North American and European species of Momipites (“Engelhardtia”) and related Genera

Abstract

Juglandaceous pollen of the Early Tertiary deposits of North America and Europe exhibit basic morphology like that of modern species of the family and some features not found in modern species. Pollen morphology suggests several phyletic trends within the family in Early Tertiary time. Morphogenetic trends among triporate species of the Juglandaceae, especially of the Engelhardia‐Alfaroa group, involve thinning, thickening, and folding of exine at the poles, or inflation of the atria. Morphologic evidence indicates close phyletic relationship between Engelhardia and Carya. Morphologic groups are defined among fossil triporate juglandaceous species, and relationships are suggested.

Momipites Wodehouse 1933 is emended, and Engelhardtiapollenites Raatz 1937, Engelhardtioidites Potonie’, Thomson, and Thiergart 1950, Engelhardtioipollenites Potonié 1951, and Maceopolipollenites Leffingwell 1971 are submerged in it. Momipites triradiatus and M. wodehousei are described as new, and 17 new combinations are proposed.