Douglas’ Thistle Milkvetch (Astragalus kentrophyta var. douglasii)  

The Thistle Milkvetch is a very thistle-like member of the legume family, the species includes around seven varieties which are distributed over a wide range of the southern USA. 

The variety discussed here was described in 1964, it was restricted to a small area on the Colombia River at the boundery of Umatilla County in Oregon and Walla Walla County in Washington, USA.

Douglas’ Thistle Milkvetch hasn’t been collected since 1883, its habitat having been destroyed by dam projects and the plant is now considered extinct.

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The photo below shows another variety, probably the nominate form.

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References: 
[1] Astragalus kentrophyta Gray var. douglasii Barneby. Field Guide to Selected Rare Vascular Plants of Washington. Washington Natural Heritage Program and U.S.D.I. Bureau of Land Management 2005

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edited: 19.09.2019