DNA barcoding has been used to resolve taxonomic ambiguity in a variety of different organisms but has also stimulated intense debate about its reliability at the species level (Plaisance et al. 2009). It should not be used as the only taxonomic tool; more traditional approaches are also necessary. To date, the International Code of Botanical Nomenclature (ICBN) does not include information about the use of DNA barcoding; however, we believe that this study together with previous evidence supports (e.g., Demes et al. 2009) the recognition of a single Macrocystis species.