Salvia pachyphylla, as currently recognized, occurs along the mountain ranges (sky islands) in the Mojave Desert of southern California and northern Baja California Norte, Mexico. A smaller disjunct group occurs in eastern Arizona near the southern edge of Navajo and Hopi reservation lands near Winslow. This curious distribution raises many questions as to the original distribution of this plant and whether its current distribution is a reflection of past evolutionary processes or use by humans. To answer these questions, S. pachyphylla and other taxa in the Salvia dorrii complex have been examined to determine the phylogenetic relationships using molecular and morphological techniques. Data sets derived from DNA and morphological characters were analyzed to test whether the current classification is supported. The molecular data set included the nuclear ribosomal DNA (nrDNA) internal transcribed spacers (ITS-1, 5.8S, and ITS-2). A morphometric analysis of nine characters was performed to determine morphological variation within the Salvia dorrii complex. Results from molecular and morphological data do not support the current classification. Molecular analysis indicates the S. pachyphylla populations in Mexico are ancestral to the rest of populations of S. pachyphylla and the southwestern varieties of S. dorrii. The populations of S. pachyphylla and three varieties of S. dorrii from the southwestern U.S. are not separated as distinct groups indicating recent gene flow or lack of genetic divergence between species within the S. dorrii complex. Morphometric analysis indicates separation between S. pachyphylla and S. dorrii and separation of populations within S. pachyphylla into three distinct groups.

Key words: Internal transcribed spacer region, Lamiaceae, morphometric, Salvia dorrii complex, Salvia pachyphylla, southwest U.S