Phylogenetic relationships were studied based on morphology and nuclear ribosomal DNA internal transcript spacer (nrDNA ITS) sequences in 49 populations of 36 Onobrychis taxa belonging to 5 sections (Dendobrychis, Lophobrychis, Onobrychis, Heliobrychis and Hymenobrychis) naturally grown in Turkey. The morphological data (46 quantitative characters) were standardized and submitted for PCA analysis before the performance of hierarchical clustering analysis. In addition, a 577-bp region of the nrDNA ITS sequences was compared to generate a dendrogram using the neighbor-joining method. According to the obtained results, the Onobrychis genus is clearly divided into the Onobrychis and Sisyrosema subgenera both molecularly and morphologically; however, in terms of molecular data, while the Onobrychis subgenus showed polyphyletic features, the Sisyrosema subgenus had monophyletic features. Additionally, long-wing taxa belonging to Dendobrychis and Onobrychis and O. crista-galli belonging to Lophobrychis located in the same clade in Onobrychis showed polyphyletic features. This finding was confirmed in terms of long-wing taxa as well as morphology and indicated that these three sections were entangled with each other under the Onobrychis subgenus.
