Abstract
We identified two previously unrecognized taxa of Rosa (Rosaceae), one from Kyushu and the other from Shikoku, Japan. To clarify their taxonomic identities, we conducted phylogenetic analyses of 36 samples of Rosa using multiplex inter-simple sequence repeat genotyping by sequencing (MIG-seq). Both SplitsTree and maximum likelihood tree revealed that the unrecognized taxon from Kyushu forms a separate cluster, which is sister to R. onoei Makino var. onoei, distributed in the same region. It is morphologically distinguishable from R. onoei var. onoei by its glaucous abaxial leaf surfaces, larger flowers, longer stamens, and typically pinkish petals. We therefore describe it as R. kirishimensis Yahara & Tagane. The other one from Shikoku is morphologically similar to R. fujisanensis (Makino) Makino subsp. fujisanensis but differs in having broader and typically circular leaflets and larger flowers. Although this taxon shows a high degree of genetic similarity to R. fujisanensis in both STRUCTURE and Principal Component Analyses, it formed a distinct clade in the maximum likelihood tree. Based on this evidence, we describe it as R. fujisanensis subsp. shikokumontana Yahara & Se.Fujii.
