Negron-Ortiz DEB-9807089 The biogeography of the West Indies can be described as intricate. The relationships of a complex geological history of the region, numerous islands with unique histories, and a rich biota ranging from pan-Caribbean species to single island endemics are not well understood. Vicariance and trans-oceanic dispersal are models proposed to explain the present-day distribution of the biota . In order to understand the origins of the Caribbean flora, studies of Caribbean taxa are needed. Until now most of the models tested have involved animals. The PI proposes to use molecular and morphological data to construct evolutionary trees of two plant genera (Erithalis and Ernodea: Rubiaceae) endemic to the Caribbean Basin. For each genus, relationships among species will be examined and these results will be integrated with distribution patterns to ascertain patterns of colonization events in the region. Multiple populations of all taxa of both genera will be examined using morphological data and two molecular markers. Many representative genera will be included as outgroups to determine the mainland geographical affinities of the two genera. Resulting evolutionary trees will be compared to geographic distributions of the species to test biogeographical hypotheses. Starting date: August 15, 1998.
