1. Key Laboratory of Biodiversity and Biogeography, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650204, P. R. China
2. Graduate School of Chinese Academy of Sciences, Beijing 100039, P. R. China
3. Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Nanxincun 20, Xiangshan, Beijing 100093, P. R. China
4. Department of Botany, University of Florida, Gainesville, Florida 32611 USA
5. Department of Botany, National Museum of Natural History, MRC 166, Smithsonian Institution, Washington, D.C. 20013‐7012 USA