Dr. Graham's research deals with the biosystematics of higher plants, in particular the classification and evolutionary history of the flowering plant family Lythraceae , the Loosestrifes. Research involves gathering and analyzing data from floral and vegetative morphology, chromosomes, pollen, and in collaboration with other laboratories, molecular data from nuclear and chloroplast genomes. Results appear primarily as taxonomic revisions and as phylogenetic histories. Recent and ongoing student projects include a pollen morphology survey of the crape myrtles using SEM, study of breeding system changes in species of Cuphea with alternating sexual and agamospermic reproduction, phylogenetic analysis of the family Lythraceae, and within the family, the genera Cuphea, Lythrum, and Heimia , and Ginoria using morphological and molecular data. Techniques learned are widely applicable to flowering plant systematics and can be used to answer a variety of questions from the family to the population level.
Several genera are of economic or prospective economic value.
Crape myrtle, Lagerstroemia , is widely planted in warm climates as a urban landscape tree. A few species of Cuphea are of growing importance in the horticultural trade and many species with attractive showy flowers and perennial habits offer prospects for new introductions. Cuphea is also on the list of USDA's alternative crop plants as an oilseed source . Lawsonia is the commercial source of the dye henna . Heimia is an auditory hallucinogen as a result of production of 5 alkaloids that act synergistically.