Previous studies of plants in the flowering plant family Saxifragaceae have used evidence from morphology, chemistry, chromosomes, and hybridization experiments. These earlier investigations have helped to clarify taxonomic relationships among genera in what has traditionally been considered a troublesome group. But given the evidence of parallel and convergent evolution in morphological and phytochemical characters in other plant groups, the phylogenetic affinities of these saxifrages remain problematic. Dr. Douglas Soltis of Washington State University will apply the powerful new methods of mutational analysis of chloroplast DNA, and to a lesser extent, nuclear ribosomal DNA, to examine evolutionary change within this group. The goals of Dr. Soltis's molecular systematic analysis are to: l. construct a phylogenetic framework for the nine genera of Saxifragaceae under study, including the large genera Heuchera, Lithophragma, and Mitella; 2. examine the placement of single-species or monotypic genera among such larger, speciose genera; and 3. compare the results from this analysis of DNA with data from other lines of taxonomic evidence such as flavonoid chemistry, chromosomes, and floral morphology. In this way, it will be possible to assess patterns of evolutionary change in morphology, chromosomes, and phytochemistry.
