| Name | Oidium obtusum Thümen |
| Authorship | Thümen |
| Rank | Species |
| NomenclaturalStatus | NomLeg |
| Placed in | Oidium |
| Citation | 1875 Cent. 3: no. 289 |
| Holdings | 3 Specimens held in the Harvard University Herbaria identified as Oidium obtusum Thümen |
| Identification made in | [no date] (3) |