Home/Species/ Currant Milkvetch

Astragalus uncialis

Barneby

Currant Milkvetch

G3Vulnerable Found in 2 roadless areas NatureServe Explorer →

G3VulnerableGlobal Rank

HighThreat Impact

Identity

Unique IDELEMENT_GLOBAL.2.154911

Element CodePDFAB0F9A0

Record TypeSPECIES

ClassificationSpecies

Classification StatusStandard

Name CategoryVascular Plant

Endemicendemic to a single nation

KingdomPlantae

PhylumAnthophyta

ClassDicotyledoneae

OrderFabales

FamilyFabaceae

GenusAstragalus

Other Common Names

currant 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

Rank Method Rank calculation - Biotics v2

Review Date2025-08-25

Change Date1990-09-05

Edition Date2025-07-18

Edition AuthorsB. Franklin, rev. A. Treher (2014), rev. Johnson, J. (2025)

Threat ImpactHigh

Range Extent5000-20,000 square km (about 2000-8000 square miles)

Number of Occurrences21 - 80

Rank Reasons

Astragalus uncialis is a small perennial herb that is endemic to the central Great Basin in Nevada and Utah, United States. With its small size, this species is easily overlooked outside of the blooming period. Despite a moderate range and number of occurrences, this species faces widespread threats from solar energy development, mining, grazing, and climate change and should be considered vulnerable.

Range Extent Comments

Astragalus uncialis is found in the central Great Basin of the western United States in White Pine and eastern Nye counties, Nevada, and Millard County, Utah (FNA 2024, NatureServe 2025). The largest concentration of occurrences is near Sevier Lake, Utah, on old lakeshore terraces of Lake Bonneville. Range extent was estimated using herbarium specimens, photo-based observations, and NatureServe Network occurrence data collected between 1994 and 2025 (GBIF 2025, iNaturalist 2025, NatureServe 2025, RARECAT 2025, SEINet 2025).

Occurrences Comments

In Utah, there are eleven survey-based element occurrences and six specimen or photo-based occurrences (UNHP 2024, GBIF 2025, iNaturalist 2025, RARECAT 2025, SEINet 2025). By applying a 1 km separation distance to herbarium specimens, photo-based observations, and NatureServe Network occurrence data in Nevada documented between 1994 and 2025, it is estimated that there are 5 additional occurrences (GBIF 2025, iNaturalist 2025, NatureServe 2025, RARECAT 2025, SEINet 2025).

Threat Impact Comments

Many Astragalus uncialis occurrences are in grazing allotments but serious impacts from grazing have not been observed (UNHP 2024). Some mining has occurred on Long Ridge, Utah and a large lithium claim in Railroad Valley, Nevada, could disturb thousands of acres of valley habitat if developed (Hidalgo 2025). One occurrence in Nevada is on the edge of a highway department gravel pit based on aerial imagery (RARECAT 2025). Solar development is possible in a large part of the range due to the flat valley habitat. Many occurrences are near roads and trails but this may be due to survey bias more than specific threats. The climate in this region is expected to become slightly warmer in the future with longer droughts but the habitat is likely to remain suitable for the xeric sagebrush and salt desert shrub vegetation types where Astragalus uncialis grows (Comer et al. 2019).

Ecology & Habitat

Habitat

Astragalus uncialis grows on dry, open, sparsely-vegetated, calcareous sandy-clay soils on flats and gentle slopes of hillsides and alluvial fans with shadscale, budsage, horsebrush, and sagebrush and greasewood (NNHP 2001, FNA 2024).

Terrestrial Habitats

Shrubland/chaparralDesert

Other Nations (1)

United StatesN3

Province	Rank	Native
Utah	S2	Yes
Nevada	S2	Yes

Threat Assessments

Threat	Scope	Severity	Timing
2 - Agriculture & aquaculture	Pervasive (71-100%)	Moderate - slight	High (continuing)
2.3 - Livestock farming & ranching	Pervasive (71-100%)	Moderate - slight	High (continuing)
3 - Energy production & mining	Pervasive (71-100%)	Moderate or 11-30% pop. decline	High (continuing)
3.2 - Mining & quarrying	Restricted (11-30%)	Moderate or 11-30% pop. decline	High (continuing)
3.3 - Renewable energy	Pervasive (71-100%)	Moderate or 11-30% pop. decline	High (continuing)
6 - Human intrusions & disturbance	Restricted (11-30%)	Moderate or 11-30% pop. decline	High (continuing)
6.1 - Recreational activities	Restricted (11-30%)	Moderate or 11-30% pop. decline	High (continuing)
11 - Climate change & severe weather	Pervasive (71-100%)	Moderate - slight	High (continuing)
11.2 - Droughts	Pervasive (71-100%)	Moderate - slight	High (continuing)

Plant Characteristics

DurationPERENNIAL

Economic Value (Genus)Yes

Roadless Areas (2)

Nevada (2)

Area	Forest	Acres
Grant - Irwin	Humboldt-Toiyabe National Forest	11,196
Grant - Troy	Humboldt-Toiyabe National Forest	3,826

References (15)

Barneby, R.C. 1964. Atlas of North American Astragalus. 2 Vols. New York Botanical Garden, Bronx, New York. 1188 pp.
Barneby, R.C. 1989. Fabales. In A. Cronquist, A.H. Holmgren, N.H. Holmgren, J.L. Reveal, and P.K. Holmgren (eds.). Intermountain flora: Vascular plants of the Intermountain West, U.S.A. Vol. 3, Part B. New York Botanical Garden, Bronx. 279 pp.
Comer, P.J., J.C. Hak, M.S. Reid, S.L. Auer, K.A. Schulz, H.H. Hamilton, R.L. Smyth, and M.M. Kling. 2019. Habitat Climate Change Vulnerability Index Applied to Major Vegetation Types of the Western Interior United States. Land 8(7), 108; doi:10.3390/land8070108.
Franklin, M. A. 1996. Field survey for Astragalus uncialis Barneby in the Warm Springs Resource Area, Millard County, Utah. Final report for 1995 Challenge Cost Share Project. Unpublished report prepared for USDI Bureau of Land Management, Richfield District Office.
Global Biodiversity Information Facility (GBIF). 2025. Global Biodiversity Information Facility (GBIF) data portal. Online. Available: https://www.gbif.org/ (accessed 2025).
Hidalgo, J. 2025. BLM approves drilling for massive Nevada lithium project fast-tracked by Trump. Reno Gazette Journal, July 4, 2025. https://www.rgj.com/story/news/money/business/2025/07/04/blm-approves-massive-nevada-lithium-project-fast-tracked-by-trump/84464987007/
iNaturalist. 2025. Online. Available: https://www.inaturalist.org (accessed 2025).
Kartesz, J.T. 1988. A flora of Nevada. Ph.D. dissertation. Univ. of Nevada, Reno. 3 volumes. 1729 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.
Mozingo, H.N., and M. Williams. 1980. The threatened and endangered plants of Nevada. U.S. Fish and Wildlife Service and Bureau of Land Management, Portland, OR. 268 pp.
NatureServe. 2025. NatureServe Network Biodiversity Location Data. NatureServe, Arlington, Virginia.
Nevada Natural Heritage Program (NNHP). 2001. Rare Plant Atlas.
NatureServe's Rapid Analysis of Rarity and Endangerment Conservation Assessment Tool (RARECAT). 2025. Version: 2.1.1 (released April 04, 2025).
Southwest Environmental Information Network (SEINet). 2025. Collections Databases. Online. Available: https://swbiodiversity.org/seinet/collections/index.php (accessed 2025).
Utah Natural Heritage Program (UNHP). 2024. Element Subnational Ranking Form: Sphaeromeria ruthiae in Biotics 5 database. NatureServe, Arlington, Virginia (accessed 4 February 2025).

Astragalus uncialis

Habitat

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