A Taxonomic And Floristic Study On The Dicranaceae In Xinjiang

Dicranaceae belongs to Bryophyta Musci,Bryidae,Dichranales,which is a large family and widely distributed in the world.In this paper,the taxonomic,cladistic and floristic studies of the Dicranaceae that more than 1300 specimens,which were collected from Xinjiang from 1987 to 2019,were carried out.The results of this study can provide basic data for bryophyte research and even plant research in Xinjiang,as well as scientific basis for its protection and utilization.The main results are as follows:(1)According to the classification and identification of the specimens,28 species and10 genera of Dicranaceae were recorded in Xinjiang.(2)Based on 45 morphological features,the phylogeny of 28 species of Dicranaceae was analyzed.The important morphological characteristics of Dicranaceae were determined by Phylogenetic Analysis Using PAUP,phylogenetic trees were established,and morphological matrix was analyzed by MP method.The results show that the exotaxa form a branch independently,and 28 species form 10 branches.Each genus forms a separate branch,and the bootstrap value of Dicranoweisia is more than 90,which shows that the branch is reliable and consistent with the results of classical taxonomy.(3)The morphological characteristics of spores and capsule teeth of 10 different species of Dichranum Hedw.were observed by Light Microscope,LM and Scanning Electron Microscope,SEM.The results show that: the capsules of 10 species of Dicranum are cylindrical;the spores are spherical,near spherical,ellipse or triangular ovate,they are yellow,brown,yellowish brown,the faces near pole concave,the ornamentation is verrucous,granular,spore;the peristome of 10 species of Dicranum mostly are lanceolate,some are broad lanceolate.These peristomes are apricot yellow,oxblood red,browinish yellow or reddish brownin color,the ornamentation is striate and verrucous,perforated into a net structure,some species have a smooth structure without perforation,with verruca on the surface.The study provides a taxonomic basis for the division of Dicranum and an important reference value for the taxonomic classification and evolution of bryophytes.(4)The floristic composition,vertical distribution and community types of Dicranaceae in Xinjiang are studied as follows:(1)Floristic geographical components can be divided into five categories: Northern temperate elements,Asia-North American elements,East Asia elements,old world temperate elements and the world's composition,they accounted for 80%,12%,4% and 4% respectively;(2)The vertical distribution can be divided into mountain steppe belt(7genus,20species),mountain forest zone(9genus,25species),subalpine meadow(7genus,20species),alpine meadow zone(7genus,17species)and Alpine cushion vegetation zone(5genus,10species);(3)The community is divided into four types,such as soil(8genus,24species),stone(7genus,21species),wood(8genus,24species)and aquatic(6genus,10species).