Astragalus mollissimus

Woolly Milkvetch - Astragalus mollissimus
North Wicks Canyon
East of Hillsboro, NM, USA

To say that this is Woolly Milkvetch, Astragalus mollissimus, is only part of the story.  New Mexico State University has published an identification key to the Locoweeds and Milkvetches found in the state.  Seventy-five species of Astragalus are known to exist in New Mexico.  Seven varieties of the subject species are known to exist in the state - I make no attempt to key this individual to variety.

This species contains swainsonine (an indolizidine alkaloid) which can be poisonous to cattle.  “Swainsonine causes a wide variety of toxicological problems, including neurological, cardiovascular, and reproductive effects; emaciation; and habituation.” (Page 2 at link above.)

The stems and leaflets of this species are covered in hairs, giving the plant a very silvery appearance.

The range of this species, within the United States, is shown on the BONAP map to the right.  The light green color indicates that the species is native to, but not rare within, the county indicated.  It is also found in northern Mexico.

Astragalus mollissimus is also known as Woolly Locoweed, Purple Locoweed, and Woolly Loco.

The Navajo used this species in various ceremonies, as an emetic, and as forage for sheep (?).

© Robert Barnes 2018-2023