Dissertation Research: Evolution of Floral Morphology and Systematics of Cobaea Cav. (Polemoniaceae)

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9412174 Turner Graduate student Alan Prather, under the direction of faculty adviser Billie Turner at the University of Texas, is conducting a combined field and laboratory study of the tropical plant genus Cobaea of the phlox family, Polemoniaceae. The group is estimated to include ca. 20 species distributed in the American tropics, with most species occurring only in small, isolated populations primarily on mountain slopes. The floral morphology of these species is diverse and often spectacular, the plants usually producing large blossoms that are hypothesized to be bat pollinated. In addition to morphological study of floral, fruit, and vegetative features, the student is analyzing pollen by scanning electron microscopy, to acquire new characters for taxonomic discrimination. Also, methods of DNA sequencing of the nuclear ribosomal regions called ITS (internal transcribed spacers) are being employed to collect comparative nucleotide data across all species, for estimation of mutation differences and reconstruction of phylogenetic relationships. The combination of molecular and morphological approaches to the study of all extant species of a neotropical genus promises an improved classification for these plants, insight to their genealogical affinities, and understanding of the pathways by which floral features have diversified in relation to pollinating agents.