Arasbaran, a protected region of Iran contains a large variety of bio diversity, some of them on the endangered lost. This paper introduces an anatomical-structural study and its relation with ecological, systematic characters of some 400 rare species in a very valuable protected area, named Arasbaran. This mountainous region was designated as a protected area in 1971. It is about 72465 hectares, and encompasses a variety of natural features, such as high mountains, deep valleys, sharp slopes, dense forests and vast rangeland, indicating a very rich environmental diversity. The altitude variations are between 450 to 2841 meters. The average temperature in February and August are 1.8 and 25C respectively. The annual precipitation is around 450-500 mm. (semi-humid zone). In the Arasbaran protected area, some 785 plant species have been recognized so far. Research on adaptive characters has been directed mainly towards leaves. Given the importance of foliar anatomy on ecological development in environment, systematic efforts are required for research and investigation of the maximum number of species possible. Some 400 samples from various ecological situations and different altitudes have been collected representing some 60 families, including: Compositae, Caryophyllaceae, Papilionaceae, Chenopodiaceae, Labiateae, Liliaceae, Rosaceae, Boraginaceae, Rhammnaceae , Anacardiaceae, Cruciferae, Malvaceae, Umbelliferae, Zygophyllaceae. Structural and anatomical studies were conducted to compare anatomical characters of similar families in different ecological conditions and observe the impact of ecological factors on the structure of the plant. From the systematics point of view, this work led to recognition of certain unknown or incorrectly known species in some cases. From the ecological and protection point of view, this study has contributed to the recognition of some elements, which have impact on rare and endangered species. This paper presents proposals for future analysis and plans for the management of the ecosystem.

Key words: Arasbaran protected region, drought adaptation, Iran, rare species