Abstract: The morphological characters of leaves on₁₆ species in Cymbidium,Paphiopedilum and Dedrobium were investigated under SEM.There are different characters of epidermis on leaves in the three genera.The cells of upper and lower epidermis are rectangular and the surfaces of cells are glandular protrusions in Cymbidium.The cells of ventral and dorsal epidermises in leaves are polygonal both in Dendrobium and Paphiopedilum.Papillae or protrusions occur on surfaces of the ventral epidermal cells in Paphiopedilum,/i>.But the surfaces of ventral epidermal cells are flat without ornamentation in Dendrobium.Palisade tissue is absent in the leaf mesophyll of species investigated in Cymbidium and Dendrobium.It is also absent in that of species with green leaves, but present in that of species with white streaks or spots at leaf adacial surface in Paphiopedilum.