The genus Rosa (Rosoideae, Rosaceae) revisited: molecular analysis of nrITS-1 and atpB-rbcL intergenic spacer (IGS) versus conventional taxonomy

Sequences of the nrDNA internal transcribed spacer 1 (nrITS-1) and atpB-rbcL intergenic spacer (IGS) of the cpDNA were analysed for all sections of the genus Rosa L. (Rosoideae, Rosaceae) to study molecular infrageneric taxonomy and relationships of Rosa with respect to conventional taxonomy based upon morphological and anatomical data as well as phytochemical characters. The results suggest that Rosa in its traditional infrageneric circumscription is not reflected by molecular data. Cinnamomeae, Carolinae and Pimpinellifoliae are not monophyletic based on the molecular data and this is mirrored in conventional taxonomy that separates these sections by weak morphological characters such as sepal performance, existence of bracts, and number of flowers per inflorescence. Section Pimpinellifoliae is split by the monotypic sections Laevigatae, Platyrhodon, Bracteatae and Hesperhodos. Section Caninae is a natural allopolyploid group characterized by its autapomorphic ITS C-type and Canina-meiosis. CpDNA subdivides sect. Caninae into two natural clusters of eglandular and glandular species. NrITS shows sect. Synstylae/Indicae to be the direct sister group to sect. Caninae, not Rosa (Gallicanae) although both groups are morphologically characterized by pinnate sepals. From our molecular data sect. Indicae and sect. Synstylae are consectional. The highest taxonomic rank below the generic level should be the sectional status. © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society, 2005, 147, 275–290.