The characteristic Mesozoic pollen genusEucommiiditesis 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 toErdtmanitheca texensisgen. 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 abundantEucommiiditespollen in their micropyles. The seeds are referred toErdtmanispermum balticumgen. et sp. nov. They are ovoid, and weakly triangular in transverse section and gradually taper at the apex into an elongated tube. The megaspore membrane is granular and well developed, and apparently surrounded by three separate tissues interpreted as nucellus, a thin inner integument and a sclerified outer envelope.Eucommiiditespollen in the micropyles of the seeds has a laminated endexine and an ektexine comprising two homogeneous parts separated by a granular layer. Réévaluation of other seeds known to containEucommiiditespollen indicates that they share significant similarities withErdlmanispermumand that they may have been produced by closely related plants. Comparison of “Eucommiiditesplants” with other seed plants suggests that they are probably most closely related to the anthophytes comprising Bennettitales, Pentoxylales, Gnetales and angiosperms.