| Name | Erysiphe communis f. calthae-palustris P. Karsten |
| Authorship | P. Karsten |
| Rank | Forma |
| NomenclaturalStatus | NomInvalid |
| Placed in | Erysiphe communis (Wallroth) Schlechtendal: Fries |
| Citation | 1868 Fungi Fenniae Exsicc. 8: 784 |
| Holdings | 1 Specimen held in the Harvard University Herbaria identified as Erysiphe communis f. calthae-palustris P. Karsten |
| Identification made in | [no date] (1) |