Salvia pachyphylla, as currently recognized, has a disjunct distribution with one large division that occurs along the mountain ranges of southern California, Nevada, and the northern part of Baja California Norte, Mexico. The second, smaller division occurs in the eastern part of Arizona near Winslow. This curious distribution raises many questions as to the original distribution and adaptive radiation of this pant and the evolutionary processes that have taken place. To answer these questions, Salvia pachyphylla and a close relative of the Salvia dorrii complex have been examined to determine the relationship between Salvia pachyphylla and the other members of the complex using molecular techniques. The independent data set derived from nuclear ribosomal DNA (nrDNA) DNA sequences (ITS-1 and ITS-2) was then correlated with morphological characters. The results were used to determine where the most sequence diversity was and the adaptive radation point of the original population.

Key words: Adaptive radiation, ITS 1, ITS 2, Lamiaceae, phylogeny, Salvia pachyphylla