Molecular systematics of the tribe Hedysareae (Fabaceae) based on nrDNA ITS and plastid trnL-F and matK sequences

This study represents the molecular phylogeny of the tribe Hedysareae using nrDNA ITS and plastid trnL-F and matK sequence data. The molecular analyses united nine Hedysaroid genera in a well-supported monophyletic group (tribe Hedysareae). The tribe is circumscribed here as comprising Alhagi, Corethrodendron, Ebenus, Eversmannia, Hedysarum, Onobrychis, Sulla, Taverniera, and Greuteria. Our analyses revealed that Caragana and allies form a well-supported clade, the so-called Caraganean clade, which is weakly allied with the Hedysareae. Within the Hedysareae, Alhagi is the first diverging lineage followed by Sulla clade and a large assemblage of the other Hedysaroid genera. Ebenus and Taverniera were monophyletic. All analyses showed that Hedysarum is not monophyletic in the present circumscription. Most members of the genus with the inclusion of Sartoria hedysaroides were gathered in a single clade. The two other Hedysarum species (H. membranaceum and H. argyreum) were sister taxa and placed in a clade with Eversmannia subspinosa and Corethrodendron. Onobrychis was retrieved as a weakly supported clade. On the basis of the present sequence data together with non-molecular characteristics, we transferred H. aculeolatum to Sulla and S. hedysaroides to Hedysarum as well as elevated H. membranaceum and H. argyreum to the new generic rank named as Greuteria Amirahmadi & Kaz. Osaloo. A diagnostic key to the genera of the tribe is provided.