1. State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany Chinese Academy of Sciences Beijing 100093 China
2. Beijing Botanical Garden, Institute of Botany Chinese Academy of Sciences Beijing 100093 China
3. Institute for Evolution and Biodiversity University of Muenster Muenster 48149 Germany
4. Sino‐Africa Joint Research Center Chinese Academy of Sciences Wuhan 430074 China
5. University of Chinese Academy of Sciences Beijing 100049 China
6. Department of Botany, National Museum of Natural History Smithsonian Institution Washington DC 20013‐7012 USA