CPC Plant Profile: Holmgren's Milkvetch
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Plant Profile

Holmgren's Milkvetch (Astragalus holmgreniorum)

Astragalus holmgreniorum-Flowering Photo Credit: Ally Searle
Description
  • Global Rank: G1 - Critically Imperiled
  • Legal Status: Federally Endangered
  • Family: Fabaceae
  • State: AZ, UT
  • Nature Serve ID: 128690
  • Date Inducted in National Collection: 10/15/2005

Astragalus holmgreniorum (Holmgrens Milkvetch) is a short-lived desert perennial. The first known collection of A. holmgreniorum occurred in 1941. It was discovered again in 1979 by Patricia and Noel Holmgren who, it was named for. In 1980 it was considered a candidate for federal listing it advanced to a category 1 in 1993. In 1999 the Southwest Center for Biological diversity requested that the U.S. Fish and wild life list the endemic plant as endangered. On October 29, 2001 this plant was listed as endangered. Holmgrens Milkvetch may break through the soil as early as February and flowers from March to mid-May. Plants are acaulescent, low growing rosettes with pinnately compound leaves that arise from the root crown. The inflorescence grows erect to spreading and bears continuous racemes of about 16 purple flowers on average. Fruits are purplish plum colored legumes measuring 1-2 inches long. Pods are bilocular and completely open along an apparent seam where seeds are securely enclosed in each half of the legume. At the end of its short lived season Holmgrens Milkvetch reduces back to the soil and remains there until the following year.

Participating Institutions
Updates
Nature Serve Biotics
  • 05/02/2017

This species' total known range consists of a few square km on the Arizona-Utah border. It is locally common within this tiny range. Threatened by highway and power line construction, ORV use, displacement by exotic weeds, grazing, and mineral development (Harper 1997 and Stubben 1997, cited by USFWS 2000).

Wendy Yates
  • 01/01/2010

This plant is threatened by off road vehicle use, development, invasive non-native plants, and domestic cattle grazing.

Wendy Yates
  • 01/01/2010

Populations have been reported in 6 locations in Washington County.

Wendy Yates
  • 01/01/2010

For the past decade Astragalus holmgreniorum has been a focus of research in southern Utah. Studies have focused primarily on demography and density within populations of this species. This plant is monitored on an annual basis by the Bureau of Land Management.

Wendy Yates
  • 01/01/2010

A portion of habitat is managed by the BLM, while other populations fall within the boundaries of the school Institutional Trust Land (SITLA).

Wendy Yates
  • 01/01/2010

we must continue to actively find answers regarding the life history of this species. Continued monitoring of populations is important to understand long-term fluctuations.

Wendy Yates
  • 01/01/2010

Due to development, Propagation protocols are important for the survival of this species. Propagated plants may be placed in areas where the habitat is protected.

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Photos
Nomenclature
Taxon Astragalus holmgreniorum
Authority Barneby
Family Fabaceae
CPC Number 44453
ITIS 25535
USDA ASHO5
Common Names Holmgren's Milkvetch | Paradox milkvetch | Holmgren milk-vetch
Associated Scientific Names Astragalus holmgreniorum
Distribution This plant is restricted to Washington County, Utah. It is limited to approximately 820-850 m.
State Rank
State State Rank
Arizona S1
Utah S1
Habitat

This plant generally occurs on barren gravelly slopes and washes and inhabits soils derived from Virgin Limestone, a member of the Moenkopi Shale formation.

Ecological Relationships

This species is pollinated by small ground nesting bees.

Pollinators
Common Name Name in Text Association Type Source InteractionID

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