Morphometric analyses of the leaf variation within Quercus L. Sect. Cerris Loudon in Turkey

Abstract

Oaks are classified heavily based on the leaf morphology. However, identification of specimens without acorns is usually controversial in Cerris section. Although members of Cerris section have a broad distribution area, there are only few taxonomic studies. Therefore, the current study is the first to show the discrimination of species in Cerris section based on leaf characters from Turkey. Discrimination among the members of Cerris section over Turkey (Q. cerris L. var. cerris, Q. ithaburensis Decne. subsp. macrolepis (Kotschy) Hedge and Yalt, Q. brantii Lindley, Q. libani Olivier, and Q. trojana P. B. subsp. trojana.) was aimed and variations within and among the species based on 15 qualitative leaf characters was presented. In this work we have studied the natural variability of these species by analysing leaf materials collected from 44 populations around Turkey. Cluster Analysis (CA) and Principal Component Analysis (PCA) were performed to assess intra-specific differentiation and to compare the distribution of variance in the individual and population level. The results showed that the leaf characters presented a good discrimination of five Cerris taxa in PCA at the population level, but the relationships between Q. ithaburensis subsp. macrolepis and Q. brantii showed complex groups in CA. Among the studied taxa, the highest variation was found within Q. cerris populations. In this work, we obtained discrimination of Cerris section species from Turkey based on leaf characters which is quite useful for those herbarium specimens without acorns and in other systematic observations. Additional key words: cluster analysis, numerical taxonomy, oak, principal component analysis Address: Abant Izzet Baysal University, Faculty of Science and Art, Department of Biology, Golkoy 14280 Bolu, Turkey; e-mail: uslu_e@ibu.edu.tr