Discussed are relationships of the species within Astragalus section Conjuncti; A. conjunctus var. rickardii Welsh, Beck, & Caplow var. nov. is proposed.
Welsh, Stanley L.; Caplow, Florence; and Beck, Kathryn
"New variety of Astragalus conjuctus S. Watson from Benton County, Washington,"
Great Basin Naturalist: Vol. 57
, Article 7.
Available at: http://scholarsarchive.byu.edu/gbn/vol57/iss4/7