For flowering plants, there are multiple drivers of shape change that effect the process of speciation. In the background, species are constrained by their phylogenetic history, i.e. evolutionary changes that were advantageous to their ancestors, might turn out to no longer be beneficial. At the same time, speciation brought about by pollinator pressure is highly dynamic and can happen quickly.
Sara van de Kerke will defend her doctoral thesis on this subject on November 20. "In my research, I aimed to bring together multiple layers of influence on floral shape in Pelargonium (Geraniaceae) in order to paint a comprehensive picture of the evolution of floral diversity in this clade. By building upon the extensive knowledge on speciation processes in the South African Greater Cape Floristic Region, we find that speciation in this clade may not be as clear-cut as expected and place Pelargonium in a broader, evolutionary perspective."