Dr. Larry Prather of Michigan State University is exploring the process of diversification in the tropical subfamily Cobaeoideae of the Polemoniaceae (Phlox family) by providing comprehensive taxonomic and phylogenetic studies of all the species and by combining morphological, ecological, and phylogenetic data to explore patterns of evolution in the lineage. The tropical subfamily, as defined here, includes five genera: Acanthogilia, Bonplandia, Cantua, Cobaea and Huthia. Taxonomic studies will be based on herbarium, field, and greenhouse studies and will include new data on morphological variation, pollen and seed morphology, distribution, ecology, chromosome numbers, pollination, reproductive biology, biogeography, and phylogeny. Morphological phylogenetic studies will be complemented by molecular studies using nuclear (ITS) and chloroplast DNA sequences (trnT - trnL 5' and trnL 3' - trnF spacer regions, and partial ndhF coding region). Prather, graduate student Anna K. Wiese, and J. Mark Porter of Rancho Santa Ana Botanic Garden, will perform twelve weeks of South American fieldwork to document morphological variation and pollination systems. Phylogenetic data will be combined with comparative morphological studies in at least two sets of species that have convergent floral morphologies associated with similar pollination mechanisms. These analyses will help to discern how homology and character evolution contribute to the repetitive evolution of similar floral syndromes. Groundbreaking evolutionary and ecological studies have been performed on members of the plant family Polemoniaceae, yet little is known about the tropical members of this group. Several of these species have important cultural contributions; they have been in cultivation since the time of the Incas, who used these beautiful plants to adorn their temples. One species, Cantua buxifolia, is the national flower of both Bolivia and Peru. These species are distributed in the neotropics and occur in environments from desert to rainforest; many are narrow endemics and are threatened with extinction, thus this study will provide the basic information needed for conservation of these species. Preliminary studies suggest that several new species may be described as a part of this study, thus furthering our understanding of tropical diversity. This study will also provide insight into the mechanisms and pattern of evolutionary diversification. For example, at least two sets of species that are unrelated, but that have the same floral shape, size, and color, will be studied in detail so that we can learn how these similar morphologies arise multiple times. These studies will provide insight into how these evolutionary patterns develop not only in the Polemoniaceae, but in plants in general.
