| Name | Usnea longissima f. tenuis Th. Fries |
| Authorship | Th. Fries |
| Rank | Forma |
| Placed in | Usnea longissima Acharius |
| GUID | urn:lsid:indexfungorum.org:names:424413 |
| Holdings | 13 Specimens held in the Harvard University Herbaria identified as Usnea longissima f. tenuis Th. Fries |
| Identification made in | [no date] (13) |