01979oam 2200541 450 991070683710332120180309075139.0(CKB)5470000002459098(OCoLC)896810485(OCoLC)995470000002459098(EXLCZ)99547000000245909820141123d1976 ua 0engurmn|||||||||txtrdacontentcrdamediacrrdacarrierPaleozoic origin of the cycads /by Sergius H. MamayWashington :United States Department of the Interior, Geological Survey,1976.1 online resource (iii, 48 pages, 5 unnumbered pages of plates) illustrationsGeological Survey professional paper ;934Title from title screen (viewed October 6, 2014)."Megasporophylls and associated plant parts from the Upper Pennsylvanian and Lower Permian rocks of the southwestern United States are interpreted as a lineage of cycads, derived from the pteridosperms. Cycadean foliage is thought to be derived from Paleozoic taeniopterids."Includes bibliographical references (pages 44-46) and index.Cycads, FossilPaleobotanyPaleozoicPaleobotanyWest (U.S.)Cycads, FossilfastPaleobotanyfastPaleozoic Geologic PeriodfastSouthwest, NewfastCycads, Fossil.PaleobotanyPaleobotanyCycads, Fossil.Paleobotany.Paleozoic Geologic Period.Mamay Sergius H.1920-1386004Geological Survey (U.S.),COPCOPOCLCOOCLCFGPOBOOK9910706837103321Paleozoic origin of the cycads3511959UNINA