中国新记录种——摩拉维采真藓(新拟)

Bryum moravicum Podp.(Bryaceae,Musci)Reported New to China

该文首次报道了摩拉维采真藓(新拟)在中国的分布。研究表明:(1)摩拉维采真藓的主要识别特征为:叶常聚集在茎顶成莲座状,叶倒卵状披针形至匙形,具长毛尖,具分化边缘,中肋消失于叶尖下,叶细胞长菱形至六边形,叶腋处着生大量单列细胞构成的分枝或不分枝的丝状芽胞。(2)通过对摩拉维采真藓的命名和系统位置的讨论,确认该种是真藓属细叶真藓组的有效种。(3)摩拉维采真藓与近缘种细叶真藓和幽美真藓有诸多相似特征:莲座状的茎顶、有分化边和菱形至六边形中上部细胞的倒卵形叶,但该种以具有大量叶腋生丝状芽胞和叶中肋不及顶等特征区别于细叶真藓的无腋生芽胞、叶中肋突出叶尖成长芒状,以具有叶湿时平展、干时卷曲和叶腋有芽胞等特征区别于幽美真藓的叶湿时内凹、干时紧贴于茎和无腋生芽胞;拟三列真藓、圆叶真藓和灰黄真藓的部分种群都曾报道有与摩拉维采真藓相似的腋生丝状芽胞,但摩拉维采真藓的假根集生于植株基部、叶有狭分化边、叶缘平直、中肋消失于叶尖下而区别于拟三列真藓的茎中下部密被假根、叶有宽分化边、叶缘背卷、中肋及顶或短出,摩拉维采真藓有分化边和长毛尖的倒卵状披针形区别于圆叶真藓叶有无分化边和圆钝叶尖的卵圆形叶,区别于灰黄真藓有中肋及顶和短尖的卵状披针形叶;柔叶真藓有与摩拉维采真藓相似、中肋不及顶的叶,但无芽胞而易与新记录种区分。(4)该种在北温带有较广泛分布,形成欧洲-北亚-中亚-西亚和北美两个主要分布区;作者在四川和新疆等地的发现可以推测摩拉维采真藓在中国可能有更广泛的分布。

This is the first report to Bryum moravicum Podp.in China.The study showed that:(1)The species is characterized by slightly rosulate plants,obovate to spathulate leaves with a hair point and weak bordered margins,rhomboidal to hexagonal upper cells,costa ending below apex,aboundant branched or unbranched,uniseriate,filiform axillary gemmae.(2)Based on analysis of nomenclature and systematic position of the newly reported species,B.moravicum is the only valid name for the taxon,and it belongs to Section Capillaria,Genus Bryum.(3)B.moravicum can sometimes be confused with B.capillare and B.elegans by rosulate plants,obovate lanceolate leaves with differentiated borders,rhomboidal to hexagonal upper leaf cells.However,filiform gemmae in the leaf axils are abundant,and costa end well below the leaf apex in B.moravicum versus absent gemma and costa are excurrent in long awn in B.capillare;leaves are flat when moist,irregularly contorted when dry,and having gemmae in B.moravicum versus leaves are concave when moist,evenly imbricate when dry,and absent gemmae in B.elegans.Axillary filiform gemmae have also been seen in some populations of B.pseudotriquetrum,B.cyclophyllum and B.pallens.B.moravicum is characterized by rhizoids being in clusters on proximal stem,leaves with narrow borders,plane margins,and costa ending below the apex,while B.pseudotriquetrum is characterized by rhizoids arising from the base to middle of the stem,leaves with wide borders,revolute margins,and costa being percurrent to short excurrent.Obovate lanceolate leaves with apical hair tips and differentiated borders of B.moravicum are distinct from ovate elliptic leaves with rounded obtuse apex and undifferentiated borders of B.cyclophyllum,are distinct from ovate lanceolate leaves with costa being percurrent to short excurrent as a stout awn of B.pallens.Although some leaves of B.cellulare are similar with those of B.moravicum,the former can be readily recognized by absent specialized asexual reproduction.(4)The world distribution map shows that the specie is widely distributed in the northern temperate zone,and it has two main distribution areas:Europe Nrothern Asia Central Asia Western Asia and North America.With the more investigation,the species possibly be found in other area of China including Sichuan and Xinjiang in the future.