1. Department of Biology, University of Missouri—St. Louis, One University Boulevard, St. Louis, MO 63121, USA
2. Graduate Studies Program, Division of Science and Conservation, Missouri Botanical Garden, PO Box 299, St. Louis, MO 63166, USA
3. Present address: Department of Integrative Biology, University of California, 3060 Valley Life Sciences Building, Berkeley, CA 94720-3140, USA
4. Center for Conservation and Sustainable Development, Division of Science and Conservation, Missouri Botanical Garden, PO Box 299, St. Louis, MO 63166, USA