Conclusion
We found dominant genetic diversity and existence of phylogeographic structure in Cerasus serrulata . The estimated divergence time and expansion events further indicated that the distribution pattern and center of C. serrulata was formed before LGM. Two geographical lineage were inferred. One was confined to Qingling Mountain and Taihang Mt. The other was from the Wuling Mt to Lu-Huang Mt, and then went northeast to the coast of Asia, totally with two separate steps. Taxonomic statements of several controversial related species were reconsidered. C. xueluoensis was close to C. serrulata but also exhibited differentiation at species level, which needs further study. C. lannesiana is confirmed rather than C. serrulatavar. lannesiana . And finally a new variation, C. serrulatavar. huangangensis is identified.