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In this study, phylogenetic relationships and evolutionary trends of morphological characters of Astragalus sects. Acanthophace and Aegacantha were studied using nrDNA ITS and rpl32-trnL^UAG datasets while Astragalus stocksii was selected as the outgroup. The phylogenetic results indicated the non-monophyly of A. sect. Acanthophace in its current circumscription due to the distant exclusion of A. ovigerus from the core group, and incongruence between nuclear and plastid datasets on the basis of different position of latter species in the resulted phylogenetic trees. Astragalus sect. Aegacantha was also found to not being monophyletic due to the distant position of A. montis-parrowii from the other representatives of the section while accompanying with other spiny Astragalus species. The Optimization of 32 morphological characters on the Bayesian combined tree indicated that some characters were most useful for delimitation of taxa in sections Acanthophace and Aegacantha. The results obtained from the evolution of characters showed that standard blade constriction, legume shape and possessing unilocular pods were of diagnostic importance for the separation of A. ovigerus from other species. The traced characters were in accordance with the phylogenetic position of A. montis-parrowii, which was separated from other members of sect. Aegacantha, as the number of flowers in inflorescences, the presence of peduncle, hairy petal, pandurate standard and constriction of standard that is differentiatiated to claw, the presence of claw in standard and the length difference between keel and wing were different from those in other members of the sect. Aegacantha.
 

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In this study, the phylogeny and morphological variation of 6 species of the genus Cousinia sect. Stenocephalae, i.e., C. hypopolia, C. decipiens, C. esfandiarii, C. renominata, C. stahliana and C. daryoushiana, distributed in NE regions of Iran, were investigated. ITS, ETS and rpl32-trnL ^(UAG) sequences for 12 species (17 specimens) were generated. Phylogenetic interspecies relationships were constructed by Bayesian method and likelihood analysis. The specimens were also investigated in terms of morphological characters. Despite very similar morphological characters and geographical distributions, the separation of these species was confirmed by the obtained results of the molecular data (combined data of plastid and nuclear sequences). On the basis of the present study, the above-mentioned species were almost separated from each other by morphological characters and molecular data. A diagnostic key and the description of these species were also presented. These results did not conform with the previous palynological and anatomical studies of the species.