Graduate student Jose Villasenor under the guidance of Dr. Tom Elias of Rancho Santa Ana Botanic Garden is studying the Mexican and Guatemalan species of Senecio section Mulgedifolii, a poorly known group of tropical montane sunflower relatives. He plans a broad survey of features of morphology, chromosome composition, and analysis of variation in chloroplast DNA. The goals include evaluation of morphological characters that provide stable, reliable guides to the identification of species; mapping of the geographic distributions of the estimated 15 or so species throughout Mesoamerica; and inference of the evolutionary relationships among these species and with closely related groups of Senecio. Villasenor has published a number of papers on the plant resources of Mexico, and has conducted field work in several regions of the country. The broad approach he is taking to the study of plant biodiversity, encompassing both traditional morphological investigation and laboratory analysis of genetic and genomic variation, will bring increased understanding of tropical plant resources in the Americas, and in turn the research will contribute to training of the next generation of plant scientists.