ANATOMICAL STUDIES OF THE GENUS PYRUS L. (ROSACEAE) IN IRAN AND ITS TAXONOMICAL IMPLICATIONS

In this study leaf and petiole anatomy of 10 species of the genus Pyrus L. belonging to four sections, Pashia, Pyrus, Xeropyrenia and Argyromalon, and one cultivated specimen (close to P. syriaca) is presented. These species include Pyrus boissieriana Buhse, P. kandevanica Ghahreman amp; Khatamsaz, P. turcomanica Maleev, P. hyrcana Fedor., P. mazanderanica SchönbeckTemesy, P. syriaca Boiss., P. glabra Boiss., P. oxyprion Woron., P. salicifolia Pall., P. elaeagnifolia Pall. Among 43 studied anatomical characters, 29 characters vary in different localities, seven are constant in all species and four are valuable and can be used in distinguishing species. These characters include number of layers of palisade parenchyma layer, density of palisade parenchyma layers, and presence of lower palisade parenchyma layer between auricles. On the basis of the present study, anatomical characters are useful for separating Zagros species from Alborz ones and also in sectional level.