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an order of extinct gymnosperms. The parts of the members of the order are described by the various type genera: the leaves, by Cordaites and Rufloria; the strobile clusters, by Cordaianthus; the seeds, by Cardiocarpus; the wood, by Dadoxylon and Araucarioxylon; and the impressions, by Artisia. The Cordaitales were large trees. Their wood typically had tightly grouped, sealed pores on the walls of the tracheids. The leaves were 20–50 cm and more in length and lanceolate, linear, or scapular in shape, with a parallel or flabellate vein system. The reproductive organs, which looked like catkins, bore strobiles. Each strobile contained scales in a tight spiral around the axis that gave way on the upper side to ovules in the female and groups of microsporangia in the male.
Cordaitales evolved from plants of the progymnosperm type, and it is possible that they in turn were the ancestors of the conifers. In the Carboniferous period and at the beginning of the Permian, the Cordaitales grew in tropical Euramerican areas, in the nontropical Angara, or Tungus, region, and in the Gondwara; in the later Permian they could be found in large numbers only in the Angara region. The leaves of Cordaitales are important in stratigraphy.
REFERENCESMeien, S. V. Kordaitovye verkhnego paleozoyia Severnoi Evrazii. In Trudy Geologicheskogo in-ta AN SSSR, 1966, issue 150.
Florin, R. “Evolution in Cordaites and Conifers.” Acta Horti Bergiani, 1951, vol. 15, no. 11.
V. A. VAKHRAMEEV