A FLORA FROM THE CHESTER SERIES (UPPER MISSISSIPPIAN) OF SOUTHERN ILLINOIS

New localities in southern Illinois have yielded a flora consisting of 9 taxa. The plant remains occur in sandstones of the Chester Series and consist of casts, molds, and flattened impressions. The most important elements in the flora are: Archaeocalamites radiatus, Lepidodendron volkmannianum, Stigmaria ficoides, Rhynchogonium fayettevillense, and an unnamed Trigonocarpus. Stems probably referable to Lepidodendron veltheimii and Dictyoxylon also occur, as do numerous casts of the Knorria and Bergeria types. The range of features found in specimens of Lepidodendron volkmannianum allows some revision to be made of several species previously described by White in the Wedington Sandstone flora of northwest Arkansas, with which the present flora is closely comparable. The difficulties in making precise correlations with Upper Mississippian floras in other parts of the world are discussed. The necessity for critical re-examination of existing described collections and of undertaking more extensive field-work in the Mississippian of N. America is emphasized.