Moss Genus Research Articles

Shevockia (Neckeraceae), a new moss genus with two species from southeast Asia

Shevockia (Neckeraceae), a new moss genus with two species from southeast Asia

Environmental variation obscures species diversity in southern European populations of the moss genus Ceratodon

AbstractA major problem in taxonomy is to determine if morphological variation in field–collected specimens is caused by genetic differentiation, and therefore corresponds to evolutionary distinct units, or is caused by environmental variation acting on a single interbreeding population. To evaluate the effect of environmental variation on the taxonomy of the moss genus Ceratodon, we compared biometric analyses based on 22 morphological characters on both field–collected plants and cultivated plants to a clustering based on DNA sequence and genome size data published previously. We sampled Ceratodon species from mountainous areas of the Mediterranean region, and other mountain regions and lowlands, mostly from southern Europe. We found that the expression of several gametophytic traits changed between field and laboratory conditions, confirming that environmental variability complicates taxonomic inferences, and suggesting that some characters should be used with caution in distinguishing among species. However, consistent with the genetic and flow cytometry data, we found a clear biometric discontinuity between some plants collected from southern Spain, and those from other parts of the world. Samples considered of hybrid origin, based on genetic data, were morphologically indistinguishable from plants from the southern Spanish mountains. Integrative taxonomy based on genetic, genome size and morphological data unambiguously support the recognition of a new species, Ceratodon amazonum. These data also suggest that the previously recognized C. conicus is a recombinant between C. amazonum and C. purpureus and is considered here to be a nothospecies, for which an epitype is designated because the lectotype is demonstrably ambiguous.

A taxonomic revision of Oligotrichum Lam. & DC. (Polytrichaceae) in the Sino-Himalaya

A taxonomic revision of the moss genus Oligotrichum Lam. & DC. (Polytrichaceae) is provided for the Sino-Himalayan region. This area includes the Himalaya and the Hengduan Mountains of south-western China (Yunnan, Sichuan, and Xizang [Tibet] Provinces). Field work in recent decades has resulted in much new material for taxonomic revision. Light microscopy was used to distinguish seven species from the study area: O. aligerum Mitt., O. crossidioides P.C.Chen & T.L.Wan ex W.X.Xu & R.L.Xiong, O. falcatum Steere, O. falcifolium (Griff.) G.L.Sm., O. nepalense G.L.Sm., O. obtusatum Broth., and O. semilamellatum (Hook.f.) Mitt. Two species are excluded: O. hercynicum (Hedw.) Lam. & DC., as no specimens of this European and North American species have yet been found from the Sino-Himalayan region, and O. glaciale C.C.Towns., which has been transferred to a recently established genus Delongia N.E.Bell, Kariyawasam, Hedd. & Hyvönen, described elsewhere. The material now available has facilitated new observations on important characters such as the structures of the leaf lamellae and sporophytes. A key to accepted species is provided, as well as descriptions, synonymy, typification, line drawings, an ecological summary, and biogeographical information including distribution maps for all species. Oligotrichum falcatum is reported as new to India and Nepal, and O. obtusatum new to India and the Sichuan Province of China. Two varieties (O. semilamellatum var. darjeelingense Gangulee and var. edentatum Gangulee) are newly synonymised with O. semilamellatum. Finally, some observations on the regional ecology and phytogeography of the species are made and a list of specimens studied is appended.

Molecular Data Suggest Long-Term in Situ Antarctic Persistence Within Antarctica's Most Speciose Plant Genus, Schistidium

From glacial reconstructions it is clear that Antarctic terrestrial life must have been extremely limited throughout Quaternary glacial periods. In contrast, recent biological studies provide clear evidence for long-term in situ persistence throughout glacial times within most extant Antarctic faunal and several microbial groups. However, even now, the evolutionary history of the Antarctic flora - despite playing major role in Antarctic ecosystems - remains poorly studied. We assessed the diversity, richness and relative age divergences within Schistidium (Grimmiaceae, Bryophyta), the most species-rich plant genus in the Antarctic, as well as the plant genus containing most Antarctic endemic species. We applied phylogenetic and molecular dating methods based on nuclear ribosomal Internal Transcribed Spacer sequences, including all known Antarctic Schistidium species with available sample material. We additionally investigated the continent-wide genetic diversity within the most common Antarctic representative of the genus - the endemic species Schistidium antarctici - and performed preliminary phylogeographic analyses of the bipolar species Schistidium rivulare. Most previously described Antarctic Schistidium species were genetically distinct, confirming their specific status. Interspecific divergences of all species took place at least ~1 Mya, suggesting a likely in situ persistence in Antarctica for (at least) all endemic Schistidium species. The widespread endemic species, Schistidium antarctici, diverged from other Antarctic congeners in the late Miocene, thereby revealing the oldest extant plant species currently known in Antarctica, and providing increasing support for the hypothesis of vegetation survival through multiple glacial periods. Within S. antarctici we identified several distinct clades dividing the eastern Antarctic Peninsula and Scotia Arc islands from the western Antarctic Peninsula and all continental locations. This suggests that the mountainous spine on the Antarctic Peninsula forms a strong barrier to gene flow in this species, while increased genetic diversity in the northern Maritime Antarctic indicates likely glacial refugia in this area. This study provides an important first step towards assessing the diversity and evolutionary history of the most speciose moss genus in the Antarctic. The multi-million year presence of several endemic species contributes to studies on their adaptive potential to survive climate change over both historical and contemporary timescales.

Peripatric speciation associated with genome expansion and female-biased sex ratios in the moss genus Ceratodon.

A period of allopatry is widely believed to be essential for the evolution of reproductive isolation. However, strict allopatry may be difficult to achieve in some cosmopolitan, spore-dispersed groups, like mosses. We examined the genetic and genome size diversity in Mediterranean populations of the moss Ceratodon purpureus s.l. to evaluate the role of allopatry and ploidy change in population divergence. We sampled populations of the genus Ceratodon from mountainous areas and lowlands of the Mediterranean region, and from Western and Central Europe. We performed phylogenetic and coalescent analyses on sequences from five nuclear introns and a chloroplast locus to reconstruct their evolutionary history. We also estimated genome size using flow cytometry (employing propidium iodide) and determined the sex of samples using a sex-linked PCR marker. Two well-differentiated clades were resolved, discriminating two homogeneous groups: the widespread C. purpureus and a local group mostly restricted to the mountains in Southern Spain. The latter also possessed a genome size 25% larger than the widespread C. purpureus, and the samples of this group consist entirely of females. We also found hybrids, and some of them had a genome size equivalent to the sum of the C. purpureus and Spanish genome, suggesting that they arose by allopolyploidy. These data suggest that a new species of Ceratodon arose via peripatric speciation, potentially involving a genome size change and a strong female-biased sex ratio. The new species has hybridized in the past with C. purpureus.

Spores potentially dispersed to longer distances are more tolerant to ultraviolet radiation: A case study in the moss genus Orthotrichum.

Ultraviolet (UV) radiation influences the viability of algal spores and seed-plant pollen depending on the species, the dose, and the wavelength. In bryophytes, one of the dominant groups of plants in many habitats, UV radiation could determine their spore dispersal strategy, and such data are critical for reconstructing the ancestral state in plants and for determining the distribution range and persistence of bryophyte species. Spores of four bryophyte species of the moss genus Orthotrichum that were either hygrochastic or xerochastic (spores dispersed under wet or dry conditions, respectively) were exposed to realistic doses of UV radiation under laboratory conditions. Spore viability was evaluated through germination experiments and, for the first time in bryophytes, ultrastructural observations. Given that the UV-B doses used were relatively higher than the UV-A doses, the UV effect was probably due more to UV-B than UV-A wavelengths. All four species reduced their spore germination capacity in a UV dose-dependent manner, concomitantly increasing spore ultrastructural damage (cytoplasmic and plastid alterations). Most spores eventually died when exposed to the highest UV dose. Interestingly, spores of hygrochastic species were much more UV-sensitive than those of xerochastic species. UV tolerance determines moss spore viability, as indicated by germination capacity and ultrastructural damage, and differs between spores of species with different dispersal strategies. Specifically, the higher UV tolerance of xerochastic spores may enable them to be dispersed to longer distances than hygrochastic spores, thus extending more efficiently the distribution range of the corresponding species.

Three Remarkable Additions ofOrthotrichumSpecies (Orthotrichaceae) to the Moss Flora of China

Skoupá, Z., Ochyra, R., Guo, S.-L., Sulayman, M. & Plášek, V. 2018. Three remarkable additions of Orthotrichum species (Orthotrichaceae) to the moss flora of China. - Herzogia 31: 88–100.Three species of the narrowly constituted moss genus Orthotrichum are reported for the first time from China. Two of these, O. moravicum and O. scanicum, have been found in the Xinjiang Uyghur Autonomous Region. The third species, O. rogeri, was detected in Qinghai Province and at the same time this is the first discovery of it in Central Asia. Ecological and distributional details of the newly recorded species are provided and their local distribution in China is mapped. Considering the present records, Orthotrichum in a narrow sense consists of 30 species in China.

­Phylogenetic Analysis of the Genus Pohlia (Bryophyta, Bryaceae) Using Chloroplast and Nuclear Ribosomal DNA

The genus Pohlia Hedwig is a large moss genus that has been placed in the Bryaceae family as traditionally determined. However, a molecular phylogenetic analysis has indicated that the Pohlia genus is more closely related to genera that are traditionally classified into the Mniaceae or Mielichhoferiaceae families. In this study, we performed a molecular phylogenetic analysis using evidence from four chloroplast regions (atpB-rbcL, rps4, trnG, and trnL-trnF) and one nuclear ribosomal intragenic spacer region (ITS) using different methods (maximum parsimony, maximum likelihood, and Bayesian inference). The phylogenetic relationships between Pohlia and its related genera are discussed. Two large clades among our samples were well supported in all of the datasets. The traditionally defined Bryaceae species, including Brachymenium pendulum, Bryum caespiticium, Bryum capillare, Anomobryum gemmigerum, and Rhodobryum ontariense, formed a monophyletic clade with high support. The second clade corresponding to the Mielichhoferiaceae-Mniaceae complex also had high support. All of the Pohlia, Mielichhoferia and Mniaceae samples were included in this latter clade. The clearest result from the phylogenetic analysis is that the Pohlia genus is non-monophyletic. The analysis is identical when using three methods and concludes that Pohlia is closer to the genera in Mielichhoferiaceae and Mniaceae. A formal taxonomic treatment of this clade was not performed because we lacked sufficient specimens of the species, although this work will be included in a future study.

On the identity of Schistidium malacophyllum Herzog (Grimmiacaea, Bryophyta)

Schistidium Bruch & Schimper (in Bruch et al. 1845: 93) is one of the most complex and difficult moss genera, and is still poorly known and understudied taxonomically in South America. In the Neotropics, there are around twenty names for this genus without a real status acknowledged (Churchill et al., 2000) as no taxonomical or nomenclatural revision was ever conducted.

Phantomia vadimii(Dicranaceae), a New Moss Genus and Species from Northern Vietnam

Phantomia vadimii S. He & W. R. Buck, a new moss genus and species, is described from Lao Cai Province, northern Vietnam. The new taxon is characterized by its abruptly convolute leaf shoulders; the presence of a median row of stereid cells in the upper lateral costal cross sections; a weakly differentiated marginal border at the leaf base; and the absence of a central strand in the stem. The new genus shares some characteristics with Chorisodontium (Mitt.) Broth. in having a narrow basal costa that flares outward at the midleaf and persistent, inflated alar cells. It also has an anatomical similarity to the leaf costal cross sections (especially the upper leaf costa) of Dicranodontium Bruch & Schimp. The similarities and differences of the new genus in comparison with the genera of Campylopodioideae and Dicranoideae are discussed.

Bryophytes of Kédougou (Eastern Senegal), with a key to the Fissidens of Senegal

The bryophyte flora of the Sahelian region of sub-Saharan Africa is characterized by a low species richness, but is also extremely poorly documented. We present here the results of a floristic survey in Kedougou (eastern Senegal), which yielded 22 species. Two liverworts and 15 moss species are new to the country, so that the bryophyte flora of Senegal now includes a total of 4 liverwort and 34 moss species. An identification key is provided for Fissidens, which, with eight species, is the richest moss genus of the country.

Nomenclatural Notes on Pterogonium (Bryophyta, Leucodontaceae)

Abstract A taxonomic and nomenclatural history of the moss genus Pterogonium Sw. is outlined and the illegitimacy of this name is confirmed. Nogopterium Crosby & W. R. Buck, the name of a new genus erected to replace the illegitimate Pterogonium, is accepted as validly published. This genus consists of five species, two of which, N. coreense (Cardot) Tad. Suzuki and N. tenellum (Tad. Suzuki & Z. Iwats.) Tad. Suzuki, have only recently been transferred to this genus. The transfer of the fifth species, N. tsilingense (P. C. Chen) Tad. Suzuki ex Ochyra & Bedn.-Ochyra, comb. nov., is effected in the present account.

Resolving the northern hemisphere source region for the long‐distance dispersal event that gave rise to the South American endemic dung moss Tetraplodon fuegianus

PREMISE OF THE STUDY:American bipolar plant distributions characterize taxa at various taxonomic ranks but are most common in the bryophytes at infraspecific and infrageneric levels. A previous study on the bipolar disjunction in the dung moss genus Tetraplodon found that direct long‐distance dispersal from North to South in the Miocene–Pleistocene accounted for the origin of the Southern American endemic Tetraplodon fuegianus, congruent with other molecular studies on bipolar bryophytes. The previous study, however, remained inconclusive regarding a specific northern hemisphere source region for the transequatorial dispersal event that gave rise to T. fuegianus.METHODS:To estimate spatial genetic structure and phylogeographic relationships within the bipolar lineage of Tetraplodon, which includes T. fuegianus, we analyzed thousands of restriction‐site‐associated DNA (RADseq) loci and single nucleotide polymorphisms using Bayesian individual assignment and maximum likelihood and coalescent model based phylogenetic approaches.KEY RESULTS:Northwestern North America is the most likely source of the recent ancestor to T. fuegianus.CONCLUSIONS:Tetraplodon fuegianus, which marks the southernmost populations in the bipolar lineage of Tetraplodon, arose following a single long‐distance dispersal event involving a T. mnioides lineage that is now rare in the northern hemisphere and potentially restricted to the Pacific Northwest of North America. Furthermore, gene flow between sympatric lineages of Tetraplodon mnioides in the northern hemisphere is limited, possibly due to high rates of selfing or reproductive isolation.

Molecular phylogeny of Plagiothecium and similar hypnalean mosses, with a revised sectional classification of Plagiothecium.

We investigated the systematic relationships within the pleurocarpous moss genus Plagiothecium, based on cladistic analyses of sequence data from one nuclear (ITS) and two plastid (trnK-psbA (matK) and rpl16 intron) DNA regions for 110 specimens of Plagiothecium and similar hypnalean mosses. Plastid and nuclear trees were mostly similar, but differed in the placement of several species of Plagiothecium, and in the relationships among other genera. The phylogenetic hypotheses based on plastid markers were well resolved; in contrast, nuclear data were insufficient to resolve some of the lowest-level relationships within the genus. In the main Plagiothecium is natural, includes more taxa than are often recognized, and is most closely related to Isopterygiopsis and Herzogiella. Nine sections are recognized within Plagiothecium, four new: SectionPseudo-Neckera to accommodate P.neckeroideum and its allies, SectionOrtholimnobium for P.handelii and P.paleaceum, SectionStruckia for P.argentatum and P.enerve, and SectionRectithecium for P.piliferum. The geographical distribution of the sections suggests that Plagiothecium originated in Asia. The derived, mainly autoicous sections Plagiothecium and Leptophyllum may have spread to the Southern Hemisphere through long distance dispersal. Three new species in section Leptophyllum (P.funale, P.pacificum and P.rhizolucidum) and two new taxa in section Pseudo-Neckera (P.decoratum and P.neckeroideum fo. exile) are described. A limited phylogenetic hypothesis for the superficially similar hypnalean genus Taxiphyllum, which was used as outgroup, is included. A related genus (Longiella) is described, with a single species (L.plagiothecioides). The aquarium species T.barbieri is transferred to Ectropothecium.

The Moss GenusZygodon(Orthotrichaceae) in Poland — Distribution, Ecological Preferences and Threats

Abstract The moss genus Zygodon Hook. & Taylor (Orthotrichaceae) is represented by five species in Poland, namely: Z. dentatus (Limpr.) Kartt., Z. gracilis Wilson, Z. rupestris Schimp. ex A.W.H.Walth. & Molendo, Z. stirtonii Schimp. and Z. viridissimus (Dicks.) Brid. Their current distribution in Poland is reviewed and mapped, and lists of their localities are presented. The ecological preferences, altitudinal limits, reproduction and threats for each species are shortly discussed. A key for determination of these species is given.

Mitogenomic analyses support the recent division of the genus Orthotrichum (Orthotrichaceae, Bryophyta)

A recently presented taxonomical arrangement of the moss genus Orthotrichum Hedw. s.l. substantially changed the traditional view of the taxon that had been accepted throughout the twentieth century. This paper provides the results of mitogenomic studies that strongly support the new taxonomical concept. Comparative analyses presented in this study confirmed the stable structure of moss mitogenomes. Moreover, 17 complete mitogenome sequences were used to identify the major evolutionary groups, including 11 newly sequenced ones, for this study. The analysis of mitochondrial hotspots revealed intron 4 of the cox1 gene to be the most variable non-coding region. The most variable protein-coding genes in the tribe Orthotricheae were ccmFC and tatC. The intergenic and intronic hotspots of Orthotrichum s.l. identified in the present study do not correspond to those described in vascular plant mitogenomes.

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.

Syntrichia norvegica shoots exhibit a complex inducible response to desiccation: separating the effects of rate of drying and water content

Plants in the moss genus Syntrichia are considered to have constitutive desiccation tolerance (DT), as in, able to tolerate a rapid drying event without incurring significant damage upon rehydration. However, few researchers have considered the separate effects of rate of drying and water content, and incorporated fully dehardened (to DT) plants in the experiments. Plants of Syntrichia norvegica F.Weber were cultured under conditions of suprasaturation, and adult shoots were exposed to a range of drying rates and equilibrating relative humidities (RHs), rehydrated, and assessed for chlorophyll fluorescence and regeneration potential. Adult shoots exhibited severe damage across all drying rates when equilibrated at RHs <30%. However, an inducible response to desiccation was present across all water contents as the rate of drying was extended from 0 to 4 d. The least desiccation damage occurred at longer drying times and higher water contents (8 d at 75% RH). A constitutive phenotype for DT was not strictly evident in S. norvegica. Rather, we observed an incomplete pattern of environmentally inducible DT, coupled with heavy shoot damage at lower water contents. Rate of drying and equilibrating RH clearly interact in producing the pattern and strategy of DT for this species.

A simple parsimony-based approach to assess ancestor-descendant relationships

One of the main goals of systematics is to reconstruct the tree of life. Half a century ago, the breakthrough of cladistics was a major step towards this objective because it allowed us to assess relatedness patterns among species, an abstract kind of relationship. Unfortunately, the philosophy of cladism forbade to go further and to seek more realistic relationships, like the ancestor-descendant relationship, which is the expected fundamental kind of relationship of the tree of life according to Darwinian evolution. Here, I describe a simple parsimony-based procedure which can be used to transform a classical cladogram into a genuine phylogenetic tree, i.e. a caulogram. It consists in deleting as many unobserved and unnamed nodes as possible and replacing them with observed and named species. A new Bayesian non-stochastic weighting scheme is used to assess character reliability for both this procedure and classical cladogram construction. I illustrate the whole process by assessing the relationships between the species of the moss genus Didymodon sensu lato (Pottiaceae) and discuss the resulting caulogram by confronting it with the previous methodology from the evolutionary literature. I finally argue that strictly adhering to cladist epistemology is untenable and that we must seek new formal methods to find ancestral species as well as ancestral higher taxa.

Species delimitation in the recalcitrant moss genus Rhynchostegiella (Brachytheciaceae)

AbstractBryophytes, with their reduced morphologies and challenging taxonomy, appear as ideal candidates for the application of the fast‐developing tools of molecular species delimitation. Here, we apply species delimitation techniques to the moss genus Rhynchostegiella, which has long served as a convenient repository for small pleurocarpous species. Species delimitation analyses, including the Generalized Mixed Yule Coalescent approach and its Bayesian variant, congruently identified 13 putative species within Rhynchostegiella. To avoid inflation in the number of species with sympatric distributions that can only be recognized molecularly, we identified only one species when two or more molecular species were monophyletic, sympatric, and morphologically impossible to tell apart. After exclusion of 33 species from the genus based on earlier revisions or studies of type specimens, we recognized 11 Rhynchostegiella species. Eight of these species were already described, but were recircumscribed. In particular, the widespread R. litorea is split into three species with narrower distribution ranges: R. litorea s.str. occurs across continental Europe, western Asia and Africa (excluding Macaronesia), while R. pseudolitorea sp. nov. and R. tubulosa sp. nov. are Macaronesian and Aegean‐Cypriotic endemics, respectively. The Macaronesian endemic R. macilenta is reduced to synonymy with R. teneriffae while the Macaronesian endemic status of R. bourgeana is re‐instated. Altogether, Rhynchostegiella thus includes four Macaronesian endemic species, namely R. azorica, R. bourgeana, R. pseudolitorea, and R. trichophylla, making it the bryophyte genus with the highest number of Macaronesian endemic species. Given the difficulties in identifying some of those species from morphology, as highlighted in the identification key presented here, we describe easy‐to‐use DNA “barcodes” that can be a useful tool for specimen identification when key morphological characters lead to uncertain identification.