A vascular conducting strand in the early land plant Cooksonia

  title={A vascular conducting strand in the early land plant Cooksonia},
  author={D. Edwards and Kevin L. Davies. and Lindsey Axe},
THE late Silurian–early Devonian genus Cooksonia, characterized by smooth isotomously branching axes and solitary, terminal sporangia1, has long been regarded as the archetypal vascular plant because of its age and simplicity of organization. The discovery of stomata, sterome2 and thick-walled spores1,3 in Cooksonia pertoni and C. hemisphaericaconfirmed its land-plant status, but tracheids have never been demonstrated in attached axes4. Here we report on tubes with differentially thickened… 
Novel conducting tissues in Lower Devonian plants
Elongate cells presumed to comprise water-conducting tissues are described from the central regions of short lengths of two naked, stomatiferous, coalified, axial fossils from Lochkovian (Lower
Xylem in early tracheophytes
The architecture of the presumed water-conducting cells of the major lineages of early tracheophytes recorded in Silurian and Devonian rocks is reviewed, together with descriptions of further diverse
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Franhueberia is one of the three oldest euphyllophytes exhibiting secondary growth documented in the Early Devonian, and represents basal lineages that predate the evolution of stem-leaf-root organography and indicates that underlying mechanisms for secondary growth became part of the euphllophyte developmental toolkit very early in the clade's evolution.
Tracheid Structure in a Primitive Extant Plant Provides an Evolutionary Link to Earliest Fossil Tracheids
Congruence of tracheid structure in extant Huperzia and Late Silurian and Early Devonian vascular plants supports the hypothesis of a single origin oftracheids in land plants.
The distribution of stomata
In Zosterphyllum myretonianum, stomata up to 120 µm long were recorded (Lele and Walton, 1960–61).
Vascular architecture in shoots of early divergent vascular plants, Lycopodium clavatum and Lycopodium annotinum.
The authors' data showed limited interrelationships between lycopod vasculature and microphyll phyllotaxis, which may suggest that both systems developed independently, then evolved together to form the integrated supply system.
Isolation and handedness of helical coiled cellulosic thickenings from plant petiole tracheary elements
Leaf stalks (petioles) are critical components of the vascular system that conducts water from the roots to the photosynthetic apparatus of most green plants. Helical coiled cellulosic microfibrils
Morphometric analysis of Rhynia and Asteroxylon: testing functional aspects of early land plant evolution
New morphometric data gathered from cross-sections of two Lower Devonian land plants are interpreted in terms of the evolution of the function of vascular bundles in early land plants, finding that Rhynia and Asteroxylon with their distinct stelar geometries represent two different constructional types for which no transitional stages are known.


The anatomy of Lower Devonian Gosslingia breconensis Heard based on pyritized axes, with some comments on the permineralization process
Xylem and peripheral support tissues are described in axes of Gosslingia breconensis preserved as iron sulphide permineralizations and it is suggested that coalified layers mainly represent regions of lignification.
Aglaophyton major, a non-vascular land-plant from the Devonian Rhynie Chert
The genus Aglaophyton is described to accommodate the plant formerly known as Rhynia major, re-examined using new material and techniques and cannot be considered a member of either group; at the present time it is not assigned to a higher category.
Water-Conducting Cells in Early Fossil Land Plants: Implications for the Early Evolution of Tracheophytes
Wall structure in the water-conducting cells of Rhynia gwynne-vaughanii and Asteroxylon mackiei from the Lower Devonian Rhynie Chert was examined and compared, implying that the gametophytes of all extant `pteridophytes' are phylogenetically reduced.
Stomata and sterome in early land plants
Exceptionally preserved coalified fossils from the basal Devonian of Shropshire are reported which show that Cooksonia also possessed stomata and thick walled supporting tissues although evidence for vascular tissue still eludes us.
The earliest vascular land plants: continuing the search for proof
New collections from Bringewoodian strata (Silurian, Ludlow Series, Saetograptus leintwardinensis incipiens Zone) in Wales have yielded the oldest known specimens of the plant Cooksonia. From
Miospores, correlation and age of some Scottish Lower Old Red Sandstone sediments from the Strathmore region (Fife and Angus)
The age of some Lower Old Red Sandstone sediments (Arbuthnott Group) is reassessed and confirmed as Lower Devonian (lower Gedinnian) on the basis of a reinvestigation of spore assemblages. The data
On the Plant-Remains from the Downtonian of England and Wales
The strata from which the plant-remains to be described in this paper are derived are those which are grouped as Downtonian in the extended sense of this term employed by Mr. W. Wickham King. They
A low-viscosity epoxy resin embedding medium for electron microscopy.
  • A. Spurr
  • Materials Science
    Journal of ultrastructure research
  • 1969
A late Wenlock flora from Co. Tipperary, Ireland
It is concluded that these plants provide the earliest record of erect fertile land plants of possible pteridophyte affinity and sedimentological and palaeontological studies of the region provide little direct evidence for the habitats of the plants which are considered to have been terrestrial.