Nunataks or massif de refuge? A phylogeographic study of Rhodiola crenulata (Crassulaceae) on the world's highest sky islands.

Our results support a scenario that both nunataks and the massif de refuge hypotheses could explain the distribution of R. crenulata. We also confirmed that Quaternary climatic oscillations could promote plant speciation in some circumstances. This study adds to a growing body of evidence suggesting that the QTP plant lineages exhibited diverse reactions to the Quaternary climatic oscillations.