XVI International Botanical Congess

Flowers of Asclepiadaceae are well-known for unique and highly conserved traits, such as the pollinium (coherent pollen), translator (device attaching the pollinium to pollinators), gynostegium (fused androecium and gynoecium), and corona (structure between androecium and corolla). The evolutionary origins of most of these structures have been studied in some detail by comparison with the closest relatives of Asclepiadaceae in Apocynaceae. The origins of the corona, however, have remained obscure, and, unlike other characteristic structures, has diversified remarkably. I will present an analysis of the diversification of the corona in an explicitly historical framework based on a phylogenetic hypothesis for the family derived from analysis of chloroplast matK DNA sequences. I will present an analysis of the evolution of corona ontogenies that will address such questions as the origin(s), homology, and modes of diversification of the corona. Correlated evolution of corona and corolla morphology will also be explored.