中文摘要：

运用植物学及植物地理学方法，结合野外实地调查，对黑河中游湿地植物区系组成、地理成分、生态特征和物种多样性进行了分析。结果表明：黑河中游湿地共有84种植物，隶属于32科70属，其中，菊科、禾本科的种类最多，占所有植物种类的29．8％；植物区系地理成分多样，温带分布型是主要组成部分；黑河中游湿地草本植物占数量优势，以多年生为主。双向指示种分析法（TWINSPAN）将42个湿地样方划分为10个群落，不同植物群落类型的物种多样性指数均较低，且存在较大差异；以重要值计算的Margalef丰富度指数（Rm）介于0．344～1．202，Simpson多样性指数（D）介于0-0．840，Shannon多样性指数（H）介于0～1．999，Pielou均匀度指数（J）在0．712～1．0，表明了黑河中游湿地植物群落的结构简单、组织水平低。

英文摘要：

By using the methods of botany and phytogeography, in combining with field investiga- tion, this paper studied the wetland flora composition, geographical elements, ecological charac- teristics, and species diversity in the middle reaches of Heihe River, Northwest China. A total of 84 plant species were recorded, belonging to 70 genera and 32 families. The species of Composi- tae and Gramineae were dominant, occupying 29.8% of the total. The geographic elements of the flora were of multiplicity, most of which embodied the feature of temperate zone. Herbs had the numerical advantage, and perennial herbs were the main component. By using two-way indi- cator species analysis （TWINSPAN）, the vegetation in 42 sampling plots could be classified into 10 communities. The species diversity indices of the communities were relatively low, but had large differences among each other. According to the importance value, the Margalef richness in- dex （Rm） ranged from 0. 344 to 1. 202, Simpson diversity index （D） was between 0 and 0. 840, Shannon diversity index （H） ranged from 0 to 1. 999, and Pielou evenness index （J） was within the range of 0. 712-1.0, indicating that the structure of the wetland plant communities in the middle reaches of Heihe River was relatively simple.