1. Department of Plant and Microbial Biology North Carolina State University Raleigh NC 27695 USA
2. State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany Chinese Academy of Sciences Beijing 100093 China
3. Department of Biological Sciences University of North Carolina at Charlotte Charlotte NC 28223 USA
4. Harvard University Herbaria 22 Divinity Avenue Cambridge MA 02318 USA