Abstract: The leaf lower epidermal characters of 17 species and 7 varieties of Polygonum sect.Cephalophilon in China were observed under light microscope(LM).Four main types of leaf lower epidermal micro-morphology could be recognized in the present paper:(1)The stomata are anomocytic;the shape of the leaf epidermal cells is irregular,and the anticlinal walls undulate or sinuate;(2)The stomata are non-typical anisocytic,rarely anomocytic;the shape of the leaf epidermal cells is polygonal or irregular,and the anticlinal walls straight,undulate to sinuate;(3)The stomata are paracytic;the shape of the epidermal cells is irregular,and the anticlinal walls sinuate;(4)The stomata are paracytic and non-typical anisocy-tic;the shape of the epidermal cells is irregular,and the anticlinal walls undulate.A new viewpoint of four new series which are series Palmatifolia,series Perennes,series Criopolitana,series Annui was proposed in this paper on the basis of the evidences from stomata type of leaf lower epidermis as well as gross morphology and habts.