| Name | Leptodictyum riparium f. fluitans (Lesquereux & James) Grout |
| Authorship | (Lesquereux & James) Grout |
| Rank | Forma |
| Placed in | Leptodictyum riparium (Hedwig) Warnstorf |
| Citation | 1931 Moss Fl. N. Amer. 3: 65 |
| Holdings | 14 Specimens held in the Harvard University Herbaria identified as Leptodictyum riparium f. fluitans (Lesquereux & James) Grout |
| Identification made in | [no date] (13), 1945 (1) |