Is it really you,Orthotrichum acuminatum? Ascertaining a new case of intercontinental disjunction in mosses

Intercontinental disjunct distributions are a main issue in current biogeography. Bryophytes usually have broad distribution ranges and therefore constitute an interesting subject of study in this context. During recent fieldwork in western North America and eastern Africa, we found new populations of a moss morphologically similar to Orthotrichum acuminatum. So far this species has been considered to be one of the most typical epiphytic mosses of the Mediterranean Basin. The new findings raise some puzzling questions. Do these new populations belong to cryptic species or do they belong to O. acuminatum, a species which then has a multiple‐continent disjunct range? In the latter case, how could such an intercontinental disjunction be explained? To answer these questions, an integrative study involving morphological and molecular approaches was conducted. Morphological results reveal that Californian and Ethiopian samples fall within the variability of those from the Mediterranean Basin. Similarly, phylogenetic analyses confirm the monophyly of these populations, showing that O. acuminatum is one of the few moss species with a distribution comprising the western Nearctic, the western Palaearctic and Palaeotropical eastern Africa. Pending a further genetic and phylogeographical study to support or reject the hypothesis, a process of long‐distance dispersal (LDD) is hypothesized to explain this distribution and the origin of the species is suggested to be the Mediterranean Basin, from where diaspores of the species may have migrated to California and Ethiopia. The spore release process in O. acuminatum is revisited to support the LDD hypothesis, © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2016, 180 , 30–49.     

Taxonomic notes on African Orthotrichaceae 2: Macrocoma – new synonymy and first report of multicellular spores

Type material of two poorly known species of Macromitrium, described from East Africa and Madagascar, was examined and both were found to belong to the genus Macrocoma. Macromitrium megalosporum Thér. & Naveau was found to be morphologically very close to Macrocoma abyssinica (Müll.Hal.) Vitt., with the only significant difference between these taxa being the large multicellular spores of M. megalosporum, which is also the first report of multicellular spores for the genus Macrocoma. This name is here transferred to Macrocoma as Macrocoma abyssinica var. megalospora (Thér. & Naveau) Wilbraham comb. nov. Macrocoma abyssinica var. megalospora is reported new for the Comoros, which is the first record for the species in the East African Islands. Macromitrium adelphinum Cardot in Grandidier was found to be conspecific with Macrocoma tenuis (Hook. & Grev.) Vitt. subsp. tenuis and an appropriate synonymy is proposed. Macrocoma tenuis. subsp. tenuis is also reported here new to the Comoros.     

Taxonomic notes on African Orthotrichaceae I. New synonymy in Macromitrium

New synonymy and distribution records for the genus Macromitrium Brid. in sub-Saharan Africa are presented. Seven names are placed in synonymy, reducing the number of accepted taxa for Macromitrium in sub-Saharan Africa to 33. Macromitrium anomodictyon Cardot was found to be conspecific with M. serpens (Bruch ex Hook. & Grev.) Brid.; M. mauritianum Schwägr. and M. sanctae-mariae Renauld & Cardot are placed in synonymy with M. subtortum (Hook. & Grev.) Schwägr. and M. belangeri Müll.Hal., M. seriatum Paris & Broth., M. bequaertii Thér. & Naveau and M. trollii Dixon in Herz. are all placed in synonymy with M. sulcatum (Hook.) Brid. subsp. sulcatum. The precise lectotypification is implemented for six species within the genus. Macromitrium chloromitrium (Besch.) Wilbraham and M. orthostichum Nees ex Schwägr. are reported new to Tanzania and M. chloromitrium new to continental Africa.     

新疆木灵藓科植物的初步研究

在研究标本和文献的基础上,报道了新疆产木灵藓科植物３属１４种,即：瓶藓属Ａｍｐｈｉｄｕｉｍ（１种）,木棂藓属Ｏｒｔｈｏｔｒｉｃｈｕｍ（１２种）和木衣藓属Ｄｒｕｍｍｏｎｄｉａ,对它们的生境、识别特征和地理分布作了初步讨论,并编制了新疆木灵藓科植物的分属、分种检索表。     

Taxonomic notes on African Orthotrichaceae 3. New synonymy in Madagascan Macromitrium

Examination of type material of Macromitrium taxa described from Madagascar has unveiled three names to be placed in synonymy. Macromitrium nanothecium var. sublaeve Thér. was found to be conspecific with Macromitrium fimbriatum (P.Beauv.) Schwägr.; Macromitrium ancistrophyllum Cardot is placed in synonymy with M. nanothecium Cardot and Macromitrium semipapillosum Thér. & P.de la Varde is placed in synonymy with Macromitrium calocalyx Müll.Hal. Lectotypification is effected for four taxa within the genus. A range extension is reported for M. nanothecium, which is recorded here as new to Tanzania.     

中国木灵藓科植物的分类研究概况

木灵藓科(Orthotrichaceae)是世界性藓类植物大科,本文综述了该科植物在中国早期和现代的分类研究概况,在此基础上,对中国木灵藓科植物研究意义和研究趋势进行了展望。     

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.