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Field Guide


Hamilton's Milkvetch

Hamilton's Milkvetch (Astragalus hamiltonii)
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Photo by Bill Gray; Bill Gray

Astragalus hamiltonii

NatureServe conservation status

Global (G-rank): G2
State (S-rank): S2

Utah Wildlife Action Plan status

  • SGCN

External links


General information

Astragalus hamiltonii is a candidate species for federal listing known from Uintah County, Utah where it is fund only in the Unita Basin. This species grows on gullied bluffs and barren hilltops in desert shrub and juniper communities. Hamilton's Milkvetch is an upright herb topped with faint yellow flowers and pendulous hanging fruit. This species has thin leaves and an overall slender-stemmed form that brightens up the dry desert landscape with a burst of life wherever it grows.

Description

Astragalus hamiltonii is a candidate species for federal listing known from Uintah County, Utah where it is fund only in the Unita Basin. This species grows on gullied bluffs and barren hilltops in desert shrub and juniper communities. Hamilton's Milkvetch is an upright herb topped with faint yellow flowers and pendulous hanging fruit. This species has thin leaves and an overall slender-stemmed form that brightens up the dry desert landscape with a burst of life wherever it grows.

Phenology

This species flowers between May and June. 

Diagnostic characteristics

Astragalus hamiltonii can be look similar to Astragalus lonchocarpus and is essentially a more pronouced version of Astragalus lonchocarpus which is more slender and and has narrower leaflets and fruit.

Astragalus hamiltonii has petals that are light yellow, the fruit is 25-35 mm long and 4-7.5 mm thick, the leaflets are 2-7 mm wide

Astragalus lonchocarpus has flowers that are almost white to light yellow, the fruit is 22–50 mm long and 3.3–6.2 mm wide, the leaflets are 0.5-4 mm wide.

Species range

A Uintah Basin endemic, found in Uintah County, Utah

Threats or limiting factors

Threats include grazing, recreation and drought.

Taxonomy

No, this species does not have taxonomic discrepancies