Feb., 5, ’14. In an article titled, “Speciation of two desert poplar species triggered by Pleistocene climatic oscillations,” published in the current issue of Heredity (112:156-164), J. Wang and six of his associates affiliated to well-known laboratories in China and T Källman at the Evolutionary Biology Center, Uppsala University, Sweden, have suggested that the Pleistocene climatic fluctuations have seriously affected the distribution of intraspecific diversity in the two poplar species, Populus euphratica Oliv. and P. pruinosa Schrenk. The authors sequenced 11 nuclear loci in 60 individuals from the two species to estimate the divergence time between them and to test whether the gene flow occurred after species separation. They estimated that the divergence time between the two species was between 0.66–1.37 million years ago. This was the time at which glaciation was at its maximum in China and deserts developed widely in central Asia. The above results highlight the importance of Pleistocene climate oscillations in triggering plant speciation as a result of divergence of habitats.