| Name | Fenestella princeps f. betulae P. Karsten |
| Authorship | P. Karsten |
| Rank | Forma |
| NomenclaturalStatus | NomInvalid |
| Placed in | Fenestella princeps Tulasne & C. Tulasne |
| Citation | 1870 Fungi Fenniae Exsicc. 10: 940 |
| Holdings | 1 Specimen held in the Harvard University Herbaria identified as Fenestella princeps f. betulae P. Karsten |
| Identification made in | [no date] (1) |