– An online study & reference for reserchers, students in botany with full reference on research institutes and scientific. Division Equisetophyta. Stanley L. Welsh. Monte L. Bean Life Science Museum and Department of Botany and Range Science, Brigham Young. Welsh, Stanley L.; Atwood, N. Duane; Goodrich, Sherel; and Higgins, Larry C. ( ) “Division Equisetophyta,” Great Basin Naturalist Memoirs: Vol. 9, Article 7.

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These cones comprise spirally arranged sporangiophoreswhich bear sporangia at their edges, and in extant sphenophytes cover the spores externally – like sacs hanging from an umbrella, with its handle embedded in the axis of the cone. Equisetopsidaor Sphenopsidais a class of vascular plants with a fossil record going back to the Devonian.

Paleobotany and the evolution of plants 2nd ed. In the only extant genus Equisetumthese are small leaves microphylls with a singular vascular trace, fused into a sheath at each stem node. The plants have intercalary meristems in each segment of the stem and rhizome that grow as the plant gets taller.

The spores bear characteristic elatersdistinctive spring-like attachments which are hygroscopic: The horsetails and their fossil relatives have long been recognized as distinct from other seedless vascular plants.

“Division Equisetophyta” by Stanley L. Welsh, N. Duane Atwood et al.

Plant systematics, a phylogenetic approach. The Biology and Evolution of fossil plants. Recent phylogenetic analysis has produced evidence that this group of plants belongs firmly within the fern clade of vascular plants.

American Journal of Botany.

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Retrieved from ” https: This page was last edited on 28 Novemberat Morphology and evolution of vascular plants 3rd ed. This contrasts with the seed plants, which grow from an apical meristem equisetopyyta i. Charophyceae Coleochaetophyceae Zygnematophyceae Mesotaeniaceae.


The vascular bundles trifurcate at the nodes, with the central branch becoming the vein of a dviision, and the other two moving left and right to merge with the new branches of their neighbours. Charophytes basal Streptofilum Klebsormidiophyceae.

Equisetophyfa Equisetopsida were formerly regarded as a separate division of spore plants and also called EquisetophytaArthrophytaCalamophyta or Sphenophyta ; today they have been recognized as rather close relatives of the typical ferns Pteridopsida and form a specialized lineage of the Pteridophyta.

The extant horsetails are homosporousbut extinct heterosporous species such as Calamostachys casheana appear in the fossil record.

In other projects Wikimedia Commons Wikispecies.

New York and London: Charophytes non-basal Charophyceae Coleochaetophyceae Zygnematophyceae Mesotaeniaceae. The underground parts of the plants consist of jointed equisetophgtafrom which roots and aerial axes emerge.

The organisms first appear in the fossil record during the late Devonian, [9] a time when land plants were undergoing a rapid diversification, with roots, seeds and leaves having only just evolved.

However, the leaves of Equisetum probably arose by the reduction of megaphyllsas evidenced by early fossil forms such as Sphenophyllumin which the leaves are broad with branching veins.

When recognized as a separate division, the literature uses many possible names, including Arthrophyta, [12] Calamophyta, Sphenophyta, [1] [13] or Equisetophyta. Articles with ‘species’ microformats All articles with unsourced statements Articles with unsourced statements from July Commons category link is on Wikidata.

The Origin and early diversification of land plants: Data related to Equisetopsida at Wikispecies. All extant species of Equisetum are herbaceous, and have lost the ability to produce diision growth. At the junction “node”, see diagram between each segment is a whorl of leaves. By using this site, you agree to the Terms of Use and Privacy Policy. Archived from the original PDF on In extinct groups, further protection was afforded to the spores by the presence of whorls of bracts – big pointed microphylls protruding from the cone.


Evolution of horsetails Equisetales within the major euphyllophyte clade Sphenopsida”. According to that study, the age of the crown group of Equisetum dates at least to the Early Cretaceous, and most probably divisiln to the Jurassic. Sphenophytes bear cones technically strobilising.

eqjisetophyta Other authors have regarded the same group as a class, either within a division consisting of the vascular plants or, more recently, within an expanded fern group. The Equisetales existed alongside the Sphenophyllalesbut diversified as that group disappeared into extinction, gradually dwindling in diversity to today’s single genus Equisetum.


Diviision Sphenophytes comprise photosynthesising, “segmented”, hollow stems, sometimes filled with pith. Sphenophyllales Archaeocalamitaceae Calamitaceae, A. From Wikipedia, the free encyclopedia. Views Read Edit View history.

The biology and evolution of fossil plants. See also the list of plant orders. Morphology of vascular plants Lower Groups.

When ranked as a class, the group has been termed the Equisetopsida [14] or Sphenopsida. There were three orders of Equisetopsid; the Idvisionwhich first appeared in the late Devonian.

Cyanidiophyceae Porphyridiophyceae Compsopogonophyceae Stylonematophyceae Rhodellophyceae Bangiophyceae Florideophyceae.