Phylogenetic relationships and character evolution in tribe Lycieae (Solanaceae)
This National Science Foundation funded project (with co-PI Dr. Rachel A. Levin) examines evolutionary relationships among three closely-related genera (Grabowskia, Lycium, Phrodus) in Tribe Lycieae in the tomato family (Solanaceae).  This research will contribute to understanding evolutionary relationships among members of Lycieae and particularly within the largest genus Lycium (wolfberry; ca. 80 species worldwide).  Our work will guide revised taxonomic classifications and provide a new systematic treatment of the group.  In addition, the proposed work will permit determination of the number of times that dimorphic breeding systems (i.e., separate male and female plants) have evolved from hermaphroditic ancestors in Lycium, and existing hypotheses concerning the association of polyploidy, loss of self-incompatibility, and gender and sexual dimorphism will be tested. More broadly, this project will advance understanding of angiosperm phylogeny, as well as contribute to on-going, global efforts toward deciphering relationships in the economically important plant family Solanaceae. Follow this link for more details or check out project LycieaeWeb here.

Architectural effects and the analysis of sexual size dimorphism
This National Science Foundation award examines the importance of architectural effects to the expression of floral sexual size dimorphism.  Unisexual flowers have evolved repeatedly among angiosperms, and male and female flowers frequently show sexual size dimorphism, with one gender having larger flowers.  However, an important component of flower size variation is floral position within inflorescences and inflorescence position within the overall architecture of the plant.  Despite this positional variation, the role of architecture and its potential importance in explaining sexual size dimorphism has not been explored. Thus, the overall goal of this research is to explore the hypothesis that positional effects can contribute to the expression of sexual dimorphism. More information is here. This project is in collaboration with Dr. Pam Diggle in the Department of Ecology and Evolutionary Biology at the University of Colorado, Boulder.

Evolutionary genetics of gametophytic self-incompatibility
I had an Amherst College Faculty Research Award (FRAP) during 2005-2006 to investigate the relationship between polyploidy and the putative breakdown of gametophytic self-incompatibility.  The genes controlling self-incompatibility are well characterized in Solanaceae and my students and I have been investigating patterns of allelic diversity at the S-RNase gene in both diploid and polyploid species of Lycium.  More information on this project is here.

Reproductive ecology of Lobelia (Campanulaceae) in MA
This is a field project (June-September) to study of the reproductive biology of two native Lobelia species. Lobelia spicata and L. siphilitica are both dimorphic in sexual expression and populations consist of two mating types: hermaphroditic plants and female plants. Follow this link to read more about this system.

Evolutionary diversification of andromonoecy in Solanum section Lasiocarpa
In collaboration with Dr. Pamela K. Diggle at the University of Colorado, I investigated the origin and diversification of andromonoecy among a dozen species in Solanum section Lasiocarpa. Additional information is here.

Evolution of gender dimorphism (separate sexes) in North American Lycium
My dissertation focused on evolutionary transitions between cosexual and dimorphic sexual systems. Read more about this work here.