Abstract: Leaf epidermis of 9 species and 1 variety of Sisymbium was investigated using light microscopy(LM). The main conclusions are as follows: The cells of the upper epidermis are usually polygonal, and the patterns of anticlinal walls are straight or arched, few slightly sinuolate. The cells of the lower epidermis are usually irregular and the patterns of anticlinal walls are sinuous or sinuate. The type of stomatal apparatuses is mainly anisocytic, rarely anomocytic and only occasionally paracytic. According to the leaf epidermal characters, the genus Sisymbrium from China can be divided into three types: (1) The upper epidermis has no or very few stomatal apparatuses. (2)The stomatal apparatuses of upper epidermis are usually gathered with 3 or 5 or arranged in short rows，and the stomatal density is less than that of the lower epidermis. (3) The stomatal apparatuses of upper epidermis are regularly dispersed, and the stomatal density is similar to that of lower epidermis.Leaf epidermis of 9 species and 1 variety of Sisymbium was investigated using light microscopy(LM). The main conclusions are as follows: The cells of the upper epidermis are usually polygonal, and the patterns of anticlinal walls are straight or arched, few slightly sinuolate. The cells of the lower epidermis are usually irregular and the patterns of anticlinal walls are sinuous or sinuate. The type of stomatal apparatuses is mainly anisocytic, rarely anomocytic and only occasionally paracytic. According to the leaf epidermal characters, the genus Sisymbrium from China can be divided into three types: (1) The upper epidermis has no or very few stomatal apparatuses. (2)The stomatal apparatuses of upper epidermis are usually gathered with 3 or 5 or arranged in short rows，and the stomatal density is less than that of the lower epidermis. (3) The stomatal apparatuses of upper epidermis are regularly dispersed, and the stomatal density is similar to that of lower epidermis.

Key words: Sisymbrium, Brassicaceae, leaf epidermis, China