Abstract: The upper laminal cell morphology of 17 genus of the family Pottiaceae were observed by light microscope (LM) and scanning electron microscope (SEM). The results show that the upper laminal cells of Pottiaceae have large similarity in cell shape, size and surface characteristic. According to its surficial characteristic, cells of Pottiaceae can be divided into three types: smooth or mammillae, hemispherical papillose and dichotomous horseshoe papillose. In addition, there are distinctive differentiations among different genus and species. The conclusion is drawn that leaf cell morphological characteristics can provide evidence for Pottiaceae on the delimitation of genus and subfamily.

Key words: Pottiaceae, leaf cell morphology, systematic significance