Plants of the Swamp Forests
Giant relatives of scouring rushes or horsetails, Calamites, grew around lake edges. Lycopods, such as Lepidodendron and Lepidophloios, dominated swamps. Ancient ancestors of conifers, Cordaites, and the lycopod Sigillaria, grew on river levees and drier parts of swamps. The levees also hosted other plant species, such as ferns, seed ferns, and vines. Nearly 400 types of plant fossils have been described from the coal swamp deposits of Illinois.
Coal was formed from plants that lived in the swamps during the Pennsylvanian.
Fossils from these environments are frequently found during mining operations