1. Hunan University of Arts and Science, CN-415000 Changde, Hunan, China
2. Central South Inventory and Planning Institute of National Forestry and Grassland Administration, CN-410081 Changsha, Hunan, China
3. Department of Life Sciences, Hunan Normal University, CN-410081 Changsha, Hunan, China
4. Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations, Kunming Institute of Botany, Chinese Academy of Sciences, CN-650201 Kunming, China