The species relationship of the genus Carduus L. (Asteraceae) based on morphological characters in Iran

Carduus L. of the genus Compositae include about 90 species which are distributed mainly in the Europe، Asia and Africa as the three major centers of diversity of Carduus. About 8 species of Carduus are distributed in Iran among which 1 species is endemic. In this study، 45 quantitative and qualitative morphological characters from vegetative and reproductive parts were considered and evaluated in 37 populations of 8 species of Carduus from different localities in Iran. The aim of this study was to evaluate the species relationship in Iran. To evaluate the species relationships، cluster analysis and ordination based on principal component analysis and PCO were implemented. Statistical analysis indicated that characters as Capitulum shape، Capitulum length، phillary bract spine length، phillary bract width، number of rows phillary bract، number of phillary bract، involucre length، involucres width، length to width ratio involucres had the most important role as diagnostic characters in inter-genus variation. Based on statistical results and diagnostic characters، an identification key was provided for Carduus species in Iran.