| Scientific Name | TSN | Taxon Author | Common Name | Name Source | Usage | Reason (ITIS) | Taxon Rank |
|---|
| Gyrosigma attenuatum attenuatum | 4635 | (Kuetzing) Rabenhorst | | ITIS | accepted | | Variety |
| Gyrosigma attenuatum hippocampus | 4636 | (Smith) Brockman | | ITIS | accepted | | Variety |
| Gyrosigma hippocampus | 4637 | Smith | | ITIS | not accepted | synonym of Gyrosigma attenuatum hippocampus | Species |
