Natural populations of C arpinus orientalis Mill. shrublands occur mainly in high and middle altitudes of the Hyrcanian forests, N. Iran, particularly on steep rocks and forest outcrops. There are some discrepancies on the intra-specific delimitation of this important woody species. The aim of the current study is to examine the anatomical variation of stems and leaves of sixteen populations of C a r p i nu s o r ie n t a lis collected in four north and northeastern provinces of Iran for the first time. It was shown that the anatomical characteristics of stem have some correlations with climatic variables such as temperature, altitude and precipitation, whereas midrib anatomical characteristics did not show any correlation with the above mentioned parameters.
