中国种子植物特有属在秦岭的地理分布及其特征

THE GEOGRAPHICAL DISTRIBUTION AND FLORESTIC CHARAC TERISTICS OF GENERA ENDEMIC SPERMATOPHYTES TO CHINA IN QINLING

秦岭是中国种子植物特有属分布的一个重要北界,分布有36个中国特有属,它们具有起源古老,但也有相对年青成分,地理成分混杂,在现代地理分布格局上,呈现出与西南尤其四川的共有属数最多,华中次之,华北—东北最少。分布于秦岭的中国种子植物特有属具有明显的温带性特点。在水平分布上极不均匀,西端和南坡较东端和北坡属种为多,各特有属及其种类广布程度都很低。在垂直分布上,主要分布于中海拔地区。秦岭东、西两端在植物区系和中国种子植物特有属的分布上具有明显分异,南、北坡既有联系,又有差别,西端的“三江”流域(白龙江、白水江和嘉陵江)是分布于秦岭的中国种子植物特有属的避难所和向北迁移的主要路线之一。

Qinling situated in Central China, is an important distributional limit of endemic to China towards the north. There are 36 genera endemic Spermatophytesto China in Qinling range.Among them 14 are monotypic, 17 are oligotypic and 5 are polytypic ones. The former two types tabe a great part of the total and together make up more than 86.1%. Most of them are ancient-originated. Few are relatively young ones. The geographical elements of them are very complex aud varied. Concerning to the modern distributional pattern, it showes that Qinling has maxium genera endemic Spermatophytes to China common with Southwest China geographical group, especially with Sichuan province. The Central China geographical group (eg. Hubei province) is the second place and minimum with North China geographical group. The genera endermic Spermatophytes to China distributied in Qinling show obvious temperate charateristics. The horizontal distributions of them are very uneven. So far as the vertical distribution, most of them are concentated in intermediate altitude. The floristic characteristics and the distribution of genera endemic in Qinling are very different between east and west terminal. The reaches of the three rivers(Beilong Jiang, Beishui Jiang and Jialing Jiang) in west terminal is one of the most important refuges and migrating route stoward north of genera endemic Spermatophytes to China.