Majid Aghaahmadi - Faculty of Science, University of Isfahan, Isfahan, P. O. Box ۸۱۷۴۶-۷۳۴۴۱, Iran.
Hojjatollah Saeidi - Faculty of Science, University of Isfahan, Isfahan, P. O. Box ۸۱۷۴۶-۷۳۴۴۱, Iran.
Mostafa Assadi - Research Institute of Forests and Rangelands, Agricultural Research, Education and Extension Organization (AREEO).

Determining the boundaries of genera in subtribe Trigonellinae Small has been one of the most controversial taxonomic issues in this field in last ۱۰۰ years. Proposing the many characters for separating these genera by various botanists can be considered as a reason for this claim. Characters of the flower parts as well as other vegetative traits have been used extensively. Here on the basis of ۵ qualitative and ۱۹ quantitative flower characters we separated Trigonella species (especially perennial section Ellipticae (Boiss.) Sirj.) from other genera of this subtribe and showed the results in dendrogram and scatter plot. Placement of the Medicagoid species of section Bucerates (Boiss.) Sirj. and Medicago L. in one branch and presence of Melilotus indicus (L.) All. along with other Trigonella species (except section Ellipticae as a distinct branch) are the main results of this investigation.

Phenetic analysis, Fabaceae, Trifolieae, character evolution, PCO analysis, UPGMA method