The morphological characteristics of the glumes and lemmas of Alopecurus including seven species from China were observed under scanning electron microscopy. The results showed that: (1) The glume micromorphological feature of Alopecurus was characterized by longtubular long cells with undulated wall, reniform or round short cells, sparse or abundant or lacking stomata, frequent or rare crown cells, common or rare prickle cells, elliptic or round silica cells. Presence, distribution of crown cell and stomata and prickle cells varied greatly among speices of Alopecurus. (2) The lemma morphology of Alopecurus was characterized by longtubular or shorttubular long cells with undulated wall, elliptic or rectangular round short cells, frequent or lacking stomata, frequent prickle cells, elliptic or round or rectangular silica cells, common or sparse crown cells. The lemma morphology of Alopecurus varied in presence or absence of short cells and stomata, shapes of silica cells. (3) The morphology of lemma and glume was conducted by UPGMA analysis. Two major clades were formed in the tree. Clade Ⅰ included A. aequalis, A. longiaristatus and A. japonicus, clade Ⅱ included A. arundinaceus, A. pratensis, A. brachystachyus and A. myosuroides. A key of Alopecurus on the basis of glume and lemma micromorphology was presrent. The glume and lemma morphology could provide for classification of the genus Alopecurus. Moreover, the type division based on the glume and lemma morphology was mainly congruent with sections according to external morphology except Alopecurus brachystachyus. The glume and lemma morphology indicated A.brachystachyus should be ascribed to sect. Alopecurus.