北京山区与城区植物组成比较

Comparison of plant composition between mountainous area and city zone in Beijing

通过典型抽样法对北京山区与城区植物物种进行了调查,结果表明北京山区有植物种1283种,隶属于127科,538属,北京城区(五环内)共有维管束植物99科,307属,536种。含25种以上的科的数量在北京山区和城区都比较少,含5种以下的科的数量在北京山区和城区都比较多,而城区只含有1种植物的科要比山区多一些。植物种在属上的分布与其在科上的分布相似。城区植物中乔木、灌木和多年生草本和一年生草本的比例相差不大,而在山区,多年生草本植物优势极为明显,也是山区和城区植物种数差异的主要来源。在属级水平上,植物区系中温带成分在北京山区和城区均占有绝对优势,二者的差异主要表现在城区植物的热带成分明显高于山区,而温带成分的比例则要稍低于山区。山区和城区共有植物有329种,隶属于72科,201属。主要集中在菊科、禾本科、蔷薇科等世界性大科中。

The plants were investigated with the representative sample in the mountainous area and city zone of Beijing. There are 1 283 species belonging to 127 families,538 genera in the mountalns,and 536 species belonging to 99 families,307 genera in the city zone of Beijing. The amount of families over 25 species is less than those under 5 spedes in both areas,and the families with 1species is more in the city zone than in the mountains. The distribution of species in genera is similar to that in the families. The-proportion of life-form of all plants in the city zone is similar to that in the mountains, while the proportion of the amount of perennial herbs is dominant in the mountains,which is led to the significant difference of the amount of species between the mountains and the city zone. The areal-type of temperate distribution is dominant in both the mountains and the city zone in genera level, the difference is the proportion of tropic distribution is higher,and the proportion of temperate distribution is lower in the city zone than those in the mountains. There are 329 species, belonging to 72 families and 201 genera,in both the mountains and the city zone, and most of them belong to several cosmopolitan families such as Composita, Gramineae, Rosaeeae.