1. College of Life Sciences, Shaanxi Normal University , Xi’an 710119 , China
2. Carnegie Museum of Natural History , Pittsburgh, PA 15213 , USA
3. Department of Biological Sciences, University of Pittsburgh , Pittsburgh, PA 15213 , USA
4. Holden Forest and Gardens , Kirtland, OH 44094 , USA
5. National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China, Shaanxi Normal University , Xi’an 710119 , China
6. Guangdong Provincial Key Laboratory of Silviculture, Protection and Utilization, Guangdong Academy of Forestry , Guangzhou 510520 , China