Plant systematics and the evolution of floral diversity constitute the primary foci of research in my lab. Our ultimate goal is to combine studies of floral specialization at the phylogenetic level and the population level in the same plant group. Our research has focused specifically on the phylogeny of the Polemoniaceae and Lamiaceae, the evolution of pollination systems, patterns of morphological evolution, and evolutionary lability. We combine data from molecular, morphological, and field studies to explore these topics.
One of the ongoing foci of our research is floral lability and phylogenetics in the Polemoniaceae subfamily Cobaeoideae. There are four genera and over 30 species in this primarily tropical group and we are using multiple molecular markers to estimate their evolutionary history. Using a newly developed, phylogenetically based method we have determined that floral morphology is not significantly more labile than vegetative morphology, despite considerable variation in floral features among the species of Cobaea. Ongoing work focuses on the evolution of morphological traits in the entire subfamily. A monograph of Cobaea has been published and one of Cantua is being prepared. This research has resulted in discovery of several species new to science from each genus.
My lab group is also developing a phylogenetic framework for taxonomic studies of the tribe Mentheae of the Lamiaceae. We are using both nuclear and chloroplast DNA regions to show that prior morphological studies of the Lamiaceae are in many ways inadequate, due to the complicated morphological evolution of the group. We have evidence that many genera in this tribe are not monophyletic as currently circumscribed. Taxonomic work is underway in all of these genera.
Another current project in my lab is understanding how polyploidy generates morphological diversity in the genus Phlox. This is part of an ongoing collaboration with Dr. Carolyn Ferguson of Kansas State University and Dr. Shannon Fehlberg of Desert Botanical Garden. The larger project focuses on how polyploidy in a taxonomically challenging set of species generates phylgenetic, taxonomic, population genetic, and morphological diversity.
Finally, my lab group has also contributed to our knowledge of the natural history of rare plants, the lichen flora of Michigan, and we are actively involved in developing ways of integrating herbarium collections into a broader array of research activities.