1. College of Life and Health Sciences Northeastern University Shenyang 110004 China
2. College of Life Sciences Northwest A&F University Yangling Shaanxi 712100 China
3. Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden Chinese Academy of Sciences Guangzhou 510650 China
4. College of Life Sciences Northwest University Xi'an 710069 China
5. Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture and College of Landscape Architecture Beijing Forestry University Beijing 100083 China
6. Department of Botany National Museum of Natural History, MRC 166, Smithsonian Institution Washington DC 20013‐7012 USA