| details |
Pennsylvanian |
|
Iowa |
Potonie,R. Synopsis of the Sporae in situ. |
1962 |
| details |
Nd |
|
Nd |
Balme,B.E. Fossil in situ, spores and pollen grains: An annotated catalogue. |
1995 |
| details |
Middle Pennsylvanian |
|
Iowa |
Millay,M.A. Studies of Paleozoic Marattialeans |
1979 |
| details |
Middle Pennsylvanian |
|
USA |
Taylor,T.E. et al. Studies of spores from Carboniferous fructifications. 1. Introduction and preliminary survey utilizing the Scanning Electron Microscope. |
1969 |
| original |
Desmoinesian |
|
Iowa |
Mamay,S.H. Some American Carboniferous fern fructifications. |
1950 |