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Jason Hilton - One of the best experts on this subject based on the ideXlab platform.
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exploring the stem to crown group transition in Marattiales a new species of frond from the late permian of china with features of the psaroniaceae and marattiaceae
Review of Palaeobotany and Palynology, 2021Co-Authors: Jason Hilton, Shijun Wang, Xinshi ChengAbstract:Abstract 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.
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the anatomically preserved tripinnate frond rothwellopteris pecopteroides gen et sp nov from the latest permian of south china timing the stem to crown group transition in Marattiales
International Journal of Plant Sciences, 2019Co-Authors: Shijun Wang, Jun Wang, Jason HiltonAbstract: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 rachise...
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the anatomically preserved tripinnate frond rothwellopteris pecopteroides gen et sp nov from the latest permian of south china timing the stem to crown group transition in Marattiales
International Journal of Plant Sciences, 2019Co-Authors: Shijun Wang, Jun Wang, Jason HiltonAbstract: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 sp...
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A unique trunk of Psaroniaceae (Marattiales) - Psaronius xuii sp. nov. , and subdivision of the genus Psaronius Cotta
Review of Palaeobotany and Palynology, 2013Co-Authors: Shijun Wang, Jean Galtier, Jason Hilton, Longyi ShaoAbstract: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
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Fertile pinnules of Danaeites rigida Gu and Zhi (Marattiales) from the Upper Permian of south China
Botanical Journal of the Linnean Society, 2001Co-Authors: Zhao-hua Liu, Jason HiltonAbstract:Recently collected specimens of Danaeites rigida Gu and Zhi from the Upper Permian of south China have been subjected to detailed morphological investigations in order to reveal features of their fertile pinnules. The specimens are preserved as compression/impressions and possess pecopteroid-type pinnules with a single row of synangia on either side of the pinnule midvien. Individual synangia are bilaterally symmetrical, sessile, and their bases are embedded in the tissues of the pinnules. Synangia possess 18–24 sporangia that are laterally fused to one another throughout their entire length. Sporangial dehiscence is through a longitudinal slit and sporangia contain trilete spores with a granular ornamentation, referable to the dispersed spore Cyclogranisporites. This combination of characters is unique in specimens preserved by compression/impression although they are similar to those known in permineralized marattialean fertile fronds. However, anatomical details salient to the identification of these permineralized taxa are not identifiable in impression/compression fossils such as Danaeites. The taxonomic and phylogenetic implications of these findings are considered in detail and we conclude that Danaeites has closer links with Marattia than with Danaea.
Shijun Wang - One of the best experts on this subject based on the ideXlab platform.
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exploring the stem to crown group transition in Marattiales a new species of frond from the late permian of china with features of the psaroniaceae and marattiaceae
Review of Palaeobotany and Palynology, 2021Co-Authors: Jason Hilton, Shijun Wang, Xinshi ChengAbstract:Abstract 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.
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the anatomically preserved tripinnate frond rothwellopteris pecopteroides gen et sp nov from the latest permian of south china timing the stem to crown group transition in Marattiales
International Journal of Plant Sciences, 2019Co-Authors: Shijun Wang, Jun Wang, Jason HiltonAbstract: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 rachise...
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the anatomically preserved tripinnate frond rothwellopteris pecopteroides gen et sp nov from the latest permian of south china timing the stem to crown group transition in Marattiales
International Journal of Plant Sciences, 2019Co-Authors: Shijun Wang, Jun Wang, Jason HiltonAbstract: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 sp...
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A unique trunk of Psaroniaceae (Marattiales) - Psaronius xuii sp. nov. , and subdivision of the genus Psaronius Cotta
Review of Palaeobotany and Palynology, 2013Co-Authors: Shijun Wang, Jean Galtier, Jason Hilton, Longyi ShaoAbstract: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
Lavalle, María Del Carmen - One of the best experts on this subject based on the ideXlab platform.
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Spore morphology of eight paleotropical species of genus Marattia Sw.
2018Co-Authors: Rolleri, Cristina Hilda, Lavalle, María Del CarmenAbstract:Este es un estudio con MEB de las esporas de 8 especies paleotropicales de Maraltia (M. douglassii C. Presl. M. fraxinea J. E. Smith. M. obesa Christ. M. rolandi-principis Rosenst., M. salicina J. E. Smith, M. smithii Mett. ex Kuhn, M. sylvatica Blume y M. werneri Rosenst.). El perisporio y el exosporio pueden tener micro-ornamentación y macro-ornamentación. Esta última es buliforme (pustulada), buliforme-muriforme (pustulado-rugada) o, más raramente, buliforme-esteliforme (pustulado-verrucosa). La micro-ornamenlación es granular y visible desde 750 x o sólo a partir de 10.000 x. La diferente ornamentación en esporas producidas por un mismo sinangio se halló sólo en M. fraxinea, y aún en esta especie es infrecuente o rara. Mientras la combinación de los rasgos de ornamentación y apertura son caracteres genéricos en Marattiales, en las especies paleolropicales de Marattia la ornamentación de perisporio y exosporio varían en el nivel específico.Facultad de Ciencias Naturales y Muse
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Sistemática de los helechos maratiáceos (Marattiales-Marattiaceae)
2014Co-Authors: Rolleri, Cristina Hilda, Lavalle, María Del Carmen, Mengascini, Adriana Susana, Rodríguez, Mónica BeatrizAbstract:Aquí se propone reunir en una sola familia, Marattiaceae, cinco géneros vivientes de helechos maratiáceos: Angiopteris, Archangiopteris, Christensenia, Danaea y Marattia, todos los cuales son diversamente afines entre sí pero cuyos rasgos en común justifican la existencia de una sola familia. Esta propuesta se basa tanto en la bibliografía previa sobre el grupo como en los numerosos trabajos de las autoras, tanto de aspectos parciales como revisiones recientes. Se consideran rasgos de familia los rizomas desnudos, erectos, ascendentes o postrados, carnosos y amiláceos, policiclostélicos a dictiostélicos; las estípulas amiláceas pareadas en la base de los estípites; el tejido secretor de mucílago; la ausencia de esclerénquima en rizomas y raíces pero su presencia en la parte distal de los estípites, costas y cóstulas; los granos de almidón simples concéntricos o excéntricos en tejidos parenquimáticos de rizomas, estípulas y estípites; los pulvínulos (“nudos”) en los estípites y/o en la zona de inserción de las costas en el raquis; la capacidad de biomineralizar SiO2 y formar ópalo A; las protuberancias intercelulares pécticas de las células del mesofilo de las frondas (PIP); los modelos epidérmicos y los estomas adultos maratiáceos ciclocíticos y/o porociclocícitos; los eusporangios, parcialmente a totalmente fusionados por sus paredes formando sinangios o libres formando soros; las clases de ornamentación en esporas monoletes y triletes y una homogeneidad citológica basada en un x=40 (39). Se consideran rasgos genéricos el tamaño de los esporófitos; la localización y morfología de los granos de almidón; las frondas dimórficas o monomórficas; la división de las láminas; los tipos de márgenes; la venación libre o anastomosante; la presencia o ausencia y la extensión del venuloide; la naturaleza glandular o eglandular del indumento; el predominio de ciertos tipos de modelo epidérmico; la ausencia o presencia y distribución de idioblastos de ópalo; el estoma maratiáceo ciclocítico, porociclocítico o ambos; la presencia o ausencia y los tipos de paráfisis; los soros o sinangios y el número de esporangios en cada uno; la apertura trilete o monolete y el predominio de una clase de macro-ornamentación (esporas pustuladas o equinadas). Se consideran caracteres específicos la arquitectura de las frondas; los patrones de venación; la extensión del Rev. Museo La Plata , Botánica 16 (117): 1-21 2 venuloide; la morfología y tamaño de los granos de almidón; los tipos de indumento glandular o eglandular; la combinación de modelos epidérmicos en epifilos e hipofilos; la densidad de estomas e idioblastos; la morfología de las paráfisis; la presencia y tipos de microornamentación de los perisporios; la densidad de las bulas en los exosporios pustulados; la variación morfológica, densidad y grados de fusión basal de las espinas en esporas equinadas.Marattiaceae Bertchtold & J. S. Presl is proposed as to be the only family of the order Marattiales to include five genera of marattiaceous extant ferns: Angiopteris Hoffm., Archangiopteris Christ. & Giesenh., Christensenia Maxon, Danaea J. E. Smith and Marattia Sw., based on characters of the sporophyte selected by the authors after comparative morphological studies of their own, and also based on previous knowledge on the group. The following characters are diagnostic at the family level: suberect to erect or postrate, naked, carnose and amylaceous, polycyclostelic to dictiostelic rhizomes; amylaceous stipules; secretory mucilage system; absence of sclerenchymatic tissues in roots and rhizomes but presence of them in distal parts of stipes, costae and costulae; simple, excentric or concentric starch grains within parenchymatic inner cortex of the rhizomes, stipules and stipes; carnose pulvinules (nodes) without mechanic tissues; ability to biomineralize SiO2 and produce opal A; intercellular pectic protuberances in the mesophyll cells; epidermal patterns and marattiaceous stomata of laminae; eusporangia free (disposed in sori) or partially to completely fused (forming synangia); classes of ornamentation of monolete and trilete spores and homogenous cytology of the genera based on an x=40(39). The following characters are diagnostic at the generic level: size of the sporophytes; distribution of starch in the plant body and gross morphology of the grains; dimorphism of the laminae; division of the laminae; types of margin of the pinnae and pinnulae; simple or anastomosing venation; presence or absence of venuloids; eglandular or glandular nature of the indument; predominance of certain epidermal patterns; presence or absense of opal idioblasts; marattiaceous cyclocytic and/or porocyclocytic stomata; sori or synangia and number of sporangia in each one; types of paraphyses, and spore aperture. Specific traits are as follows: architecture of laminae; venation patterns; extention of the venuloids; types, outline and size of starch grains; morphology of the indument; combinations of epidermal patterns in the epi- and hypophylls of the laminae; morphology of paraphyses; micro- and macro-ornamentation of the perispores and exospores, and morphology of spines of the echinate spores.Laboratorio de Estudios de Anatomía Vegetal Evolutiva y Sistemátic
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Revisión de las especies neotropicales de Marattia Sw. (Marattiacea Bercht. & J. S. Presl)
'Universidad Nacional de La Plata', 2010Co-Authors: Lavalle, María Del CarmenAbstract:Este trabajo trata sobre la morfología y taxonomía de las especies neotropicales de Marattia Sw., el único género pantropical de la familia Marattiaceae Bercht. y J. S. Presl (1820), considerada la más primitiva de los helechos actuales y la única viviente del orden Marattiales. La familia es antigua, con un registro fósil que se remonta al Carbónico (Mamay, 1950; Stidd, 1974). Aunque durante algún tiempo se la consideró sin relación clara con los actuales grupos leptosporangiados (Tryon y Tryon, 1989: 41), los análisis cladísticos y los datos más recientes sugieren, opuestamente, que se encuentra en la base de la evolución de aquéllos, a través de grupos protoleptosporangiados como las Osmundales (Kenrick y Crane, 1977: 242; Hasebe, Omori, Nakasawa, Sano, Kato e Iwatsuki, 1994; Pryer, Smith y Skog, 1996).La familia Marattiaceae presenta estructuras esporógenas de dos tipos: sinangios y soros. Los soros son típicos de los helechos, mientras que los sinangios son exclusivos de Marattiaceae. Aparentemente ambas clases de estructuras son igualmente antiguas, pueden rastrearse hasta el Pérmico superior (Lui, Li y Hilton, 2001), y aunque se ha considerado que representan dos tendencias evolutivas paralelas en el orden (Millay, 1978), también es posible que los soros sean posteriores a los sinangios y, como lo sugiere la ontogenia, derivados de éstos (Bierhorst, 1971:351).Facultad de Ciencias Naturales y Muse
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Sistemática de los helechos maratiáceos (Marattiales-Marattiaceae)
2003Co-Authors: Rolleri, Cristina Hilda, Lavalle, María Del Carmen, Mengascini, Adriana Susana, Rodríguez, Mónica BeatrizAbstract:Aquí se propone reunir en una sola familia, Marattiaceae, cinco géneros vivientes de helechos maratiáceos: Angiopteris, Archangiopteris, Christensenia, Danaea y Marattia, todos los cuales son diversamente afines entre sí pero cuyos rasgos en común justifican la existencia de una sola familia. Esta propuesta se basa tanto en la bibliografía previa sobre el grupo como en los numerosos trabajos de las autoras, tanto de aspectos parciales como revisiones recientes. Se consideran rasgos de familia los rizomas desnudos, erectos, ascendentes o postrados, carnosos y amiláceos, policiclostélicos a dictiostélicos; las estípulas amiláceas pareadas en la base de los estípites; el tejido secretor de mucílago; la ausencia de esclerénquima en rizomas y raíces pero su presencia en la parte distal de los estípites, costas y cóstulas; los granos de almidón simples concéntricos o excéntricos en tejidos parenquimáticos de rizomas, estípulas y estípites; los pulvínulos (“nudos”) en los estípites y/o en la zona de inserción de las costas en el raquis; la capacidad de biomineralizar SiO2 y formar ópalo A; las protuberancias intercelulares pécticas de las células del mesofilo de las frondas (PIP); los modelos epidérmicos y los estomas adultos maratiáceos ciclocíticos y/o porociclocícitos; los eusporangios, parcialmente a totalmente fusionados por sus paredes formando sinangios o libres formando soros; las clases de ornamentación en esporas monoletes y triletes y una homogeneidad citológica basada en un x=40 (39). Se consideran rasgos genéricos el tamaño de los esporófitos; la localización y morfología de los granos de almidón; las frondas dimórficas o monomórficas; la división de las láminas; los tipos de márgenes; la venación libre o anastomosante; la presencia o ausencia y la extensión del venuloide; la naturaleza glandular o eglandular del indumento; el predominio de ciertos tipos de modelo epidérmico; la ausencia o presencia y distribución de idioblastos de ópalo; el estoma maratiáceo ciclocítico, porociclocítico o ambos; la presencia o ausencia y los tipos de paráfisis; los soros o sinangios y el número de esporangios en cada uno; la apertura trilete o monolete y el predominio de una clase de macro-ornamentación (esporas pustuladas o equinadas). Se consideran caracteres específicos la arquitectura de las frondas; los patrones de venación; la extensión del Rev. Museo La Plata , Botánica 16 (117): 1-21 2 venuloide; la morfología y tamaño de los granos de almidón; los tipos de indumento glandular o eglandular; la combinación de modelos epidérmicos en epifilos e hipofilos; la densidad de estomas e idioblastos; la morfología de las paráfisis; la presencia y tipos de microornamentación de los perisporios; la densidad de las bulas en los exosporios pustulados; la variación morfológica, densidad y grados de fusión basal de las espinas en esporas equinadas.Marattiaceae Bertchtold & J. S. Presl is proposed as to be the only family of the order Marattiales to include five genera of marattiaceous extant ferns: Angiopteris Hoffm., Archangiopteris Christ. & Giesenh., Christensenia Maxon, Danaea J. E. Smith and Marattia Sw., based on characters of the sporophyte selected by the authors after comparative morphological studies of their own, and also based on previous knowledge on the group. The following characters are diagnostic at the family level: suberect to erect or postrate, naked, carnose and amylaceous, polycyclostelic to dictiostelic rhizomes; amylaceous stipules; secretory mucilage system; absence of sclerenchymatic tissues in roots and rhizomes but presence of them in distal parts of stipes, costae and costulae; simple, excentric or concentric starch grains within parenchymatic inner cortex of the rhizomes, stipules and stipes; carnose pulvinules (nodes) without mechanic tissues; ability to biomineralize SiO2 and produce opal A; intercellular pectic protuberances in the mesophyll cells; epidermal patterns and marattiaceous stomata of laminae; eusporangia free (disposed in sori) or partially to completely fused (forming synangia); classes of ornamentation of monolete and trilete spores and homogenous cytology of the genera based on an x=40(39). The following characters are diagnostic at the generic level: size of the sporophytes; distribution of starch in the plant body and gross morphology of the grains; dimorphism of the laminae; division of the laminae; types of margin of the pinnae and pinnulae; simple or anastomosing venation; presence or absence of venuloids; eglandular or glandular nature of the indument; predominance of certain epidermal patterns; presence or absense of opal idioblasts; marattiaceous cyclocytic and/or porocyclocytic stomata; sori or synangia and number of sporangia in each one; types of paraphyses, and spore aperture. Specific traits are as follows: architecture of laminae; venation patterns; extention of the venuloids; types, outline and size of starch grains; morphology of the indument; combinations of epidermal patterns in the epi- and hypophylls of the laminae; morphology of paraphyses; micro- and macro-ornamentation of the perispores and exospores, and morphology of spines of the echinate spores.Facultad de Ciencias Naturales y Muse
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Epidermis y estomas porociclocíticos en Christensenia-cumingiana Crist (Marattiaceae-Marattiales-Eusporangiopsida)
Facultad de Ciencias Naturales y Museo - Universidad Nacional de La Plata, 2026Co-Authors: Rolleri Cristina, Deferrari, Amelia M., Lavalle, María Del CarmenAbstract:This paper deals with the epidermic morphology and the peculiar pneumathodes found in the fronds of Christensenia cumingiana Christ (Marattiacere). The epidermic patlem has been found to differ in the abaxial and adaxial surfaces of the pinnae, with frequently sinuous and poligonal to subpoligonal models respectively. (Rolleri & Deferrari 1986). This is similar to the pattem found in especies of genus Danrea l.E. Smith. The pneumathodes are here consider as special type of cyclocitic stomata. Surfaces and cross sections of pinnae had been studied, both in juvenile and adult epidermic areas. As results of the rccording of all the probable slages of development, the genesis stomato can be consider as a perigenous one. The name porocyclocytic stomata is here proposed for the mature pneumathode. This dessignation alludes to its essential characters: the pores are always wide open, while the subsidiary cells are arranged in 2 concentric and superimposed crowns of encircling ceIls. The whole structure protrudes above the adjacent epidermis. The porocyclocytic stomata would function as doubIe structures for gaseous exchange and elimination of liquid water (guttation). They would behave as stomata and, eventually, also as a simple and passive hidathodes - which would be justified by the mesophyll characteristics, the hydric needs of the fronds and the fore ts environment where these plants grow. The porocycIocytic stomala are here considered as a functional specialization ofthe common cyclocytic typeof stomata, generally present in Marattiales sensu lato.Se estudia la morfología epidérmica y los peculiares pneumatodes de lasfrondes de Christensenia-cumingiana Christ (Marattiacere).La epidermis adulta se analiza en superficie y en cortes transversales,brindándose información origin
Robert Noll - One of the best experts on this subject based on the ideXlab platform.
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petrified Marattiales pinnae from the lower permian of north western gondwana parnaiba basin brazil
Review of Palaeobotany and Palynology, 2014Co-Authors: Tatiane Marinho Vieira Tavares, Rosemarie Rohn, Ronny Roβler, Robert NollAbstract:Abstract This study concerns silicified fertile pecopterid pinnae from the Permian of the Parnaiba 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.
Xinshi Cheng - One of the best experts on this subject based on the ideXlab platform.
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exploring the stem to crown group transition in Marattiales a new species of frond from the late permian of china with features of the psaroniaceae and marattiaceae
Review of Palaeobotany and Palynology, 2021Co-Authors: Jason Hilton, Shijun Wang, Xinshi ChengAbstract:Abstract 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.