Pollen Organs and Seeds withEucommiiditesPollen

Abstract

Abstract The characteristic Mesozoic pollen genus Eucommiidites is described from pollen organs and seeds recovered in Cretaceous strata of North America and Europe. The pollen organs are from the lowermost Upper Cretaceous (Cenomanian) of Texas and are referred to Erdtmanitheca texensis gen. et sp. nov. They are spherical heads, composed of numerous, densely crowded, radiating pollen sacs that contain abundant well-preserved pollen. Combined LM, SEM and TEM investigations show that the pollen grains each have a distinct distal colpus flanked by two lateral colpi in an equatorial position. Pollen wall ultrastructure is gymnospermous with a thick lamellate inner layer (endexine) and an outer layer (ektexine) composed of a granular inner part and a homogeneous outer part. The endexine is thickened in the region of the colpi. Small seeds from the Lower Cretaceous (upper Berriasian to Valanginian) of Bornholm, Denmark contain abundant Eucommiidites pollen in their micropyles. The seeds are referred to Erdtman...