Phylogenetic analysis of Japanese Rosa species using matK sequences

The matK DNA was sequenced in each of the 15 Japanese Rosa taxa, 17 other Asian taxa, and two American taxa to analyse their phylogenetic relationships. All the 14 tested taxa in the section Synstylae, associated with the section Indicae, formed one clade. It was confirmed that sections Synstylae and Indicae, with the common styles exserting from the hypanthium, are closely related to each other. Furthermore, R. brunonii and R. moschata in the section Synstylae formed an inner clade which is consistent,vith their common morphological traits. Two clones of R. acicularis formed one single clade which was separated from the remaining species of the section Rosa. This finding suggests that R. acicularis might be a distinctive species in the section Rosa. The remaining species of the section Rosa formed one clade which was further subdivided into two inner clades: R. rugosa and R. marretii formed one clade, while R. acicularis var. nipponensis and R. willmottiae formed another clade. The distinctive relationship with R, acicularis implies that diploid R. acicularis var. nipponensis, traditionally treated as one variety of polyploid R. acicularis by some authors, is a primitive taxon and that it should be reassigned to its original specific rank as R. nipponensis.