New observations on <i>Sawdonia ornata</i> from Scotland

Rayner, R. J.

doi:10.1017/s026359330001018x

Cited by 53 publications

(42 citation statements)

References 48 publications

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“…Further variation is exemplified by the development of lateral branching again showing regularity because it is associated with branch points. Examples include: axillary/subaxillary tubercles, as in Gosslingia (Edwards 1970) and parts of Anisophyton potonei (angularorgans: Remy et al 1986); more extensive branching systems, downwardly directed in spiny Deheubarthia splendens (Edwards et al 1989) and erect in Anisophyton gothani (Remy et al 1986); smaller protuberances (?dormant structures) on the lower surfaces at the base of lateral branches in Sawdonia ornata (Rayner 1983); and aborted branches forming parts of trichotomies in Psilophyton dawsonii . A rare example of less ordered, clustered branches in a Lower Devonian tracheophyte was illustrated in the enigmatic tracheophyte, Bitelaria dubjanskii (Johnson & Gensel 1992).…”

Section: Branching: From Process To Pattern (Or Lack Of It!)mentioning

confidence: 99%

Embryophytic sporophytes in the Rhynie and Windyfield cherts

Edwards

2003

Transactions of the Royal Society of Edinburgh: Earth Sciences

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Brief descriptions and comments on relationships are given for the seven embryophytic sporophytes in the cherts at Rhynie, Aberdeenshire, Scotland. They are Rhynia gwynnevaughanii Kidston & Lang, Aglaophyton major D. S. Edwards, Horneophyton lignieri Barghoorn & Darrah, Asteroxylon mackiei Kidston & Lang, Nothia aphylla Lyon ex Høeg, Trichopherophyton teuchansii Lyon & Edwards and Ventarura lyonii Powell, Edwards & Trewin. The superb preservation of the silica permineralisations produced in the hot spring environment provides remarkable insights into the anatomy of early land plants which are not available from compression fossils and other modes of permineralisation. They include soft tissues, such as those surrounding stomata, rhizoids, apical and lateral meristems, and diversity in conducting cells, with inferences for palaeoecophysiology, including water use efficiency, transport and absorption, and for growth processes and patterns.

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Section: Branching: From Process To Pattern (Or Lack Of It!)mentioning

confidence: 99%

Embryophytic sporophytes in the Rhynie and Windyfield cherts

Edwards

2003

Transactions of the Royal Society of Edinburgh: Earth Sciences

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“…Purely dichotomous root branching patterns existed in (evolutinary) early land plants (Rayner, 1983(Rayner, , 1984; in present day life forms pure dichotomy is rare, but occurs in lycopods and ectomycorrhizal trees. Morphogenetically dichotomy is based on a top meristem splitting in two equal parts.…”

Section: Introductionmentioning

confidence: 99%

Proximal root diameter as predictor of total root size for fractal branching models

Noordwijk

Spek

Willigen³

1994

Plant Soil

105

101

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In a fractai branching pattern the same rules govern branching at each subsequent level. The initial size (diameter) and the essential branching rules thus contain the information required to construct the whole pattern. If root branching patterns have fractal characteristics, measurement of the proximal root diameter at the stem base and the branching rules as observed anywhere in the root system, would be enough to predict total root length, root diameter distribution and root length per unit dry weight (specific root length).A 'pipe stem' model is used to derive algebraic relations between total root size and proximal root diameter for two classes of branching patterns, determinate and proportionate. To predict total root length from the proximal root diameter, at least information is needed on the minimum root diameter, the average length of internal and external links (segments) and the proportionality factor between total cross sectional areas before and after branching. For the length of the longest root or the specific root length further information on the branching rules is needed, as it is highest for determinate and proportionate branching rules, respectively. Abbreviations:CSA -cross sectional area.

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“…11 D2) is observed at the tip of the spiny axes. These characters are found in certain Zosterophyllopsids such as Sawdonia ornata [Hueber, 1971;Rayner, 1983] or Odonax borealis [Gerrienne, 1996], among other species. …”

Section: Zosterophyllopsid?mentioning

confidence: 99%

“…For example, Retusotriletes sp. is produced by Psilophyton princeps, P. dawsonii [Edwards and Richardson, 1996] or Sawdonia ornata [Rayner, 1983]; the two genera Retusotriletes and Apiculiretusispora are found in the sporangia of either Psilophyton parvulum [Gerrienne, 1995] or Renalia hueberi, a plant from Gaspé (Canada) [Edwards and Richardson, 1996]. Apiculiretusispora plicata has been observed within the sporangia of Psilophyton crenulatum [Edwards and Richardson, 1996].…”

Section: Spores From the Sainte-anne Formationmentioning

confidence: 99%

Age and depositional environment of the Sainte-Anne Formation (Armorican Massif, France): the oldest (Emsian) evidence for mountain erosion in the Variscan belt

Ducassou

Strullu‐Derrien

Ballèvre

et al. 2009

Bulletin De La Société Géologique De France

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The palaeogeography of the internal zones of the Variscan belt during the early stages of the convergence remains unclear. Sedimentary sequences that recorded the denudation of an early relief have generally been removed by erosion. In the Chalonnes area (southeast of the Armorican Massif), the reefal carbonates of the Chalonnes Formation (Fm) are overlain by the immature, poorly-sorted sandstones of the Sainte-Anne Fm. This formation is characterised by the occurrence of gravity flow deposits and contains immature and poorly sorted sandstones with a large amount of plant debris and lithic fragments, suggesting a depositional environment in a delta front dominated by floods. A revision of the palaeoflora content allows to assign an Emsian age to the Sainte-Anne Fm. Lithic fragments are mainly of sedimentary and volcanic origin, suggesting moderate erosion level of the source area. Palaeocurrent data indicate a southern origin for the sediments. These features collectively demonstrate that the Sainte-Anne Fm is the record of the erosion of a continental area located farther south, and experiencing incipient tectonic uplift during the Emsian. The Sainte-Anne Fm could represent therefore the earliest record in France of the very first stages of the Variscan orogeny. Age et environnement de dépôt de la formation de Sainte-Anne (Massif armoricain, France): les plus vieux témoins (Emsien) de l'érosion de la chaîne varisqueMots-clés. -Chaîne varisque, Dévonien inférieur, Relief, PaléofloreRésumé. -La paléogéographie des zones internes de la chaîne varisque lors des premiers stades orogéniques reste dé-battue. En effet, les séries sédimentaires qui pourraient avoir enregistré la formation des premiers reliefs sont rarement préservées. Dans la région de Chalonnes (sud-est du Massif armoricain, France), la formation (Fm) de Sainte-Anne, qui succède aux faciès carbonatés récifaux de la Fm de Chalonnes, est un candidat potentiel pour améliorer la compréhen-sion des stades pré-orogéniques dans la chaîne hercynienne. La révision de la flore a permis d'établir un âge emsien pour la Fm de Sainte-Anne. Celle-ci est constituée de grès mal triés, immatures, riches en fragments lithiques et en dé-bris végétaux impliquant un fort apport continental. Les fragments lithiques sont essentiellement d'origine sédimentaire et volcanique impliquant une incision modérée des zones sources. Les mesures de paléocourants indiquent un transport des sédiments du sud vers le nord. La Fm de Sainte-Anne est caractérisée par une sédimentation dominée par les processus gravitaires, supposant un milieu de dépôt en aval d'un système deltaïque alimenté par des crues. La sédimentation de ces grès immatures au-dessus de la Fm de Chalonnes implique la réactivation de zones sources continentales, ce qui suggère l'apparition d'un relief durant l'Emsien au sud de la zone d'étude. La Fm de Sainte-Anne pourrait enregistrer, à la fin du Dévonien inférieur, l'apparition des premiers reliefs associés au début de l'orogenèse hercynienne.

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New observations on Sawdonia ornata from Scotland

Cited by 53 publications

References 48 publications

Embryophytic sporophytes in the Rhynie and Windyfield cherts

Embryophytic sporophytes in the Rhynie and Windyfield cherts

Proximal root diameter as predictor of total root size for fractal branching models

Age and depositional environment of the Sainte-Anne Formation (Armorican Massif, France): the oldest (Emsian) evidence for mountain erosion in the Variscan belt

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