A Taxonomic Revision Of The Subfamily Trichostomoideae And Timmielloideae(Musci,Pottiaceae) In Mongolian Plateau .Axillary Hairs In The Family Pottiaceae For Taxonomy

Pottiaceae Schimp.is a family of bryophytes with the largest number of genera,comprising 83 genera.Timmielloideae R.H.Zander has about 1 genus and 14 species,and Trichostomoideae(Bruch & Schimp.)Limpr.has about 11 genera and 329 species(including varieties).In this study,the main area of the Mongolian Plateau(hereafter referred to as the Mongolian Plateau),mainly Inner Mongolia and Mongolia of China,was selected as the research area.On the basis of literature research and specimen research,taxonomic study was conducted on the plants of the Timmielloideae and Trichostomoideae in this research area.The main research results are as follows:1.There are 1 genus and 2 species of Timmielloideae in the Mongolian Plateau,and Timmiella anomala(Bruch & Schimp.)Limpr has been corrected to Timmiella flexiseta(Bruch)Limpr.,which is a common species in Mongolia and Inner Mongolia.Timmiella diminuta(mull.Hal.)P.C.Chen)is endemic to China.There are 4 genera,10 species and 2 varieties of Trichostomoideae.New records of Mongolian and Inner Mongolia: Oxystegus daldinianus(De Not.)K?ckinger,O.Werner & Ros.New recorded varieties in China: Oxystegus tenuirostris var.holtii(Braithw.)A.J.E.Sm.,Tortella tortuosa var.fragilifolia(Jur.)Limpr.New recorded genera in Mongolia: Pseudosymblepharis Broth.Oxystegus tenuirostris var.holtii and Pseudosymblepharis duriuscula(Mitt.)P.C.Chen are found only in Inner Mongolia and Tortella inclinata(R.Hedw.)Limpr.is found only in Mongolia,with the remaining 8 species common to Mongolia and Inner Mongolia.In addition,the distribution of Trichostomum brachydontium Bruch in the study area could not be determined because no corresponding specimens were found.2.The main features of Timmielloideae are that the leaf apex is usually clearly serrated,with two layers except for the leaf margin,and the ventral surface is bulging and abaxial surface is almost smooth.The important taxonomic features of the division of the subfamily Timmielloideae are: plant size,leaf margin,leaf apex,upper and middle leaf cells,costa morphology and its transverse section of costa,seta,capsule,operculum,peristome and annulus.The key characteristics that distinguish the Trichostomoideae from other subfamilies are as follows: hyaline cells are often present,leaves are lanceolate,leaf margins are flat or occasionally slightly incurved at the upper part of the leaf,leaf cells are generally densely covered with papillose,basal cells occasionally have upward differentiation in a "V" shape,and KOH color reaction is yellow or yellowish-orange.The important taxonomic characteristics of the division among the genera of Trichostomoideae include: plant height,leaves when dry,leaf shape,whether the leaves are fragile,leaf apex and margin,costa morphology and its transverse section structure,leaf cells and papillose,and KOH color reaction on the upper part of the leaves.Based on the above characteristics of the two subfamilies,the latest genus and species index was compiled,and the morphological anatomy micrograph,detailed morphological description and taxonomic discussion were provided.3.The morphological characteristics of axillary hair in 31 genera of Pottiaceae showed that axillary hair of these genera were all composed of single row multi-cells,and the basal cells of the genera Didymodon Hedw.,Plaubelia Brid.,Scopelophila(Mitt.)Lindb are brown.The numerical variation trends of 7 axillary hair traits in 31 genera were all different,and the main characteristics obtained by PCA analysis were: length of remaining cells,length of axillary hair,total number of cells,ratio of length to width of apex cell,length of apex cell,width of apex cell,and ratio of the length of apex and remaining cells.The latter two traits were relatively conservative,with no significant difference between genera,and no significant correlation with the remaining 6 traits.According to the length of the remaining cells,31 genera can be divided into seven groups.According to the length of axillary hair,31 genera can be divided into eight groups.According to the total number of cells,31 genera can be divided into eight groups.According to the ratio of length to width of terminal cells,31 genera can be divided into five groups.According to the length of terminal cells,31 genera can be divided into six groups.The results of ANOVA and Cluster Analysis showed that axillary hair is a relatively conservative gametophytic feature,and in a fairly clear group,axillary hair can help to understand the relationships among its members,and sometimes it is even better than other gametophytic traits,which has certain value in evaluating the classification of mosses Pottiaceae.It also indicated that axillary hair characters alone were not enough to support the classical or molecular classification system,so the classification of taxa above the genus of Pottiaceae should be based on the comprehensive consideration of variety characters.