Cleaning a taxonomic dustbin: placing the European Hypnum species in a phylogenetic context!

The pleurocarpous moss genus Hypnum s.l. is a species-rich (> 40 species) cosmopolitan genus, of which 21 taxa occur in Europe. Although several of these species show high morphological resemblance there are strong indications that the genus is highly paraphyletic, which may be masked by convergent morphological evolution. Using molecular information, we analyse whether the morphological similarity of gametophytes of the European Hypnum taxa is explained by common ancestry or convergence. We provide a phylogenetic reconstruction of the relationships of the currently recognized European Hypnum taxa in a broad pleurocarpous moss context (192 taxa) using the nuclear ITS1-5.8S-ITS2, the plastid rps4 gene and trnL-F, and the mitochondrial nad5 intron. Bayesian tree topologies show that the genus is polyphyletic, and we retain only the Hypnum cupressiforme complex within Hypnum. The genus originally represented half of the moss species diversity, as it accommodated basically all pleurocarpous mosses; here we retain only seven species and one variety. The remainder of the species where resolved either within the three families Amblystegiaceae, Entodontaceae, and Pylaisiaceae, or in an independent clade that we describe as the new family Stereodontaceae. The Stereodontaceae includes five European species, all in the genus Stereodon, where they were already placed in the 18th century. In addition, we describe the four new genera Aquilonium, Insomniella, Jochenia, and Lignocariosa, and make new combinations for several Hypnum species.

A study of molecular sequences, sexuality, and morphological variation in Plagiomnium carolinianum, P. maximoviczii, and P. rhynchophorum (Bryophyta, Mniaceae)

Morphologically, recognition of the genus Plagiomnium may be relatively easy. Yet identifications of closely related species have met great difficulties. The contemporary species delimitations of P. carolinianum, P. maximoviczii, and P. rhynchophorum largely based on sexuality as the sole distinction have not been satisfactory. As shown from literature, character variations among these three taxa were continuous and intergraded within or among different populations throughout a wide geographic range. No gametophytic characters could be reliably used to distinguish them from each other. Molecular phylogenetic analyses using ITS2 and rps4 gene were undertaken to resolve delineations for these three morphologically similar species. The results suggest that they form a well support monophyletic clade, which can be defined as representing one single species with two subspecies, i.e. P. rhynchophorum subsp. maximoviczii and P. rhynchophorum subsp. rhynchophorum. The present molecular study supports the treatment of P. carolinianum as synonym of P. rhynchophorum as purposed previously by Koponen based on morphology.

A taxonomic revision of cleistocarpous species of Weissia (Pottiaceae, Bryophyta) in Japan

Four species, including one newly described, of Japanese cleistocarpous species of Weissia (Pottiaceae): W. exserta, W. japonica, W. kiiensis and W. parajaponica sp. nov. are recognized based on molecular phylogenetic inference and morphological reassessment. For each species, typification, description, distribution, illustrations and photographs are presented, and a key to the species is included. Rapid sporophyte modifications in Weissia and monophyletic positions of these four species are supported by the analysis using concatenated chloroplast rbcL and rps4 gene sequences. A lectotype is designated for W. controversa which is the type species of the genus, and a new combination, W. loncophylla is proposed for Trachycarpidium lonchophyllum.

Scandinavian Oncophorus (Bryopsida, Oncophoraceae): species, cryptic species, and intraspecific variation

Scandinavian members of the acrocarpous moss genus Oncophorus were revised after field observations had suggested unrecognized diversity. Based on molecular (nuclear: internal transcribed spacers 1 and 2, ITS; plastid: trnGUCC G2 intron, trnG, rps4 gene + trnS-rps4 spacer, rps4) and morphological evidence, four morphologically distinguishable species are recognized, Oncophorus elongatus (I.Hagen) Hedenäs, O. integerrimus Hedenäs sp. nov. (syn. O. virens var. elongatus Limpr.), O. virens (Hedw.) Brid., and O. wahlenbergii Brid. (O. sardous Herzog, syn. nov.). Oncophorus elongatus was earlier recognized, but much of its variation was hidden within O. wahlenbergii. Its circumscription is here expanded to include plants with long leaves having mostly denticulate or sharply denticulate upper margins and with long and narrow marginal cells in the basal portion of the sheathing leaf lamina. The new species O. integerrimus sp. nov. differs from O. virens in having more loosely incurved leaves and entire or almost entire upper leaf margins. Besides these characters, the species in the respective pairs differ in quantitative features of the leaf lamina cells. Several cryptic entities were found, in several cases as molecularly distinct as some of the morphologically recognizable species, and phylogeographic structure is present within O. elongatus and O. virens.