The Subfamily Merceyoideae(Pottiaceae,Bryophyta) In Mongolian Plateau

Pottiaceae Hampe is the family of Bryophyta with the largest number of species,the whole family contains about 83 genera and 1500 species.Merceyoideae Broth.is a subfamily of the family Pottiaceae,which are 22 genera and 548 species and variants.This study selects the main part of Mongolian Plateau,Mongolia and Inner Mongolia of China,as the research area.Based on literature verification and specimen research,this taxonomy study of Merceyoideae in Mongolian Plateau has been carried out.Below are key research findings:1.There are 11 genera,50 species and 3 varieties of Merceyoideae in Mongolian Plateau,including 2 new records in Inner Mongolia: Bryoerythrophyllum wallichii(Mitt.)P.C.Chen and Hydrogonium gregarium(Mitt.)Jan Ku?era.The genus Gyroweisia Schimp.with Bryoerythrophyllum inaequalifolium(Taylor)R.H.Zander,B.rotundatum(Lindb.& Arnell)P.C.Chen,B.sollmanianum J.A.Jiménez,Didymodon maximus(Syed & Crundw.)M.O.Hill,D.kunlunensis D.P.Zhao,S.Mamtimin & S.He and Gyroweisia yuennanensis Broth.are reported as new records to Mongolia,The genera Anoectangium Schw?gr.,Hydrogonium(Müll.Hal.)A.Jaeger and Scopelophila(Mitt.)Lindb.are only found in Inner Mongloia of China.There are 31 species and varieties in both Mongolia and Inner Mongolia of China,only 13 species are distributed in Inner Mongolia of China,and 9 species are distributed only in Mongolia.Anoectangium clarum Mitt.,A.thomsonii,Ardeuma annotinum(Mitt.ex Dixon)R.H.Zander &Brinda,Bryoerythrophyllum alpigenum(Venturi ex Jur.)P.C.Chen,B.brachystegium(Besch.)K.Saito,B.gymnostomum(Broth.)P.C.Chen,B.rubrum var.minus K.Saito,Hymenostylium recurvirostrum var.cylindricum(Hedw.)Dix.and Pseudocrossidium revolutum(Brid.)R.H.Zander are excluded bryoflora study area.In addition,the corresponding specimens of Barbula chenia Redf.& B.C.Tan and Pseudocrossidium obtusulum(Lindb.)H.A.Crum & L.E.Anderson were not seen,which is uncertain whether it is distributed in the study area,so it is temporarily doubtful.2.Merceyoideae is distinguished from other subfamily in the family Pottiaceae by its leaves keeled above midleaf,costa grooved ventally and ventral stereid bands less than dorsal stereid bands.The important taxonomic characteristics to division the genus of Merceyoideae include: the color and morphology of plants,the state of leaf when dry and when moist,the morphology of leaf,the shape of leaf apex,margin,the morphology of costa,the transveres section of costa,laminal cells,papillae,lamanal KOH color reaction and gemmae.According to the above characteristics,the latest subgenus and subspecies updated key of this subfamily were compiled,and detailed morphological description,ecological distribution information,species discussion and morphological anatomy micrographs were provided.3.Bryoerythrophyllum P.C.Chen has a large morphological variation,which makes it difficult to identify.The key characteristics of this genus include: the morphology of plants,the morphology of leaf,the shape of leaf apex,dentate above,margin,the shape of the transveres section of costa,laminal cells,gemmae and dioicous or monoicous.