一种值得关注的藓类植物:长柄蓑藓及其地理分布

长柄蓑藓(Macromitrium microstomum(Hook.&Grev.)Schwaegr.)曾以Macromtrium reinwardtii的学名在我国台湾,海南和云南有记录。报道了该种在西双版纳纳板河国家自然保护区的新分布。在查检模式标本和相关国内外标本和文献的基础上,对长柄蓑藓进行了描述和图示,讨论了该种泛热带的地理分布特点,并提供了世界分布图。     

Macromitrium maolanense Zeyou Zhang,D.D.Li,Jing Yu & S.L.Guo,a new species from China based on molecular and morphological evidence

Introduction. During a field excursion in Guizhou Province, China, we collected some interesting moss specimens with branch leaves subulate in the upper part, partially and variably bistratose laminae, and a Macromitrium-like epiphytic growth habit on tree trunks. We present morphological and phylogenetic arguments for recognising these plants as a new moss species in the genus Macromitrium Brid. (Orthotrichaceae).

Methods. We compared the morphology of the potential new species with closely related species of Macromitrium, and constructed a phylogenetic tree based on ITS2, trnL and trnG including sampling from 14 other morphologically similar species of Macromitrium.

Key results. The proposed new species belongs to the genus Macromitrium (Orthotrichaceae, Musci). It is closely related to M. gymnostomum Sull. & Lesq. in the phylogenetic tree and according to gametophytic morphological features, represents a hitherto undescribed species.

Conclusions. A new moss species, Macromitrium maolanense Zeyou Zhang, D.D.Li, Jing Yu & S.L.Guo, is described and illustrated. The new species can be distinguished from all congeners by the combination of the following features of the branch leaves: (1) oblong-lanceolate, lanceolate to linear-lanceolate, gradually narrowed to an easily broken subula; (2) rather obscure upper and medial cells, often with blackish stains among cells, densely pluripapillose; (3) variably and partially bistratose laminae in the upper 1/3 portion; (4) basal cells clear, hyaline and smooth, those near costae forming a ‘cancellina region’; and (5) with numerous brownish, clavate gemmae on upper portion. We also discuss the principal distinctive characters separating the new species from its nearest congeners.     

Using macroclimatic models to estimate the distribution ranges of taxonomically challenging taxa,an example with Macromitrium cavaleriei Cardot & Thér. (Orthotrichaceae)

An expanded taxonomic study of the narrowly understood Macromitrium cavaleriei Cardot & Thér. identified four new synonyms, M. cancellatum Y.X.Xiong, M. giraldii var. acrophylloides Müll.Hal., M. handelii Broth. and M. rigbyanum Dixon. With the discovery of the new synonyms, the range of M. cavaleriei is extended to India, Nepal, South Korea and Vietnam. To determine the potential distribution range of the species, we described its macroclimatic niche from its extant distribution with the maximum entropy algorithm modelling program (Maxent), contrasting the impact of different geographic backgrounds on the models. We found that the potential range of the species included central, southern, southwestern China to northern Vietnam, Myanmar, Bhutan, Nepal and India, and northwards to Japan and the Korean Peninsula. This estimation of the potential distribution range is largely confirmed by the herbarium specimens. The predicted climate suitability for M. cavaleriei is higher in the areas where the annual temperature range is about 26°C and precipitation during the warmest quarter, wettest quarter and month, and driest month are 500–600 mm, 500 mm, 200–210 mm, and 50 mm, respectively.