1. Department of Biology, Duke University, Box 90338, Durham, NC 27708, USA
2. Present address: Division of Plant Pathology and Microbiology, Department of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA
3. Present address: Department of Biology, University of Utah, Salt Lake City, UT 84112, USA
4. Present address: University of Virginia Health System, Charlottesville, VA 22908, USA
5. Present address: Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, MN 55108, USA
6. Present address: Department of Mycology, Federal Research Station Agroscope Changins-Wadenswil ACW, Nyon, Switzerland
7. Present address: Department of Biology, Molecular Phylogenetics, University of Kaiserslautern, Postfach 3049, 67653 Kaiserslautern, Germany