Kučera, J. & M.S. Ignatov. Revision of phylogenetic relationships of Didymodon sect. Rufiduli (Pottiaceae, Musci)

Arctoa (2015) 24: 79-97

doi: 10.15298/arctoa.24.11

Molecular phylogenetic analysis of the Didymodon species, which were assigned to Sect. Rufiduli (P.C. Chen) R.H. Zander by different authors showed that most of these species constitute a monophyletic lineage which largely fits the original concept of Chen. Didymodon asperifolius, D. sinuosus, and surprisingly also D. revolutus need to be included in the section, while D. anserinocapitatus is more closely related to D. cordatus of the sect. Didymodon. The genus Fuscobryum R.H. Zander (sect. Rufiduli in the sense of Zander) represents a well-supported lineage within sect. Didymodon, and is therefore combined as a subsection thereof, after D. norrisii is removed to sect. Vineales. Didymodon gaochienii and D. asperifolius have been found polyphyletic in present morphological circumscriptions and hybridization between D. hedysariformis and the Russian lineage of D. gaochienii s.l. has been suggested by incongruence between nuclear and chloroplast data. Revision of types revealed that D. murrayae seems to be identical with the type of D. gaochienii and at the same time, current understanding of these taxa differs from what is represented by their types, which will probably necessitate description of new taxa following a dedicated study. Additions to known distribution of Didymodon hedysariformis, D. johansenii, D. murrayae, D. rivicola and D. zanderi are listed.