| Name | Leptodictyum riparium f. elongatum Mönkemeyer |
| Authorship | Mönkemeyer |
| Rank | Forma |
| Placed in | Leptodictyum riparium (Hedwig) Warnstorf |
| Holdings | 1 Specimen held in the Harvard University Herbaria identified as Leptodictyum riparium f. elongatum Mönkemeyer |
| Identification made in | [no date] (1) |