Abstract:In order to solve the taxonomic problems of Orchidaceae Pleione and explore the significance of leaf ultrastructure in taxonomy, this study uses scanning electron microscopy to mature 15 species of Pleione 15 leaf epidermal ultra-features such as cell boundaries, cuticle and stomatal apparatus’ restrict and et al, to determine their taxonomic significance. (1) Cell boundaries, epidermal cell wax quality, stratum corneum texture, stomatal distribution, wax around the stomatal, inner edge of the outer arch of the stomatal, keratinization, relative height of the stomatal, epidermal cell length, epidermal cell area and guard cell length the nine indicators of guard cell area are of great value and significance for the classification of this genus. (2) The above characteristics are used to further refine the intra-group differentiation of S. Humiles and S. Pleione and P. bulbocodioides complex. (3) P. jinhuanaT has lots of blocky wax around the stomata, P. maculate has lots of scab wax around the stomata, and P. saxicola has lots of granular wax around the stomata, these are special phenomena in Pleione. (4) Both upper and lower epidermis have stoma, which is more primitive, and the epidermal stomata of the genus Pleione are gradually degrading. (5) The epidermal cell is smaller, the stoma is smaller, and it is more adaptable to the environment. (6) The stomatal apparatus of P. formosana was more sagging, so it more adaptable to drought conditions. (7) P. scopulorum is probably the most primitive species and P. saxicola may be a more primitive species in 15 species of Pleione. (8) The cluster analysis clustered 15 species of Pleione into four branches, which is basically consistent with the results of traditional taxonomy and molecular systematics. (9) Based on the results, it is speculated that branch IV is the most primitive and branch III is the more primitive.