The Tribe Pottieae (Pottiaceae, Bryophyta) In Mongolian Plateau

Pottiaceae Hampe is the largest family in Bryophyta,represented by approximately 83 genera and 1500 species.Pottieae Besch.is a tribe of Pottioieae in the family Pottioideae Broth.,with about 21 genera and 329 species.It is the dominant tribe in the arid and semi-arid climate regions,which plays an important role in revealing the species diversity in the primary succession stage.This study selects Mongolia and Inner Mongolia of China,the main part of Mongolian Plateau,as the study area.Based on relevant literature and examing specimen of HIMC,UBA,MO,NY,KUN,this taxonomy study of Pottieae in Mongolian Plateau has been carried out.The main results are as follows:1.According to statistics,9 genera,37 species and 4 varieties of Pottieae are reported in Mongolian Plateau,including 3 new records in China: Syntrichia calcicola J.J.Amann,S.submontana(Broth.)Ochyra and Microbryum starckeanum var.brachyodus(Bruch & Schimp.)R.H.Zander;5 taxa are recorded new to Mongolia: Syntrichia calcicola J.J.Amann,S.handelii(Schiffn.)S.Agnew & Vondr.,S.pseudohandelii(J.Froehl.)S.Agnew & Vondr.,Tortula capillaris(Dixon ex P.C.Chen)R.H.Zander and Syntrichia caninervis var.gypsophila.The genera Acaulon Müll.Hal.,Chenia R.H.Zander and Microbryum Schimp.are only found in Inner Mongloia of China.Hennediella Paris is only found in Mongolia.20 species(including varieties)are found in both Mongolia and Inner Mongolia of China.Owing to previously misidentified,2 taxa has been corrected.Microbryum starckeanum(Hedw.)R.H.Zander is corrected as M.starckeanum var.brachyodus(Bruch & Schimp.)R.H.Zander,and Phascum cuspidatum Schreb.ex Hedw.var.cuspidatum is corrected as P.cuspidatum var.schreberianum(Dicks.)Brid..Syntrichia princeps(De Not.)Mitt.and Tortula raucopapillosa(X.J.Li)R.H.Zander are excluded from mossflora of the study area.Unfortunately,there is no material of T.yuennanensis P.C.Chen available for the present study,therefore this species is treated as doubtful record.2.Pottieae Besch.is distinguished from Hyophileae M.Fleisch.by its margins recurved,one stereid band(dorsally)in the costa and upper laminal cells superficially convex on both side.The significance characteristics of Pottieae are: size of plants,leaf state when dry,leaf shape,leaf apex,margin,the transveres section of costa,laminal cells,papillae,lamanal KOH color reaction,seta,capsule,operculum,peristomal teeth and gemmae.Based on the above characteristics,the updated key to genera and species are compiled,and morphological anatomical micrographs,detailed morphological descriptions and taxonomic discussions are provided.3.Syntrichia Brid.and Tortula Hedw.have a large number of species and the morphological variation is complicated in this tribe,thus,it is difficult to identify.In this study,the gametophytic and sporophytic characteristics of these two genera have been observed and analyzed detailedly.Syntrichia Brid.is characterized by the present or absent of central strand,the occurrence and shape of gemmae,leaf shape,constricted in midleaf or not,ornamentation of the hair point,cells shape on the ventral and dorsal surfaces of the costa,the structure of the transverse section of the costa,laminal stratosity and length of the hyaline basal area in the leaf lamina.Tortula Hedw.is characterized by leaf shape,marginal bordered or not,the position of costa and leaf apex,the shape and size of seta,capsule and peristomal teeth,and basal membrane height.