XVI International Botanical Congess

Phylogenetic studies of Hawaiian lineages, such as the silversword alliance, lobelioids, and Alsinoideae, have yielded data on the importance of hybridization in insular evolution, the relative importance of interisland dispersal versus in situ radiation in generating ecological diversity on islands, and the timing of insular diversifications. In general, radiations appear to have been rapid, with even the silversword alliance diversification having occurred during the history of modern high islands (< ca. 5 Ma). Phylogenetic evidence for an evolutionary role of hybridization is surprisingly limited, but compelling for Dubautia on Kauai. Examples of ecological radiation on individual islands are extreme from a worldwide perspective, especially in comparison with evolutionary patterns in Atlantic archipelagos.