The evolution of island lineages provides outstanding opportunities to understand evolutionary processes affecting the diversification of species, plant reproductive systems, and pollination systems. Using Schiedea (Caryophyllaceae), the fifth-largest plant radiation in the Hawaiian Islands, we have investigated genetic and ecological factors promoting separate sexes or autogamy and changes in pollination systems as species radiated into a variety of habitats. Hybridization and gene flow may also promote evolution of separate sexes through introgression of male sterility genes from gynodioecious or dioecious species into hermaphroditic species. Ongoing studies using genomic approaches may help to resolve not only the phylogeny of Schiedea but also the number and relative timing of independent transitions to dioecy, the inference of which may be impacted by historical introgression, incomplete lineage sorting, and genome duplication throughout the radiation of the genus. Complete genome sequences for three species will be used to support the inference of these processes, particularly the history of whole genome duplication. Initial estimates of gene diversity relative to species diversity will be based on these genome data as well as transcriptome data for twelve species. While preliminary, this work will also contribute to the ongoing conservation of Schiedea in Hawaii.