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Fossil plants of the carboniferous rocks of Great Britain
01 Jan 1923-
About: The article was published on 1923-01-01 and is currently open access. It has received 233 citations till now. The article focuses on the topics: Carboniferous.
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646 citations
TL;DR: Analysis of a critically revised morphological data set for seed plants indicates that trees in which Gnetales are nested in conifers, as in molecular analyses, are almost as parsimonious as those inWhich G netales are linked with angiosperms, suggesting that the molecular arrangement should be accepted.
Abstract: Doyle, J.A. (Section of Evolution and Ecology, University of California, Davis, California 95616, USA). Seed ferns and the origin of angiosperms. J. Torrey Bot. Soc. 133: 169–209. 2006.—If molecular analyses are correct in indicating that Gnetales are related to conifers and no other living gymnosperm group is directly related to angiosperms, studies on the origin of angiosperms must focus on fossil taxa, including “seed ferns.” Some authors have homologized the angiosperm carpel with the cupule of seed ferns, but because angiosperm ovules have two integuments rather than one, cupules are more likely to be homologous with the outer integument. Cupules of the earliest seed ferns may be derived from fertile appendages of “progymnosperms,” but those of later taxa appear to be modified leaves or leaflets, with ovules borne on the abaxial surface in some (peltasperms, corystosperms), the adaxial surface in others (glossopterids, Caytonia). Positional relationships and developmental genetic data sugges...
203 citations
TL;DR: The arborescent lycopods dominated many coal-swamp plant communities of the Middle Pennsylvanian, and each species had determinate, dendritic crowns and each tree apparently reproduced during a short, unrepeated interval late in determinate growth.
167 citations
Additional excerpts
...Lepidophloios hallii produced megasporangiate cones, Lepidocarpon, and microsporangiate cones, Lepidostrobus oldhamius (Schopf, 1941a; Felix, 1954; Crookall, 1964; Balbach, 1967; Phillips, 1979)....
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01 Oct 1962
TL;DR: In this article, a petrological and palynological investigation of a number of coal seams containing crassidurain, in the Yorkshire Coalfield, was undertaken, and the results show four distinct assemblages of miospores, each assemblage being more or less associated with coal of a distinctive petrographic type.
Abstract: Summary The lack of ecological data concerning the vegetation of the peat deposits and adjoining areas in the Carboniferous period is a limiting factor in the use of spores for stratigraphical purposes. For this reason, a petrological and palynological investigation of a number of coal seams containing crassidurain, in the Yorkshire Coalfield, was undertaken. The results show four distinct assemblages of miospores, each assemblage being more or less associated with coal of a distinctive petrographic type. Their vertical sequence is similar in the different seams. The succession culminates in the crassidurain, above which, under favourable conditions, the sequence is reversed. The peats producing this sequence are considered to be autochthonous in origin although a partly allochthonous coal type is also recognized. Existing theories, which do not take account of palynological evidence, attribute the petrographic differences in the humic coals to varying degrees of aerobic decomposition controlled by environmental factors such as degree of drainage, or depth of water covering the peat surface at the time of deposition. They do not satisfactorily explain all the new evidence. The possibility that at least part of the sequence, and particularly the crassidurain, was the result of climatic factors is suggested.
156 citations
TL;DR: Detailed comparison of venation in Paleozoic leaves with that of modern leaves for which developmental mechanisms are known suggests developmental interpretations for the origination and early evolution of leaves.
Abstract: Four vascular plant lineages, the ferns, sphenopsids, progymnosperms, and seed plants, evolved laminated leaves in the Paleozoic. A principal coordinate analysis of 641 leaf species from North American and European floras ranging in age from Middle Devonian through the end of the Permian shows that the clades followed parallel trajectories of evolution: each clade exhibits rapid radiation of leaf morphologies from simple (and similar) forms in the Late Devonian/Early Car- boniferous to diverse, differentiated leaf forms, with strong constraint on further diversification beginning in the mid Carboniferous. Similar morphospace trajectories have been documented in studies of morphological evolution in animals; however, plant fossils present unique opportunities for understanding the developmental processes that underlie such patterns. Detailed comparison of venation in Paleozoic leaves with that of modern leaves for which developmental mechanisms are known suggests developmental interpretations for the origination and early evolution of leaves. The parallel evolution of a marginal meristem by the modification of developmental mechanisms available in the common ancestor of all groups resulted in the pattern of leaf evolution repeated by each clade. Early steps of leaf evolution were followed by constraint on further diversification as the possible elaborations of marginal growth were exhausted. Hypotheses of development in Paleozoic leaves can be tested by the study of living plants with analogous leaf morphologies.
150 citations