2.1 | Sampling and DNA extraction
A total of 271 samples were collected from 15 sites in the Qinling Mountains of China (Figure 1). Of these locations, SZA and SYX are located in fragmented landscape, which are surrounded by roads, railway line and villages. Moreover, Cymbidium goeringii , Cymbidium ensifolium , Cymbidium kanran and Cymbidium sinense were collected as outgroups. DNA was extracted using Tiangen Extraction Kit (Beijing, China).