Drs. Raven and Hoch of the Missouri Botanical Garden will continue their multi-disciplinary, multi-investigator study of the evening primrose family of plants, the Onagraceae, a group of 16 genera and ca. 650 species worldwide. The goals are to complete thorough taxonomic evaluations of all genera and all species, and to use the comprehensive morphological, chromosomal, and biochemical information produced over the years to generate a synthesis of the evolutionary patterns and processes in a medium sized family of flowering plants. Specific goals of this renewal grant are completion of taxonomic revisions of Epilobium (fireweeds) and Ludwigia, two of the largest and most difficult genera; preparation of taxonomic treatments of the family for several floristic inventories including several for tropical America; and determination of phylogenetic relationships among the genera and species, using cladistic analyses of various morphological, chromosomal, and biochemical datasets. Comparison of results from phylogenetic analyses on different datasets will provide unique insights into differences in rates of evolution in various plant features and will determine the relative importance of change in chromosome organization and change in breeding system in speciation and geographic dispersal.
