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Fossil floras have been recovered from a unique deposit of early Permian age in North-Central Texas. The site, Kola Switch, preserves three distinct floras in different lithofacies, in a succession from a single outcrop. The sedimentary environment appears to be a floodplain channel fill of primarily siltstones and claystones. The lowermost flora, preserved in a kaolinitic siltstone, indicates active water flow. It is dominated by plants typical of well-drained substrates, dominated by Sphenopteris germanica, and contains no wetland elements. The middle flora is from a finely laminated carbonaceous claystone and is dominated by marattialean tree ferns, with no elements from habitats typical of seasonal moisture availability. It contains no roots and appears to have formed as a floating peat mat. The upper flora is a mixed assemblage of wetland taxa and those typical of well-drained soil environments or a seasonal rainfall regime. Unlike the two lower floras, it has a relatively even distribution of dominance and is the most diverse of the three assemblages. Palynofloras also were recovered from each of these beds. The palynofloras, although varying between and even within the beds, indicate a common background species pool during the time interval sampled, suggesting that these distinct floras reflect local changes in microhabitat conditions under a constant climatic background. The palynoflora from each bed has characteristics in common with the macroflora of that bed, but also distinct differences. Together, the macroflora and microflora provide an unusually broad picture of this site through time. Kola Switch compares favorably with the recently described flora from the nearby Sanzenbacher Ranch site of approximately the same age and also with floras of Rotliegend age from Central Europe.

Pecopteris (Brongniart) Sternberg is a morphological fossil genus with a cosmopolitan distribution during the Permo–Carboniferous, of which most species belong to the marattialean and or "filicalean" ferns or less frequently to pteridosperms. The taxonomic affinity is uncertain unless distinctive reproductive organs or rachis anatomy is known. Among the numerous species of Pecopteris in the Permian Wuda Tuff Flora, Inner Mongolia, China, Pecopteris lativenosa Halle has been considered as a pteridosperm based on its larger variation of frond morphology, although evidence of fertile organs or rachises are unknown. Newly discovered specimens of this species from the Wuda Tuff Flora are mostly impression fossils. However, some have partially permineralized petioles and have fronds in organic connection to Caulopteris -type stem. Fronds are tripinnate; penultimate pinnae lengths are variable as are ultimate pinnae lengths. Pinnules are oval and thick, and their midveins are straight and are of stable thickness. Lateral veins are dense, bifurcating 1–3 times. Petiole and rachises are anatomically preserved and show sclerenchyma, fundamental tissue and vascular tissue. Vascular bundles of petioles and rachises are C-shaped with two laterally inrolled ends, which are typically stewartiopterid petiole/rachis of Marattiales. These features allow us to assign Pecopteris lativenosa to the late Paleozoic marattialean family Psaroniaceae. [ABSTRACT FROM AUTHOR]

Premise of research. Fern fronds are common in Late Paleozoic and Mesozoic strata. Large tri- or multipinnate fronds are mainly preserved as impression/compressions, while anatomically preserved specimens are typically smaller and comprise dispersed petioles, rachides, ultimate pinna, and pinnules. Here, we describe a large, anatomically preserved tripinnate frond from the latest Permian of southwest China that provides the first detailed histological information for a Cathaysian marattialean with pinnule morphology of the cosmopolitan Carboniferous-Permian pecopteriod type, but with different frond anatomy. Methodology. Specimens were prepared by the cellulose acetate peel technique and studied by light microscopy. Pivotal results. The tripinnate frond has a main rachis and a primary pinnae rachis with many (>70) small vascular bundles arranged in cycles and abundant tanniferous cells. Pinnules are small, and their bases are entirely attached to the ultimate rachis. Abundant vascular bundles in the rachises are distinct from previously recognized marattialean genera, justifying the establishment of Rothwellopteris pecopteroides gen. et sp. nov. Comparison of pinnule morphology with impression/compression fossils shows the specimen to be an anatomically preserved equivalent of Pecopteris marginata Li et al. Conclusions. Rothwellopteris pecopteroides displays a novel combination of marattialean characters from the extinct Paleozoic family Psaroniaceae and the extant family Marattiaceae. Its frond morphology resembles Psaroniaceae including Psaronius but differs from extant Marattiaceae that are monopinnate, palmate, or, as in Angiopteris , bipinnate and that have large pinnules with contracted bases. By contrast, its anatomy, with abundant vascular bundles, is similar to Marattiaceae, especially Angiopteris , but it is distinct from members of the Psaroniaceae in which the rachis possesses one or two tangentially elongate vascular bundles. Pecopteris marginata shows that, by the latest Permian, Marattiales had already evolved frond anatomy typical of extant genera, demonstrating that the stem group to crown group transition commenced prior to the Triassic. [ABSTRACT FROM AUTHOR]

Premise of research. The Río Genoa Formation of Argentine Patagonia hosts Early Permian fossil assemblages that document levels of plant diversity rare among coeval floras. Ongoing work to exhaustively characterize the diversity of these assemblages is key to understanding Permian vegetation and plant evolution. A new fern type identified in the Río Genoa Formation exhibits a novel combination of characters that required taxonomic assessment. Methodology. Observations and measurements of vegetative and reproductive morphology of compression fossils were used in a comparative framework to address the taxonomic placement of the fossils. Pivotal results. The new fern, Floratheca apokalyptika gen. et sp. nov., is characterized by small pinnules with a free base, weakly lobed margin, highly decurrent midvein, and rarely branched lateral veins, as well as radially symmetrical synangia with stellate dehiscence, consisting of six spindle-shaped sporangia. This unique combination of characters distinguishes Floratheca from the more than 25 Permo-Carboniferous marattialean genera known from compressions. Floratheca exhibits variable synangium morphology during development and variation in pinnule base morphology due to a combination of adaxial-abaxial asymmetry of ultimate rachises and taphonomic effects. Conclusions. Floratheca is one of only three late Paleozoic bona fide marattialean compression genera endemic to Gondwana and the second late Paleozoic endemic South American marattialean with preserved fertile structures. Floratheca adds to an increasing diversity of fossils that diminish the disparity between the Southern and Northern Hemispheres, in terms of the extent and intensity of exploration of the plant fossil record, currently skewed taxonomically toward Northern Hemisphere taxa. Variability of synangium and pinnule base morphology in Floratheca cautions against potential taxonomic inflation produced by establishment of new taxa based on small numbers of specimens and incomplete understanding of development and taphonomy. [ABSTRACT FROM AUTHOR]

Premise of the Study: Recent clarification of the distribution of Marattiales through time provides the impetus for “total evidence” phylogenetic analyses of a major fern clade with a rich fossil record. These analyses serve as empirical tests for results from systematic analyses of living species and also of the belief that relationships among living species accurately reflect the overall pattern of phylogeny for clades with an extensive fossil record and a large percentage of extinction. Methods: Species of living and fossil Marattiaceae are analyzed employing a “total evidence approach” via maximum parsimony. Analyses were conducted using TNT implemented through WinClada. Key Results: Systematic analyses of living species and of living + extinct species provide roughly concordant topologies for living taxa. However, living species of Marattiales are only one component of a much larger clade with two major subclades. One consists of Psaroniaceae and extends through time to at least the Early Cretaceous. The other consists of Marattiaceae and includes all living species. Various analyses support the generic‐level clades of living species from earlier analyses, but the arrangement of such clades varies from analysis to analysis. Conclusions: Marattiales is a monophyletic group that is extremely common in late Paleozoic and early Mesozoic deposits, with a stem group Psaroniaceae and a crown group Marattiaceae. Because Marattiaceae represents only a small component of overall marattialean diversity, living species alone neither account for evolutionary changes within the clade over time, nor accurately reflect the overall pattern of marattialean fern phylogeny. [ABSTRACT FROM AUTHOR]

Much is known about the biology and ecology of the plants that comprised the forest ecosystems during the Carboniferous and Early Permian. However, a broad understanding of the interrelatedness between the plants and other organisms living in these forests has been slow to develop. The tree fern Psaronius (Marattiales), an important element in many Pennsylvanian and Early Permian peat-forming forest ecosystems, gained mechanical stability from a massive root mantle. Thin sections of a permineralized Psaronius root mantle from the Manebach Formation (Asselian, Lower Permian/Cisuralian) near Ilmenau, Germany, show a diverse assemblage of predominantly intracellular fungi in all root tissues. Especially interesting is a fungus that produces prominent, boot-shaped swellings close to where it passes through host cell walls and what appear to be physiological interfaces comprised of short, densely clustered hyphal branches within the host cells. Other fungal remains occur in the form of chytrid-like sporangia, several types of basidiomycete hyphae with simple, medallion, and ampulliform clamp connections, and tenuous mycelia resembling present-day ‘fine endophytes.’ This fungal assemblage represents one of the best preserved Carboniferous-Early Permian fungal communities documented to date. It strengthens the hypothesis that plant-fungus associations were highly diverse and complex in late Paleozoic forests, likely because many plants in these ecosystems were long-lived and complex in morphology and internal organization, and thus provided multiple contact sites and ecologically distinct microhabitats for fungi. [ABSTRACT FROM AUTHOR]

The eusporangiate fern order Marattiales are represented in the living flora by the family Marattiaceae but have an extensive fossil record stretching back to the Carboniferous. The family Psaroniaceae included important wetland plants in the Carboniferous and Permian. In this work we present a new member of the Psaroniaceae from the Lloyd Cove Seam of the Brogan's Mine, Sydney Coalfield, Nova Scotia, Canada dated to the Kasimovian Stage (lower Stephanian, Pennsylvanian) of the Carboniferous. The new fern is represented by a small specimen with distinctive fertile pinnules and reproductive organs including large synangia that possess a well-developed synangial sheath with a central parenchymatous filling. Small monolete in situ spores are compared to the dispersed miospore species Punctatosporites pygmaeus. Based on well preserved reproductive organs, we are proposing a new species Diplazites campbellii sp. nov. A new evolutionary model combining species that produced the smallest monolete spores and significant characters of their reproductive organs is suggested. Four following subgroups are suggested: the Unita , Hemitelioides , Multisporangiate and Crenulopteris. • Well preserved a new reproductive organs from adpression. • New species Diplazites campbellii. • Evolutionary context of marattioid ferns. • Detailed discussion of ferns having small monolete spores. [ABSTRACT FROM AUTHOR]

Marattiaceous ferns are conspicuous fossil element in upper Paleozoic and lower Mesozoic deposits, but become rarer to almost absent in Cretaceous to Holocene deposits. In this contribution, fragmentary synangia recovered from the Aptian Cerro Negro Formation (Livingston Island, Antarctica) are described. Synangia are bivalvate, containing at least four lachrymiform sporangia per valve. Valves are fused at the base, and connect to the leaf blade by a short peduncle. Sporangia contain more than 400 oval to reniform (probably monolete), smooth to microgranulate spores. The reproductive structures have morphological similarities with extant Marattia and Ptisana , and the apparent absence of labia suggests a closer relationship with the latter genus. The presence of Marattiaceae, along with previously described ferns (e.g. Cyatheales) supports warm climatic conditions during the Aptian in this region of Antarctica. [ABSTRACT FROM AUTHOR]

The genus Asterotheca is a representative marattialean fern of reproductive organs associated with Pecopteris fronds in the Late Paleozoic. The species of Asterotheca orientalis (Schenk) Potonié has a wide distribution in Eastern Asia, and for a long time it has been regarded as an index fossil of the Early Permian floras in North China. However, the detailed structures of sporangia and in situ spores for A. orientalis were poorly understood. In this study, exceptionally well-preserved fertile specimens of A. orientalis from the Lower Permian Kaipaicileike Formation in the Tarim Basin, Xinjiang, northwestern China, were investigated based on the studies on the material using light and scanning electron microscopies. Fertile pinnules are morphologically similar to sterile ones but bear Asterotheca -type synangia. Each synangium consists of a ring of 4–6 sporangia. The spores are trilete, with circular to subcircular amb, diameter of ca. 40 μm, and granulate sculpture. Comparisons were made between A. orientalis spores and those of other related in situ spores, as well as dispersed spores based on morphological and microstructural evidence. The dispersed spore species of Cyclogranisporites minutus (Bharadwaj)share the closest similarities in both the shape and size with in situ spores of A. orientalis. The present observations on the fertile organs of A. orientalis enrich diversity of the Asterotheca in situ spores, and provide clues for further understanding on the systematics and evolution of marattialean plants fen linage. • Exceptionally well-preserved compression and impression material of Asterotheca orientalis were investigated. • Fertile organs including synangia, sporangia and in situ spores were examined in details • General morphological reconstruction of Asterotheca orientalis was proposed. • New insights for further understanding the systematics and evolution of fossil marattialean fern linage. [ABSTRACT FROM AUTHOR]

The “Monilophyte” clade comprising ferns, horsetails and whisk ferns receives unequivocal support from molecular data as the sister clade to seed plants. However, the branching order of its earliest emerging lineages, the Equisetales (horsetails), the Marattiales, the Ophioglossales/Psilotales and the large group of leptosporangiate ferns has remained dubious. We investigated the mitochondrial nad2 and rpl2 genes as two new, intron-containing loci for a wide sampling of taxa. We found that both group II introns – nad2i542g2 and rpl2i846g2 – are universally present among monilophytes. Both introns have orthologues in seed plants where nad2i542g2 has evolved into a trans -arrangement. In contrast and despite substantial size extensions to more than 5 kb in Psilotum , nad2i542g2 remains cis -arranged in the monilophytes. For phylogenetic analyses, we filled taxonomic gaps in previously investigated mitochondrial ( atp1 , nad5 ) and chloroplast ( atpA , atpB , matK , rbcL , rps4 ) loci and created a 9-gene matrix that also included the new mitochondrial nad2 and rpl2 loci. We extended the taxon sampling with two taxa each for all land plant outgroups (liverworts, mosses, hornworts, lycophytes and seed plants) to minimize the risk of phylogenetic artefacts. We ultimately obtained a well-supported molecular phylogeny placing Marattiales as sister to leptosporangiate ferns and horsetails as sister to all remaining monilophytes. In addition, an indel in an exon of the here introduced rpl2 locus independently supports the placement of horsetails. We conclude that under dense taxon sampling, phylogenetic information from a prudent choice of loci is currently superior to character-rich phylogenomic approaches at low taxon sampling. As here shown the selective choice of loci and taxa enabled us to resolve the long-enigmatic diversifications of the earliest monilophyte lineages. [ABSTRACT FROM AUTHOR]

Amongst the species referred to the genusLobatopterisWagner, 1959, three are especially abundant:Lobatopteris micromiltonii(Bertrand ex Corsin) Wagner,Lobatopteris vestita sensuWagner (1959) andLobatopteris lamuriana(Heer) Wagner. However, despite their biostratigraphical significance the taxonomy of these three species has remained poorly resolved and their nomenclature, typification and generic position problematical. This paper attempts to correct these deficiencies and, based upon new characters, transfers these taxa to the new genusCrenulopterisWittryet al. gen. nov. Biostratigraphically, reassignment of these taxa does not impact the validity of the scheme introduced by Wagner (1984) and modified by Cleal (1991), but does necessitate the re-naming of some biozones. [ABSTRACT FROM AUTHOR]

A new fossil eusporangiate fern Marattiopsis vodrazkae J. Kvaček, sp. nov. has been recovered from the Hidden Lake Formation, the Campanian of James Ross Island, Antarctica. Its fertile and sterile pinnules are described and compared to the other species of the fossil genus Marattiopsis Schimper and the living genera Marattia, Ptisana and Eupodium (Marattiaceae). In contrast to the other species of the genus Marattiopsis, M. vodrazkae is characterised by stalked synangia, a smaller number of sporangia per synangium, generally small sized pinnules, and the absence of venuli recurrentes. It shows a mosaic of characters present in the living Marattiaceae: it shares stalked sporangia with the genus Eupodium and some species of Marattia and exhibits a suture (an abscission scar at pinnule bases), a character typical for the genus Ptisana. Additionally, M. vodrazkae provides important palaeoenvironmental signals for climate reconstructions, arguing for warm (paratropical to warm-temperate) and humid climatic conditions on the Antarctic Peninsula and adjacent volcanic islands during the Campanian. [ABSTRACT FROM AUTHOR]

Abstract: This study concerns silicified fertile pecopterid pinnae from the Permian of the Parnaíba Basin, State of Tocantins, northern Brazil, attributed to a new fern taxon of Marattiales, Buritiranopteris costata gen. nov. et sp. nov. This fern bears groups of three or four sporangia radially arranged in closely spaced synangia, as in some species of Scolecopteris and Acitheca, but they are completely enclosed in thick and long down-curved foliar lobes. This morphology may represent a xeromorphic adaptation against long seasonal drought and direct solar irradiation. These pinnae obviously belonged to one of the abundant marattialean tree ferns, most probably Tietea, which were apparently successful as riparian vegetation of ephemeral rivers. [Copyright &y& Elsevier]

Abstract: A new species of permineralised marattialean fern trunk is described from Lopingian (late Permian) aged volcaniclastic tuffs from Panxian County, western Guizhou Province, China and named Psaronius xuii sp. nov. The stem has vascular bundles that are encircled by a bi-layered sheath and has a ground tissue consisting of thicker-walled and thinner-walled parenchymatous cells and dispersed nests of sclerenchymatous cells. Two sclerenchymatous strands occur between neighboring stelar cycles, with this species lacking a peripheral sclerenchyma sheath and possessing a “chrysanthemum”-shaped sclerenchyma strands in the adaxial bay of the peripheral vascular bundles. Although distinct from other species, comparisons demonstrate a consistent organisation amongst contemporaneous species from South Cathaysia that have sclerenchymatous strands in the adaxial bay of the peripheral vascular bundles, vascular bundles and leaf traces surrounded by a vascular bundle sheath, and the middle part of the leaf trace is depressed inward after departing from the peripheral vascular bundle. These features are used to define the Panxianensis Group named after the most comprehensively known species, P. panxianensis. Species within the Panxianensis Group differ from other species from the Carboniferous and Permian floras of Euramerica, Gondwana and North Cathaysia that we place in the Blicklei Group that lack sclerenchymatous strands in the adaxial bay of the peripheral vascular bundles, lack vascular bundle sheaths, and the middle part of the leaf trace is arched outwards when they depart from the peripheral vascular bundles. Members of the Panxianensis Group appear to represent a relatively derived group that appears to be endemic to South Cathaysia, with these presumably evolving from members of the Blicklei Group in the Cisuralian or Guadalupian. [Copyright &y& Elsevier]

Abstract: During the Middle–Upper Triassic the fern genus Danaeopsis was widely distributed in both hemispheres. Danaeopsis fronds are simple pinnate with elongate pinnae characterised by a strong midrib and secondary veins that anastomose near the margin. The sporangia of the fertile pinnae are roundish and organised in two parallel rows between the veins. From the main collections of Triassic plants in Europe more than 750 specimens belonging to this genus have been studied and this study has been implemented with literature data. After this study four different species can be distinguished in Europe, based on the angle of pinna attachment to the rachis and the venation pattern: Danaeopsis angustifolia (pinnae attached perpendicularly, almost no anastomosing near the margin), Danaeopsis marantacea (pinnae attached perpendicularly, anastomosing of secondary veins covering up to 1/3rd of the lamina), Danaeopsis lunzensis (pinnae attachment acute, anastomosing of secondary veins covering up to half of the lamina) and Danaeopsis fecunda (pinnae attachment acute, veins anastomose scarcely near the margin). From three species, D. marantacea, D. lunzensis and D. fecunda, trilete in situ spores were extracted which differ only in dimensions. Danaeopsis belongs to the Marattiaceae and represents, together with Symopteris, the ferns with the biggest fern fronds during the Middle–Late Triassic. Although no complete fronds were found so far, the fronds probably reached a length of 1–2m. [Copyright &y& Elsevier]

The genus Asterotheca, represented by Asterotheca cf. pitnitzkyi (Frenguelli) emend Vieira et al. 2007 is described for the first time from the Upper Permian Tacuary Formation of Paraguay. Those forms are widely distributed in the levels of similar age of the Paraná Basin as such but also under names like Pecopteris pedrasica Read and P. cambuhyensis Read and perhaps also P. taguaiensis Rohn & Rösler, and P. dolianitii Rohn & Rosler and P. cadeadensis Rohn & Rosler. The polymorphism of those taxa is also briefly discussed. It is possible also that, given the big size of the frond, the species could be related with Tuvichapteris Herbst, a big marattialean fern known from its stem anatomy in Paraguay. It seems noteworthy that this fern is not accompanied by any other fossil plant at the source levels. [ABSTRACT FROM AUTHOR]

Abstract: Several European species of the Triassic fern genus Symopteris Xu are studied and the genus is subsequently subject to revision. Moreover, the botanical affinity of the genus is discussed and its relation to the Marattiales debated. Symopteris fronds have a typical fasciculate venation, usually a crenulate pinnule margin and contracted pinnule bases; in addition, the margin of the fertile pinnules is recurved to supposedly protect the sporangia. Most of the fossils have originally been attributed to the genus Bernoullia Heer, a junior synonym of Bernoullia Oliver (extant Bombacaceae). So far, eight species could be identified, three from Europe [Symopteris helvetica (Heer) Xu in Xu et al., Symopteris lunzensis (Stur ex Krasser) Xu in Xu et al., Symopteris rumpfii (Schenk) nov.comb.], one from Kazakhstan (Symopteris aktjubensis Brik) and four from East Asia [Symopteris zeilleri (P''an) Xu in Xu et al., Symopteris pecopteroides (Feng et al.) nov. comb., Symopteris densinervis Xu et Duan in Xu et al., Symopteris pseudolobifolia (Yang in Chen et al.) nov. comb.]. One additional species assigned earlier to Bernoullia (i.e. Bernoullia waehneri Stur) has to be attributed to another genus. The oldest known representatives of Symopteris occurred in the Ladinian of Europe; during the Upper Triassic, the genus increased in species number in Europe and Asia, while the latest occurrence is in the Rhaetian of Vietnam. [Copyright &y& Elsevier]

Abstract: Psaronius housuoensis sp. nov. is described from the Upper Permian Xuanwei Formation deposits of Housuo Coal Mine, Fuyuan County, Yunnan Province, southwest China, adding to the marattialean fern community of the Cathaysian flora. The permineralized stem shows a polycyclic dictyostele with five leaf traces arranged in a helical manner and exhibiting 2/5 phyllotaxy. Vascular bundles arranged in 6 concentric rings with cauline bundles in 5 radial rows. Stem bound externally by a peripheral sclerenchyma sheath. Leaf trace configuration comprised of three vascular bundles resulting from the division of a single originally C-shaped strand. Ground tissue replaced with coprolites and sediments. Stem surrounded by a thick mantle of roots. Occurrence of coprolites within the stem indicates well developed plant–animal interaction during the Late Permian times and that the habitat in which Psaronius grew was abounding with diversity of arthropod or the oribatid mite community preferring the rotting P. housuoensis sp. nov. stem ground tissue as a suitable microenvironment for shelter. Evolutionary pattern of leaf trace development is described in the new species and its possible ecological significance. [ABSTRACT FROM AUTHOR]

Abstract: The Pennsylvanian foliage morphogenus Lobatopteris is commonly referred to the marattialean ferns based on the presence of synangia in fertile specimens. This paper reports on a seed-bearing frond segment from the Westphalian D (Upper Pennsylvanian) of the Zwickau–Oelsnitz Basin, Germany, that corresponds to Lobatopteris with regard to gross morphology and venation. Seeds are ovoid and occur in place of basiscopic pinnules positioned proximally on the ultimate pinnae. Lateral extensions of the seed integument appear to form two wings in a primary plane. Discovery of a seed-bearing lobatopterid reveals that this type of foliage was not exclusively produced by ferns, but also by seed plants. [ABSTRACT FROM AUTHOR]

A marattialean trunk of Psaronius laowujiensis sp. nov. is described from the Upper Permian of the Xuanwei Formation, Panxian County, Guizhou Province, South China. The specimen most likely represents the lower part of the trunk, because the preserved thickness of the root mantel is somewhat larger than the diameter of the stem. Meristeles of the stem are arranged in approximately five tangential stelar cycles but not in radial files. Inner meristeles are in small number, ∼12-13, and loosely arranged. Leaf traces diverge helically and are organized in a 2/5 phyllotaxy. The leaf base vascular configuration consists of three strands that include a large U-shaped, centrifugal strand, a small centripetal strand, and an inverted ϙ-shaped internal strand. A vascular bundle sheath one or two cell layers thick surrounds each meristele. Within the centripetal concavity of each peripheral cauline bundle there are anchor-shaped sclerenchymatous strands. Ground tissue appears to consist of aerenchymatous parenchyma, in which secretory cavities are dispersed. Bound roots mostly possess seven to nine protoxylem poles. The vascular bundle sheath is one or two cell layers thick. The inner cortex consists of aerenchymatous parenchyma. A detailed comparison of the present specimen with known species of Psaronius from the Permian of South China is made. Our specimen is similar to Psaronius wangii in many aspects, but the two can be clearly distinguished by the structure of the ground tissue of the stem and the leaf base vascular configuration, which leads to the erection of a new species, P. laowujiensis, for this specimen. Certain important characters in species from the Permian of South China are discussed. The tree- or anchor-shaped sclerenchymatous configuration within the centripetal concavity of the peripheral cauline bundles is unique to species from the South China Permian. The permanent vascular bundle sheath surrounding the meristeles of the stem and the stele of the root is another remarkable feature of those species. The analogous tissue, termed "inner cortex" by certain authors, is also present in some Psaronius from the Euramerican and North China floras, but in those cases it is thinner walled and not as remarkable as the vascular bundle sheath in the species from South China. The leaf base vascular configuration of the species from the Permian in South China is more diverse than those from other places. [ABSTRACT FROM AUTHOR]

Abstract: Pinnules of the holotype of Filicites miltoni Artis (Duckmantian–early Moscovian, Middle Pennsylvanian age) have two rows of synangia, one on each side of the midvein. Each synangium is borne on a short receptacle and consists of three or four claviform sporangia that are separated from each other along most of their length. The sporangia contain trilete spores with a microverrucate to microgranulate exine. F. miltoni appears to be congeneric with the syntypes of Pecopteris vestita Lesquereux, which is the type species of the morphogenus Lobatopteris Wagner. [Copyright &y& Elsevier]

A new species of the Marattialean fern frond Rothwellopteris is proposed for specimens preserving both morphology and anatomy from the Wuchiapingian–Changshingian (late Permian) aged Xuanwei Formation of South China. Fronds are at least bipinnate and bear falcate, pecopteroid pinnules with a thin lamina. The penultimate pinna rachis has a polycyclic vascular system with endarch primary xylem and longer vascular bundles located abaxially in a single radial row, and shorter vascular bundles adaxially arranged in two radial rows, with a vascular bundle sheath of sclerenchyma cells. Ground tissue comprises parenchyma cells and numerous secretory ducts. Features of the new species suggest that it was adapted for mesomorphy, while the previously recognized species Rothwellopteris pecopteroides was adapted for xeromorphy or was a sun-leaf. Like R. pecopteroides , the new species displays a mosaic of morphological and anatomical features characteristic of both the Paleozoic family Psaroniaceae and the extant family Marattiaceae; we interpret it to be a member of the evolutionary stem-group from which stratigraphically younger Marattiaceae evolved. Our findings show that the stem- to crown-group transition within Marattiales commenced before the end of the Permian and that a greater diversity of transitional forms can now be recognized from the late Permian and include the genera Compsopteris, Rothwellopteris , Tietea and Tuvichapteris. • New species of the Marattialean fern Rothwellopteris established. • Species displays a mosaic of features from Paleozoic Psaroniaceae and extant Marattiaceae. • Species placed in the evolutionary stem group lineage from which Marattiaceae evolved. • Crown to stem group transition in Marattiales commenced before the Triassic period. • Species of Rothwellopteris adapted for either xeromorphy or mesomorphy. [ABSTRACT FROM AUTHOR]

A new species of the marattialean fern trunk Psaronius Cotta is described from the Upper Permian Cathaysian flora in the Xuanwei Formation of Guizhou Province, SW China, and named P. panxianensis sp. nov. Stems possess a helically diverging sequence of leaf traces organized in a 2/7 phyllotaxy and are characterized by stages of leaf trace development that include an early ontogenetic stage with a single vascular bundle ( Stewartiopteris-type), a middle stage with two vascular bundles ( Stipitopteris-type), and a late stage with three vascular bundles. Roots diverge singly or occasionally in pairs, arising alternately from the centrifugal surface of the peripheral cauline bundles (PCB) near the tip, and form both bound and free root mantles. This species is distinguished from all previously recognized species from the Euramerican and Gondwana floras in having an anchor-shaped sclerenchymatous strand internal to the PCB and a large V-shaped strand formed by the connection of two anchor-shaped strands. Psaronius panxianensis sp. nov. is important as its leaf traces show three distinct ontogenetic development stages within the trunk, with this organization interpreted as a derived condition within psaroniaceous marattialean fern evolution. In the stem abundant air space suggests that P. panxianensis lived in waterlogged substrates with aerenchyma facilitating gaseous exchange. However, the presence of marattialean fern dominated communities in the Upper Permian of SW China suggest an overall drying trend with these plants replacing earlier lycopsid and sphenopsid dominated wetland communities. [ABSTRACT FROM AUTHOR]

Marattia aganzhenensis sp. nov. from the Lower Jurassic Daxigou Formation of Lanzhou, Gansu, China, is the second species of Marattia known in fertile structure from China, in addition to Marattia asiatica. The new species demonstrates the variability of the genus through its distinct character states. This new species is distinguished by the absence of venuli recurrentes, the shorter synangia, exclusively monolete spores without surface ornamentation, and the low number of spores produced per sporangium. [ABSTRACT FROM AUTHOR]

The article presents a study that determines the complete plastid genome of the fern plant Angiopteris evecta that belongs to the family of marattioid ferns. The authors used flourescence activated cell sorting (FACS) to classify organelles. They found out that several unique characters are observed in the genome, like a repeat structure in a pseudogene.

Several isolated marattialean synangia and sporangia are reported from coal balls collected from Coal Seam No.1 (C605) in the uppermost Permian Wangjiazhai Formation in Guizhou Province, south-western China. The synangia are radially symmetrical with diameters between 0.8 and 1.2 mm and are 1.7 mm long, consisting of 3–4 elongate sporangia that are fused basally, free distally and possess a pointed apex. The outer-facing sporangial wall is 4–5 cells thick and conspicuously differentiated. Spores are trilete, have a granular ornamentation and are nearly round equatorially with a diameter of 55–60 µm. Comparisons with other anatomically preserved Palaeozoic marattialean synangia from the Euramerican and Cathaysian floras permit their assignment to the genus of Scolecopteris (Zenker) Millay. In this species the thick, outer-facing sporangial walls and large trilete spores are features consistent with those of the Oliveri Group within Scolecopteris, a group that has previously been considered primitive within this genus. Distinctions from all other previously recognized species within the Oliveri Group lead to the creation of a new species, S. guizhouensis sp. nov. This species is the youngest of the reported species of Scolecopteris recognized from the Euramerican and Cathaysian floras, and provides important evidence on the organization of marattialean ferns from the Upper Permian strata of south China. © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society, 2006, 151, 279–288. [ABSTRACT FROM AUTHOR]

Abstract: The Pennsylvanian genus Acitheca Schimper, 1879 is revised based on re-examination of the sterile types, plus evidence from well-preserved fertile and sterile material from Canada and the Czech Republic (n =750 specimens). Acitheca was an arborescent marattialean fern about 3.5m high with large, tripinnate or quadripinnate fronds which produced Caulopteris-like frond scars on the trunk. Although its reproductive structures are similar to those of Asterotheca Presl, Acitheca differs in a number of characters of the sterile foliage (especially the venation), and its palynology. The veins fork at least twice (except in the smallest pinnules): after the first dichotomy, the upper branch divides and then the lower branch divides, producing polymorphopterid veining pattern. Synangia occur in two rows, one on either side of the midvein, and usually consist of four elongate sporangia that extend beyond the pinnule margin. Recovered in situ spores show a much greater ontogenetic variability than any other known Pennsylvanian marattialean; the size varies from 34μm to 116μm, and exine ornamentation from laevigate (immature spores), finely microgranulate to scabrate (intermediate spores), to microverrucate–microgranulate (mature spores). Three species are described in the paper: Acitheca polymorpha (Brongniart) Schimper, Acitheca ambigua (Sternberg) Němejc, and a new species Acitheca alii sp. nov. Distributional evidence suggests that Acitheca probably originated in eastern North America and Western Europe in middle Pennsylvanian, and towards the end of it its geographical range had extended to Eastern Europe, the Caucasus, and into Permian of China. [Copyright &y& Elsevier]

This paper investigates the taxonomic diversity of marattialean stems from the family Psaroniaceae preserved in-situ within the Wuda Tuff Flora. Three species of the permineralized stem Psaronius and eight species of the compression/impression stem Caulopteris are documented, but it has not been possible to associate the anatomically preserved species with the compression/impression ones due to preservational limitations. The higher diversity of Caulopteris species may relate to anatomical features that could distinguish additional species of Psaronius not being preserved, or it may reflect the rarity of anatomical preservation in the flora limiting the available dataset and it is also possible that a "generalized" Psaronius anatomy was common to several stem species showing distinct leaf scars (Caulopteris) and distinct leaves (Pecopteris). The eight species of Caulopteris recorded are very close to the previously reported diversity of nine species of the vegetative leaf Pecopteris from the Wuda flora, which also indicates a high diversity within the family. However, intraspecific variation makes the identification of species of Pecopteris and Caulopteris rather difficult, potentially inflating the taxonomic diversity of these genera. We show that Psaronius stems from the Wuda flora include one species from the Psaronius blicklei -group, one species that shares characters with both Psaronius blicklei and Psaronius panxianensis groups, and one species that shares characters with Psaronius blicklei -group but possesses a unique one different from both Psaronius blicklei and Psaronius panxianensis groups. These species appear to represent transitional forms evolved from the Carboniferous–Cisuralian (early Permian) Psaronius blicklei -group that are on the evolutionary lineage leading to the Lopingian (late Permian) Psaronius panxianensis -group. In addition, a single occurrence of a stem of Psaronius in organic attachment to a tri-pinnate frond of Pecopteris orientalis (Schenk) Pot. is documented, representing an important starting point for future Psaroniaceae whole-plant reconstructions within the Cathaysian flora. • Permineralized and impression/compression psaroniaceous stems are described from Wuda Tuff Flora. • Impression/compression stems (Caulopteris) show a high diversity (8 species, including 3 new ones). • Permineralized stems (Psaronius) have a lower diversity (3 species), which is probably caused by 4 factors. [ABSTRACT FROM AUTHOR]

The paleoflora of the Matzitzi Formation has been studied since the beginning of the last century. Recent surveys have allowed the collection of abundant unregistered material, within which there is a notable group of leaves with a morphology similar to Ginkgophyta. The morphological analysis of more than 100 specimens resulted in the identification of large laminae with a long petiole, fan-shaped leaves with dichotomous venation and a characteristic constant segmentation that occurs up to three times and ends at the apex with 12 segments. It exhibits epidermal cells with sinuous to crenulated walls on the abaxial side, where anomocytic stomata and trichome bases can be observed. Given the absence of reproductive structures and the age of the material, its affinity to the order Ginkgoales is not possible; the comparisons were thus made with genera of the artificial group Ginkgophyta from different localities of the Upper Paleozoic. The results show significant morphological differences that support the proposal of a new genus and species, denominated Velascoa pueblensis. We also identified 10 orders and 27 genera that update the floristic lists created over 50 years ago. This information is important since it will allow to resolve future taxonomic, distributional, and/or environmental aspects that allowed the establishment of the taxa mentioned above. • A new genus is proposed after revision of 104 specimens. • Velascoa has Ginkgophyta-type characters and a large leaf and stem size. • The Matzitzi Formation is considered an area of high diversity during the Permian. [ABSTRACT FROM AUTHOR]