Selected Middle Pennsylvanian coals and one Upper Pennsylvanian coal from three outcrop sections and one exploratory drillcore in the central and northern Appalachian basin were analyzed for their spore content. In the studied assemblages, the most frequently encountered taxa were species of Lycospora, Laevigatosporites, Punctatisporites, Densosporites (and related crassicinulate genera), Granulatisporites (and related sphaerotriangular genera), and Florinites. Mid-Middle Pennsylvanian assemblages are generally dominated by Lycospora, with L. pellucida, L. pusilla, L. granulata, L. orbicula, and L. micropapillata being the most common species. A few beds in this interval, however, show more even distributions of Lycospora (produced by arboreous lycopsids) and forms related to tree ferns, calamites, and cordaites. In general, a stratigraphic upward increase in tree fern taxa is observed, with upper Middle Pennsylvanian coals being codominated or dominated by tree fern spores.

In addition, the range zones of the following taxa appear to be useful for palynologic delineation of Middle Pennsylvanian strata on both intra- and interbasinal scales: Microreticulatisporites sulcatus, Triquitrites sculptilis, Laevigatosporites globosus, Radiizonates difformis-rotatus, Torispora securis, Thymospora pseudothiessenii, Murospora kosankei, Mooreisporites inusitatus, Granasporites medius, Schulzospora, Densosporites, Schopfites, Lycospora, Cirratriradites, and Vestispora. The recognition of these taxa in Appalachian spore assemblages allows for comparison and correlation of Pennsylvanian strata in the Eastern and Western Interior basins of North America and the Upper Carboniferous of Western Europe.