Sergius H Mamay

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Plant fossils from Lower Permian strata of the southwestern United States have been interpreted as cycadalean megasporophylls. They are evidently descended from spermopterid elements of the Pennsylvanian Taeniopteris complex; thus the known fossil history of the cycads is extended from the Late Triassic into the late Paleozoic. Possible implications of the(More)
Early Permian (late Leonardian Series) plant assemblages from King, Knox, and Stonewall Counties of North-Central Texas are dominated by seed plants, some apparently congeneric with taxa heretofore known only from the Late Permian or the Mesozoic. Conifers are the dominant elements, including one or more species of Ullmannia, Pseudovoltzia liebeana, both(More)
Ovule-bearing leaves from the Paleozoic of North America assigned to Spermopteris and Phasmatocycas have been interpreted as primitive cycad megasporophylls. According to this hypothesis, Cycas megasporophylls were derived from a Spermopteris-like ancestor via Phasmatocycas and various other taeniopterid forms. This putative transformation entailed the(More)
Abundant Permian plant megafossils were discovered in the Del Norte Mountains of Brewster County, Trans-Pecos Texas. The flora is dominated by a new and distinctive type of gigantopteroid leaves. Marine invertebrates are closely associated, and this admixture of continental and marine fossils indicates a deltaic depositional setting, probably on the(More)
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