Article: Combined transmission and scanning electron microscopy of in situ Palaeozoic spores

This paper discusses pollen and spores isolated from Carboniferous reproductive organs, including fructifications belonging to lycopods, cordaites, and seed ferns. Microspores of the monosaccate genus Endosporites were macerated from sporangia of a single cone. Morphological variability ranges from grains still within the tetra-hedral arrangement to solitary spores. Information is provided concerning saccus-corpus organization and exine infrastructure, ornamentation, and stages of saccus ontogeny. Pollen grains included within the genus Florinites were examined in cordaitalean pollen sacs from different localities and stratigraphic levels. Both proximal and distal attachments between saccus and corpus are demonstrated. Spores of a new Pennsylvanian reproductive structure are described as consisting of a complex tectate exine supporting a verrucate ornamentation. Prepollen grains of the Schopfipollinites-type were isolated from a number of medullosan pteridosperm reproductive structures including the genera Dolerotheca, Rhetinotheca, Aulacotheca, Whittleseya, and Halletheca. Comparative studies of the spore exines suggest the occurrence of fundamental ultrastructural differences among the grains. Information is presented concerning the possible site of gamete emission from Schopfipollinites prepollen grains.