The Rhizomorphic Lycopsids: A Case-Study in Paleobotanical Classification

DiMichele, William A.; Bateman, Richard M.

doi:10.2307/2419613

Cited by 90 publications

(101 citation statements)

References 48 publications

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“…Such anatomy is similar to that of, and phylogenetically links it with, Lepidophloios (DiMichele, 1979) and Hizemodendron Bateman and DiMichele (1991) in the Lepidodendraceae (sensu Bateman et al, 1992;DiMichele and Bateman, 1996 Description.-Leaf cushions are typical of this species and are the key characters for identification. These are higher than wide, serpentine in shape, with the tails strongly curved and confluent with leaf cushions above and below (Plate II,(2)(3).…”

mentioning

confidence: 61%

“…This latter genus, by virtue of its bisporangiate cones, would also reside in the family Flemingitaceae of Thomas and Brack-Hanes (1984). DiMichele and Bateman (1996) placed it in the parataxon Ulodendrineae, and suggested a close relationship between Paralycopodites and Ulodendron sensu Thomas (1967). Álvarez-Vázquez and Wagner (in press) refer Ulodendron sensu Thomas (1967) to Bergeria.…”

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confidence: 99%

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The Okmulgee, Oklahoma fossil flora, a Mazon Creek equivalent: Spatial conservatism in the composition of Middle Pennsylvanian wetland vegetation over 1100km

Moore

Wittry

DiMichele

2014

Review of Palaeobotany and Palynology

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confidence: 61%

mentioning

confidence: 99%

The Okmulgee, Oklahoma fossil flora, a Mazon Creek equivalent: Spatial conservatism in the composition of Middle Pennsylvanian wetland vegetation over 1100km

Moore

Wittry

DiMichele

2014

Review of Palaeobotany and Palynology

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“…It is difficult to detect species differences with confidence due to the very different forms of preservation between coal balls and adpressions (compressions and impressions; see Shute and Cleal 1986) and, hence, the different character suites on which much of the taxonomy is based. Direct comparisons are possible and have been made in some instances (e.g., pteridosperm foliage species [Oestry-Stidd 1979;Mickle and Rothwell 1982;Beeler 1983;Reihman and Schabilion 1985;Cleal and Shute 2012;Raymond et al 2013], lycopsid stem taxa [Bateman et al 1992;DiMichele and Bateman 1996]). However, comparisons at a broader level show consistent differences in quantitative aspects of composition, such as the more common occurrence of the lycopsid Sigillaria or the greater dominance of pteridosperms (King et al 2011;Wagner and Castro 2011) in mineral substrate wetlands than in peat swamps.…”

Section: Roof Shales Versus Peat-forming Florasmentioning

confidence: 99%

Wetland-Dryland Vegetational Dynamics in the Pennsylvanian Ice Age Tropics

DiMichele¹

2014

International Journal of Plant Sciences

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161

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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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“…i) more or less spherical microsporangia, and possibly ii) distal dehiscence (reversal to plesiomorphic condition from radial dehiscence), iii) 4 megaspores per sporangium, iv) suspension of stele in cavity by trabeculate endodermal cells, and v) echinate microspores (Kenrick and Crane 1997). i) cambium, ii) pseudobipolar growth involving rhizomorphic root system, and iii) monarch xylem strand in root (Bateman et al 1992, DiMichele andBateman 1996). i) circinate growth, ii) two-rowed sporangia!…”

Section: Discussionmentioning

confidence: 99%

Problems in Cladistic Classification: Higher-Level Relationships in Land Plants

Crane¹,

Kenrick²

1996

aliso

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Recent cladistic analyses of green plants recognize an extensive hierarchical series of relatively well-supported monophyletic groups. Translating this hierarchical pattern of relationships into a usable and informative written classification is important for purposes of scientific communication, research and teaching. However, in the context of the "Linnean" hierarchy, as manifested in the current International code of Botanical Nomenclature (ICBN), effecting this translation confronts substantial practical difficulties--especially the proliferation of hierarchical levels. These problems are exacerbated by the current emphasis of the ICBN on a hierarchy in which different ranks have different formal rank-based endings. These difficulties could be ameliorated by de-emphasizing the importance of ranks in the ICBN and relaxing the constraints on how they are treated, especially at the higher taxonomic levels. Modifications are needed that permit a more straightforward integration of systematic knowledge and botanical nomenclature, and at the same time foster increased stability in the association between names and the groups of organisms that they designate.

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The Rhizomorphic Lycopsids: A Case-Study in Paleobotanical Classification

Cited by 90 publications

References 48 publications

The Okmulgee, Oklahoma fossil flora, a Mazon Creek equivalent: Spatial conservatism in the composition of Middle Pennsylvanian wetland vegetation over 1100km

The Okmulgee, Oklahoma fossil flora, a Mazon Creek equivalent: Spatial conservatism in the composition of Middle Pennsylvanian wetland vegetation over 1100km

Wetland-Dryland Vegetational Dynamics in the Pennsylvanian Ice Age Tropics

Problems in Cladistic Classification: Higher-Level Relationships in Land Plants

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