重庆地区蕨类植物区系的初步研究

对重庆地区蕨类植物从科、属分布区类型进行了统计分析,同时将该区区系特征与其它几个地区进行了对比分析.结果表明:(1)该区共有蕨类植物389种(含变种和变型),隶属于109属,43科.(2)该区蕨类植物中优势科、属十分明显,其中优势科为:鳞毛蕨科、金星蕨科、水龙骨科、蹄盖蕨科、凤尾蕨科;优势属为鳞毛蕨属、耳蕨属、凤尾蕨属、铁角蕨属、卷柏属、凤丫蕨属.(3)从蕨类植物科、属分布区类型的所占比例来看,该地区区系性质以热带成分占优势,其中热带分布科22科,占总科数的75.00%;热带分布属有60属,占总属数的64.52%(剔除世界分布).(4)本区区系成分古老,古老孑遗的科属较为丰富,但特有现象不明显.(5)该区地形、气候条件对于蕨类植物的散布和充分发育比较适宜,为其在该区的充分发育创造了极为有力的条件.(6)经对比分析和聚类分析表明:该区与临近的几个地区属的相似性系数很高,特别是与西南地区的西藏、横断山区的属相似性系数较大,表明区系上与这些地区有着广泛的联系;而与华北的内蒙古,东北的辽宁等相距较远的地区属的相似性系数较低,表明区系上联系较为疏远.

A preliminary study on the pteridophytes flora in Chongqing

The paper report the floristic components and geographical distribution of the pteridophyte in Chongqing. The statistics and analysis of the pteridophytes floristic composition and geographical elements between Chongqing city and other regions are also discussed, the results indicate as follow:(1)It is now known that there are 389 species (including varieties) of fern in Chongqing city,which belong to 109 genera and 43 families.(2)The dominant families and genera are prominent.The dominant families are Dryopteridaceae, Thelypteridaceae, Polypodiaceae, Athyriaceae, Pteridaceae; The dominant genera are Dryopteris Adens, Polystichum Roth., Pteris L., Asplenium L., Lycopodioides Boehm., Coniogramme Fee. (3)The flora of pteridophyte in Chongqing has typical characteristics of tropic distribution compositions.There are 22 tropic families in the area which account for 75.00% of overall families; There are 60 tropic genus in the area which account for 64.52% of overall genus(% excepting the families of cosmopolitan). (4)The flora are ancient origin and complex in geographical, the ancient families and genus are abundant, but endemic families and genus are scare.(5)The pteridophyte get great development and far distance distribution because of the advantageous climax and landforms in the area.(6)Comparative and clustering analysis can clearly reflect the differences of flora,the result indicate the region are much more closely allied to Tibet, Hengduan Mountains and East of China than to Intramongolica and Liaoning province in flora.