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

ABSTRACT

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.

KEYWORDS:

• China
• molecular phylogeny
• Orthotrichaceae
• taxonomy

Acknowledgments

We are grateful to Si He (Missouri Botanic Garden) for his hospitality and guidance during the present work. Thanks are also due to the curators of BM, E, FH, H, H-BR, KRAM-B, L, MICH, MO, NY, PC, SHTU and US for their help in sending specimens on loan, and to Prof. Rod Seppelt, Bundall, Queensland, Australia, for his valuable suggestions and for improving the English text.

Notes on contributors

Zeyou Zhang is a candidate for Ph.D. degree, researching in bryophyte ecology and taxonomy.

Dandan Li is a postdoctoral fellow, researching in bryophyte ecology and taxonomy.

Jing Yu is a bryologist of Shanghai Normal University, focusing on bryophyte ecology, taxonomy and palynology.

Shuiliang Guo is a bryologist at the herbarium (SHTU), Shanghai Normal University. His research mainly focuses on bryophyte ecology and taxonomy, more specifically on Ptychomitriaceae and Orthotrichaceae.

ORCID

Shuiliang Guo http://orcid.org/0000-0001-5666-6045

Additional information

Funding

We are grateful for the financial support of the National Nature Science Foundation of China [Grant Number 31370233, 31860162, 31570208] and the Shanghai Engineering Research Centre of Plant Germplasm Resources [Grant Number 17DZ2252700].