| The specific interest of this thesis study was to understand geographic parthenogenesis, i.e., the geographic distribution of closely related sexual and apomictic organisms, and focused on the distribution of sexual and apomictic plants of the species Erigeron strigosus Muhl. ex Willd. (prairie fleabane), Asteraceae, in the southeastern United States. Analyses included an analysis of pollen size and quality from herbarium specimens (to estimate reproductive mode), a coarse-scale Geographic Information Systems (GIS) overlay analysis, and an analysis of fine scale environmental data collected in the field. The analyses revealed that apomictic plants exhibited greater ecological amplitude relative to sexual plants. The geographic distribution of sexual and apomictic E. strigosus is likely shaped by plant population dynamics, environmental, and historical factors. Studies of geographic parthenogenesis relate to population dynamics, evolutionary history, and the advantages and disadvantages of sexual reproduction. Central to such studies are detailed geographic maps and the use of GIS. |
