Phylogeny,character evolution,and classification of Selaginellaceae(lycophytes)

Selaginella is the largest and most taxonomically complex genus in lycophytes.The fact that over 750 species are currently treated in a single genus makes Selaginellales/Selaginellaceae unique in pteridophytes.Here we assembled a dataset of six existing and newly sampled plastid and nuclear loci with a total of 684 accessions(74%increase of the earlier largest sampling)representing ca.300 species to infer a new phylogeny.The evolution of 10 morphological characters is studied in the new phylogenetic context.Our major results include:(1)the nuclear and plastid phylogenies are congruent with each other and combined analysis well resolved and strongly supported the relationships of all but two major clades;(2)the Sinensis group is resolved as sister to S.subg.Pulviniella with strong support in two of the three analyses;(3)most morphological characters are highly homoplasious but some characters alone or combinations of characters well define the major clades in the family;and(4)an infrafamilial classification of Selaginellaceae is proposed and the currently defined Selaginella s.l.is split into seven subfamilies(corresponding to the current six subgenera t the Sinensis group)and 19 genera(the major diagnosable clades)with nine new species-poor genera.We support the conservation of Selaginella with a new type,S.flabellata,to minimize nomenclatural instability.We provide a key to subfamilies and genera,images illustrating their morphology,their morphological and geographical synopses,a list of constituent species,and necessary new combinations.This new classification will hopefully facilitate communication,promote further studies,and help conservation.

Prediction of Suitable Habitat for Lycophytes and Ferns in Northeast China: A Case Study on Athyrium brevifrons

Suitable habitat is vital for the survival and restoration of a species.Understanding the suitable habitat range for lycophytes and ferns is prerequisite for effective species resource conservation and recovery efforts.In this study, we took Athyrium brevifrons as an example, predicted its suitable habitat using a Maxent model with 67 occurrence data and nine environmental variables in Northeast China.The area under the curve(AUC) value of independent test data, as well as the comparison with specimen county areal distribution of A.brevifrons exhibited excellent predictive performance.The type of environmental variables showed that precipitation contributed the most to the distribution prediction, followed by temperature and topography.Percentage contribution and permutation importance both indicated that precipitation of driest quarter(Bio17) was the key factor in determining the natural distribution of A.brevifrons, the reason could be proved by the fern gametophyte biology.The analysis of high habitat suitability areas also showed the habitat preference of A.brevifrons: comparatively more precipitation and less fluctuation in the driest quarter.Changbai Mountains, covering almost all the high and medium habitat suitability areas, provide the best ecological conditions for the survival of A.brevifrons, and should be considered as priority areas for protection and restoration of the wild resource.The potential habitat suitability distribution map could provide a reference for the sustainable development and utilisation of A.brevifrons resource, and Maxent modelling could be valuable for conservation management planning for lycophytes and ferns in Northeast China.

Ferns and Lycophytes in Two Areas of Ecotone between Seasonal Semideciduous Forest and Mixed Ombrophilous Forest in Campo Mourão, Paraná, Brazil

The aim of the present study was to present the wealth, ecological characteristics and the floristic similarity of ferns and lycophytes from two forest areas of the municipality of Campo Mour?o, PR, Brazil. The vegetation of the municipality is characterized mainly by an ecotone between the Seasonal Semideciduous Forest and Mixed Ombrophilous Forest. We recorded 56 species, distributed in 31 genera and 16 families. The most representative families were Pteridaceae (14) and Polypodiaceae (11) and the wealthier genre was Thelypteris (6). The terricolous species were predominant (72%) and the preferential environments were riparian vegetation and forest interior (70%). The flora of Campo Mour?o was more similar to the studies conducted in the state of Rio Grande do Sul, and the cophenetic correlation coefficient (r = 0.9058) showed a consistent adjust. In the principal components analysis (PCA) the variance explained by the two principal components was 72.99%. The wealth found in this study corresponds to approximately 11.4% of the flora of ferns and lycophytes of Paraná. Future contributions are needed to increase the knowledge about the flora of ferns and lycophytes in areas of ecotone, mainly in the region of Campo Mour?o, where the studies are scarce.

Chemical constituents and biological activities of lycophytes and ferns

Lycophytes and ferns are unique and charismatic members of many terrestrial ecosystems and occupy the pivotal position in land plant origin and evolution.The Chinese lycophytes and ferns flora,with approximately 2000 species,contributes a substantial component to the global lycophytes and ferns diversity,with estimates of 12000 species.Among them,about 433 species are medicinally recorded and researches based on their phytochemical properties are important topics in natural medicines.This paper reviewed the research history and current status of chemical constituents and biological activities of lycophytes and ferns,which had highlighted the research progress of our group.

Paleo-polyploidization in Lycophytes

Lycophytes and seed plants constitute the typical vascular plants.Lycophytes have been thought to have no paleo-polyploidization although the event is known to be critical for the fast expansion of seed plants.Here,genomic analyses including the homologous gene dot plot analysis detected multiple paleo-polyploidization events,with one occurring approximately 13–15 million years ago(MYA)and another about 125–142 MYA,during the evolution of the genome of Selaginella moellendorffii,a model lycophyte.In addition,comparative analysis of reconstructed ancestral genomes of lycophytes and angiosperms suggested that lycophytes were affected by more paleopolyploidization events than seed plants.Results from the present genomic analyses indicate that paleo-polyploidization has contributed to the successful establishment of both lineages—lycophytes and seed plants—of vascular plants.

Lycophyte transcriptomes reveal two whole-genome duplications in Lycopodiaceae:Insights into the polyploidization of Phlegmariurus

Lycophytes are an ancient clade of the non-flowering vascular plants with chromosome numbers that vary from tens to hundreds.They are an excellent study system for examining whole-genome duplications(WGDs),or polyploidization,in spore-dispersed vascular plants.However,a lack of genome sequence data limits the reliable detection of very ancient WGDs,small-scale duplications(SSDs),and recent WGDs.Here,we integrated phylogenomic analysis and the distribution of synonymous substitutions per synonymous sites(Ks)of the transcriptomes of 13 species of lycophytes to identify,locate,and date multiple WGDs in the lycophyte family Lycopodiaceae.Additionally,we examined the genus Phlegmariurus for signs of genetic discordance,which can provide valuable insight into the underlying causes of such conflict(e.g.,hybridization,incomplete lineage sorting,or horizontal gene transfer).We found strong evidence that two WGD events occurred along the phylogenetic backbone of Lycopodiaceae,with one occurring in the common ancestor of extant Phlegmariurus(Lycopodiaceae)approximately 22-23 million years ago(Mya)and the other occurring in the common ancestor of Lycopodiaceae around 206-214 Mya.Interestingly,we found significant genetic discordance in the genus Phlegmariurus,indicating that the genus has a complex evolutionary history.This study provides molecular evidence for multiple WGDs in Lycopodiaceae and offers phylogenetic clues to the evolutionary history of Lycopodiaceae.