CPC Plant Profile: Barr's Milkvetch
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Plant Profile

Barr's Milkvetch (Astragalus barrii)

A closeup of this small, cushion-shaped herb with purple flowers. Photo Credit: J. Locklear
  • Global Rank: G3 - Vulnerable
  • Legal Status: N/A
  • Family: Fabaceae
  • State: MT, NE, SD, WY
  • Nature Serve ID: 130006
  • Date Inducted in National Collection: 05/28/1986

Springtime is fleeting in the Powder River country of eastern Wyoming and Montana, but at its peak it turns the tops of bluffs and buttes into rock gardens of remarkable beauty. An assortment of low-growing plants grace these windswept places, including Barr's milkvetch, a cushion-forming plant with silvery foliage and rose-purple blossoms that is limited to this region of the Great Plains.

Participating Institutions
  • 10/13/2020
  • Seed Collection

Successfully propagated from seed using scarification pretreatment (Nebraska Statewide Arboretum).

  • 10/13/2020
  • Propagation Research

Successfully propagated from seed using scarification pretreatment (Nebraska Statewide Arboretum).

Nature Serve Biotics
  • 05/02/2017

Regional endemic with ca. 100 occurrences; new coalbed methane threats warrant consideration. May require ""semi-natural matrix"" landscape.

Jim Locklear
  • 01/01/2010

Montana: 33 occurrences (Fertig 2000). Nebraska: 1 occurrence (Weedon 2001). South Dakota: 7 occurrences (Ode 1988). Wyoming: 26 occurrences (Hartman and Nelson 1995).

Jim Locklear
  • 01/01/2010

Successfully propagated from seed using scarification pretreatment (Nebraska Statewide Arboretum).


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Taxon Astragalus barrii
Authority Barneby
Family Fabaceae
CPC Number 371
ITIS 25432
Common Names Barr's milkvetch
Associated Scientific Names Orophaca barrii | Astragalus barrii
Distribution Centered in the Powder River Basin of northeastern Wyoming (Campbell, Johnson, Natron, Niobrara, Sheridan and Weston counties) and adjacent southeastern Montana (Big Horn, Carter, Powder River and Ros
State Rank
State State Rank
Montana S3
Nebraska S1
South Dakota S3
Wyoming S3

Buttes, hilltops, badlands, and gullied knolls and draws, in shallow rocky soils derived from limestone, calcareous sandstone, shale or siltstone. Occurs in cushion plant communities within more densely vegetated mixed grass prairie. Elevation 2940-4000 ft.

Ecological Relationships

Common Name Name in Text Association Type Source InteractionID
Bumble bees Bombus Confirmed Pollinator Link

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