Ahmadreza Meharbian - Department of Biodiversity and Ecosystems Management, Research Institute of Environmental Science (ESRI), Shahid Beheshti University, Evin, Tehran, Iran, P. O. Box.۱۹۸۳۹۶۳۱۱۳
Shahin Zarre - Department of Plant Sciences, Faculty of Biology, Tehran University, Tehran-Iran
Dina Azizian - Department of Plant Sciences, Faculty of Biology, Shahid Beheshti University, Tehran-Iran
Dieter Podlech - Institut fur Systematische Botanik der LMU, Menzinger , Munchen, Germany

Cross sections of petioles in ۲۴ species of Astragalus Sect. Incani has been studied for a comparison of anatomical characters based on phylogeny in this section. The characters which employed in this study are as follows: Numbers of parenchymatous cell layers in pith, number of bundles, length of ventral axis, length of dorsiventral axis, diameter of ventral latéral vascular bundle (VLB) and diameter of dorsal médian bundle (DMB). Furthermore the evolutionary direction in anatomical characters (character polarity) is studied. The results reveal that anatomical characters are not useful for circumscribing section but are suitable evidences for taxonomical differentiation in species in this section and can be use for delimiting small natural groups. Moreover, they are helpful characters for determining some complexes in this section.

Astragalus, Incani, Petiole, Anatomy, Iran