Taxonomic Studies On Chinese Lejeuneaceae

The Lejeuneaceae, with about 1000 species in about 90 genera, is the largest family of liverworts (Marchantiophyta) and the most dominant group of the flora of tropical rainforests and subtropical natural forests. Owing to the largest number of species, difficulties in identification and sample collection (most species occur on tree trunks, branches or leaves), there is still no specific systematical study on Chinese Lejeuneaceae. Therefore, study on Chinese Lejeuneaceae's taxonomy has important significance for revealing the flora of China and the world.By means of field investigation and supplementary collections,87 type specimens borrowed mainly from herbaria abroad and about 6000 specimens collected from China housed in Chinese herbaria were examined. The thesis aims to revise Chinese Lejeuneaceae's taxonomy and analyse the flora's components and the geographical distribution patterns. The main results are as follows:1. Based on the present study,222 species and three varieties belonging to 29 genera of Lejeuneaceae are recognized as occurring in China. Among them, one species in Acanthocoleus, Caudalejeunea, Chondriolejeunea, Harpalejeunea, Lepidolejeunea, Metalejeunea, Otolejeunea, Phaeolejeunea, Ptychanthus, Pycnolejeunea, Stenolejeunea and Tuzibeanthus, two species in Ceratolejeunea, Schiffneriolejeunea and Trocholejeunea, two species and two varieties in Tuyamaella, three species in Archilejeunea, Diplasiolejeunea, Spruceanthus and Thysananthus, four species in Mastigolejeunea, six species in Acrolejeunea, seven species in Colura, eight species in Lopholejeunea, nine species in Leptolejeunea,18 species and one variety in Drepanolejeunea,23 species in Cheilolejeunea,42 species in Lejeunea and 73 species in Cololejeunea. All species of Ptychanthoideae and most species of Lejeuneoideae were described, and 80 plates were presented.2. One new species(Cololejeunea subplanissima R.L.Zhu & J.Wang, sp. nov.) are described. Nine species(Acrolejeunea arcuata (Nees) Grolle & Gradst., A. securifolia (Endl.) Watts ex Steph. ssp. hartmannii (Steph.) Gradst., A. sikkimensis (Mizut.) Gradst., Lejeunea lumbricoides (Nees) Nees, L. micholitzii Mizut., Lopholejeunea herzogiana Verd., L. latilobula Verd, Mastigolejeunea virens (Angstr.) Steph. and Schiffneriolejeunea polycarpa (Nees) Gradst.) are newly recorded in China.3. One new name was proposed:Lejeunea laii R.L.Zhu (≡Lejeunea ramulosa (Herzog) R.M.Schust.). Two new combinations(Lejeunea barbata (Herzog) R.L.Zhu & M.J.Lai and Lejeunea luzonensis (Steph.) R.L.Zhu & M.J.Lai) are made. Taxilejeunea subcompressiuscula Herzog, nom. inval. is treated as a synonym of Lejeunea obscura Mitt.. Two genera (Rectolejeunea and Taxilejeunea) were excluded from the liverwort flora of China.4. Based on the analysis of the distribution of Lejeuneaceae in China, four regions (Lingnan region, East China region, Hengduan Mts region and Yunnan-Guizhou region) are main distribution regions of Lejeuneaceae in China. The provinces with larger number of Lejeuneaceae are Hainan (141 species,63.51%), Taiwan (119 species,53.60%) and Yunnan (113 species,50.90%). Twenty six species are known only from Hainan, twelve and eight species only from Taiwan and Yunnan respectively. Of all 23 species known only from China, four species are distributed in Hainan, eight species in Taiwan and 11 species in Yunnan.5. Floristic analysis revealed that East-Asia element is the largest element in the Chinese Lejeuneaceae flora with 84 species, accounting ca.37.84% of the total number of species of Lejeuneacea in China. Among East-Asia elements,35 species for China-Japan element,23 species are known only from China,15 species for Himalaya-Japan and 11 species for Sino-Himalaya. Tropical Asian element with 64 species, which is the second largest element, accouting ca.28.83% of the total number of species. The Chinese Lejeuneaceae flora is highly composed of the East-Asia element and Tropical Asian element.