旬河上、中游及邻区森林植被的区系组成特征

运用植物地理学的基本原理和方法，通过对秦岭坡旬河流域上、中游及其邻近地区森林植被区系组成野外调查资料的统计分析与研究，揭示出构成该地区森林植被的主要区系组成具如下基本特征：1）种子植物区系组成中，含属、种数较多的科多为主产温带地区的科。2）属地理成分的归纳表明，各类温带成分合计占77．5％，其中以北温带分布为主，占40．2％，其次为东亚分布成分，占15．3％。3）森林建群种及主要优势种多为生长与分布于中国东半壁的特有种或东亚分布种。上述特征显示出区系组成的总体温带基调。

General Features of Floristic Composition of Forest Vegetation in Upper and Middle Reaches of Xunhe River Basin and Adjacent Area

The principles and methods of plant geography have been applied in this paper to reveal the general features of floristic composition of forest vegetation in the upper and middle reaches of Xunhe River basin and its adjacent area on the southern side of Qinling Mountain through statistic analysis of field investigation data. The results show: 1) Of floristic composition of spermatophytes, families with more geneva and species are the ones mainly distributing in temperate zones. 2) The temperate geographic elements in the fegion totally up to 77.5%, of which the Northern Temperate takes 40.2% and Eastern Asia 15.3%. 3) Edificators and dominant species of forest are chiefly Endemic to China or Eastern Asia elements, both of which only distribute and grow in eastern part of China. Those features give a general impression of temperate folristic composition