Anatomical and external characters of stem and leaf of the genus Cyperus of Korea were examined. The epidermal patterns of leaf were investigated by a scanning electron microscope (SEM) and a light microscope (LM). Morphological characters (length and width of stem, leaf, leaf sheath) and anatomical characters (transectional shape of the stem and leaf, the number and shape of sclerenchyma strands in leaf, presence/absence of bulliform cells in the midrib and air cavity, circumvascular sclerenchyma, vascular bundles in stem and epidermal patterns were useful for an identification and of the selected taxa. Cyperus orthostachyus A type, C. orthostachyus B type and C. orthostachyus C type were differentiated on the basis of the shape of subsidiary cell, the number of silica body, the number of vascular bundles and their pattern of arrangement in the leaf. Although C, iria was similar to C. amuricus and C. microiria in morphological characters in spikelet, number of stigma, those could be distinguishable on the basis of the number of silica body, arrangement of sclerenchyma strands and vascular bundles in the leaf. Similarily it was difficult to tell C. rotundus from C. haspan in shape of inflorescence, spikelet, scale, achene and number of stigma, but C. rotundus was smaller than C. haspan in the number of vascular bundles and sclerenchyma strands, intercostal cell rows.