Pollen Morphology of Some Woody Species Belonging to the Betulaceae

Morphological characteristics of pollen grains, such as shape, size, number of pores, and exine thickness, may vary among species, thereby enabling the reliable use of palynologi-cal data in taxonomic studies. In this context, this study aims to investigate the pollen morphology of selected seven taxa of the Betulaceae, including Alnus glutinosa, Betula pen-dula, Carpinus betulus, Carpinus orientalis, Corylus avellana, Corylus colurna and Ostrya carpinifolia. Detailed morphological measurements were carried out using Light Micros-copy (LM), and high-resolution images were obtained using Scanning Electron Microsco-py (SEM). Thirty measurements were taken under the LM for each morphological charac-ter, including polar axis length (P), equatorial diameter (E), pore length (plg), pore width (plt), and exine thickness (Ex). Interspecific differences were evaluated using one-way ANOVA, Tukey’s HSD test, and Principal Component Analysis (PCA), and a pollen iden-tification key for the investigated species was developed in this study. The first principal component (PC1) was primarily associated with pollen size (P and E), along which Carpinus betulus was clearly separated from the remaining species. The second principal component (PC2) was mainly related to pore length (plg) and particularly contributed to the separation of Alnus glutinosa from the other small-pollen species.