| original |
Middle Pennsylvanian |
|
Illinois |
Schopf,J.M. Pteridosperm male fructifications |
1948 |
| details |
Middle Pennsylvanian |
|
Nd |
Potonie,R. The phylogeny of the spore shape in regard to families of fossil plants (except the angiosperms). |
1961 |
| details |
Late Carboniferous |
|
Illinois |
Potonie,R. Synopsis of the Sporae in situ. |
1962 |
| 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 |