A rediscovered 114‐foot <i>Lepidodendron</i> from Bolton, Lancashire

Thomas, Barry A.; Watson, Joan

doi:10.1002/gj.3350110102

Cited by 52 publications

(36 citation statements)

References 6 publications

(3 reference statements)

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“…These trees, supported by a cylinder of bark rather than a core of wood, are among the most unusual in all of earth history (Andrews and Murdy 1958). Some of the larger species reached heights of more than 30 m (Thomas and Watson 1976), whereas others were of more modest size. The trees comprised three dominant growth architectures (Bateman et al 1992;DiMichele et al 2013a): those that grew as unbranched poles, producing cones periodically on short, trunk-borne peduncles (mainly Sigillaria); those of monocarpic habit, in which a dichotomously branched crown, bearing the reproductive organs, was produced only in the final phases of growth (primarily Lepidodendraceae; fig.…”

Section: Wetland Floral Compositionmentioning

confidence: 99%

Wetland-Dryland Vegetational Dynamics in the Pennsylvanian Ice Age Tropics

DiMichele¹

2014

International Journal of Plant Sciences

158

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Premise of research. The Late Paleozoic Ice Age was the last extensive pre-Pleistocene ice age. It includes many climate changes of different intensities, permitting examination of many and varied biotic responses. The tropical Pennsylvanian Subperiod, usually visualized as one vast wetland coal forest, in fact also was dominated, periodically, by seasonally dry vegetation that, in turn, covered most of the central and western Pangean supercontinent. Equatorial wetland and dryland biomes oscillated during single glacial-interglacial cycles. This recognition changes understanding of the Coal Age tropics; examination of their spatiotemporal patterns indicates that these vegetation types responded differently to global environmental disturbances and long-term trends and points to potentially different underlying controls on evolutionary histories of their component lineages.Methodology. This study is based on the published literature and on examination of geological exposures and fossil floras, mainly from North America but also from other parts of the world.Pivotal results. Wetlands and seasonally dry habitats were equally part of the Coal Age Pangean tropics. They dominated these landscapes at different times, under different climatic regimes. Wetland vegetation was likely forced into refugia during seasonally dry (subhumid to semiarid) parts of glacial-interglacial cycles; it reemerged/reassembled during wet (humid to perhumid) periods. Seasonally dry vegetation resided permanently in areas of western and central Pangea and in microhabitats within the Central Pangean Mountains. Both floras had lower biodiversity than modern floras in similar habitats. The wetland flora species pool was more phylogenetically disparate than any modern vegetation. In contrast, seasonally dry floras were dominated by seed plants. These biomes responded differently to acute environmental changes and chronic long-term aridification.Conclusions. From ecological or evolutionary perspectives, the present-day world is but one possibility. Lower-diversity worlds such as the late Paleozoic, with a rich spectrum of environmental variations, offer insights into relationships between organisms and environments that expand understanding of these phenomena and enlarge our sense of what is possible or probable as we look to the future.

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Section: Wetland Floral Compositionmentioning

confidence: 99%

Wetland-Dryland Vegetational Dynamics in the Pennsylvanian Ice Age Tropics

DiMichele¹

2014

International Journal of Plant Sciences

158

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“…Prone trees on a forest floor offer unrivalled opportunity for reconstruction from root systems to tree height, including such things as trunk taper, branching patterns, the distribution of leaves and reproductive structures (e.g. Thomas & Watson 1976;Wnuk & Pfefferkorn 1984), but also require large bedding surface exposures, generally found only in mines, which few palaeobotanists have the opportunity (or the inclination!) to visit in the present day, but more regularly accessed in the past e.g.…”

Section: Whole-plant Reconstruction and Growth Formmentioning

confidence: 99%

Pennsylvanian ‘fossil forests' in growth position (T ⁰ assemblages): origin, taphonomic bias and palaeoecological insights

DiMichele

Falcon-Lang

2011

JGS

110

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Fossil forests, buried in growth position in a geological instant (T° assemblages) are far more abundant in Pennsylvanian successions than in any other part of the geological record. In this review paper, we evaluate the fundamental controls on the origin of these phenomena, investigate the taphonomic biases that influence their composition, and summarize their palaeoecological significance. Following earlier workers, we highlight that high rates of burial and accommodation are essential for the formation and preservation of T° assemblages. Contexts especially favourable for their origin include ashfalls proximal to volcanic centres, coastal plains drowned by relative sea-level rise, and fluvial environments such as channel bars, crevasse splays, and distributary lobes. Long-term preservation requires high rates of subsidence. Consequently, the vast majority of Palaeozoic T° assemblages are confined to wetland settings at, or close to, sea level, whereas drylands are poorly represented and uplands rarely sampled, if ever. However, this is not the only major bias in the fossil record; taphonomic processes selectively preserve plants dependent on their anatomy and stature, and on groundwater chemistry. Thus, although T° assemblages offer unrivalled insights into the nature of ancient forests (whole-plant reconstructions, tree density, canopy height, productivity, plant hydraulics, cohort dynamics, spatial heterogeneity, ecological gradients, tree-sediment interactions, and animal-plant interactions, to name but a few), it is naive to believe they provide 'photographic snapshots' of palaeoecosystems. None the less, careful taphonomic analysis of T° assemblages offers the potential for a nuanced understanding of these evocative phenomena, and much remains to be learned from these important palaeoecological resources.

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“…Lycophyte trees up to 50 m in height (3,4) were dominant components of coal swamp forests (5,6). They were key components of coal-forming environments throughout the Carboniferous period but dominated in the lower-middle Pennsylvanian (Namurian-Wetsphalian) where they typically contribute between 60% and 95% of the biomass in buried peat (7)(8)(9)(10)(11)(12)(13).…”

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confidence: 99%

Networks of highly branched stigmarian rootlets developed on the first giant trees

Hetherington

Berry

Dolan

2016

Proc. Natl. Acad. Sci. U.S.A.

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Lycophyte trees, up to 50 m in height, were the tallest in the Carboniferous coal swamp forests. The similarity in their shoot and root morphology led to the hypothesis that their rooting (stigmarian) systems were modified leafy shoot systems, distinct from the roots of all other plants. Each consists of a branching main axis covered on all sides by lateral structures in a phyllotactic arrangement; unbranched microphylls developed from shoot axes, and largely unbranched stigmarian rootlets developed from rhizomorphs axes. Here, we reexamined the morphology of extinct stigmarian systems preserved as compression fossils and in coal balls from the Carboniferous period. Contrary to the long-standing view of stigmarian systems, where shoot-like rhizomorph axes developed largely unbranched, root-hairless rootlets, here we report that stigmarian rootlets were highly branched, developed at a density of ∼25,600 terminal rootlets per meter of rhizomorph, and were covered in root hairs. Furthermore, we show that this architecture is conserved among their only extant relatives, herbaceous plants in the Isoetes genus. Therefore, despite the difference in stature and the time that has elapsed, we conclude that both extant and extinct rhizomorphic lycopsids have the same rootlet system architecture.evolution | paleobotany | Carboniferous forests | stigmarian root systems | Isoetes T he spread of the first wetland forests with tall trees during the Carboniferous period (359-300 million years ago) had a dramatic impact on the carbon cycle by burying large amounts of organic carbon in the form of peat in coal swamps (1, 2). Lycophyte trees up to 50 m in height (3, 4) were dominant components of coal swamp forests (5, 6). They were key components of coal-forming environments throughout the Carboniferous period but dominated in the lower-middle Pennsylvanian (Namurian-Wetsphalian) where they typically contribute between 60% and 95% of the biomass in buried peat (7-13). The preserved remains of lycophyte trees form some of the most extensive fossil plant deposits of any geological period. This is in part because of their size and ecological dominance but also the result of the high probability of preservation in the waterlogged conditions in which these trees grew (4). Detailed descriptions of the morphology of these plants on a range of scales-from entire in situ tree lycophyte forests (14, 15) to cellular descriptions of developing spores (16)-have made these trees some of the best understood fossil plants of the Carboniferous coal swamps.The rooting system of the arborescent lycopsids-stigmarian systems-consist of large shoot-like axes (rhizomorphs) that develop lateral organs called rootlets (4,(17)(18)(19)(20). Rootlets, which have been described as largely unbranched and root hairless (4,5,(17)(18)(19)(20)(21)(22)(23)(24), are arranged in a characteristic pattern or rhizotaxy on the rhizomorph (25). It is the arrangement of these largely unbranched leaf-like rootlets on a shoot-like axis that first led to the theory that stigm...

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A rediscovered 114‐foot Lepidodendron from Bolton, Lancashire

Abstract: Sixteen specimens of known heights from a Lepidodendron trunk, about 3 4 5 m long. are described in detail. The surface features show upward change from fissured bark to well defined leaf cushions. These features are discussed in relation to growth patterns in arborescent lycopods.

Cited by 52 publications

References 6 publications

Wetland-Dryland Vegetational Dynamics in the Pennsylvanian Ice Age Tropics

Wetland-Dryland Vegetational Dynamics in the Pennsylvanian Ice Age Tropics

Pennsylvanian ‘fossil forests' in growth position (T ⁰ assemblages): origin, taphonomic bias and palaeoecological insights

Networks of highly branched stigmarian rootlets developed on the first giant trees

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A rediscovered 114‐foot Lepidodendron from Bolton, Lancashire

Abstract: Sixteen specimens of known heights from a Lepidodendron trunk, about 3 4 5 m long. are described in detail. The surface features show upward change from fissured bark to well defined leaf cushions. These features are discussed in relation to growth patterns in arborescent lycopods.

Cited by 52 publications

References 6 publications

Wetland-Dryland Vegetational Dynamics in the Pennsylvanian Ice Age Tropics

Wetland-Dryland Vegetational Dynamics in the Pennsylvanian Ice Age Tropics

Pennsylvanian ‘fossil forests' in growth position (T 0 assemblages): origin, taphonomic bias and palaeoecological insights

Networks of highly branched stigmarian rootlets developed on the first giant trees

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Resources

About

Pennsylvanian ‘fossil forests' in growth position (T ⁰ assemblages): origin, taphonomic bias and palaeoecological insights