Abstract:Hedysarum scoparium is a common xerophytic shrub of Papilionaceae, found in Shapetou region in the south-eastern part of Tengeli desert. (1) The xeromorphism of Hedysarum scoparium is shown by the following characteristics.Large reticulat water-storing tissue is only found on the abaxial sides of the leaf when section paralled to the leaf surface are examined.The water-storing tissue is between the epidermis on the abaxial side and the palisade tissue.In cross-section,cells of the water-storing tissue are round or oblate and separated or only slightly attached to one another, while in section parallel to the leaf surface,these cells are seen to be reticulat.In addition,below epidermis of the adaxial surface or between the mesophyll cells are large cylindrical or conical idioblasts.Water contained in the reticulat water-storing tissue and the idioblasts may check the passage of water. (2) The special pattern of the time course of transpiration observed in this plant is considered as an adaptive evidence for withstanding condition unfavourable to stomatal behavior or transpiration,by increasing income and decreasing expenditure of water. (3) Physiologically,Hedysarum scoparium showed high osmotic pressure, and high bound and free water ratio.This may be due to the high tanning content of the large idioblasts and the reticulat water-storing tissue,its drought resistance is,therefor,evidently increased.