1. Key Laboratory of Plant Resources, Institute of Botany Chinese Academy of Sciences 100093 Beijing China
2. China National Botanical Garden Beijing 100093 China
3. University of Chinese Academy of Sciences Beijing 100049 China
4. Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, College of Landscape Architecture Beijing Forestry University Beijing 100083 China
5. College of Forestry Inner Mongolia Agricultural University Huhhot 010020 China