Structural Characteristics of Leaf Epidermis and Their Systematic Significance in Davalliaceae

Because the classification in Davalliaceae is significantly controversial, we observed for the first time the leaf epidermis of 39 species representing six genera of Davalliaceae in the classification system of Ching RC using scanning electron microscopy (SEM). Results showed that Davalliaceae had nine types of cuticular layer. Humata had dense pinhole structures; Wibelia had thick projections in stripes, which were orderly arranged, fine and compact; Davallodes had many types of cuticular layers, and required further subdivision under the genus. Our research also examined the relationship among many relative species on the basis of cuticular layer characteristics, which could be used among and below genera for classification in Davalliaceae.However, both the shape of guard cells and stomatal density could not be used for classification of genera and species in Davalliaceae. Our classification is consistent with that of molecular systematics by Kato & Tsutsumi.