| Name | Canthium barbatum f. tubuai Fosberg | 
| Authorship | Fosberg | 
| Rank | Forma | 
| NomenclaturalStatus | NomLeg | 
| Placed in | Canthium barbatum (G. Forster) Seemann | 
| Citation | 1937 Occas. Pap. Bernice Pauahi Bishop Mus. 13: 259 | 
| Holdings | 1 Specimen held in the Harvard University Herbaria identified as Canthium barbatum f. tubuai Fosberg | 
| Identification made in | [no date] (1) | 
