Note: Kjellman (1900), using anatomy as a primary criterion, recognized 62 species of Galaxaura, 47 of which were new. Certain sections and subsections contained only tetrasporophytes or only sexual plants, suggesting that the life history involves an alternation of subisomorphic phases. Efforts to match tetrasporophytes with sexual plants and otherwise to reduce the number of recognized species were initiated by Howe (1917; 1918c). The greatest reduction of species is to be found in the monograph by Papenfuss, Mshigeni, & Chiang (1982) emphasizing representatives in the western Indian Ocean. In a revision of the Australian members of the genus, Huisman & Borowitzka (1990) made further reductions and segregated two species, G. cylindrica and G. oblongata, into a new genus, Tricleocarpa. These investigations were based on static comparative morphology unsupported by culture studies. To what degree culture studies would affect current taxonomic schemes remains to be seen.
Galaxaura contigua Kjellman, 1900: 78, pl. 17: figs. 1–14; pl. 20: figs. 2, 3 (type locality: Hawaiian Islands).—Weber-van Bosse, 1921: 216.— De Toni, 1924: 135–136.
INDIAN OCEAN DISTRIBUTION: Indonesia (Semau).