Abstract:The micro-morphological characteristics of leaf epidermises of the major species of sect. Racemosus, sect. Leymus and sect. Anisopyrum in Leymus from China were examined by manual scraping method. The result showed that: (1)The leaf epidermis consists of long cell, stomatal cell, short cell and prickle hair. It belongs to the typical festucoid type. Meanwhile, there are also obvious differences existing on the anatomical characteristics of leaf epidermises including length and width of long-cells, magnitude and distribution of stomatal apparatus, shape of subsidiary-cells, abundance and growing form of prickle-hairs, etc. (2)According to the evolutionary trends of leaf epidermal characteristics of three sections, their evolutionary positions and relationships were inferred. The results show that the sect. Racemosus is the most primitive one among three sections, the sect. Leymus is slightly more advanced than the former, and the sect. Anisopyrum is the most advanced of them. The sect. Racemosus might produce immediately the sect. Leymus, whereas the sect. Anisopyrum might derive immediately form the sect. Leymus. The biosystematic relationships of these three sections are corroborated by the evolutionary trend of external morphology.