Leaf architecture in Quercus subgenus Cyclobalanopsis (Fagaceae) from China

Leaves of 46 species of Quercus subgenus Cyclobalanopsis were studied. A comprehensive description of leaf architecture for subgenus Cyclobalanopsis is provided. Ten leaf architectural characters were examined, including leaf venation type, tooth type, areoles, veinlets and marginal ultimate venation. Four types of venation pattern and three types of teeth are recognized. Evolutionary trends of some leaf architectural features, e.g. venation pattern, tooth type, tertiary veins, areoles and veinlets, are suggested. Based on the comparison of leaf architecture of subgenus Cyclobalanopsis, subgenus Quercus and Trigonobalanus doichangensis, we support the taxonomic treatment of Cyclobalanopsis as a subgenus of Quercus and speculate that subgenus Cyclobalanopsis is relatively primitive within the genus Quercus.