Abstract
THE abundance of large fronds in Rhaetic, Jurassic, and Wealden rocks, closely resembling in habit those of some recent Cycads, and the occurrence of hundreds of petrified trunks in Jurassic and Neocomian strata in North America and, in smaller numbers, in many other parts of the world, have led palajobotanists to speak of these periods as the “age of Cycads.” It is, however, a remarkable fact that the reproductive shoots of these Cycad-like plants differ very,widely from the corresponding organs in the true Cycads; had1 we possessed no knowledge of the vegetative organs, the reproductive shoots would not have been styled cycadean. The differences between the reproductive organs of the recent and extinct forms find expression in the reference of the Jurassic and Lower Cretaceous plants to a separate group, Bennettitales, the existing cycadean genera being included in the Cycadales.
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SEWARD, A. New Knowledge of a Puzzling Group of Gymnosperms . Nature 103, 115–116 (1919). https://doi.org/10.1038/103115b0
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DOI: https://doi.org/10.1038/103115b0