Astragalus oniciformis
Picabo Milkvetch

Hitchcock, C. L., A. Cronquist, M. Ownbey, and J. W. Thompson. 1961. Vascular plants of the Pacific Northwest. Part 3. University of Washington Press, Seattle. 614 pp. Illustration by Jeanne Janish. Reprinted with permission of the University of Washington Press.