Group Of Ferns Research Articles

The Indo-Burma biodiversity hotspot for ferns: Updated phylogeny, hidden diversity, and biogeography of the java fern genus Leptochilus (Polypodiaceae)

The Indo-Burma Biodiversity Hotspot is renowned for its rich biodiversity, including that of vascular plants. However, the fern diversity and its endemism in this hotspot have not been well understood and so far, the diversity of very few groups of ferns in this region has been explored using combined molecular and morphological approaches. Here, we updated the plastid phylogeny of the Java fern genus Leptochilus with 226 (115% increase of the latest sampling) samples across the distribution range, specifically those of three phylogenetically significant species, Leptochilus ovatus, L. pedunculatus, and L. pothifolius. We also reconstructed the first nuclear phylogeny of the genus based on pgiC gene data. Based on molecular and morphological evidence, we identified three new major clades and six new subclades, redefined three existing species, discovered a number of cryptic species of the genus, and elucidated the evolution of the three most variable characters. Our divergence time analyses and ancestral area reconstruction showed that Leptochilus originated in the Oligocene and diversified from early Miocene and 15 dispersal events from lower to higher latitudes are identified. The evolution of three most important morphological characters is analyzed in a context of the new phylogeny. Our analysis showed that 30 (59% of total 51) species of Leptochilus occur in Indo-Burma hotspot, 24 (80% of the 30 species) of which are endemic to this hotspot. We argue that the Indo-Burma hotspot should be recognized as a diversity hotspot for ferns.

Exploring the diversity of the Java fern genus Leptochilus (Polypodiaceae) in the Indo-Burma Biodiversity Hotspot

The species diversity of certain groups of ferns in Indo-Burma Biodiversity Hotspot remains largely unexplored using combined molecular and morphological approaches. Here, based on morphology and an updated phylogeny of Leptochilus with 121 (115% increase of the latest sampling) new samples across Asia added, specifically those of three systematically significant “old” species, L. ovatus, L. pedunculatus, and L. pothifolius, we discovered 11 new species of the genus and made two new combinations. The new species are described in detail, the taxonomic treatment is given, and a key to the 51 currently known species of the genus is provided.

Genome-wide data reveal cryptic diversity and hybridization in a group of tree ferns

Discovery of cryptic diversity is essential to understanding both the process of speciation and the conservation of species. Determining species boundaries in fern lineages represents a major challenge due to lack of morphologically diagnostic characters and frequent hybridization. Genomic data has substantially enhanced our understanding of the speciation process, increased the resolution of species delimitation studies, and led to the discovery of cryptic diversity. Here, we employed restriction-site-associated DNA sequencing (RAD-seq) and integrated phylogenomic and population genomic analyses to investigate phylogenetic relationships and evolutionary history of 16 tree ferns with marginate scales (Cyatheaceae) from China and Vietnam. We conducted multiple species delimitation analyses using the multispecies coalescent (MSC) model and novel approaches based on genealogical divergence index (gdi) and isolation by distance (IBD). In addition, we inferred species trees using concatenation and several coalescent-based methods, and assessed hybridization patterns and rate of gene flow across the phylogeny. We obtained highly supported and generally congruent phylogenies inferred from concatenated and summary-coalescent methods, and the monophyly of all currently recognized species were strongly supported. Our results revealed substantial evidence of cryptic diversity in three widely distributed Gymnosphaera species, each of which was composite of two highly structure lineages that may correspond to cryptic species. We found that hybridization was fairly common between not only closely related species, but also distantly related species. Collectively, it appears that scaly tree ferns may contain cryptic diversity and hybridization has played an important role throughout the evolutionary history of this group.

Global patterns and climatic determinants of phylogenetic structure of regional fern floras.

Knowledge of relationships between phylogenetic structure of a biological assemblage and ecological factors that drive the variation of phylogenetic structure among regions is crucial for understanding the causes of variation in taxonomic composition and richness among regions, but this knowledge is lacking for the global flora of ferns. Here, we fill this critical knowledge gap. We divided the globe into 392 geographic units on land, collated species lists of ferns for each geographic unit, and used different phylogenetic metrics (tip- vs basal-weighted) reflecting different evolutionary depths to quantify phylogenetic structure. We then related taxonomic and phylogenetic structure metrics to six climatic variables for ferns as a whole and for two groups of ferns (old clades vs polypods) reflecting different evolutionary histories across the globe and within each continental region. We found that when old clades and polypods were considered separately, temperature-related variables explained more variation in these metrics than did precipitation-related variables in both groups. When analyses were conducted for continental regions separately, this pattern holds in most cases. Climate extremes have a stronger relationship with phylogenetic structure of ferns than does climate seasonality. Climatic variables explained more variation in phylogenetic structure at deeper evolutionary depths.

Phytochemical Characterization and In Vitro and In Silico Biological Studies from Ferns of Genus Blechnum (Blechnaceae, Polypodiales)

The genus Blechnum represents one of the most ecologically and therapeutically important groups of ferns that grow in tropical, subtropical and temperate regions. In this work, the chemical fingerprint of lyophilized extracts of Blechnum chilense, B. hastatum, B. magellanicum and B. penna-marina species, the determination of their antioxidant activity through ORAC, FRAP and DPPH assays and inhibition of cholinesterase enzymes (AChE and BChE), and an in silico analysis of selected majority compounds on cholinesterase enzymes were identified. Nineteen compounds were recorded for B. chilense, nine in B. hastatum, seventeen in B. magellanicum and seventeen in B. penna-marina by liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry (UHPLC-ESI-QTOF-MS). The content of phenolic compounds, flavonoids, antioxidant activity and enzyme inhibition were variable among species, with best results for B. penna-marina. Molecular docking evidenced low toxicities, significant pharmacokinetic properties, and significant binding affinities of the tested compounds for the AChE and BChE enzymes. These fern species show high diversity of bioactive compounds and represent a promising resource in phytotherapy, especially for their optimal levels of phenolic compounds that support their antioxidant activity.

Inventory of Ferns (Class: Filicinae) in West Block, Batang Toru Forest, North Tapanuli North Sumatra

Batang Toru Forest is one of the conservation areas in North Sumatra which has a diversity of flora and fauna, one of which is ferns. A study on ferns in the Batang Toru Forest area has never been carried out, so the species diversity and distribution are unknown. Ferns are classified into 4 classes, one of which is the Filicinae class. The class Filicinae is a group of ferns that has the highest number of species. This study aims to inventory the class Filicinae ferns in the Batang Toru Forest area by using the exploration method, namely exploring along the track. Found 52 species of ferns belonging to 14 families and 29 genera. Of the 52 species found, 33 species were classified as terrestrial ferns and 19 types of epiphytic ferns.

Deep vicariance and frequent transoceanic dispersal shape the evolutionary history of a globally distributed fern family.

The historical biogeography of ferns is typically expected to be dominated by long-distance dispersal due to their minuscule spores. However, few studies have inferred the historical biogeography of a large and widely distributed group of ferns to test this hypothesis. Our aims were to determine the extent to which long-distance dispersal vs. vicariance have shaped the history of the fern family Blechnaceae, to explore ecological correlates of dispersal and diversification, and to determine whether these patterns differ between the northern and southern hemispheres. We used sequence data for three chloroplast loci to infer a time-calibrated phylogeny for 154 of 265 species of Blechnaceae, including representatives of all genera in the family. This tree was used to conduct ancestral range reconstruction and stochastic character mapping, estimate diversification rates, and identify ecological correlates of diversification. Blechnaceae originated in Eurasia and began diversifying in the late Cretaceous. A lineage comprising most extant diversity diversified principally in the austral Pacific region around the Paleocene-Eocene Thermal Maximum. Land connections that existed near the poles during periods of warm climates likely facilitated migration of several lineages, with subsequent climate-mediated vicariance shaping current distributions. Long-distance dispersal is frequent and asymmetrical, with New Zealand/Pacific Islands, Australia, and tropical America being major source areas. Ancient vicariance and extensive long-distance dispersal have shaped the history of Blechnaceae in both the northern and southern hemispheres. The exceptional diversity in austral regions appears to reflect rapid speciation in these areas; mechanisms underlying this evolutionary success remain uncertain.

A revised subfamilial classification of Polypodiaceae based on plastome, nuclear ribosomal, and morphological evidence

AbstractThe polygrammoid fern family Polypodiaceae represents one of the most diversified epiphytic fern groups, with more than 1600 species distributed on all continents except Antarctica, with the highest species diversity in tropical and subtropical regions. Despite progress in recent phylogenetic studies of Polypodiaceae, the infrafamilial classification of this group of ferns is still problematic. Here, we explore the phylogenetic relationship within Polypodiaceae using plastid genome (plastome) and nuclear ribosomal cistron genome data obtained from high‐throughput sequencing. Although genome skimming data strongly support the monophyly of many genera and clades of Polypodiaceae, relationships within some clades and along the backbone of the phylogeny remain incongruent between plastome and nuclear data. The explanation is possibly a factor of complex evolutionary history found in these clades, such as rapid radiation, incomplete lineage sorting, ancient hybridization, and recent introgression. Based on the concatenated dataset, our phylogenetic analyses support nine major clades in Polypodiaceae, which merit the recognition as subfamilies, Crypsinoideae, Grammitidoideae, Loxogrammoideae, Microsoroideae, Platycerioideae, Polypodioideae, Adetogrammoideae, Campyloneuroideae, and Serpocauloideae, while the latter three are separated from Polypodioideae as new subfamilies. All of these infrafamilial divisions, identified with molecular data, are further supported by non‐molecular features including leaf dissection, venation, scales and paraphyses, soral features, and geographical distributions. Systematic and taxonomic discussions on the subfamilial treatment are also provided.

A global review and network analysis of phytophagous insect interactions with ferns and lycophytes

Ferns and lycophytes are the second and third largest lineages of vascular plants, yet our understanding of their interactions with phytophagous insects is very limited. In this study, we reviewed herbivorous insects, their feeding habits and host preferences on these two plant groups, searched for any evidence of coevolution, and discussed possible biases of our current knowledge on fern–insect interactions. We analyzed 2318 records of fern–insect interactions from 122 literature sources, based on the feeding habit of insects, fern taxa, and geographic location. We report interactions comprising 809 insect species (mainly Hemiptera, Lepidoptera, and Coleoptera) and 382 fern species (mainly Dennstaedtiaceae, Dryopteridaceae, and Pteridaceae). Leaf-chewers comprised over 50% of the species, followed by sap-sucking insects (29.1%) and spore feeders (6.5%). The overall interaction analyses revealed that the entire network was not significantly nested and had relatively low levels of specialization (H2′ = 0.24). The interaction networks of Coleoptera were the most specialized at family (H2′ = 0.40) and genus level (H2′ = 0.65), whereas six out of 10 most specialized insect families were Lepidoptera (d′ ≥ 0.44). At the genus level, all networks had a plant-biased asymmetry. Although insect specialists were common, few cases of coevolutionary radiation have been documented. We discuss the possible biases of our dataset, which also highlight gaps to fill in future research and suggest that many more fern-feeding insects remain to be discovered, especially sap-sucking, gall-forming, and spore-feeding insects on modern fern groups.

Pleopeltis (Polypodiaceae) in Brazil

Polypodiaceae is notable for being one of the richest, most diverse, and abundant groups of ferns in tropical and subtropical forests. Currently, 65 genera and approximately 1652 species are recognized in the family. Pleopeltis is a monophyletic genus and comprises approximately 90 species, most of which are exclusive to the Neotropics. The aim of this scientific contribution is a taxonomic treatment of the Pleopeltis species occurring in Brazil. It has been based on the morphological data of specimens from Brazilian and foreign herbaria, as well as on observations and collections made in the field. Eighteen species are recognized in Brazil and occur in all Brazilian biomes, notably the Atlantic Forest (16 spp.). At least one species occurs in all Brazilian states, and the states of Espírito Santo and Minas Gerais (southeastern Brazil) are the richest (11 spp. each). According to the Brazilian Flora Red List, three species are officially threatened, P. alborufula and P. monoides are endangered, and P. trindadensis is critically endangered; however, we suggest including two more species in the official list: P. aturensis and P. stolzei. The taxonomic treatment includes a genus description, identification key to the species, synonyms, species description, distribution maps, illustrations, list of specimens studied, taxonomic comments, and information on habitat and distribution.

Evolution of genome space occupation in ferns: linking genome diversity and species richness.

The dynamics of genome evolution caused by whole genome duplications and other processes are hypothesized to shape the diversification of plants and thus contribute to the astonishing variation in species richness among the main lineages of land plants. Ferns, the second most species-rich lineage of land plants, are highly suitable to test this hypothesis because of several unique features that distinguish fern genomes from those of seed plants. In this study, we tested the hypothesis that genome diversity and disparity shape fern species diversity by recording several parameters related to genome size and chromosome number. We conducted de novo measurement of DNA C-values across the fern phylogeny to reconstruct the phylogenetic history of the genome space occupation in ferns by integrating genomic parameters such as genome size, chromosome number and average DNA amount per chromosome into a time-scaled phylogenetic framework. Using phylogenetic generalized least square methods, we determined correlations between chromosome number and genome size, species diversity and evolutionary rates of their transformation. The measurements of DNA C-values for 233 species more than doubled the taxon coverage from ~2.2 % in previous studies to 5.3 % of extant diversity. The dataset not only documented substantial differences in the accumulation of genomic diversity and disparity among the major lineages of ferns but also supported the predicted correlation between species diversity and the dynamics of genome evolution. Our results demonstrated substantial genome disparity among different groups of ferns and supported the prediction that alterations of reproductive modes alter trends of genome evolution. Finally, we recovered evidence for a close link between the dynamics of genome evolution and species diversity in ferns for the first time.

A new method to determine the diet of pygmy hippopotamus in Taï National Park, Côte d’Ivoire

AbstractDiet determination of endangered species is an essential element in defining successful conservation strategies and optimising captive breeding programmes. In this study, we developed a new diet identification system, derived from standard faecal analysis, to determine the diet of an elusive and endangered herbivore, the pygmy hippopotamus (Choeropsis liberiensis). We collected faecal samples from 10 free‐ranging individuals covering a combined home range area of about 50 km2 in Taï National Park, Côte d’Ivoire. In subsequent laboratory analyses, we extracted a large number of leaf epidermis fragments from spatially separated faecal samples and compared them with a reference plant database. Using Multiple Correspondence Analysis (MCA) of epidermis fragments combined with direct visual inspection, we identified the most frequently consumed plant species, which revealed that pygmy hippopotami qualified as intermediate feeders. Their diet was based on at least seven species of monocotyledonae, dicotyledonae and fern groups, with a preference for a small number of other plant species. We evaluate the merit of our method and discuss our findings for developing effective conservation and captive breeding strategies in an endangered species with a wild population of less than 2500 adult individuals.

Plastid phylogenomics provides novel insights into the infrafamilial relationship of Polypodiaceae.

The polygrammoids (Polypodiaceae) are the most species-rich and diversified epiphytic fern lineages, and hold an important role to understand the deep diverging events and rapid adaptation to changing environments in the plant tree of life. Despite progress in the phylogeny of this group of ferns in previous multilocus phylogenetic studies, uncertainty remains especially in backbone relationships among closely related clades, and the phylogenetic placement of recalcitrant species or lineages. Here, we investigated the deep phylogenetic relationships within Polypodiaceae by sampling all major lineages and using 81 plastid genomes (plastomes), of which 70 plastomes were newly sequenced with high-throughput sequencing technology. Based on parsimony, maximum-likelihood, Bayesian and multispecies coalescent analyses of genome skimming data, we achieved a better resolution of the backbone phylogeny of Polypodiaceae. Using simulated data matrices, we detected that potential phylogenetic artefacts, such as long-branch attraction and insufficient taxonomic sampling, may have a confounding impact on the incongruence of phylogenetic inferences. Furthermore, our phylogenetic analyses offer greater resolution than previous multilocus studies, providing a robust framework for future phylogenetic implications on the subfamilial taxonomy of Polypodiaceae. Our phylogenomic study not only demonstrates the advantage of a character-rich plastome dataset for resolving the recalcitrant lineages that have undergone rapid radiation, but also sheds new light on integrative explorations understanding the evolutionary history of large fern groups in the genomic era.

Comparative genomic analysis of Polypodiaceae chloroplasts reveals fine structural features and dynamic insertion sequences

BackgroundComparative chloroplast genomics could shed light on the major evolutionary events that established plastomic diversity among closely related species. The Polypodiaceae family is one of the most species-rich and underexplored groups of extant ferns. It is generally recognized that the plastomes of Polypodiaceae are highly notable in terms of their organizational stability. Hence, no research has yet been conducted on genomic structural variation in the Polypodiaceae.ResultsThe complete plastome sequences of Neolepisorus fortunei, Neolepisorus ovatus, and Phymatosorus cuspidatus were determined based on next-generation sequencing. Together with published plastomes, a comparative analysis of the fine structure of Polypodiaceae plastomes was carried out. The results indicated that the plastomes of Polypodiaceae are not as conservative as previously assumed. The size of the plastomes varies greatly in the Polypodiaceae, and the large insertion fragments present in the genome could be the main factor affecting the genome length. The plastome of Selliguea yakushimensis exhibits prominent features including not only a large-scale IR expansion exceeding several kb but also a unique inversion. Furthermore, gene contents, SSRs, dispersed repeats, and mutational hotspot regions were identified in the plastomes of the Polypodiaceae. Although dispersed repeats are not abundant in the plastomes of Polypodiaceae, we found that the large insertions that occur in different species are mobile and are always adjacent to repeated hotspot regions.ConclusionsOur results reveal that the plastomes of Polypodiaceae are dynamic molecules, rather than constituting static genomes as previously thought. The dispersed repeats flanking insertion sequences contribute to the repair mechanism induced by double-strand breaks and are probably a major driver of structural evolution in the plastomes of Polypodiaceae.

Reinvestigation of the marattialean Zhutheca densata (Gu et Zhi) Liu, Li et Hilton from the Lopingian of Southwest China, and its evolutionary implications

Marattialeans were the most species-rich fern group in the Lopingian (late Permian) Cathaysian floras in the South China Block. However, most previous studies on marattialean ferns focused on their vegetative morphology; in contrast, their reproductive biology has rarely been examined. New compression materials of Zhutheca densata (Gu et Zhi) Liu, Li et Hilton from the Lopingian Xuanwei Formation in Qujing City, Yunnan Province, Southwest China, were studied and provide additional micromorphological and ultrastructural details about the reproductive organs of this marattialean plant. Reproductive organs of the Z. densata plant are characterized by radially symmetrical synangia in two or three rows on each side of the midvein, four to six exannulate sporangia laterally fused in a synangium, sporangial walls comprising three to four layers of cells, and monolete Laevigatosporites/Latosporites-type in situ spores. The spatiotemporal distribution of marattialean reproductive organs was analyzed based on a thorough comparison of 29 genera recorded in upper Paleozoic strata. Our analysis indicated that, during the Pennsylvanian and Permian periods, marattialeans with radially symmetrical synangia notably decreased in both diversification and distribution; in contrast, marattialeans with bilaterally symmetrical synangia notably increased in both diversification and distribution. After the Lopingian, marattialeans with bilaterally symmetrical synangia gradually became predominant in terms of their diversification and geographic distribution. Our study sheds new light on the evolution of marattialeans.

<p><strong>Insight of phylogeny and the number of sporangium annulus cells in <em>Coniogramme </em>ser. <em>Coniogramme</em></strong></p>

Coniogramme ser. Coniogramme is a perennial herbaceous fern group of the subfamily Cryptogrammoideae in Pteridaceae. The phylogenetic reconstruction of this series was performed using five chloroplast markers (matK/psbA-trnH/rbcL/rps4-trnS/trnL-F). The sporangium annulus cell numbers of eight species have also been counted and statistically assessed. The results showed that the present defined C. ser. Coniogramme is not a monophyletic group. Coniogramme merrillii, which has the highest number of annulus cells (median 18), is sister to the other species of this genus, and the number of sporangium annulus cells is stable at the species level and of great phylogenetic significance. It is not supported by both molecular and morphological evidence to synonymize C. merrillii, C. petelotii and C. gigantea in C. fraxinea. C. merrillii should be treated as a synonym of C. macrophylla, while C. lanceolata be accepted as a distinct species.

Cryptic diversity in the model fern genus Ceratopteris (Pteridaceae)

Cryptic species are present throughout the tree of life. They are especially prevalent in ferns, because of processes such hybridization, polyploidy, and reticulate evolution. In addition, the simple morphology of ferns limits phenotypic variation and makes it difficult to detect cryptic species. The model fern genus Ceratopteris has long been suspected to harbor cryptic diversity, in particular within the highly polymorphic C. thalictroides. Yet no studies have included samples from throughout its pan-tropical range or utilized genomic sequencing, making it difficult to assess the full extent of cryptic variation within this genus. Here, we present the first multilocus phylogeny of the genus using reduced representation genomic sequencing (RADseq) and examine population structure, phylogenetic relationships, and ploidy level variation. We recover similar species relationships found in previous studies, find support for the cryptic species C. gaudichaudii as genetically distinct, and identify novel genomic variation within two of the mostly broadly distributed species in the genus, C. thalictroides and C. cornuta. Finally, we detail the utility of our approach for working on cryptic, reticulate groups of ferns. Specifically, it does not require a reference genome, of which there are very few available for ferns. RADseq is a cost-effective way to work with study groups lacking genomic resources, and to obtain the thousands of nuclear markers needed to untangle species complexes.

Phylogeny and classification of the tribe Lepisoreae (Polypodiaceae; pteridophyta) with the description of a new genus, Ellipinema gen. nov., segregated from Lepisorus

Lepisoroid ferns (tribe Lepisoreae, Polypodiaceae) are arguably one of the most confusing fern groups in Polypodiaceae in terms of delimitation of genera largely because of their simple morphology. Previous molecular studies either had very small taxon sampling of the non-Lepisorus genera and did not well resolve the relationships among these genera, or had a relatively large sampling at species level but the critical species were missing or their relationships were not well resolved. A recent study resolved the newly sampled Lepisorus jakonensis as sister to the remaining genera in Lepisoreae excluding Paragramma, and the authors lumped all the six well recognized genera into Lepisorus. In the present study, to infer a phylogeny we used DNA sequences of five plastid markers (matK, rbcL, rbcL-atpB, rps4 &rps4-trnS, trnL &trnL-F) of 172 accessions representing ca. 44 species of non-Lepisorus genera and 54 accessions representing ca. 50 species of Lepisorus as ingroup, and 10 non-Lepisoreae accessions from the most closely related four genera (Leptochilus, Microsorum, Phymatosorus, and Goniophlebium) in Microsoroideae and one genus (Pyrrosia) in Platycerioideae. Our major results include: (1) All seven currently defined genera except Lepisorus in Lepisoreae are confirmed to be monophyletic; (2) The Lepisorus jakonensis clade is confirmed to be the second earliest diverged lineage in Lepisoreae; (3) Neolepisorus is resolved as sister to the rest in a clade containing all non-Lepisorus genera except Paragramma; (4) Lemmaphyllum is sister to a clade containing Lepidomicrosorium, Neocheiropteris, and Tricholepidium; and (5) Ellipinema gen. nov. is segregated from Lepisorus based on the phylogeny and morphology in order to stabilize the current usage of the existing six non-Lepisorus genera and species names in these genera. A key to all eight genera of Lepisoreae is provided.

Sporangia and Spores in the Fern Genera Spicantopsis and Struthiopteris (Blechnaceae, Polypodiopsida)

Struthiopteris (Blechnaceae) has recently been classified on the basis of molecular and morphological evidence, and some of its species are now included in the sister genus Spicantopsis. However, the lack of studies on several important morphological features impedes a sound assessment of their congruence with this new systematic arrangement, as well as of their range of variation and taxonomic value in this group of ferns. Here we present a study on the spores and sporangia using both light and scanning electron microscopy in Struthiopteris and Spicantopsis, using samples of all their species, and almost all their varieties. We provide full morphological descriptions of the spores and sporangia of all these taxa. We point out that the perispore structure and ornamentation and the number and the thickness of stomium cells in the sporangium clearly distinguish both genera.

The complete chloroplast genome of a Woodwardia japonica

Woodwardia japonica is one of the diverse members of the fern group and medicinally important genus. In Korea, the natural resources of W. japonica are being exhausted by excessive exploitation and require urgent conservation. In this study, the complete chloroplast genome of W. japonica was generated, and its structure was compared with that of other members of same family. The chloroplast genome was 153224 bp long, with a typical quadripartite structure including a pair of inverted repeat regions (24591 bp) separated by a large (82480 bp) and small (21562 bp) single-copy (SC) region. The genome encodes a total of 88 protein-coding genes, 35 tRNA genes, and eight rRNA genes. Additionally we identified 87 RNA editing sites in 52 genes; most of the substitution was U to C (50 sites), while C to U conversion occurred in 37 positions. The phylogenetic analysis strongly supported the relationship of W. japonica with W. unigemmata and. A. melanocaulon (Blechnoideae).