Bursera graveolens (Kunth) Triana & Planch. (Burseraceae), or palo santo, is an economically and ecologically important tree species found throughout the seasonally dry tropical forests (SDTF) of southern Mexico south to Peru. No study to date has evaluated the relationship among the many disparate island and continental populations of B. graveolens, which are among the most widespread in the genus and rivaled only by those of B. simaruba, a distantly related species of Bursera. subg. Bursera. My research examines the population genetics and phylogeography of palo santo to test biogeographic hypotheses regarding the formation of the SDTF on a continental scale and population genetic variation across its range. I am also completing a taxonomic revision using morphological and phylogenetic data to determine if palo santo as currently described comprises a single, widespread lineage or segregate taxa. In this presentation I will share the outcomes of my field collection expeditions to Mexico, Colombia, Ecuador, and Peru and present preliminary findings from phylogenetic and morphological analyses related to species delimitation.