Abstract:Leaf epidermis of 17 species and 2 varieties of Calamus was oberserved under light microscope. The species studied are all reported for the first time, except C. simplicifolius, C. egregius and C. tetradactylus. The leaf epidermal structure of Calamus L. （Palmae） is of the same type： the stomatas are tetracytic with 4 subsidiary cells in which 2 are terminal and 2 lateral. The epidermal cells are oblong, longitudinally extended. There are 3 kinds of trichomes： single hair, multicellular, in single file （C. macrorrhynchus） ; single hair, multicellular, in 2-3 files （C. thysanolepis etc. ） ; ramose hair （C. tetradac tylus etc.）. The length and width of epidermis cells, the thickenss, undulatory depth and shape of cell wall, and the character of terminal subsidiary cells are different among species. Leaf epidermal morphology may verify the relationships of Calamus species and is of significance for classification and systematics of Calamus.