Stem anatomical study in some annual Polygonum L. (Polygonaceae) species in Iran

In this project stem anatomical structure of 61 populations of 6 annual Polygonum L. species of Iran, comprising P. aviculare, P. arenastrum, P. polycnemoides, P. patulum P. argyrocoleon and P. olivascens were studied. Polygonum is a genus with palisade mesophyl under stem epidermis, containing oxalate calcium crystals and a specialized xylem tissue. Stem anatomical structures are compared between species. Species relationships and affinities are discussed due to the results of statistical analysis. Results indicated the difference between fiber patch numbers, vascular bundles, stem average diameter, and stem protruding shape in cross sections, stele diameter and general outline of stem cross sections. P. aviculare show a great variation in studied species of this genus in Iran. Based on observed differences identification was done for species. Results indicate that stem anatomical characters can provide some diagnostic values for species delimitation in some morphologically similar species of this genus in Iran.