To reveal the role of climate oscillations of the Quaternary in forming the contemporary plant diversity in the temperate Sino-Japanese Floristic Region of mainland China, we assess the phylogeographical patterns of four Sagittaria species in the region using sequence data from plastid DNA non-coding regions (psbA-trnH, the rpl16 intron and trnC-ycf6) and the internal transcribed spacers of …