Topic
Lyginopteris
About: Lyginopteris is a research topic. Over the lifetime, 21 publications have been published within this topic receiving 438 citations.
Papers
TL;DR: Fossils of extinct seed plants evolved a structural and functional diversity of xylem architectures broader, in some ways, than the range observable in living seed plants, suggests this morphospace analysis of water transport cells.
Abstract: We present a morphometric analysis of water transport cells within a physiologically explicit three-dimensional space. Previous work has shown that cell length, diameter, and pit resistance govern the hydraulic resistance of individual conducting cells; thus, we use these three parameters as axes for our morphospace. We compare living and extinct plants within this space to investigate how patterns of plant conductivity have changed over evolutionary time. Extinct coniferophytes fall within the range of living conifers, despite differences in tracheid-level anatomy. Living cycads, Ginkgo biloba, the Miocene fossil Ginkgo beckii, and extinct cycadeoids overlap with both conifers and vesselless angiosperms. Three Paleozoic seed plants, however, occur in a portion of the morphospace that no living seed plant occupies. Lyginopteris, Callistophyton, and, especially, Medullosa evolved tracheids with high conductivities similar to those of some vessel-bearing angiosperms. Such fossils indicate that extinct seed plants evolved a structural and functional diversity of xylem architectures broader, in some ways, than the range observable in living seed plants.
67 citations
TL;DR: Evidence supports the view that Pitus should be classified in the Lyginopteridaceae although it was arborescent and in some respects more advanced than many of the more shrub-like Pteridosperms.
Abstract: Past work on the genus Pitus is reviewed and evidence adduced in favour of the view that it was a genus of arborescent Pteridosperms bearing the sterile bifurcate fronds known as Lyginorachis papilio Kidston. These probably resembled Sphenopteris affinis L. & H. in the compression state. Fertile organs were probably borne on trifurcate fronds in which a stemlike median rachis (Tristichia ovensi Long) bore synangia (Telangium sp.) composed of eight microsporangia, or alternatively seed-cupules of Stamnostoma huttonense Long. Branching in Pitus produced single branches at a wide angle, or pseudo-whorls (close spirals) of about five branches. An anomalous ring of medullary xylem was sometimes associated with branching as in Lyginopteris. This supports the view that Pitus should be classified in the Lyginopteridaceae although it was arborescent and in some respects more advanced than many of the more shrub-like Pteridosperms.
65 citations
TL;DR: The vegetation of many Euramerican coal swamps is known from coal-ball peats in the tropical rainy zone across the paleocontinent of Laurussia in the Upper Carboniferous as mentioned in this paper.
61 citations
TL;DR: The slender Calamopitys stem differs in mechanical terms from the plesiomorphic arrangement observed in aneurophytalean progymnosperms as a result of the support provided by numerous petiolar bundles, which contrasts with the structural divergence observed in Lyginopteris oldhamia.
Abstract: Biomechanical parameters are presented for permineralized Calamopitys stems from the Lower Carboniferous of central Germany. A centrisymmetrical model of the fossilized plant stem as viewed in transverse section suggests that slender stems up to 15 mm in diameter were semi-self-supporting. Analysis of the contribution of various tissue types to the mechanical stability of the stem shows that the outer cortex (alternating bands of fibres and parenchyma) was the principal contributor to flexural stiffness of the stem followed by the multi-fascicular petiole bundles. The cylinder of wood located near to the centre of the stem is of relatively minor structural importance. The slender Calamopitys stem differs in mechanical terms from the plesiomorphic arrangement observed in aneurophytalean progymnosperms as a result of the support provided by numerous petiolar bundles. This contrasts with the structural divergence observed in Lyginopteris oldhamia, which resulted from an increased diameter of the procambium and larger role of the wood cylinder for mechanical support.
54 citations
TL;DR: This study provides the earliest evidence for parasitism in Oomycetes and reports a new heterokont eukaryote based on exquisitely preserved fossil oogonia, antheridia and hyphae from the Carboniferous of UK.
Abstract: Thin sections of petrified fossils made during the latter part of the nineteenth and early twentieth centuries to investigate the internal tissue systems of plants now provide an important new source of information on associated micro-organisms. We report a new heterokont eukaryote (Combresomyces williamsonii sp. nov.) based on exquisitely preserved fossil oogonia, antheridia and hyphae from the Carboniferous (Pennsylvanian: Bashkirian stage) of UK. The structure of the oogonia and antheridia and features observed within the hyphae demonstrate a relationship with Oomycetes (Peronosporomycetes). The fossil micro-organism was documented in situ in petrified stem cortex and rootlets of the extinct seed fern Lyginopteris oldhamia (Pteridospermales). The main observed features point towards a pythiaceous Oomycete but links to biotrophic Albuginales or Peronosporaceae cannot be ruled out owing to the observation of a possible haustorium. Our study provides the earliest evidence for parasitism in Oomycetes.
48 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2017 | 1 |
| 2016 | 1 |
| 2011 | 1 |
| 2010 | 1 |
| 2009 | 1 |
| 2007 | 1 |