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Adults with relapsed or refractory B-precursor acute lymphoblastic leukaemia (R/R BCP-ALL) have very poor outcome. Blinatumomab as single agent has shown activity in R/R BCP-ALL. We aimed to assess the activity of blinatumomab in concomitant association with intensive chemotherapy. Seventeen patients with R/R BCP-ALL were treated with combination of blinatumomab and VANDA (etoposide, cytarabine, mitoxantrone, dexamethasone and asparaginase) regimen. Complete remission (CR) was achieved in 14/17 patient (82%) and 11/17 (65%) were transplanted. One-year leukaemia-free survival was 58.8% for the whole cohort and 90.9% for transplanted patients. These preliminary data suggest that the VANDA-blinatumomab salvage regimen leads to a very high rate of CR and HSCT in suitable patients.

International audience; Tyloses are protoplasmic swellings of parenchyma cells into the lumen of adjacent conducting cells. They develop as part of the heartwood formation process, or in response to embolism or pathogen infection. Here, we report the oldest fossil evidence to date of tylosis formation that occurs in permineralized wood of the (pro)gymnosperm Dameria hueberi from the Tournaisian (lower Mississippian, ca. 350 Ma) of Australia. Different developmental stages of tylosis formation are recognizable that range from small bubble-like protrusions to dense tyloses entirely filling the lumen of the conducting cells. The trigger for the development of tyloses in D. hueberi remains unknown. A survey of the fossil record of tyloses shows their occurrence in most groups of vascular plants since the Carboniferous. Future research in this field will screen even older (Devonian) fossils for evidence of tyloses and aim to understand the roles these structures have had in plant?pathogen interactions and plant hydraulic properties in the past.

Postremission treatment is crucial to prevent relapse in acute myeloid leukemia (AML). High-dose cytarabine delivered every 12 hours on days 1, 3, and 5 (HDAC-135) is the standard of care for younger adult patients with AML. Although this standard has been unsuccessfully challenged by other treatment regimens, including multiagent chemotherapy, the timing of HDAC administration has attracted little attention. Here, we retrospectively compared the safety, efficacy, and health care resource consumption associated with HDAC-135 and another standard, condensed HDAC-123 regimen, as consolidation treatment in younger AML patients in first complete response. This study included 221 patients (median age, 46.6 years; range, 18-60 years). HDAC-123 and HDAC-135 were used in 92 and 129 patients, respectively. Both regimens were associated with similar rates of relapse-free survival, cumulative incidence of relapse, nonrelapse mortality, and overall survival, including in core binding factor AML subgroup in which levels of minimal residual disease reduction were similar in both schedules. Hematological recovery times regarding neutrophils and platelets were significantly shorter in patients receiving HDAC-123, with an average difference of 3 to 4 days for each consolidation cycle. The total duration of hospitalization for the whole postremission program was shorter with HDAC-123 (32 days; interquartile ratio [IQR], 22.0,36.5) compared with HDAC-135 (41 days; IQR, 30.5, 50.0) (P < .0001). In conclusion, the condensed HDAC-123 regimen induced faster hematological recovery and therefore significantly reduced the length of hospital stay without affecting treatment response or outcome in younger AML patients.

The aim of this study was to evaluate the prognostic impact of the F-fluorodeoxyglucose positron emission tomography response at 1 month (M1) and 3 months (M3) after anti-CD19 chimeric antigen receptor (CAR) T-cell therapy in a multicenter cohort of 160 patients with relapsed/refractory large B-cell lymphomas (R/R LBCL). In total, 119 (75%) patients reached M1 evaluation; 64 (53%, 64/119) had a complete response (CR); 91% were Deauville Score (DS) 1-3. Progressionfree survival (PFS) and overall survival (OS) were significantly worse in patients with DS-5 at M1, than in patients with DS 1-3 (PFS hazard ratio [HR]=6.37, 95% confidence interval [CI]: 3.5-11.5 vs. OS HR=3.79, 95% CI: 1.7-8.5) and DS-4 (PFS HR=11.99, 95% CI: 5.0-28.9 vs. OS HR=12.49, 95% CI: 2.8-55.8). The 1-year PFS rates were 78.9% (95% CI: 58.9-89.9) for DS-4 at M1, similar to 67.3% (95% CI: 51.8-78.8) for patients with DS 1-3 at M1, very different to 8.6% (95% CI: 1.8-22.4) for DS-5, respectively. Only eight of 30 (26%) patients with DS-4 progressed. Response at M3 evaluated in 90 (57%) patients was prognostic for PFS with lower discrimination (HR=3.28, 95% CI: 1.5-7.0; P=0.003) but did not predict OS (HR=0.61, 95% CI: 0.2-2.3; P=0.45). Patients with a high baseline total metabolic tumor volume (TMTV) >80 mL had worse PFS (HR=2.05, 95% CI: 1.2-3.5; P=0.009) and OS (HR=4.52, 95% CI: 2.5-8.1; P80 mL, and DS-5 at M1 for OS. In conclusion, baseline TMTV and response at M1 strongly predicts outcomes of patients with R/R LBCL undergoing CAR T-cell therapy.

International audience; Premise of research. Periderm is a protective secondary tissue that replaces the epidermis in stems and roots having secondary growth. The first periderm most commonly originates immediately below the epidermis, but in some species, it arises deeper in the stem, usually in the primary phloem. Periderm is a common feature of extant plants and has been reported in numerous fossil taxa. Here we investigate the presence of this tissue in a Carboniferous representative of the cladoxylopsids, an extinct group related to the ferns s.l.Methodology. We describe anatomically preserved stems of Cladoxylon taeniatum with a well-preserved periderm from Tournaisian deposits in France and Germany. We also provide a short review of the current state of our knowledge on periderm production in Paleozoic plants, especially in relation to secondary vascular growth.Pivotal results. The new specimens are 7–15 mm in diameter. They have a well-developed secondary xylem and a thin periderm that has a deep-seated origin in the innermost part of the cortex. This shows that Cladoxylon had the ability to accommodate secondary vascular growth with the production of a periderm that replaced the cortex and epidermis. Cladoxylon taeniatum is, to date, the only cladoxylopsid in which this feature is described, and it increases the diversity of anatomical strategies for secondary growth documented in the group. Changes in the nature and geometrical distribution of tissue between typical stems with a cortex and stems with a periderm suggest that C. taeniatum was non-self-supporting, a growth habit that also differs from that of most other older cladoxylopsids.Conclusions. The new specimens increase the diversity of Paleozoic plants that produced both secondary vascular tissues and a periderm. Our review highlights the fact that anatomical homologies between the structures called “periderm” in these various taxa remain unclear; numerous questions about the origins of the periderm and the possible relation between secondary vascular growth and periderm production remain.

International audience; One of the youngest occurrences of anatomically preserved Sphenophyllum Brongn. 1828 is reported from the Permian Motuca Formation, Parnaíba Basin, central-north Brazil. At least 31 stems of this extinct sphenophyte, which are densely interwoven with each other and associated with tiny roots and leaves, occur in a silicified state within the pith of a stem of the arborescent calamitalean Arthropitys barthelii, which was additionally bored by putative xylophagous herbivores. Although restricted within natural limits, the Sphenophyllum plants show different developmental stages that encompass mostly juvenile stems but also a few with initial secondary growth. The stems are circular to elliptical in outline and consist of a central triarch actinostele made of primary vascular tissues and a variable amount of wood. Extraxylary tissues comprise a narrow innermost zone with putative phloem, internal periderm of rectangular cells arranged in radial files, inner parenchymatous cortex, outer sclerenchymatous cortex, and small-celled layers of bounding tissue. Furthermore, Sphenophyllum plants are frequently found as climbers on the trunk surfaces of Psaronius Tietea and Grammatopteris tree ferns, or they are trapped among the adventitious aerial roots of these plants. In addition, Sphenophyllum cauline members were also found dispersed with other plant organs in a particular type of fossil-rich, silicified fluvial sandstone or chert, reflecting rapid fossilisation of parautochthonous remains. The presented fossil assemblages provide evidence of a previously underestimated facet of the ecosystem in seasonally influenced, densely vegetated riparian forests bordering extended distal fluvial discharges in low-latitude Gondwana. Because of largely similar development of major anatomical traits in these late Paleozoic sphenophylls, taxonomic delimitation based on vegetative axes alone remains challenging and highlights the unexpectedly long-term stability of the primary cauline anatomy in particular and vascular architecture in general. As a result, the studied Brazilian specimens can only be identified as Sphenophyllum sp., although we emphasise close relationships to Sphenophyllum thonii, a nearly worldwide distributed species during the early Permian.

International audience; The medullosans represent a diverse group of pteridosperms that was widely distributed in forested landscapes of the late Paleozoic. These plants became widely known from the extensive tropical lowland basins of Euramerica, where they grew as slender plants with large fronds and fern-like foliage. Besides, there also exist medullosans of Late Pennsylvanian–early Permian intramontane basins of Central Europe, which have been out of research focus for more than a century. They had bigger stems with larger amounts of secondary xylem and a modified organisation of the vascular system. We provide an overview on taxonomy, anatomy and palaeoecology of these medullosans from the most important fossil localities, encompassing Chemnitz (Germany), the type locality for most taxa, Autun (France), Nová Paka (Czech Republic) and others. Late Pennsylvanian–early Permian medullosans of intramontane basins were thriving under seasonally-dry palaeoclimate on wet clastic soils showing proximity to the groundwater level. In forested landscapes, they occurred mostly sub-ordinated as part of the forest understorey. The plants' architecture and taphonomical inferences point to a (semi-)self-supporting growth habit of most of the taxa presented here. Plant architectural and anatomical peculiarities suggest a high water-conducting potential of these plants, raising questions on their ecological role in early Permian habitats. Anatomical differences with tropical relatives of Carboniferous age might reflect an evolutionary process that was driven by environmental changes during the late Paleozoic. The unusual arrangement of their stem tissues addresses the question of their role in seed plant evolution, e.g., their potential relationship with cycads.

International audience; The Late Pennsylvanian deposits of the Graissessac Basin (southern France) are well known for their abundant and diversified plant remains. Here we report on seven trackways of giant millipede-like arthropods recently discovered from two surfaces. These traces are ascribed to Diplichnites cuithensis. The trackways are up to 200 cm long, up to 36 cm wide, straight to curved and consist of two parallel rows of numerous and elongated appendage imprints that are oriented perpendicular to the midline. Although body fossils of giant millipede-like arthropods remain unknown in sediments from this basin, the morphology and size of the trace fossils indicate that the trails were made by 0.9 to 1.6 m long individuals of Arthropleura. The depositional environment is interpreted as a regularly inundated floodplain close to a fluvial channel and dominated by lycopsids. Such a vegetation was probably an attractive and important source of food for the giant herbivorous arthropods that were roaming the riparian landscapes of the Graissessac Basin. This new occurrence of Arthropleura trackways confirms that this giant arthropod was a common member of Late Palaeozoic continental biotas.

Multiple myeloma (MM) is rare in young patients, especially before age 40 years at diagnosis, representing

Elderly Hodgkin’s Lymphoma (HL), defined as occurring in patients over 60 years, represents 20% of all Hodgkin’s lymphoma cases and differ from younger HL in clinical, biological, pathological and ...

International audience; We describe a new species of the Paleozoic fern genus Botryopteris in volcanic tuffs from the Lopingian (upper Permian) aged Junlian Formation in SW China's Sichuan Province. The species has a large stem and stele compared to those of some other species of the genus. Xylem strands of the leaf trace and rachis are “ω”-shaped in cross section and comprise two long lateral arms and a single, shorter median arm. Parenchyma is distributed among the stem metaxylem tracheids and is more common in the central region of the stele that comprises a parenchymatized protostele. Several mesarch protoxylem strands, decurrent from leaf traces, are visible in each cross section of the protostele. Root traces originate from the lateral side of the leaf trace within the stem cortex. The stem surface is covered by thick, multiseriate, multicellular trichomes. Botryopteris multifolia sp. nov. represents the stratigraphically youngest known species of the genus and has a combination of derived evolutionary characteristics including its large stem size, parenchymatized protostele, elaborate trichome structure, roots originating from leaf traces, and the construction of xylem strand of the leaf trace and rachis with distinctive pinna trace formation and emission. It is more similar in leaf anatomy to the Gondwanan species B. nollii from the Permian of Brazil and less like late Pennsylvanian botryopterids from Euramerica. Finally, we consider the evolutionary implications of features shared between Permian members of the botryopterids and catenalean-type plants including members of the Osmundales stem group family Guaireaceae (Shuichengella, Zhongmingella, Tiania) and the enigmatic early ferns Rastropteris and Catenopteris.

The late Paleozoic ice age (LPIA) constitutes a unique framework in which to study deep time plant-climate interactions. Key research foci include (1) the onset of the first ice age on a vegetated planet and elucidating the role that plants played in this global cooling, (2) plant evolution and dynamics during LPIA glacial-interglacial oscillations, which have been compared to those of the Cenozoic, and (3) the establishment of polar forests with no extant equivalent as high latitudes became unglaciated in the Permian. The purpose of this talk is to present an overview of these major research topics and use the tropical floras from the Pennsylvanian and Permian of the Graissessac-Lodeve region in southern France as a case study of plant dynamics during the LPIA. The Graissessac basin contains one of the best-preserved examples of intramontane Late Pennsylvanian wetlands in southern Europe. Plant-yielding deposits have been extensively studied since the 19th century and document the vegetation of alluvial fans, fluvial channels, floodplains, and peat mires. Stands of arborescent lycopsids (Sigillaria) dominated the peat mires, while tree ferns (Psaronius), sphenopsids (Calamites, Sphenophyllum), and medullosan pteridosperms occupied different zones of the floodplains. Allochtonous logs and leaves of cordaitalean gymnosperms reflect the vegetation of higher/drier areas of the landscape. This vegetation contrasts with that of coeval coastal (paralic) wetlands from North America, which had a different spatial distribution of taxa. Permian deposits from the nearby Lodeve basin record a change towards increasingly drier conditions. The oldest macroflora in the basin is one of the most diverse Asselian plant assemblage known to date, with over 40 species. While some of the plants correspond to Carboniferous taxa that persisted in the early Permian, the flora is dominated by conifers, indicating a more seasonal and arid climate. It also contains an important diversity of peltaspermales (pteridosperms), as well as some occurrences of ginkgophytes and cycadophytes that started diversifying at that time. Younger assemblages from the basin are also dominated by conifers and other seed plants and reflect a transition to semi-arid conditions by the end of the early Permian (Artinskian-Kungurian).

International audience; Premise of research : Mississippian (Lower Carboniferous) anatomically preserved ovules are pivotal to our present understanding of the Paleozoic primary seed plant radiation, but few are known from the late Viséan stratigraphic interval approximately 330 million years ago. Here, we document an exceptionally well-preserved mesoscopic charcoalified ovule from late Viséan limestones that is adapted for wind dispersal and for deterring herbivory.Methodology : We use synchrotron radiation X-ray tomographic microscopy (SRXTM) and low-vacuum scanning electron microscopy (LVSEM) to analyze histological features not identifiable through traditional methods.Pivotal results:The ovule is small, 2 mm long and 1.25 mm in maximum diameter, and has a dense covering of spirally arranged, long, slender, hollow hairs with glandular apexes and a distal papilla. The nucellus is fused to the integument up to the nucellar apex, and above this, the integument comprises eight apical lobes, each with a single vascular bundle. The nucellar apex has a domed pollen chamber and large central column characteristic of hydrasperman-type (lagenostomalean) pteridosperms, but it lacks the distal salpinx seen in most hydrasperman ovules, leaving an exposed distal opening to the pollen chamber for pollination. Differences with existing taxa lead to the erection of Hirsutisperma rothwellii gen. et sp. nov.Conclusions : The apical glands presumably functioned as granivory deterrents; coprolites (fossilized feces) from herbivorous arthropods are abundant in the fossiliferous horizon and at this stratigraphic interval. The small ovule size and its dense covering of hairs indicate Hirsutisperma was adapted for wind dispersal and was an r-selected species, producing large numbers of small offspring in unstable or changing environments. Taphonomic implications are discussed, including preservational biases for charcoalification. Hirsutisperma provides the first clear evidence for ecological niche partitioning in Mississippian hydrasperman-type ovules.

International audience; Combresomyces cornifer is a conspicuous spheroidal microfossil (

Early Carboniferous (Mississippian) permineralized woods from Australia with multiseriate rays have been customarily assigned or compared to the European genus Pitus, despite the absence of information on their primary vascular anatomy. In the context of continuing work on the diversity of Late Devonian andMississippian floras of Gondwana, we studied new silicified woods with secondary xylem similar to that of Pitus (multiseriate rays, araucarioid radial pitting) from two sedimentary basins of Queensland, Australia. In the Drummond Basin, three morphotypes of wood of Viséan age can be distinguished based on ray size in tangential section. Although this variation is similar to that observed between the various European species of Pitus, information on the primary vascular anatomy of the trees provided by three incomplete specimens excludes an affinity with Pitus for at least two taxa. In the Yarrol Basin, two well-preserved late Viséan trunks also have characters similar to Pitus but can be distinguished from that genus and other previously described Mississippian trees, in particular by the anatomy of their primary vascular system and departing leaf traces. They are assigned to a new genus, Ninsaria. Collectively, the new specimens from Queensland show that wood traditionally referred to “Pitus” from Australia actually belongs to several other types of trees that are not known from Europe or North America, indicating probable floristic provincialism between the Northern and Southern hemisphere floras at this time. These new fossils corroborate the existence of a global Mississippian diversification of (pro)gymnosperm trees already noted in Laurussia. They also indicate that the Mississippian floras of Australia were more diverse and complex than traditionally inferred. Additional funding from: National Science Foundation (project #1636625);ALD and BMB acknowledge funding from LabEx CeMEB, France (Exploratory Project MARCON)

Agora Paleobotanica (Congrès, Montpellier, du 10 au 12 juillet 2017); International audience; Documented evidence of fungi associated with Mesozoic ferns is exceedingly rare. Three different types of fungal remains occur in a portion of a small, permineralised fern stem of uncertain systematic affinities from the Triassic of Germany. Exquisite preservation of all internal tissues made it possible to map the spatial distribution of the fungi in several longitudinal and transverse sections. Narrow, intracellular hyphae extend through the entire cortex, while wide hyphae are concentrated in the cortical intercellular system adjacent to the stele and leaf traces. Hyphal swellings occur in the phloem and adjacent cortex, while moniliform hyphae (or chains of conidia) are present exclusively in parenchyma adjacent to the stele. No host response is recognisable, but host tissue preservation suggests that the fern was alive during fungal colonisation. The highest concentration of fungal remains occurs close to the stele and leaf traces, suggesting that the fungi either utilised the vascular tissues as an infection/colonisation pathway or extracted nutrients from these tissues. This study presents the first depiction of fungal distribution throughout a larger portion of a fossil plant. Although distribution maps are useful tools in assessing fungal associations in relatively small, fossil plants, preparing similar maps for larger and more complex fossils would certainly be difficult and extremely arduous.

Fern fossils from the Triassic are predominantly impressions and compressions; structurally preserved specimens are comparatively rare and primarily known from the Southern Hemisphere. Several permineralized stem portions from the Triassic of Upper Silesia are assigned to the poorly known genus Knorripteris (Knorripteridaceae), an enigmatic taxon initially attributed to the lycopsids but later reinterpreted as belonging to the ferns. Because the new stems differ from the known species of Knorripteris, they are assigned to a new species, for which the name Knorripteris taylorii nov. sp. is proposed. K. taylorii is characterized by a discontinuous phloem cylinder, leaf trace xylem strands that continue down to and converge at the center of the stem, cells with spiral thickenings (i.e., transfusion tissue) accumulating within the central zone of the stem, and xylem strands with abaxial protoxylem. Knorripteris exhibits several major features not typically seen in ferns, including a stelar organization that does not conform to the protostele/siphonostele/dictyostele types traditionally recognized in fossil and living ferns, the abaxial versus adaxial orientation of the protoxylem in leaf traces, as well as the acropetal decrease versus increase of the xylem in the leaf trace. The vascular system of Knorripteris is unique and challenges current concepts with regard to stelar evolution in ferns. The discontinuous phloem cylinder shows a cauline dictyostelic aspect, while the xylem appears to be foliar in origin. Knorripteris lacks a central protostelic column of vascular tissue; rather, the small foliar xylem strands come into close contact, but there is no evidence of fusion of tracheid bundles. Despite the wealth of new information on the internal organization of the Knorripteris stem provided by the specimens described in this study, the position of Knorripteris and the Knorripteridaceae within the ferns remains elusive.

International audience; A new taxon of lignophyte is described based on a permineralized stem from the Late Tournaisian (Lower Carboniferous) of the Central Ahnet region, Algeria. It shows similarities with arborescent seed plants described in the Lower Carboniferous of Europe and North America such as Eristophyton waltonii Lacey and Cauloxylon ambiguum Cribbs. However, the primary and secondary vascular system of the stem display an original combination of characters and it is assigned to a new genus: Ahnetia. The preservation of extraxylary tissues (secondary phloem, periderm, cortex) allows formulating hypotheses on the stem's growth potential. The early appearance of a periderm indicates that Ahnetia was capable of significant secondary growth and that the specimen likely represents a young axis of a larger plant. By its Late Tournaisian age, this specimen represents the oldest known occurrence in North Africa of a lignophyte capable of significant secondary growth after the extinction of the progymnosperm Archaeopteris.

We review progress made during the last 25 years in our understanding of the Protopityales, Early Carboniferous plants belonging to the extinct group of the progymnosperms. Recent studies support p...

International audience; Trigonotarbids and scorpions (Arachnida: Trigonotarbida, Scorpiones) are described from the Upper Carboniferous (Late Stephanian/Late Gzehlian) of the Graissessac Basin in the Central Massif outcropping in southern France. This is the first record of trigonotarbids and the first thorough description of scorpions from this locality. Trigonotarbids are an extinct order and the new fossils express a distinctly ornamented dorsal surface and lobed carapaces implicit of the so-called ‘eophrynid-assemblage’; probably a derived clade. Although closest to Eophrynidae, the character combination preserved precludes unequivocal assignment to any of the currently recognized families, but appears to be unique among trigonotarbids and prompts us to propose the name Aenigmatarbus rasteli gen. et sp. nov. to accommodate these novel specimens. The Graissessac scorpions are preserved in dorsal view only, but two distinct morphotypes could be recognized. These are tentatively referred to here as two typical Coal Measures genera: namely the mesoscorpion Eoscorpius sp. and the more derived orthostern Compsoscorpius sp., respectively.

ACL-12-01; International audience; A distinctive fungal endophyte, Cashhickia acuminata nov. gen. et sp., is described from permineralized calamite roots from the Upper Pennsylvanian Grand-Croix cherts of France. Heavily infected roots contain numerous intracellular hyphae in the outer cortex that arise from a meshwork-like mycelium extending between cortical cells. All intracellular hyphae are oriented toward the root center; none occur on the inner periclinal host cell walls. Other roots of the same type show localized infection by this fungus in which isolated cortical cells contain or give rise to intracellular fungal growth. Within the cortical cells are host responses in the form of callosities that indicate the roots were alive at the time of infection. Other endophytes are present in the same host tissue but are less frequent. The discovery of this association provides the first detailed account on the morphology of a Carboniferous fungal root endophyte, as well as the spatial distribution within the host, and infection pathways within the cortical tissues.

The mode of preservation dictates the preparation technique that will yield the most information about a specific fossil. Such considerations also include the time needed for preparation and degree of specimen destruction. Nowhere is this more clearly demonstrated than in the history of Carboniferous coal ball and chert research where the standard technique shifted from thin section to acetate peel preparations many years ago. Despite the ease and efficiency of acetate peels and the exponential increase in information they have provided about Carboniferous plants and ecosystems, we argue that there has been a concomitant decrease in attention directed at the microbial life also preserved in many cherts and coal balls. With this paper we endorse the use of thin sections, rather than peels, in order to study accurately the morphology and diversity of late Paleozoic microbial life.

A middle Tournaisian flora comprising several taxa of arborescent lignophytes is documented for the first time in Australia. It challenges earlier hypotheses considering that the early Mississippian vegetation of Australia was impoverished and dominated by small to medium sized arborescent lycopsids until the Serpukhovian when climatic conditions became favorable to the thriving of the famous lignophyte-dominated “ Rhacopteris flora” recorded in Australia but also South America. The present account is based on anatomically preserved fragments of trunks and branches from two localities of Queensland, in the Broken River Province and the Burdekin Basin. Three taxa are recognized, Dameria hueberi gen. et sp. nov., the putative progymnosperm species Protopitys buchiana Goeppert 1850, and a taxon of uncertain affinities characterized by a Pitus type of wood but which differs from the latter genus by anatomical traits relative to its primary body. The possible occurrence of subtle growth rings in some of the woods from the Burdekin Basin and the conifer like traits of the Dameria wood are interpreted as ecological clues suggesting that these trees may have inhabited drier settings than the wetland habitats generally inferred for the lycopsids. This difference in habitats is suggested to explain the rarity of arborescent lignophytes compared to lycopsids in the Australian record of plants of early Mississippian age. The three taxa reported in this paper represent the earliest record of arborescent lignophytes in Australia after the global events that affected the vegetation at the Devonian–Carboniferous boundary and the extinction of Archaeopteris . They show that the successional pattern of arborescent lignophytes around the Devonian–Carboniferous boundary is comparable to that observed in Western Europe with the evidence of a diversification occurring as early as the middle Tournaisian. The palaeogeographic and stratigraphic distribution of Protopitys and Dameria indicates the occurrence of extensive floral exchanges between southern Laurussia and north-eastern Gondwana in the Late Devonian to Mississippian.

Ten different types of microproblematic structures occur on the surfaces, and in epidermal and hypodermal cells of fern pinnules preserved in the Late Pennsylvanian Grand-Croix cherts from France. These include thick-walled spheres, some with a prominent exit site, aggregations of variously sized spheres that may be surrounded by a membrane or sheath, a cylindrical structure composed of polygonal compartments, and branched hyphae/filaments with intercalary swellings protruding from a small opening in the surface (probably a stomatal pore). Some of the structures likely were produced by some fungal group, and may represent (resting) spores, microsclerotia, and conidiophores. The affinities of the others, and sometimes even their biological nature, remain difficult to determine. Nevertheless, documenting these structures is important because it provides the first indication for vascular plant leaves that were colonized by different types of organisms in a late Paleozoic ecosystem.

Four different morphotypes of microfungal remains occur in the partially degraded cortex of a specimen of Biscalitheca cf. musata (Zygopteridales) from the Upper Pennsylvanian Grand-Croix cherts (Saint-Etienne Basin, France). These include (1) clusters of spherical structures that appear to have developed within individual host cells; (2) relatively thick-walled spheres with one or two long, narrow protrusions; (3) spherical to pear-shaped structures in physical connection with tenuous, multi-branched filaments; and (4) pear-shaped structures with prominent surface projections. Structures resembling type (3) have also been found associated with the spores of B. cf. musata . Most of the organisms were probably saprotrophs based on the condition of the host. Although all of the fossils resemble chytrid zoosporangia, the systematic affinities of the microfungi in B. cf. musata remain equivocal because specific diagnostic features are absent. Nevertheless, the fossils provide a remarkably detailed account of the morphology of microfungi associated with land plants some 300 Ma ago.

Microscopy and Microanalysis, 15 (2), ISSN:1431-9276, ISSN:1435-8115

A survey of the anatomically preserved flora of the Grand-Croix cherts (Late Pennsylvanian, Saint-Etienne basin, France) is presented following a study of collections preserved in the Swedish Natural History Museum, Stockholm in complement to previous investigations on the original material kept in France. An exhaustive list of the flora is provided, confirming the particular importance of this permineralized plant assemblage that is one of the most diverse for the Late Pennsylvanian. The observed occurrence of taxa and organs confirms a previous quantitative study based on material in the French collections: cordaiteans are both the most common taxa and the most important contributors to peat volume, whilst leaves are the most common and abundant organs. However, the seed ferns are the most diverse group of plants before cordaiteans and ferns; the exceptional diversity of medullosan ovules is of particular interest. The Grand-Croix flora is compared with that of the nearby Early Permian basin of Autun. The two assemblages have 21 genera, but only 6 species, in common, and this may be explained by differences in age and taphonomy. The Grand-Croix flora is also similar to that of American coal balls of the same age and, despite taxonomic differences, it is significant that several species of ferns and seed ferns are common to the vegetation of the French limnic and American paralic basins.

A new taxon of probable gymnosperm affinities is described from the base of the Carboniferous (Mississippian, Middle Tournaisian) of Montagne Noire, southern France. It is based on a permineralised stem showing vascular and cortical tissues, and one attached petiole base. Faironia difasciculata gen. et sp. nov. shows the combination of a broad eustele and dense wood with a multifascicular leaf trace, originating from two non-adjacent axial strands. The Kalymma -type petiole base resembles that of the calamopityan pteridosperms but anatomy of the stele, wood and phloem more closely compares to that of early arborescent gymnosperms such as Pitus , Eristophyton or Megalomyelon the taxonomic position of which needs to be re-evaluated. Faironia is the sixth genus of seed plant affinities based on stems reported from the Montagne Noire deposits that, to date, comprise the most diverse assemblage of permineralised seed plant remains from just above the Devonian/Carboniferous boundary.

A large permineralized calamitean stem, Arthropitys yunnanensis Tian et Gu from the Upper Permian of southwest China is reinvestigated and interpreted. The stem has a broad pith and well developed and large carinal canals. Secondary xylem is thick and characterized by wide parenchymatous interfascicular zones that remain constant in width throughout the wood. Striking features of the stem include the abundant leaf traces arranged in two whorls in the cortex with this arrangement previously unrecognized within calamitean stems, and the presence of growth rings in secondary xylem that suggest frequent fluctuations in environmental stress presumably due to variations in water availability. Features of A. yunnanensis infer the stem to be in the epidogenetical phase of calamitean development, and suggest it to be the basal part of a large trunk. Comparisons with biomechanical models for calamitean stems suggest this species had a semi-self supporting habit.

A-06-19; Seed plants of the lowermost Carboniferous time (Tournaisian) display important differences in morphology and habit with at least two size classes. On one side are plants of modest stature with protostelic stems, manoxylic wood and large leaves, interpreted as calamopityan, buteoxylalean and lyginopteridalean seed ferns, and on the other side are arborescent plants, with trunks up to 2 metres in diameter, of which the systematic position remains unclear. We summarize present information on these trees characterized by a thick development of generally dense wood, a broad eustele consisting of a large number of discrete primary xylem strands, short internodes and deciduous medium-sized fronds. New data have been recently obtained on Pitus, the best known member of this group, on Eristophyton, Bilignea, Stanwoodia, Aporoxylon and on several new taxa which exhibit a broad circular parenchymatous pith surrounded by numerous sympodial xylem strands, but which differ in secondary xylem and leaf trace features. Of particular interest is a new plant that has leaf traces originating as a double strand and a petiole base of the Kalymma-type, therefore showing characteristics of calamopityan seed ferns but being quite distinct in features of the stele, secondary xylem and phloem. Emphasis is placed on the evolutionary dynamics of this important diversification of arborescent plants which included: i) a rather abrupt increase in overall diameter, ii) increase in primary xylem size, with regard to other contemporaneous early seed plants; iii) very different types of wood, instead of a single dense/pycnoxylic wood as generally assumed; iv) distinct periderm types; v) deciduous leaves. The last feature may be interpreted as an innovation, related to the tree habit, within the lignophytes. The origin and systematic position of these arborescent plants remain problematical.

Sublagenicula nuda lycophyte megaspores from the upper Visean of central France frequently host a colonial green alga as an endophyte. This association was first recorded more than 100 years ago by the French paleobotanist B. Renault, who introduced the name Lageniastrum macrosporae for the alga. However, the biological significance of the discovery was not fully assessed until recently. The L. macrosporae–S. nuda association represents the oldest compelling fossil evidence for algal endophytes in land plants, and the only example to date of an alga residing in the interior of spores of vascular cryptogams. Here we present a detailed re-evaluation and photographic documentation of the surviving original specimens from the Visean of Combres/Lay and Esnost. Moreover, a newly discovered specimen from the Stephanian of central France represents the first record of this association from the Upper Carboniferous. An emended diagnosis for L. macrosporae Renault, 1896 is provided, and a lectotype and paralectotype are designated. Although L. macrosporae displays a striking suite of morphological characters found in members of the extant chlorophyte family Volvocaceae (especially the genus Volvox), the peculiar biology of the fossil necessitates establishment of a new family, for which the name Lageniastraceae is proposed. Considerations of the adaptive advantages for the alga of occupying the interior of megaspores are offered. These include the possible effectiveness of the spores in protection during periods of desiccation and against plankton-feeding animals, and use of the spores as potential vectors for dispersal from one isolated body of water to another by spore-feeding animals.

The Tedeleaceae are late Paleozoic Filicalean ferns with two known genera, Ankyropteris and Senftenbergia, which partially overlap morphologically and have the same known stratigraphic ranges—Namurian A to Lower Permian in Euramerica. Ankyropteris is anatomically known and Senftenbergia is almost exclusively based on compression specimens. Both genera exhibit abaxially, laminar-borne sori and/or solitary sporangia with some schizaeoid attributes. The sporangia are pyriform to tear-drop shaped, erect to slightly curved with a two to multiseriate apical annulus and mature spores usually of the Raistrickia type. Detailed morphological comparisons of Ankyropteris with Senftenbergia emphasize generic overlaps as well as lack of congruence. Ankyropteris brongniartii, a classic vine in anatomy, defines the stratigraphic range of the genus and provides recurrent ecological observations of habit and associated plants in ecotonal swamp reaches as well as in volcanic environments and on other clastic substrates. Ankyropteris may have originated from the clepsydroid zygopterid clade outside of the swamps. Ankyropteris brongniartii occurred as an epiphytic vine on Psaronius tree ferns as they expanded into coal swamps and often co-occurred with Paralycopodites even earlier in Middle Pennsylvanian. Vine stem anatomy and functional morphology of aphlebiae are emphasized in A. brongniartii with comparisons to Austroclepsis, an early “vining” false tree fern. Anatomical comparisons of Ankyropteris species based on shoots emphasize divergent habits with similar robust sizes; all exhibited aphlebiae. Known only from coal balls, Ankyropteris corrugata (Westphalian A–B) had a rampant habit on exposed peat with a succulent, dichotomous rhizome and erect fronds. The Lower Pennsylvanian specimen of Ankyropteris hendricksii is a compact tree fern with crowded frond bases and intercalated roots. Tyloses commonly occur in A. corrugata and A. brongniartii indicating water-stressed conditions. Apical meristems of shoot and fronds are reported for the first time, suggesting response growth to disturbance and rapid burial.