Floral symmetry and its role in plant-pollinator systems: Terminology, distribution, and hypotheses

Floral symmetry has figured prominently in the study of both pollination bi ology and animal behavior. However, a confusion of terminology and the diff use nature of the literature has limited our understanding of the role that this basic characteristic of flower form has played in plant-pollinator in teractions. Here, we first contribute a classification scheme for floral sy mmetry that we hope will resolve some of the confusion resulting from the i nconsistent application of terms. Next, we present a short review of the di stribution of floral forms in angiosperm families. Finally, we provide a li st of hypotheses and, when available, supporting evidence for the causes of the evolution of floral symmetry.