The Hawaiian red algal flora is diverse, isolated, and well studied from a morphological and anatomical perspective, making it an excellent candidate for assessment using a combination of traditional taxonomic and molecular approaches. Acquiring and making these biodiversity data freely available in a timely manner ensures that other researchers can incorporate these baseline findings into phylogeographic studies of Hawaiian red algae or red algae found in other locations.

Fifty-six samples of the gametophyte stage of Asparagopsis taxiformis, principally from the Main and Northwestern Hawaiian Islands, were obtained from field collections and archived herbarium material. Of these, 36 were successfully sequenced for the cox2-3 spacer region, and 42 for the COI gene. Parsimony analyses of both regions for the Hawaiian collections revealed relationships that were consistent with those previously published for global A. taxiformis samples, which also included a number from the Hawaiian Islands. The Main Hawaiian Islands are dominated by lineage 1, which is known from the Pacific coast of Central America and Hawai‘i. The Northwestern Hawaiian Islands, with one exception, contain a single widespread lineage (2) that is known from the Indo-Pacific, central Mediterranean and southern Portugal. A third lineage (4) is present in Hawai‘i only along a localized region of the south shore of O'ahu, but is widespread in tropical and subtropical waters outside of the Hawaiian Isla...