Abstract

CALAMITALES THE EXTINCT LINES OF THE SPHENOPSIDA EVOLUTION

*Dr. Teena Agrawal

Abstract

Pteridohpytes are plant with the sporophytic life of the pattern, prior to the pteridophytes the life cycle pattern was the gametophytic(in bryophytes), the sporophytic body is divided in to the roots, stem and the leaves, reproduction occurs by the sporangium. Homospory and the Heterospory is the prominent feature of the reproduction of the pteridophytes. Archegonia and the antheridia are in reduces in sizes as they are in the highest of the development of the bryophytes. All pteridophytes have the heteromorphoic alternation of the generation. Pteriodphytes have been divided in to the four of the classes. These are enlisted as the psilophytopsida, Lycopsida, sphenopsida, pteropsida lines of the evolution, here in this review articles we are presenting some of the features of the class sphenopsida, the extinct orders calamitales, they were very abundant in the upper Devonian period and they forms the large forest and ecosystem, in these plants Sporophytic body is divided in to the roots, stem and leaves. The leaves are whorled in organization. The stele was protosteleic and medullated. Sporangia was thick walled and the sporoangiphores are arranged in the thick walled peltate sporagiophores. Antherozoids were multiflagellate, this group reached its highest approximation in the upper carboniferous time period, they formed the giant forest in the carboniferous with the lepidodendrales. Rapid declines occurs in the vegetation during the Permian period.

Keywords: Sphenopsida, Multiflagealltes, Peltate sporangiophores, carboniferous s period, Heteromorphic alternation of the generation.