西双版纳石灰岩山地森林蕨类区系的初步研究

西双版纳位于云南南部，与老挝及缅甸接壤。根据调查，现已知西双版纳石灰岩山地森林中蕨类区系有蕨类植物１２７种（包括变种），隶属于２４个科，５４个属，在该蕨类区系中，最大的科分别是水龙骨科，凤尾蕨科，铁角蕨科，铁线蕨科及三叉蕨科；最大的属分别为凤尾蕨属，铁角蕨属，铁线蕨属，石韦属及毛蕨属，该地蕨区系具有东南亚热带的性质，其分布区类型的组成是，热带分布或主产热带的科占总科数的７０％以上，热带分布的属占总

A PRELIMINARY STUDY ON THE PTERIDOFLORA IN XISHUANGBANNA LIMESTONE FOREST

Xishuangbanna is situated in the southern part of Yunnan Province and is contiguous to Loas and Burma. Accoding to the investigation and grasped data, up to now, 24 families, 52 genera and 127 species (include varieties) of Pteridophytes have been recorded in Xishuangbanna limestone forest. In which,the largest families and genera are Polypodiaceae,Pteridaceae,Aspleniaceae, Adiantaceae,Aspidiaceae and Pteris,Asplenium. Adiantum,Pyrrosia,Cyclosorus. Acording to the results of floristic analysis.this Pteridoflora has the tropical character of SE Asia. In the floristic composition of this forest the families of tropics and mainly tropics distribution make up 70% of the total families;the genera of tropics distribution make up 80% of the total,and the genera of tropics Asia make up 33. 3% of the total. Though the Pteridoflora in Xishuangbanna limestone hills have certain relationship with those of Guangdong and Guangxi,the coefficient of similarity is only 0. 32 on species;and many Pteridoflora components are occured in southwestern China,southern China or SE Asia of tropical Asia. There are no endemic families,genera and species in limestone hills of Xishuangbanna.