Abstract: The Cycas community is certainly a more primitive and ancient vegetation type in tropical and subtropical zones, but so far as inland Eurasia is concerned, it may extend to the boundary of Yunnan and Sichuan province, and make the most northern border line by itself. This paper deals with the natural community characters of Cycas panzhihuaensis which has been remained in moun- tain valley of Dukou City, Close to Jinsha River, at N.latitudes between 26°36′- 26°39′, E. longitudes between 101°33′,--101°35′. With a total area about 310 hectares, this community is dispersed over there, occupying the altitude 1100- 2000 m above sea level. Its habitat is a limestone mountain covered with dry open woodlands, that has resulted under a river valley climate with long dry and hot seasons (Nov.-May), spreading largely to the repeated firing, gra- zing, and shifting cultivation.

Key words: Valley of Jinsha River

摘要： 近年在金沙江干热河谷及其邻近地区陆续发现的苏铁天然植物群落，为本属植物在欧亚大陆内陆分布的最北边缘。其中，面积最大和保存较好的是渡口市攀枝花苏铁(Cycas panzhihuaensis）植物群落。本文研究了这个群落的分布与生境、生长状况、外貌、种类组成以及群落的综合特征等。认为具有稀树草原的特点，而这里的稀树草原是次生性质的，苏铁群落是其中幸存的残遗植被类型。这对研究我国植物地理有着重要意义。

关键词: 金沙江河谷, 苏铁群落