Leaf epidermal morphology in Peucedanum L. (Umbelliferae) from China

Leaf epidermal characters of 21 species representing four sections of Peucedanum (Apiaceae) were investigated using light microscopy and scanning electron microscopy. The stomata were anisocytic, anomocytic or staurocytic and existed on the abaxial epidermis in all the species examined, and on both surfaces in 12 species. The leaf epidermal cells were usually irregular or polygonal in shape, with anticlinal walls straight to arched, repand or sinuous. Under scanning electron microscopy, the inner margin of the outer stomatal rim was nearly smooth or sinuolate to erose, and the cuticular membrane of the leaf epidermis was striate, ridged, wrinkled or smooth. Few epidermal characters were relatively constant at section level, indicating that the traditional subdivision system for Peucedanum might be unnatural, and needs to be adjusted. Evidence from leaf epidermis, like that from molecular data, suggests that P. terebinthaceum should be separated from Peucedanum. Furthermore, results from epidermal analysis also suggest that P. wulongense should be treated in the same section with P. dissolutum, whereas P. violaceum should be transferred to section Elegantia.