ABSTRACT 97-07330 Armbruster, Thomson, Wolfe, Wilson Collaborative research: Floral function and phylogeny in Penstemon: tests of pollen presentation theory This research examines the evolution of floral traits within the plant genus Penstemon, a member of the snapdragon family. The investigators will derive a "family tree" of Penstemon using DNA sequences to estimate genetic similarities, so that observed changes in floral characters can be interpreted with a proper understanding of species relationships. Ecological research will be focused on ways that Penstemon anther characteristics influence size and number of pollen doses, and ultimately, plant fitness in hummingbird- and bee-pollinated plants. An untested new theory predicts that when pollinating animals visit frequently, plants that release pollen from their anthers in smaller doses per visit will donate more pollen to other plants. As the first test of pollen presentation theory, this research will help decide whether these models are correct and useful. Improved knowledge of pollination mechanics can help improve the economic evaluation of alternative pollinators of agricultural crops.
