四川及重庆蕨类植物区系组成、特有现象和珍稀种类

FLORISTIC COMPOSITION, ENDEMISM, AND RARE AND ENDANGERED SPECIES OF PTERIDOPHYTES IN SICHUAN INCLUDING CHONGQING, SOUTHWESTERN CHINA

四川及重庆为我国蕨类植物最丰富的区域之一,总计有52科,141属,约880种。鳞毛蕨科、蹄盖蕨科和水龙骨科是最重要的3个科,其种数占本区种数的50.5％,金星蕨科、中国蕨科和铁角蕨科在本区也有较多的种类分布。在本区主要的属为耳蕨属、鳞毛蕨属和蹄盖蕨属,它们的种数都超过50种,合计占本区种数的22.8％,其次有铁角蕨属、瓦韦属和毛蕨属,其种数都逾25种,而有近85％的属不足10种。热带成分的属在本区占53.9％,但它们的区系存在度不大;东亚分布的属占16.3％,其区系存在度相对较大;温带分布的属占12.7％。本区无特有科,仅光叶蕨属1个特有属,还有6个中国特有属;有387种为中国特有种,约占本区种数的44％。特有种的32％为本区特有,其余以与中国西南片区(占22.5％)和整个南方片区(占26.1％)共有为主。本区被列入国家重点保护的珍稀濒危蕨类植物有10种,其中1级3种,2级7种。

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 familie, contributing 50. 5% of the total species in this region. They are followed by Thelypteridaceae, Sinopteridaceae, Aspleniaceae, Pteridaceae, Selaginellaceae, and Hemi onitidaceae, 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 endemic (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.