The Vaccinieae (the blueberry tribe, in the heather and rhododendron family) are a diverse group of temperate and tropical woody plants found on all continents except Antarctica. The temperate members of this group are the familiar blueberries and bilberries. The lesser known tropical members of the Vaccinieae are extremely diverse in floral morphology and form a major component of many montane tropical forests (e.g., cloud forests). This project will address evolutionary relationships within the blueberry tribe using DNA sequence data from three regions in the chloroplast and nuclear genomes, and morphological data. The collaboration of a molecular systematist (PI-Kron) with the expert in tropical blueberry morphology and field work (coPI-Luteyn) is a powerful approach to such a large scale study and is key to the success of the project. The blueberries are an excellent model for testing the commonly held assumption that taxa that are most diverse in the tropics must have originated in the tropics. Because of the morphological diversity, large size (>1000 spp.) and widespread geographic distribution of this taxon, evolutionary studies of relationships within Vaccinieae will provide an important window on the general evolutionary history of the earth. The results of this study will contribute to a broader understanding of the common historical factors that have contributed to the amazing diversity in the Neotropics. These comparisons will contribute to a more complete understanding of causes and patterns of diversification in some of the most diverse ecosystems in the world.