Astragalus barrii

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Barr's milkvetch
Astragalus barrii.jpg

Vulnerable (NatureServe)[1]
Scientific classification edit
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Fabales
Family: Fabaceae
Subfamily: Faboideae
Genus: Astragalus
Species:
A. barrii
Binomial name
Astragalus barrii
Barneby

Astragalus barrii is a species of flowering plant in the legume family known by the common name Barr's milkvetch. It is native to the United States, where it is a "regional endemic", occurring in parts of southwestern South Dakota, northeastern Wyoming, southeastern Montana, and Nebraska.[1][2]

This mat-forming perennial herb grows only about 4 inches in height. The leaves are each made up of three lance-shaped leaflets. The herbage is coated in white hairs which are dolabriform, or shaped like the head of an ax.[3] The inflorescence contains iridescent pinkish purple flowers with petals up to 1.7 centimeters long. The fruit is a legume pod up to 8 millimeters in length.[1] Blooming occurs in late April through mid-June; April flowering generally only occurs in years with light snowfall.[3]

This plant occurs on buttes and badlands in the Powder River Basin and surrounding areas. The habitat is generally mixed-grass prairie on limestone, sandstone, shale, or siltstone.[4] It grows alongside other species of Astragalus including , , A. bisulcatus, A. racemosus, and , and it must be in flower to be distinguished from other species with three leaflets on each leaf.[3]

This plant was first collected in 1900 in Wyoming. It was described as a species in 1956 and named for the botanist and cattle rancher Claude Arno Barr (1887–1982).[3]

References[]

  1. ^ a b c Astragalus barrii. The Nature Conservancy.
  2. ^ "USDA Plants Database".
  3. ^ a b c d Ladyman, J. A. R. Astragalus barrii Barneby (Barr’s milkvetch): A Technical Conservation Assessment. Prepared for the USDA Forest Service, Rocky Mountain Region, Species Conservation Project, March 14, 2006.
  4. ^ Astragalus barrii. Archived October 26, 2011, at the Wayback Machine Center for Plant Conservation.

External links[]

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