9509804 Olmstead Since the time of Darwin, systematists have worked to produce classifications of organisms that represent the evolutionary or genealogical relationships among them. The fact that pre-Darwinian classifications of plants have persisted to this day for many groups attests to the conservative nature of change in the reproductive structures that were used as primary characters by Linnaeus and subsequent botanists. Research on DNA nucleotide sequence variation in flowering plants by Dr. Richard Olmstead and several others has revealed serious discrepancies between traditional family-level classification and DNA-based groupings, for several well known groups of plants including the mint, verbena, borage, and snapdragon families. Similarities in ovary and fruit morphology have apparently misled taxonomists to unite genealogically separate groups within the same family. Dr. Olmstead is continuing DNA sequencing studies of genes of the chloroplast in representative samples of Boraginaceae, Hydrophyllaceae, and Scrophulariaceae, large families with widespread distributions in temperate regions of the world. Related groups such as Convolvulaceae (morning glory family), Labiatae (mints), and Verbenaceae are being studied by colleagues and others. The DNA-based analyses of relationships will provide a phylogenetic framework for this large group of advanced dicots, independent of the schemes based on traditional morphological features and thus serving as a test of them. Because such taxa as Antirrhinum, the cultivated snapdragon, serve as model laboratory organisms, it is important to know their close evolutionary relatives in order to extrapolate genetic and physiological findings.
