Sort By:
  1. Pennsylvanian tree fern compressions Caulopteris, Megaphyton, and Artisophyton gen. nov. in Illinois /
    By: Pfefferkorn, Hermann W. - Illinois State Geological Survey. - Illinois.
    Publication info: Urbana :Illinois State Geological Survey,1976.
    Contributed by: University of Illinois Urbana Champaign
    View Book
  2. Reconstruction and interpretation of Brittsia problematica D. White (Fern, Pennsylvanian) / Hermann W. Pfefferkorn --.
    By: Pfefferkorn, Hermann W.
    Publication info: Chicago :Field Museum of Natural History,1976.
    Contributed by: University of Illinois Urbana Champaign
    View Book
  3. Some fern-like fructifications and their spores from the Mazon Creek compression flora of Illinois (Pennsylvanian)
    By: Pfefferkorn, Hermann W. - Peppers, Russel A. - Phillips, Tom Lee,
    Publication info: Urbana,Illinois State Geological Survey,1971.
    Contributed by: University of Illinois Urbana Champaign
    View Book