Abstract: The leaf abaxial epidermis structures of 15 species and 1 variety of the genus Cyperus Linnaeus from Hainan were studied under light microscope. The results showed that (1) the leaf micro-morphological characteristic is as follows: the shape of long-cells long tubular or short tubular, rarely sub-tetragonal, the margin of cell walls sinuosity and deeply sinuosity; short cells in absence; stomatal subsidiary cells tall dome-shaped, dome-shaped, triangular, dome-shaped to triangular; (2) on the basis of guard cells, Cyperus from Hainan could be divided into two types: both sides obviously thickening and not obviously thickening; (3) the micro-morphology of leaf abaxial epidermis structures of Cyperus from Hainan was consistent, indicating the genus Cyperus is a natural group. However, different characteristics existed among species, including the shape of long-cells, length/width of stomata, the shape of guard cells and the shape of subsidiary cells, which could be used for the taxonomy of the genus at the species level.

Key words: Cyperus, leaf epidermis, micro-morphology, Hainan