Abstract: As one of the regions in China abundant in pteridophytes, Sichuan including Chongqing comprises ca. 880 species of ferns and fern allies, belonging to 52 families and 141 genera in accordance with Ching’s (1978) systems, Dryopteridaceae, Athyriaceae and Polypodiaceae with 192, 133 and 119 species respectively, are the three most important families, contributing 50.5% of the total species in this region. They are followed by Thelypteridaceae, Sinopteridaceae, Aspleniaceae, Pteridaceae, Selaginellaceae, and Hemionitidaceae, with more than 20 species each. Polystichum Roth, Dryopteris Adans. and Athyrium Roth are the biggest three genera in this region, with 86, 62 and 53 species recognized respectively and accounting for 22.8% of total species, followed by Asplenium L., Lepisorus (J. Sm.) Ching, Cyclosorus Link, Pteris L., Allantodia R. Br., Selaginella Beauv. and Phymatopsis J. Sm., with more than 20 species each, while nearly 85% of the genera have less than 10 species in this region. The genera in this region can fall into 13 distribution patterns and in summary they are composed of five floristic components. The tropical genera constitute 53.9%, but their values of floristic presence (VFP) are relatively low; the East Asia genera 16.3%, and some of them have quite high VFP. The other three components are cosmopolitan (12.1%), temperate (12.7%) and Chinese endemics (5.0%). There is no endemic family, and Cystoathyrium Ching is locally endemic of the seven Chinese endemic genera in this region. The Chinese endemic species summed up to 387 and account for nearly 44% of the total number of species in this region. For these endemic species, 32% are endemic to Sichuan including Chongqing; the others are mainly shared with southwest China (22.5%) and the whole part of southern China (26.1%). There are 10 species of pteridophytes are included in the first checklist of Chinese protective rare and endangered plants, of which 3 species are grade I and 7 species grade II. Further studies are necessary to understand the intra-regional floristic differentiations and to compare the floristic components with other regions.

Key words: floristic composition, pteridophyte, endemism