My principal research interests are the systematics of Crataegus sections Crus-galli and Douglasii, particularly the relationship between phenetic variation, genetic variation, and breeding system; also in the integration of developmental data in systematic studies, morphometric analyses of shape variation, numerical taxonomy and cladistics, and comparative morphology. Current research projects include: Crataegus phylogeny (in collaboration with graduate student Eugenia Lo); rangewide morphological variation in Crataegus section Douglasii; reproductive biology of Crataegus (in collaboration with graduate student Nadia Talent); and application of morphometric and other multivariate methods to problems in systematic and developmental biology. I am also participating in an international collaboration on the evolution of Rosaceae subfamily Maloideae together with former graduate student Dr Rodger C. Evans and others.

Selected Publications