Abstract: With colourless nail polish, study on the stomatic distribution of outer epidermis in the young stem, aged stem and aged leaf sheath, and adaxial and abxial leaf epidermis of young and aged leaves in S. purpurea, Z. pendula and C. communis[WTBZ] was conducted. With computer, we compared the stomatic distribution of different organs, parts and whole from the three plants. The results showed that there are no significant difference within the stomatic distribution of outer epidermis of young and aged stem and aged leaf sheath in three plants; but there are significant or very significant difference within apex, middle and base of young and aged leaves. For the comparison of whole plant, only young stem has no significant different. There are difference within stomatic distribution of different organs of three plants in differnt genus of the same family, which related to their genetic facters and habitat condition. In the plant organs, the stomatic distribution characteristics of leaf epidermis may be taken as an evidence of plant classification. 