUS SCAPHOIDES in Montana and Idaho. Unpublished report prepared for The Nature Conservancy, Big Sky Field Office, Helena, Montana. 14 pp.
  5. Lesica, P. 1993a. Demographic monitoring of <i>Astragalus scaphoides</i> at two sites in Montana and Idaho: 1992 progress report. Prepared for Bureau of Land Management. Montana Natural Heritage Program, Helena, MT. 16 pp.
  6. Lesica, P. 1994a. Demographic monitoring of <i>Astragalus scaphoides</i> at two sites in Montana and Idaho: final report. Unpublished report for the Bureau of Land Management, Butte District. Montana Natural Heritage Program, Helena, MT.
  7. Lesica P. 1995a. Demography of <i>Astragalus scaphoides</i> and the effects of herbivory on population growth. Great Basin Naturalist 55(2): 142-150.
  8. Lesica, P. and J. C. Elliott. 1989. 1988 monitoring study of Bitterroot milkvetch populations in Lemhi County, Idaho. Unpublished report to the U.S. Department of Interior, Bureau of Land Management, Boise, Idaho, 37 pp.
  9. Moseley, R. K. 1989e. Field investigations of four ASTRAGALI all Region 4 sensitive species on the Salmon National Forest, with noted on two others. Unpublished report. Idaho Department of Fish and Game. Boise, Idaho. 44 pp.
  10. Vanderhorst, J. 1995a. Sensitive plant survey in the Horse Prairie Creek drainage, Beaverhead County, Montana. Unpublished report to the Bureau of Land Management, Butte District. Montana Natural Heritage Program, Helena, Montana. 42 pp. plus appendices.
  11. Vanderhorst, J. 1995b. Sensitive plant survey of the Tendoy Mountains in the Beaverhead National Forest, Beaverhead County, Montana. Unpublished report to the Beaverhead National Forest. Montana Natural Heritage Program, Helena, MT. 69 pp.
  12. Vanderhorst, J. P. and P. Lesica. 1994. Sensitive plant survey in the Tendoy Mountains, Beaverhead County, Montana. Unpublished report to the Bureau of Land Management, Butte District. Montana Natural Heritage Program, Helena, MT. 59 pp. plus appendices.