668 RYDBERG: ASTRAGALUS AND ITS SEGREGATES 
17. OROPHACA (T. & G.) Britton, Man. 555. Igol. 
Besides O. sericea (Nutt.) Britton, the following are found in 
Colorado : 
Orophaca tridactylica (A. Gray) Rydb. 
Astragalus tridactylicus A. Gray, Proc. Am. Acad. 6: 527. 1866. 
Orophaca aretioides (Jones) Rydb. 
Astragalus sericoleucus aretioides Jones, Cont. West. Bot. 8: 13. 
1898. 
New York BOTANICAL GARDEN. 
