| Name | Microthamnium smithii R. S. Williams |
| Authorship | R. S. Williams |
| Rank | Species |
| NomenclaturalStatus | NomLeg |
| Placed in | Microthamnium |
| Citation | 1930 Bryologist 33: 74 |
| Holdings | 1 Specimen held in the Harvard University Herbaria identified as Microthamnium smithii R. S. Williams |
| Identification made in | [no date] (1) |