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– 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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The origin of the land flora, a theory based upon the facts of alternation.

The extant horsetails represent a tiny fraction of Sphenophyte diversity in the past. In diviwion groups, further protection was afforded to the spores by the presence of whorls of bracts – big pointed microphylls protruding from the cone. At the junction “node”, see diagram between each segment is a whorl of leaves.


Charophyceae Coleochaetophyceae Zygnematophyceae Mesotaeniaceae. Sphenophytes bear cones technically strobilising.

The horsetails and their fossil relatives have equisetophhyta been recognized as distinct from other seedless vascular plants. 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. Evolution of horsetails Equisetales within the major euphyllophyte clade Sphenopsida”. According to that study, the age of the crown group of Equisetum dates at dividion to the Early Cretaceous, and most probably up to the Jurassic.


Wikimedia Commons has media related to Equisetopsida. Sphenophyllales Archaeocalamitaceae Calamitaceae, A. From Wikipedia, the free encyclopedia.

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. The Sphenophytes comprise photosynthesising, “segmented”, hollow stems, sometimes filled with pith.

This page was last edited on 28 Novemberat A recent study by Elgorriaga et al.

This contrasts with the seed plants, which grow from an apical meristem – i. 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. Morphology and evolution of vascular plants 3rd ed.

Archived from the original PDF on The 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.

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By using this site, you agree to the Terms of Use and Privacy Policy. Recent phylogenetic analysis has produced evidence that this group of plants belongs firmly divsiion the fern clade of vascular plants. Morphology of Plants and Fungi 5th 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.


Botany/Equisetophyta – Wikibooks, open books for an open world

The vascular bundles trifurcate at the nodes, with the central branch becoming the vein of a microphyll, and the other two moving left and right to merge with the new branches of their neighbours. Retrieved from ” https: The Biology and Evolution of fossil plants. They are commonly known as horsetails. When recognized as a separate division, the literature uses many possible names, including Arthrophyta, [12] Calamophyta, Sphenophyta, [1] [13] or Equisetophyta.

The underground parts of the plants consist of jointed rhizomesfrom which roots and aerial axes emerge.


Views Read Edit View history. The Origin and early diversification of land plants: Charophytes non-basal Euisetophyta Coleochaetophyceae Zygnematophyceae Mesotaeniaceae.

The spores bear characteristic elatersdistinctive spring-like attachments which are hygroscopic: There were three orders of Equisetopsid; the Pseudobornialeswhich first appeared in the late Devonian. International Journal of Plant Sciences.