Abstract: Up to now, a lot of papers on the epidermal structures of ferns have been published in the world. But in China, few people have paid attention to this work. The epidermal structures of three species, Bot rypus strictus, Sceptridium daucifolium and Botrychium lunaria, are studied by the observation with optical and scanning electronic microscopy. The description comprises the cuticle thickness, the epidermal cells, the distributions of stomata, the stomatal orientation, structures, types, frequencies and index etc.. They have common characteristics in the stomatal orientation and types, but are different in the epidermal cells, the stomatal distribution, size, frequencies, index etc. The study presents new evidences to the identification of the three species.The main diagnoses of the epidermal structures of the three species are as follows： (1) Botrypus strictus: The epidermal cell wall wavy or deeply sinuous. Sto mata confined to the lower epidermis and scattered in the interveins and on the veins. Some of the stomata closely situated and the guard cells contacted with each other. Stomata elliptical in shape with their long axes parallel to the lamina or the veins. The stoma consisting of two lens_like guard cells, 44～53 μm×11～17 μm in size, with smooth inner and outer periclinal walls. 6～7(occationally 8 or 9) neighbouring cells sur-rounding each stoma. 32～35 stomata in each mm2. Stomatal index 5.6. (2) Sceptridium dauci-folium: The epidermal cell wall straight. Stomata confined to the lower epidermis, scattered in the interveins. Stomata anomocytic, narrowly elliptical in shape, with their long axes parallell to the lamina or veins. Guard cells reniformis in shape and 76～95 μm×17～23 μm in size, with concentric stripes on the inner surface of outer periclinal wall. 6～8(occationally up to 9) neighbouring cells surrounding each stoma. 14～19 stomata in each mm2. Stomatal index 6.7～7.2. (3) Botrychium lunaria: The epidermal cell wall straight. Stomata distributed on the upper and lower epidermis, scattered. The stamata anomocytic, elliptical to round in shape, with their long axes parallel to the lamina or veins. Guard cells reniformis in shape, 48～65 μm×15～23 μm in size with concentric stripes on the outer and inner surfaces of outer periclinal wall. 5～7 (mostly 6) neighbouring cells surrounding each stoma. 23～29 stomata in each mm2. Stomatal index 6.7.