Checklist of the liverworts and hornworts of French Polynesia

The present publication is the first modern catalogue of the liverworts and hornworts of French Polynesia and accepts 161 species of liverworts and 5 species of hornworts. In addition, 40 species are doubtful records of French Polynesia and 45 species are excluded. The checklist is mainly based on a compilation of published records; a few unpublished new records are included as well. The region has been explored very unevenly and liverwort and hornwort records are available for only ten islands of French Polynesia. Several islands of considerable surface area and elevation such as Fatu Hiva, Tahuata, Ua Pou and Ua Huka in the Marquesas, and Huahine and Tahaa in the Society Islands remain completely unexplored. In the Tuamotu Archipelago, only one atoll of the 60 has been surveyed (Makemo) and the number of reports for Gambier islands is quite low. The hepatic flora of French Polynesia appears to be relatively poor in species as compared to other Pacific island groups, such as the Fiji Islands (301 spp.) and New Caledonia (475 spp.) which are large continental islands (over 18 000 km²). Nevertheless, their floras show strong similarities at the family level. One species, Treubia tahitensis (Nadeaud) Besch., is only known from French Polynesia and may be considered endemic. The lack of endemic hepatic species in French Polynesia may be explained by the relatively small size, rather low elevation, low habitat diversity and recent geological age of the islands. It supports the notion that oceanic barriers do not operate as a major impediment to bryophyte dispersal.