Abstract: The studies on the leaf epidermal characters of Podocarpus macrophyllus and 6 species belong to Pseudolarix Gord, Cedrus Trew, Pinus Linn were conducted with scanning electron microscope(SEM). Under the SEM, we can find that in all species observed, the outer surface of leaf is covered with a cuticle and epicuticular waxes. In Pseudolarix amabilis, the stoma threads are located on the adaxial epidermis of leaves, and the epidermal cells are quite different between its upper and lower epidermis. Stoma threads are located on each epidermis in Cedrus deodara, the stoma are rounded smooth cuticle. In Pinus parviflora, stoma threads are only located on the abaxial epidermis, and its stomata are stand out of the epidermis. In Pinus massoniana, Pinus thunbergii and Pinus elliottii, the stoma threads are located on both abaxial and adaxial epidermis. The results showed that there are some differences including the structure and morphology of leaf epidermis and the distribution characteristics of the stomata apparatus, they proved that the division of three genera was natural.

Key words: Pinaceae, leaf epidermis, stomata apparatus, SEM