XVI International Botanical Congess

Flowers of Asclepiadaceae are morphologically diverse, structurally complex, and exhibit specialized modes of pollination. These features result from an accumulation of evolutionary innovations, such as pollinium, gynostegium, and corona. Although such innovations are paralleled in other angiosperms, their association in a single flower is unique. Understanding the phylogenetic position of Asclepiadaceae as nested within Apocynaceae has yielded insights into the origin of innovations. However, deeper understanding of these innovations and their diversification requires knowledge of phylogeny at a fine scale and homology assessment of disparate structures. Using explicit phylogenies for Asclepiadaceae, I analyze the origin and diversification of floral novelties, emphasizing the corona. I discuss evidence for shifts from corolline to androecial positions and the origin of novel forms.