Lepidodendron aculeatum with Attached Foliage: Evidence of Stem Morphology and Fossilization Processes

Leary, Richard L.; Thomas, Barry A.

doi:10.2307/2444670

Cited by 7 publications

(5 citation statements)

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“…In fact, all of the aerial parts of arborescent lycophytes with Lepidodendron stems were probably leafy for much of their life. Leary & Thomas (1989) described large stems of Lepidodendron aculeatum with leaves still attached, while also showing leaf scars with the three characteristic lepidodendroid foliar marks; a similar albeit somewhat more slender stem with attached leaves was previously documented by Thomas (1970: text‐fig. 2F).…”

Section: Leafy Stemssupporting

confidence: 61%

The nomenclature of fossil‐taxa representing different preservational states:Lepidodendronas a case‐study

Thomas

Cleal

2020

TAXON

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The fossil‐genus Lepidodendron is normally used for adpressions, casts and moulds of Palaeozoic arborescent lycophyte stems, but it has also sometimes been used for anatomically preserved stems and even whole‐plant reconstructions. When used for anatomically preserved fossils, Lepidodendron is usually now restricted to the group of species allied to Lepidodendron hickii, but this results in confusion and potential disruption to the traditional use of the fossil‐genus for non‐anatomically preserved stems. The case is made for separate sets of fossil‐genera for the anatomically and non‐anatomically preserved stems, with the circumscription of Lepidodendron being limited to adpressions, casts and moulds. A new fossil‐genus, Dimicheleodendron gen. nov., is proposed for the lycophyte stem petrifactions typified by Lepidodendron hickii.

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Section: Leafy Stemssupporting

confidence: 61%

The nomenclature of fossil‐taxa representing different preservational states:Lepidodendronas a case‐study

Thomas

Cleal

2020

TAXON

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“…The short, awl-like and permanently attached leaves of some arborescent lycopsids, such as Paralycopodites (Figure 8A), do not allow for a determination of functional leaf lifespan. In those arborescent taxa that do have leaf abscission, axes with attached leaves (Chaloner and Meyer-Berthaud, 1983;Kosanke, 1979;Leary and Thomas, 1989;Rex, 1983;Thomas, 1970) are typically too fragmentary to determine an accurate length of a leaf-bearing stem segment. It does appear, however, that leaves covered at least a meter or so of trunk length within the crown of the monocarpic Lepidodendron (Kosanke, 1979) (Figure 6C).…”

Section: Direct Measures Of Growth Rates From Fossil Leaf Characterismentioning

confidence: 99%

Arborescent lycopsid productivity and lifespan: Constraining the possibilities

Boyce

DiMichele

2016

Review of Palaeobotany and Palynology

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One of the most enigmatic components of early terrestrial vegetation was the arborescent lycopsids. Because of the sheer abundance of their biomass in many wetland environments of the Late Paleozoic, they may have been an important variable in the global carbon cycle and climate. However, their unusual structure has invited extraordinary interpretations regarding their biology. One idea that has persisted in the literature for over forty years is that these trees had extremely short lifespans, on the order of ten years. Such an accelerated lifecycle would require growth rates twenty times higher than modern angiosperm trees (and at least 60 times higher than modern lycopsids). Here, we evaluate the morphology and anatomy of lycopsid trees-including aerenchyma, phloem, leaf base distributions, leaf structure, rootlet anatomy, and the demography of the preserved fossils-with comparison to modern plants with some similarity of overall form, most notably the palms. The environmental context of lycopsid trees also is considered in the light of the vegetation of modern water-saturated substrates. It is concluded that such rapid growth would violate all known physiological mechanisms. One hypothetical mechanism that had been proposed to provide for increased carbon fixation, a unique photosynthetic pathway, could not have been viable in these plants and there is no accounting for the increases in nitrogen and phosphorous uptake that would be necessary to sustain enormous rates of carbon fixation. Of the various aspects of lycopsid anatomy and ecology that might militate against this conclusion that productivity was not high, no line of evidence requires a uniquely rapid growth rate for the arborescent lycopsids and several lines of evidence seem to prohibit it. Thus, we conclude that the lifespans of arborescent lycopsids most likely were measured in centuries rather than years. These trees should not be expected to have been unique outliers with physiological function completely distinct from all other tracheophytes. Furthermore, they require, no special consideration in the evaluation of Paleozoic biogeochemical cycling. Finally, the conclusion that lycopsid lifespans were an order of magnitude longer than previous expectations invites reconsideration of many other aspects of their ontogeny, physiology, and structure.

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“…georgia: Gillespie and Crawford (1985), Gillespie et al (1989). illinois: Lesquereux (1879-1880), Janssen (1957), Langford (1958), Darrah (1969), Jennings (1984), Leary and Thomas (1989), Wittry (2006). indiana: Canright (1959), Wood (1963), DiMichele and Dolph (1981), Willard et al (1995).…”

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confidence: 99%

Lycopsida from the lower Westphalian (Middle Pennsylvanian) of the Maritime Provinces, Canada

Álvarez-Vázquez

Wagner²

2014

atgeol

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A taxonomic revision of lycopsids is presented as part of a reassesment of lower to middle Westphalian adpression floras from the Maritime Provinces of Canada. Being elements of the swamp flora their record reflects sedimentary bias. Systematic collecting from the “Fern Ledges” at Saint John (New Brunswick) has yielded only a few lycopsid remains as a result of the allochthonous facies. Most records (mainly by W.A. Bell in the twentieth century) correspond to sporadic collecting by Geological Survey of Canada (GSC) personnel. Their specimens are kept in GSC Ottawa. Additional remains are in museums at Montréal (Quebec), Joggins (Nova Scotia) and Saint John (New Brunswick). We introduce a new species (Lepidodendron bellii), and reinstate another (Diaphorodendron decurtatum) described by Dawson in the 19th century. Altogether, 26 taxa are described, including stem and branch remains as well as roots, leaves, strobili and sporophylls. Three specimens are illustrated from localities outside Canada so as to clarify specific characters. A copy of Lindley and Hutton’s illustration of the type of Lepidodendron dilatatum (here recorded as Bergeria dilatata) is figured in the context of a redefinition of the genus Bergeria for stem remains with false leaf scars. Problems surrounding the morphological interpretation of arborescent lycopsids of Pennsylvanian age are discussed, and the stratigraphic and paleogeographic distribution are recorded for the different taxa. The identity of the Pennsylvanian flora of the Canadian Maritimes with that of the British Isles and western Europe in general is emphasized by the synonymies discussed. Paleogeographic proximity and a similar paleolatitude justify the identity of floras.

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Lepidodendron aculeatum with Attached Foliage: Evidence of Stem Morphology and Fossilization Processes

Cited by 7 publications

References 0 publications

The nomenclature of fossil‐taxa representing different preservational states:Lepidodendronas a case‐study

The nomenclature of fossil‐taxa representing different preservational states:Lepidodendronas a case‐study

Arborescent lycopsid productivity and lifespan: Constraining the possibilities

Lycopsida from the lower Westphalian (Middle Pennsylvanian) of the Maritime Provinces, Canada

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