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Автор: K. Krassilov
Издательство: Pensoft Pub
Год издания: 2010
isbn: 9546425249
Количество страниц: 151
Язык: english
Формат: PDF
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Cercidiphyllum is a relict angiosperm bringing to us a flavor of Cretaceous Period. Its reproductive morphology was interpreted, in the spirit of the dominant evolutionary paradigm, as inflorescences of reduced flowers represented by solitary pistils and groups of stamens. Evolutionary significance of Cercidiphyllum has long been anticipated despite the unpersuasive morphological interpretation and irrelevant paleobotanical evidence. This work was initially intended for paleobotanists who willingly compare their fossil material with the living Cercidiphyllum, using schematic descriptions and illustrations of traditional plant morphology. The idea behind this book was to provide an adequately illustrated material for such comparisons. Yet it turned out that there are more things in Cercidiphyllum than are dreamed of in our traditional plant morphology. Some of morphological findings of this study, such as the replacement of the floral structure by leafy shoots or the subtending bract-leaf conversion are relevant to the experimental "evo-devo" studies and bear on general problems of angiosperm evolution. In Cercidiphyllum, the vegetative body is partly or mostly produced in the reproductive line, suggesting a neotenic ancestral form, in which the vegetative development was drastically reduced relative to reproductive domain. Later in evolutionary history, the vegetative body was rebuilt in the lineage on the way to arboreal forms, with foliation of the floral receptacles and the carpel-leaf convergence as side effects of the process. |
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