Abstract

A total of 194 species of marine algae (14 Cyanobacteria, 41 Chlorophyta, 11 Heterokontophyta and 128 Rhodophyta), as well as three species of seagrasses, represent the first published records for the isolated island of Wallis, South Pacific. The flora has its strongest affinities with Fiji and Rotuma, followed by Samoa and French Polynesia. The lack of diverse habitats and its geographical location are invoked to explain the relatively low species richness compared with localities such as Fiji and Samoa. The flora has a typically tropical component dominated by encrusting coralline red algae, the calcified green algal genera Halimeda, and assemblages of Cyanobacteria. Normally ubiquitous species such as Halimeda discoidea, and the brown algal genera Hydroclathrus, Colpomenia, Rosenvingea, Asteronema, and Chnoospora are notably absent from the island, perhaps due to seasonality and the lack of suitable habitats. The minute epiphytic red alga Acrochaetium kurogii is reported for the first time outside of its type locality in Japan, while two as yet unidentified species of red algae (Gracilaria sp. and Sebdenia sp.) could represent new taxa if further useful material is found.