Phylogenetic studies of genera restricted to the Andean paramo and puna provide a unique opportunity to explore evolutionary processes in tropical, high elevation environments. Dr. Ayers is studying the Andean plant genus Lysipomia of the Campanulaceae family, currently thought to comprise about 30 species of "cushion" plants. Two species are widespread and have many named, geographically restricted subspecies and varieties. The remaining species show little or no infraspecific variation and have extremely narrow ranges, with many endemic to a single ridge top or volcanic cone. These endemics occur throughout the Andes, but the greatest species diversity is found in Ecuador and Peru on both sides of a major geologic division of the northern Andes known as the Piura Divide or the Huancabamba Depression. Phylogenetic studies employing modern molecular and traditional morphological characters will test whether this geologic barrier and recent climatic changes associated with it have played an important role in the evolutionary history of Lysipomia. %%% Mechanisms or processes of evolutionary change can be studied only against the background of known patterns of change, in the origin and extinction of species. Dr. Ayers in a research planning grant begins a molecular (DNA-based) and morphological study of the patterns of diversification in a group of high-elevation "cushion" plants, in relation to their geographical distribution in the northern Andes. Field work to make plant collections combined with laboratory study of chloroplast DNA mutations and herbarium study of morphological features will provide insight into patterns of species divergence and the role of geographical barriers and dispersal routes.
