RESEARCH ARTICLE g o

Profound climatic oscillations during the Pleistocene resulted in repeated drastic environmental changes, which also substantially shaped the species ’ distribution, evolution, and extinction [1-4]. The Last Glacial Maximum (LGM) occurred at around 23 000–18 000 years before present, which was particularly considered an important factor in-fluencing the current plant distribution [4,5]. Numerous molecular-based phylogeographical surveys in Europe and North America have been extensively studied to unravel the locations of refugia, the potential recolonization routes and the subsequent evolution and speciation during glacial and post-glacial epochs [6-8]. In contrast to Europe and North America, most parts of China were not covered by massive ice sheet during LGM. It was clear that ice sheet had only developed in certain areas of the Qinghai–Tibetan Plateau [9]. In recent years, numerous phylogeographical surveys of plant species in China have been informative in resolving the location of glacial refugia and routes of colonization/range expansion after glacial periods. Three hypotheses on the occurrence of refugia and postglacial expansion in China have been proposed. The first hypothesis is that climatic changes during Pleistocene deeply impacted the forests in China, and large-scale vege-tation experienced long-distance southward migration during glaciations. Thus, the species subsequently colo- * Correspondence