EN
Distribution of Turkish Quercus L. has a crucial value since Turkey is a transition place between Europe and Asia and located at the meeting point of three phytogeographical regions. To compare the diversity of species and to find the distribution patterns of oaks, species richness of the most current distributions were studied. Relationships of phytogeographical regions and presence of the Anatolian Diagonal relevant to oak distributions were also investigated. Analyses were performed on Davis'grid square system. The highest richness of Quercus species were found at north-western Turkey which were located in the meeting place of Asia and Europe. The lowest richness scores were found at eastern and south-eastern Anatolia. Moreover, latitude, longitude and altitude histograms showed a correlation with species richness. However, the presence of Anatolian Diagonal is partially supported.