Curator/Director of Graduate Studies
• Broad scale aspects of plant evolution
• Systematics and phylogeny of Onagraceae
• Impacts of human-influenced environmental changes
• Floral phenology and pollination biology
Web Page: MBG
We have strong congruent evidence from multiple data sets that Ludwigia is sister to the rest of the Onagraceae. Recent molecular phylogenetic work in Ludwigia has generated hypotheses about relationships in the genus that differ from the traditional understanding of the genus. Morphological features, particularly of the capsules and seeds, show considerable variability, and may provide insight into relationships in this interesting aquatic genus. The external seed morphology of only a few species has been examined, yet even those partial results suggest that seed coat morphology is quite variable, and may be particularly useful not only for assessing the phylogeny generated by molecular data, but also for understanding adaptations to the wet habitats occupied by Ludwigia. This aquatic habit stands in sharp contrast to that of most other Onagraceae, most of which grow in decidedly drier habitats. This project will entail sampling seeds widely within Ludwigia (and some outgroups), examining the seeds with scanning electron microscopy, and if necessary with light microscopy of sectioned seeds, and analyzing the results in light of hypotheses of relationships and habitat evolution.