| details |
Late Mississippian |
Permian |
Nd |
Millay,M.A. et al. Paleozoic seed fern pollen organs. |
1979 |
| original |
Late Pennsylvanian |
|
Illinois |
Eggert,D.A. et al. Stewartiothece, gen.nov., and the nature and origin of complex permineralized Medullosan pollen organs. |
1979 |
| details |
Late Carboniferous |
|
Nd |
Millay,M.A. et al. Ultrastructure of Stewartiothece (Medullosaceae) prepollen. |
1980 |
| details |
Pennsylvanian |
|
USA |
Taylor,T.N. Ultrastructural studies of Paleozoic seed fern pollen |
1982 |
| details |
Carboniferous |
|
USA |
Balme,B.E. Fossil in situ, spores and pollen grains: An annotated catalogue. |
1995 |