Abstract: The leaf epidermis of 11 species belonging to 6 genera in Lactuceae(Compositae) was investigated using light microscopy. Morphological characters of leaf epidermis, such as the shape of leaf epidermal cells, patterns of anticlinal wall, stomatal type and distribution, are of important taxonomic significance. The results show that the shape of epidermal cell is irregular, and rarely polygonal; the patterns of anticlinal walls are sinuolate or sinuate, and rarely straight; the stomatal apparatus, which are randomly distributed, only exist in the abaxial epidermis for a few species, but for others, they occur in adaxial and abaxial epidermis simultaneously. All the stomatal apparatuses fall into anomocytic type. In a certain extent, leaf epidermal characters reflect the relationship among or between the taxa, thus providing new evidence for taxonomy of Lactuceae.

Key words: Compositae, Lactuceae, leaf epidermis, morphological characters, taxonomic significance