A genetic approach to the taxonomy of Mentzelia lindleyi and M. crocea (Loasaceae) Henry J. Thompson OriginalPaper Pages: 81 - 93
Petalostemon candidum and P. occidentale (Leguminosae) Duane IselyS. L. Welsh OriginalPaper Pages: 114 - 118
Studies on Lactarius—I the North American species of sect. Lactarius L. K. HeslerAlexander H. Smith OriginalPaper Pages: 119 - 139