Morphometric leaf variation in oaks (Quercus) of Bolu, Turkey

Genus Quercus (Fagaceae) has a problematic taxonomy because of widespread hybridization between the infrageneric taxa. The pattern of morphological leaf variation was evaluated for evidence of hybridization in Bolu, Turkey, since previous studies suggested that in oaks leaf morphology is a good indicator of putative hybridization. Principal components analysis was applied to data sets of leaf characters from five populations to describe variation in leaf morphology. Leaf characters analyzed in this study showed high degrees of variation as a result of hybridization between four taxa (Q. pubescens, Q. virgiliana, Q. petraea and Q. robur) of subgenus Quercus while Q. cerris as a member of subgenus Cerris was clearly separated from the others.