– 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 Biology and Evolution of fossil plants. 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.

This page was last edited on 28 Novemberat Developmental morphology and fuzziness of organ identities”. The underground parts of the plants consist of jointed rhizomesfrom which roots and aerial axes emerge. Retrieved from ” https: Equisetopsidaor Sphenopsidais a class of vascular plants with a fossil record going back to the Devonian. Morphology of Plants and Fungi 5th ed.

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.

Sphenophyllales Archaeocalamitaceae Calamitaceae, A. New York and London: A recent study by Elgorriaga et al. All extant species of Equisetum are herbaceous, divieion have lost the ability to produce secondary growth.


There were three orders of Equisetopsid; the Pseudobornialeswhich first appeared in the late Devonian. The plants have intercalary meristems in each segment of the stem and rhizome that grow as the plant gets taller. The biology and evolution of fossil plants.

Evolution of horsetails Equisetales within the major euphyllophyte clade Sphenopsida”. At the junction “node”, see diagram between each segment is a whorl of leaves.


Glaucocystophyceae Glaucocystis Cyanophora Gloeochaete. Views Read Edit View history. Plant systematics, a phylogenetic approach. The origin of the land flora, a theory based upon the facts of alternation. Morphology and evolution of vascular plants 3rd ed. The extant horsetails are homosporousbut extinct heterosporous species such as Calamostachys casheana appear in the fossil record. This contrasts with the seed plants, which grow from an apical meristem – i.

International Journal of Plant Sciences. The horsetails and their fossil relatives have long been recognized as distinct from other seedless vascular plants. 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 Origin and early diversification of land plants: From Wikipedia, the free encyclopedia. The spores bear characteristic elatersdistinctive spring-like attachments which are divisoin By using this site, you agree to the Terms of Use and Privacy Policy. Sphenophytes bear cones technically strobiliequisftophyta. 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.

Wikimedia Commons has media related to Equisetopsida. Charophyceae Coleochaetophyceae Zygnematophyceae Mesotaeniaceae. The Sphenophytes comprise photosynthesising, “segmented”, hollow stems, sometimes filled with pith.


The extant horsetails represent a tiny fraction of Sphenophyte diversity in the past. When recognized as a separate division, the literature uses many possible names, including Arthrophyta, [12] Calamophyta, Sphenophyta, [1] [13] or Equisetophyta.

Charophytes basal Streptofilum Klebsormidiophyceae. 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.


In extinct groups, further protection was afforded to the spores by the presence of whorls of bracts – big pointed microphylls protruding from the cone. In other projects Wikimedia Commons Wikispecies. They are commonly known as horsetails.

Data related to Equisetopsida at Wikispecies.

In the only extant genus Equisetumthese are small leaves microphylls with a singular vascular trace, fused into a sheath at each stem node. See also the list of plant orders. Similar spaces, the vallecular canals are formed in the cortex.

Archived from the original PDF on American Journal of Botany. Cyanidiophyceae Porphyridiophyceae Compsopogonophyceae Stylonematophyceae Rhodellophyceae Bangiophyceae Florideophyceae.

Paleobotany and the evolution of plants 2nd ed. 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. When ranked as a class, the group has been termed the Equisetopsida [14] or Sphenopsida.