locoweed
Oxytrophis spp, Astragalus spp
‘snake’s food’
Drug: poison. Toll 1914 documents the plant of this name was used for “poisoning arrows.”
Arapahos today report that they are warned to stay away from a “purple flower” which has the above Arapaho name, because it belongs to the snakes. I have not had an opportunity to verify the identification in the field.
Oxytrophis lamberti