Penstemon caryi (Scrophulariaceae) is an endemic of the Big Horn Mountains of Wyoming and the Pryor Mountains of Montana. The species is ecologically restricted to exposed limestone outcrops that occur infrequently throughout the region. Twenty-five individuals from fifteen populations of P. caryi were collected across the entire range of this species. Ten of these populations were collected for The Nature Conservancy's Tensleep Preserve, which occurs at the southern extent of the species range. The remaining five populations were collected from the remaining range of the species at intervals of fifteen to twenty-five miles. Five inter-simple sequence repeat (ISSR) markers were used to evaluate the genetic diversity of this species using Analysis of Molecular Variance (AMOVA). The relationship between genetic distance and geographic distance has also been investigated. Results form these analyses, in conjunction with a larger ecological study, will be used to determine conservation strategies for this species on Nature Conservancy lands.

Key words: Conservation Genetics, Genetic Diversity, ISSR, Penstemon caryi, Population Genetics