Evidence for a conducting strand in early Silurian (Llandoverian) plants: implications for the evolution of the land plants

  title={Evidence for a conducting strand in early Silurian (Llandoverian) plants: implications for the evolution of the land plants},
  author={Karl J. Niklas and Vassiliki Betty Smocovitis},
  pages={126 - 137}
Macerations of fragmented plant compressions of Silurian (Llandoverian) age yield sheets of organic material bearing ridges and depressions (interpreted as corresponding to surficial dimensions of cells), fragments of smooth walled tubular elements, and fragments of tubular elements with differentially thickened walls (“banded tubes”). A fragment of tissue (1.2 mm long), consisting of smooth walled tubes (17 ± 6.9 μm in diameter), surrounding 2–3 larger (18.8 ± 2.1 μm in diameter) banded tubes… 
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.
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
Studies of Specialized Pitted Parenchyma Cells of the Liverwort Conocephalum Hill and Their Phylogenetic Implications
These specialized pitted cells of Conocephalum are not directly homologous to metzgerialean water‐conducting cells, moss hydroids and leptoids, or G‐type and S‐type water‐ Conducting cells of early fossil land plants, although there are some shared characters with each of these cell types.
Cyanobacterial macrophytes in an Early Silurian (Llandovery) continental biota: Passage Creek, lower Massanutten Sandstone, Virginia, USA
A compression macrofossil with structure consisting of mineral-replaced filaments embedded in an amorphous carbonaceous matrix is described as a macrophytic cyanobacterial colony from continental
The Structure and Function of Xylem in Seed-Free Vascular Plants: An Evolutionary Perspective
Mapping stelar patterns onto the fern phylogeny reveals that in the more derived eupolypod lineages, selection has favoured the evolution of simpler, less divided vascular networks.
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.
Classification of uppermost Ordovician to Lower Devonian tubular and filamentous macerals from the Anglo-Welsh Basin
Dispersed tubes and filaments from the uppermost Ordovician, Silurian and Lower Devonian of the Anglo-Welsh Basin of Great Britain are described and classified using the artificial Anteturma system
Cells and tissues in the vegetative sporophytes of early land plants.
  • D. Edwards
  • Environmental Science
    The New phytologist
  • 1993
Remarkable preservation in coalified and pennineralized fossils from Upper Silurian and Lower Devonian sediments provides insight into the major anatomical innovations associated with the early stages in the colonization of the land by higher plants.


Evidence of non-vascular land plants from the early Silurian (Llandoverian) of Virginia, U.S.A.
Anatomy of the Medulla of Nereocystis)
An explanation for the observed events in the transition of sieve filaments to trumpet filaments is suggested, and it is argued that trumpet füaments are produced from sieve Filaments by mechanical stretching in longitudinal sections of young stipe medulla.
Evidence for Lignin-Like Constituents in Early Silurian (Llandoverian) Plant Fossils
The presence of parallel-aligned banded tubes, with annular to spiral thickenings and occasional end walls, in conjunction with lignin-like constituents fulfill most of the morphological and chemical criteria for cell types that could have functioned as water-conducting cells.
On the fine structure of sieve tubes and the physiology of assimilate transport in Alaria marginata
Alaria marginata Postels and Ruprecht has a sieve tube system which extends through the lamina, especially the midrib, and through the stipe, and the translocate consists mainly of mannitol and free amino acids, which were analyzed qualitatively and quantitatively.
Foerstia and recent interpretations of early, vascular land plants
Foerstia should be regarded as a marine fucoid, contrary to the recent interpretation of Gray and Boucot who relate these fossils to land plants.
Early vascular land plants: proof and conjecture
Positive correlation between abundance and diversity of trilete spores and shallow-water, nearshore sites reinforces conclusions based on morphology that a terrestrial flora existed well prior to the appearance of vascular plant megafossils.
The Devonian land plant Protosalvinia
The weight of evidence supports neither a fucoid nor even an algal attribution for this enigmatic plant, and Protosalvinia should be treated as the representative of a separate group of land plants, as previously advocated.
Several lines of evidence strongly suggest the presence of a diverse terrestrial flora significantly earlier than the Upper Silurian bench mark currently used for the first appearance of plants with vascular tissue.
Did Multicellular Plants Invade the Land?
The invasion of the land coincided with and depended upon the evolution of the diploid sporophyte from the haploid gametophyte, and the two generations are almost indistinguishable from each other except for the kinds of reproductive cells.