The most abundant plant fossils in Kentucky are found in Pennsylvanian rocks in the State's two coal fields. The Pennsylvanian, for the eastern United States, was a time of tropical, humid climate and lush forests. The large number of coals in the coalfields is a result of these conditions; coal is fossil peat, and peat is the accumulation of plant debris, and the abundance of plant debris results from the large lowland forests. For more discussion about coal, see our section on coal information.
The plants of the Pennsylvanian were not like those of today. The forests of the eastern United States today are dominated by seed-bearing woody trees, bushes and herbaceous plants. During the Pennsylvanina, the dominate plants were spore-bearing (they reproduced by spores, not seeds). Large trees existed, but they were not woody trees; they were composed of thick bark with a central, pithy core. There were seed-bearing plants during the Pennsylvanian, but they were not similar to the modern ones. There were no flowering plants at all. Let's take a look at the kinds of plants that were common then.
Gymnospermopsida (conifers, cordaites, ginkoes, seed ferns)
The spores from the spore-bearing plants are also preserved as fossils, although they must be studied by a microscope. Specialists who study them are called palynologists (the Kentucky Geological Survey has a palynologist on staff, Dr. Cortland Eble). Fossil spores, which must be chemically removed from the rocks, are very useful in determining the relative age of rocks, especially for Pennsylvanian and younger rocks.
Other Information about Pennsylvanian Plants
KGS publication "Pennsylvanian plants of eastern Kentucky."
Links to other Pennsylvanian plant fossil sites