Morphological and molecular results from a geographical transect focusing on Quercus pubescens/Q. virgiliana ecological-altitudinal vicariance in peninsular Italy

Quercus pubescens and Q. virgiliana are the most cited taxa in the Italian deciduous oak forests floristic and phytosociological literature. According to some authors, Q. pubescens is typical of inland areas and higher altitudes whereas Q. virgiliana restricted to the coastal plain and the hilly belt. Seven pubescent oak populations distributed along an altitudinal transect in central Italy have been analyzed from a coenological, morphological and molecular point of view. The vegetation sampling was carried out using the phytosociological approach. Morphological variation of tree individuals was analyzed using 14 leaf traits, while leaf shape variation was investigated using the Procrustes ANOVA. Genetic analyses were carried out through twelve EST-SSRs markers. Results: only the leaf pubescence exhibited discriminating power among all the leaf morphological traits considered. Very low differences in the leaf-shape emerged from geometric morphometric analysis. Genetic analyses did not evidence statistically significant clusters. Bayesian analyses including data from genetically pure populations of Q. pubescens, Q. petraea and Q. frainetto assigned all the seven populations investigated to Q. pubescens. Neither the morphological nor the genetic results allowed to identify specimens attributable to Q. pubescens or Q. virgiliana nor to highlight a possible ecological-altitudinal vicariance between these two species.