| Scientific Name | TSN | Taxon Author | Common Name | Name Source | Usage | Reason (ITIS) | Taxon Rank |
|---|
| Diatoma elongata | 590904 | C. Agardh | | ITIS | not accepted | synonym of Diatoma tenue var. elongatum | Species |
| Diatoma elongatum | 3229 | (Lyngb.) C. Agardh | | ITIS | not accepted | synonym of Diatoma tenue var. elongatum | Species |
| Diatoma elongatum var. elongatum | 3230 | (Lyngb.) C. Agardh | | ITIS | not accepted | synonym of Diatoma tenue var. elongatum | Variety |
| Diatoma elongatum var. tenue | 3235 | (C. Agardh) Van Heurck | | ITIS | not accepted | synonym of Diatoma tenue var. elongatum | Variety |
| Diatoma elongatum var. tenuis | 3233 | (C. Agardh) Van Heurck | | ITIS | not accepted | synonym of Diatoma tenue var. elongatum | Variety |
| Diatoma tenue var. elongatum | 3234 | Lyngb. | | ITIS | accepted | | Variety |
| Diatoma tenue var. pachycephala | 3232 | Grunow | | ITIS | accepted | | Variety |
