| Name | Polysiphonia opaca var. tripinnata (J. Agardh) Ardissone |
| Authorship | (J. Agardh) Ardissone |
| Rank | Variety |
| Placed in | Polysiphonia opaca (C.Agardh) Moris & De Notaris |
| Holdings | 1 Specimen held in the Harvard University Herbaria identified as Polysiphonia opaca var. tripinnata (J. Agardh) Ardissone |
| Identification made in | [no date] (1) |