AN ANATOMICAL STUDY ON XEROMORPHIC STRUCTURES OF PEGANUM IN NORTHWEST CHINA The Xeromorphic and Saline Morphic Structure of Leaves and Assimilating Branches in Ten Chenopodiacea Species in Xinjiang Xeromorphic Characters in the Vegetative Organs of Peqanum harmala AN ANATOMICAL STUDY ON XEROMORPHIC STRUCTURES OF THE PSAMMOPHYTES IN XINJIANG Comparative Studies on Water Relations and Xeromorphic Structures of Some Plant Species in the Middle Part of the Desert Zone in China A COMPARATIVE ANATOMY OF DIFFERENT POPULATIONS ON APOCYNUM VENETUM AND POACYNUM HENDERSONII