Comparative Morphology of Leaf Epidermis in the Fern Genus Phymatopteris(Polypodiaceae)

Leaf epidermises of 24 taxa,representing 2 series and 5 subseries of the genus Phymatopteris(Polypodiaceae),were examined by light microscopy(LM)and scanning electron microscopy(SEM)to determine the systematically informative characters.The leaf epidermal cells were usually irregular in shape.The patterns of anticlinal walls were sinuolate,sinuous,and sinuate.The stomatal apparatus were restricted in abaxial epidermises for all species,and generally could be assigned to polocytic,copolocytic,coaxillocytic,axillocytic,and anomocytic types.Under SEM observation,the inner margin of the outer stomatal rim was often sinuous and seldom smooth.Strikingly tall,upright outer stomatal rims occurred in most species.The cuticular membrane of the leaf epidermis was sinuous and occasionally granular.Leaf epidermal features in Phymatopteris appeared to be constant within species,and thus could be used for distinguishing some species.The microcharacters of leaf epidermises(the patterns of anticlinal walls and the stomatal apparatus types)could not be used as evidence for the classification of the series and subseries in Phymatopteris.