Microhistological characterisation of some species of the genus Quercus L. from Sierra Morena range (southern Iberian Peninsula)

The micromorphological characters of leaves in the genus Quercus have proved very useful in their taxonomy. A microhistological study of the most representative species of the genus Quercus in the eastern part of Sierra Morena (southern Iberian Peninsula) is carried out in this work: Q. coccifera, Q. faginea subsp. faginea, Q. pyrenaica, Q. rotundifolia and Q. suber. The leaves microcharacters were studied, measured, photographed and compared in order to provide a good description by optical microscope. In particular, features related to trichomes, stomata and epidermal cells on adaxial and abaxial leaf surface have been used. The data for 21 variables were collected. Our study confirms the usefulness of the micromorphological characters of the leaf epidermis and optical microscopy to distinguish between Quercus species, and has helped to identify the studied species. Some of the species can be identified by a single diagnostic character, and others by a combination of few characters. Based on the set of analyzed characteristics, a dichotomy key for the differentiation of the five taxa studied in this work is proposed.