XIV.—Some Lower Carboniferous Fructifications from Berwickshire, together with a Theoretical Account of the Evolution of Ovules, Cupules, and Carpels

Long, A. R.

doi:10.1017/s0080456800023668

Cited by 68 publications

(58 citation statements)

References 48 publications

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“…Many earlier discussions of the origin of angiosperms concluded that angiosperms were ''derived from'' seed ferns (e.g., Long 1966, Cronquist 1968, Takhtajan 1969. From a cladistic viewpoint, such statements are not very informative, since all phylogenetic analyses of living and fossil seed plants have indicated that ''seed ferns'' are a paraphyletic grade made up of lines that are basal to more derived groups (Crane 1985, Doyle and Donoghue 1986, Rothwell and Serbet 1994, Doyle 1996.…”

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confidence: 99%

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Perspective: The Origin of Flowering Plants and Their Reproductive Biology?a Tale of Two Phylogenies

Friedman¹,

Floyd²

2001

Evolution

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. Recently, two areas of plant phylogeny have developed in ways that could not have been anticipated, even a few years ago. Among extant seed plants, new phylogenetic hypotheses suggest that Gnetales, a group of nonflowering seed plants widely hypothesized to be the closest extant relatives of angiosperms, may be less closely related to angiosperms than was believed. In addition, recent phylogenetic analyses of angiosperms have, for the first time, clearly identified the earliest lineages of flowering plants: Amborella, Nymphaeales, and a clade that includes Illiciales/Trimeniaceae/Austrobaileyaceae. Together, the new seed plant and angiosperm phylogenetic hypotheses have major implications for interpretation of homology and character evolution associated with the origin and early history of flowering plants. As an example of the complex and often unpredictable interplay of phylogenetic and comparative biology, we analyze the evolution of double fertilization, a process that forms a diploid embryo and a triploid endosperm, the embryo‐nourishing tissue unique to flowering plants. We demonstrate how the new phylogenetic hypotheses for seed plants and angiosperms can significantly alter previous interpretations of evolutionary homology and firmly entrenched assumptions about what is synapomorphic of flowering plants. In the case of endosperm, a solution to the century‐old question of its potential homology with an embryo or a female gametophyte (the haploid egg‐producing generation within the life cycle of a seed plant) remains complex and elusive. Too little is known of the comparative reproductive biology of extant nonflowering seed plants (Gnetales, conifers, cycads, and Ginkgo) to analyze definitively the potential homology of endosperm with antecedent structures. Remarkably, the new angiosperm phylogenies reveal that a second fertilization event to yield a biparental endosperm, long assumed to be an important synapomorphy of flowering plants, cannot be conclusively resolved as ancestral for flowering plants. Although substantive progress has been made in the analysis of phylogenetic relationships of seed plants and angiosperms, these efforts have not been matched by comparable levels of activity in comparative biology. The consequence of inadequate comparative biological information in an age of phylogenetic biology is a severe limitation on the potential to reconstruct key evolutionary historical events.

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“…Similar problems affect Long's (1966) derivation of the carpel from the lobate, dichotomously organized cupule of Carboniferous seed ferns. On recognizing the problem of the bitegmic ovule, Long was forced to postulate that the second integument arose de novo as an outgrowth of the first.…”

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confidence: 99%

Perspective: The Origin of Flowering Plants and Their Reproductive Biology?a Tale of Two Phylogenies

Friedman¹,

Floyd²

2001

Evolution

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“…Such a hypodermis has been occasionally mentioned in other representatives of the genus. In S. berwickensis, from both volcanic and fluviatile environments (Scott and Galtier, 1996) the occurrence of this tissue was suggested but not illustrated by Long (1966). Cichan and Taylor (1982) mentioned a narrow hypodermis in the main axis of S. biseriata.…”

Section: Ecological Adaptationmentioning

confidence: 98%

“…is still unknown. The genus currently includes four species: the homosporous S. oldhamia Binney (1872) is the type-species; it shows a quadriseriate branching pattern; S. burntslandica (Bertand, 1909) and S. berwickensis (Long, 1966) have also a quadriseriate branching pattern but are heterosporous. The fourth species, S. biseriata (Cichan and Taylor, 1982), exhibits a biseriate branching pattern; its reproductive biology is unknown.…”

Section: Introductionmentioning

confidence: 99%

The fern Stauropteris oldhamia Binney: New data on branch development and adaptive significance of the hypodermal aerenchyma

Farahimanesh

Gerrienne

Galtier

et al. 2014

Comptes Rendus Palevol

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General palaeontology, systematics and evolution (Palaeobotany) The fern Stauropteris oldhamia Binney: New data on branch development and adaptive significance of the hypodermal aerenchyma a b s t r a c tWell-preserved specimens of Stauropteris oldhamia are described. The material was collected in the early 1920s from the Lower Westphalian (Early Pennsylvanian) Saurue seam from Belgium. The fossil plants occur as permineralized axes fragments within a coal ball. This study confirms most of the interpretations made by previous researchers. The observation of immature axis however suggests a less regular organization than previously interpreted beyond the three first branching orders. We also highlight the presence of profusely and dichotomously branched aphlebiae, the lack of laminate organs as well as the presence of hypodermal aerenchyma in all plant parts. We interpret these features as part of a very specialized assimilatory apparatus indicating an adaptation to a humid swamp environment.© 2014 Académie des sciences. Published by Elsevier Masson SAS. All rights reserved. ainsi que la présence d'un hypoderme aérenchymateux dans toutes les parties de la plante. Nous interprétons ces caractéristiques comme faisant partie d'un appareil assimilateur très spécialisé indiquant une adaptation à un environnement marécageux humide.

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“…Similarly, among the earliest known conifers, the Permian genera Ernestiodendron and Walchiostrobus included some species with erect and some with reflexed ovules (Florin, 1951). Even earlier still, in the Lower Carboniferous, while most of the pteridosperm ovules so far discovered were orthotropous, one was campylotropous-Camptosperma and another was anatropous-Anasperma (Long, 1966). Throughout the hundreds of millions of years of ovule evolution, therefore, the overall shape of the ovule appears to have mattered scarcely at all What was important in Carboniferous times was the number of envelopes round the nucellus, and this still seems to be true of angiosperm ovules today.…”

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The Ovule as an Indicator of Evolutionary Status in Angiosperms

Sporne

1969

New Phytologist

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Summary The crassinucellate ovule has long been regarded as more primitive among angiosperms than the tenuinucellate. Support for this view is provided by thirteen highly significant statistical correlations between the crassinucellate condition and other dicotyledon characters, both floral and vegetative. This character is therefore included among a total of twenty‐two characters believed to be of use in assessing evolutionary status. The ‘advancement indices’ of dicotyledon families are re‐calculated, using the most recently available facts. While the most primitive families are among the Magnoliales, there are also some very primitive ones among the Myrtiflorae, Violates, Geraniales, Rosales, Guttiferales and Fagales. It is concluded that the ancestral type of ovule in angiosperms was crassinucellate with three envelopes (two integuments and an aril) each of which received a vascular supply.

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XIV.—Some Lower Carboniferous Fructifications from Berwickshire, together with a Theoretical Account of the Evolution of Ovules, Cupules, and Carpels

Cited by 68 publications

References 48 publications

Perspective: The Origin of Flowering Plants and Their Reproductive Biology?a Tale of Two Phylogenies

Perspective: The Origin of Flowering Plants and Their Reproductive Biology?a Tale of Two Phylogenies

The fern Stauropteris oldhamia Binney: New data on branch development and adaptive significance of the hypodermal aerenchyma

The Ovule as an Indicator of Evolutionary Status in Angiosperms

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