| Name | Gracilaria horizontalis Collins & Hervey |
| Authorship | Collins & Hervey |
| Rank | Species |
| NomenclaturalStatus | Unknown |
| Placed in | Gracilaria Greville |
| Remarks | Created from Taxon Name Import: Gracilaria horizantalis F.S.Collins & Hervey |
| GUID | urn:lsid:marinespecies.org:taxname:668773 |
| Citation | 1917 Proc. Amer. Acad. Arts 53: 1-195 |
| Holdings | 1 Specimen held in the Harvard University Herbaria identified as Gracilaria horizontalis Collins & Hervey |
| Identification made in | [no date] (1) |