9800887 SOLTIS The flowering plant family Crassulaceae (the stonecrops) is large and diverse. Many species are used as ornamentals. Others are used as experimental organisms, especially in photosynthesis research. Despite this interest, little is certain about the historical (phylogenetic) relationships among members of the Crassulaceae. The challenge of obtaining robust reconstructions of these relationships tests the ability of scientists to resolve complex problems in plant biology. Robust reconstructions should (for example) assist investigators who seek a biological context for the appearance of, and changes in, significant traits among these plants. In this doctoral dissertation research, Douglas E. Soltis and student Mark E. Mort will reconstruct the phylogenetic relationships among members of the Crassulaceae. The reconstructions will be based primarily on data from molecular sequences, but will also use information from the morphology, anatomy, and physiology of the plants. They will work intensively on the Crassulaceae of Macaronesia (Canary Islands), and especially on the Macaronesian genus Aeonium. Aeonium is chosen to test the idea that a single founding species on an island can rapidly give rise to many species, each differing profoundly from the parent and from each other in morphology, anatomy, physiology and ecology. The research will evaluate the challenges to phylogeny reconstruction presented by this type of history in plants. Principles learned from the Macaronesian work will be applied to efforts to reconstruct the phylogenetic relationships among the genera of Crassulaceae worldwide.
