In this study we explore the biogeographic patterns and processes underlying the diversification of Sabal, a genus of palm with a range that expands from the tropical rainforests of northern South America into the deciduous subtropical forests of the southeastern United States. We estimate divergence times among species of Sabal using two dated fossils as calibration points to inform ancestral reconstructions of the historical distribution of Sabal, and then use floral volatile composition data in select species of Sabal to integrate plant ecological interactions into our discussion of species distributions. Our results suggest extant Sabal originated within the last 21 million years with a divergence event ~14 Mya that effectively split the most recent common ancestor of all southeastern US and West Indian species from the ancestor of a clade of species with their current distribution in Mexico. This divergence event corresponds with the end of the mid-Miocene climatic optimum, which resulted in cooler ... : Gene alignment used to estimate divergence times: A supermatrix was generated from all gene alignments generated by Heyduk et al. 2015 (https://doi.org/10.5061/dryad.jm78g) by concatenating separate gene alignment files. We used PartitionFinder V. 2.1.1 (Lanfear et al. 2017) to estimate the optimal partitioning scheme among genes. The partitioned alignment contained 49 partitions with substitution models assigned as either GTR, GTR+G, and GTR+G+I. ...