Abstract: There are only two species in Stipagrostis in Xinjiang, i.e. S. grandiglumiss and S. pennata. They can survive in deserts because of their adaptability to desert environment. In this study, the micro-morphological features of plant leaves of these two species were observed with an optical microscope, and their anatomical structures were compared. The results show that the structure of leaves of the two species is typical and adaptable to desert environment. The thickness of epidermis of their leaves is different, there is thorn hair over the upper epidermis of their leaves, and the outer wall of epidermis cells is thicker than the inner ones. The character of epidermis cell, type of stoma apparatus, shape and number of vascular bundle of midrib are all quite different. These differences of micro-morphological features might do some favors for studying the classification of Stipagrostis Nees. The type of stoma of S. pennata is hardly round or triangle and quite pristine, but S. grandiglumis is mostly round and evolutional. Moreover, S. pennata survives in north Xinjiang, while S. grandiglumis in south Xinjiang. The length and the shape of the tubercles are also distinctive because of the different species and environment. The tubercle of S. pennata is round, whereas S. grandiglumis is acuate. These traits are not only related to their different species but also consisted in their different entironment.

Key words: Stipagrostis grandiglumis, Stipagrostis pennata, leaf, anatomical structure, drought resistance, Xinjiang