Bennettitales(redirected from Cycadeoid)
Also found in: Dictionary, Thesaurus.
a group of woody, gymnospermous fossil plants, closely related to the living fern palms (Cycadales). Named after the English botanist J. Bennett (1801–76). The stalk was simple or branched; in some species it was dolioform. Leaves as a rule were pinnate, more rarely simple. Flowers were located in the leaf axils and in most Bennettitales were monoecious. Seeds had two cotyledons, without endosperms. Bennettitales were probably descended from spermous ferns of the Paleozoic era and appeared in the Carboniferous period; they attained their greatest development in the Jurassic period and the first half of the Cretaceous. At that time Bennettitales were distributed all over the earth’s surface, although their number in northern Asia (Siberian paleofloral region) in the Jurassic period was insignificant. They disappeared at the beginning of the late Cretaceous period. Bennettitales numbered about 20 genera. Of these, four have been more closely studied than the others, and their organs of reproduction have been investigated: these are Wielandiella, Williamsonia, William-soniella, and Cycadeoidea.