Phylogenetic relationships among Japanese flowering cherries (Prunus subgenus Cerasus) based on nucleotide sequences of chloroplast DNA

Flowering cherries are classified into Prunus subgenus Cerasus (family Rosaceae). Nine species and some varieties originated in Japan were used in this study. Phylogenetic relationships among Japanese taxa were analyzed by four chloroplast regions using 46 individuals from 16 taxa. Eighteen haplotypes were distinguished. P. pendula f. ascendens and P. cerasoides formed a clade which is distantly related to other Japanese taxa. These two species were morphologically different from other taxa. All Japanese taxa except for P. pendula f. ascendens formed another clade. All taxa in this clade except for P. maximowiczii showed very similar sequences. However, these taxa could be identified by many morphological characters. Even now, based on previous work, it is thought that interspecific hybridization frequently occurs in flowering cherries. We conclude from the current study, Japanese flowering cherries have experienced complicated speciation arising from hybridization.