神农架蕨类植物科的区系地理分析

A Monographic Study on Families of Pteridophytes in Shennongjia

运用经典的方法 ,从科这一等级上对神农架蕨类植物进行了区系地理学 (包括科、属和种类组成 ,区系起源 ,地理成分特点及其与其他区系之间的关系等 )研究 .结果表明 ,神农架蕨类植物种类十分丰富 ,共有 30 8种 ,隶属 34科、75属 ,其中鳞毛蕨科 (5属 74种 )、水龙骨科 (1 2属 5 3种 )、蹄盖蕨科 (8属 37种 )属种优势明显 ,3科种数共占 5 3.2 % ,代表了该地区蕨类植物区系的一个重要特征 ,可作为不同区系相似性的一个重要参考指标 ;区系起源古老 ,但次生成分突出 ,蕨类植物科演化呈现两极分化 ;地理成分复杂 ,相互交错 ,但以亚热带成分为主 (共有 1 7科、43属、1 80种 ,分别占总科、属、种数的 5 0 % ,5 7.3% ,5 8.4% ) ,温带成分也占有较大的比重 ,还有一定数量的热带成分 ,这表明成分具有多样性并具有热带亲缘性 ,表明神农架地区是南部热带、亚热带与北部温带的过渡地带 ,是联系中国—喜马拉雅和中国—日本区系的桥梁 ,是多种区系成分的集中地和扩散中心或亚中心 ;三大科所占的比例与西南区的相似率大于与华中区的相似率 。

Monographic studies on the families of pteridophytes of Shennongjia Mountains in the Western part of Hubei Province were made. It is a preliminary research on the Floristic phylogeographics at the level of families(incl. Families as well as genus and species composition,florogenesis, phylogeographyic comparison of pteridophyte,and the relationships between this flora and some other ones ) .The results are as follows:This region is abundant in pteridophytes including 308 species,34 families,75 genera.Among them Dryopteridaceae(5 genera,74 species),Polyodiaceae(12 genera,53 species) and Athyriaceae(8 genera,37 species),occupying 53.2% of all the pteridophytes are dominant and have a large number of genera and species in this fern flora.The high proportion of species can stand for the important feature of some fern flora, and can be seen as a important reference of the fern floristic coefficient of similarity. The flora which originated anciently has a large number of new born elements ,and the phytogeographic components are complex and inter located,but the majority of them are the subtropical elements including 17 families,43 genera,180 species,which are 50%,57.3% and 58.4% of all its kind respectively, as well as a lot of temperate ones and some tropical ones.This shows that the fern flora is diverse in composition and tropic relative. This also shows that flora is a tie of fern flora between Sino Himalayas and Sino Japan, the transition region from subtropical elements to temperate ones, the convergence of distribution and the center or sub center of transfer. It is the east margin of the fern flora of Southwest China,because the coefficient with the Southwest China is higher than that with Central China.