Studies On Taxonomy And Flora Of Merceyoideae In China

Detailed investigation and research on the flora of Merceyoideae will provide not only basic information to the protection of species diversity but also samples for studying physiology, developmental biology and phylogeny of Pottiaceae. However, there are lots of difficulties in traditional Merceyoideae classification and identification due to intrinsic problems such as polymorphy, taxonomic importance of anatomical characters, obscure areolation, and sterility of many specimens.According to statistics,13 genera,73 species and 7 varieties of the family are considered to be taxonomically recognizable entitles in China.5 species are new to Inner Mongolia and other provinces. Keys to the genera and species, herbarium numbers of collection and detailed discussion are given.The author conducted a preliminary analysis of the Merceyoideae components. In Chinese moss species composition,4 dominant genera(over and including 9 species) Barbula,Bryoerythrophyllum,Didymodon,Hydrogonium consist of 57 species, which make up 71.25% of the total number. Didymodon is the first major genera, of 26 species, which occupies 32.50% of the total number.The species of Merceyoideae could be grouped into 10 distribution types as Cosmopolitan (7.50%),Tropical Asian—Tropical American elements (2.50%), Tropical Asian—African elements (2.50%), Tropical Asian elements (7.50%),North Temperate elements (23.75%), Old World Temperate elements (1.25%), Asian and North American elements (8.75%), East Asian elements (25.00%),Temperate Asian elements (2.50%) and Endemic to China (18.75%).The Merceyoideae in Chinese Autonomous Region shows distinct characteristics of those in Temperate Zone, and the East Asia elements and North Temperate elements play an important role. The statistics of geographical distribution indicate that Yun-Gui region had the highest species diversity (67 species,83.75%), the Qingzang region (59 species,73.75%) is second to it, and the lowest diversity appears in Northeast region (28 species 35.00%).And Xizang had the highest species(58 species,72.50%), the second one was Sichuan Province (56 species,70.00%).The similarity coefficient of species shows that the flora of China is closer to those in USSR, Japan and North America, but farthest to Altai. Mt.