This is some additional information about the taxonomy of Galaxaura rudis Kjellman and Microthoe lapidescens Harvey (Silva, Basson and Moe 1996, Indian Ocean Catalogue, pages 110-111). Currently, both taxa are considered taxonomic synonyms of Galaxaura rugosa (Ellis & Solander) Lamouroux. I have recently examined the Type specimen on which Galaxaura rudis is based (Type locality Tonga, Harvey Nr 51, BM 000610865 and 610866, photo attached) and the internal anatomy agrees with the concept of Galaxaura subverticillata Kjellman (1900, Floridé-slägtet: p. 48, pl. 3 figs 12-14, pl. 120 fig. 17, type locality Virgin Islands). The axes are compressed, and both short and long assimilatory filaments are present, which distinguishes it from Galaxaura fasciculata Kjellman. Galaxaura rugosa has far fewer assimilatory filaments, and the axes are terete (Abbott 1999, Marine Red Algae of the Hawaiian Islands, pp. 66-70). On the same BM sheet as the Type of G. rudis is a specimen of G. rugosa from Mangaia, Cook Islands (BM 000770096) and from the attached photo you can see the marked difference in morphology between the two entities, which I can confirm from field observations.
Galaxaura subverticillata is reported from the Indian Ocean as a synonym of Galaxaura rugosa, but in my opinion the Indian Ocean G. rugosa should be separated from the Pacific G. lapidescens / G. rudis plants, and G. subverticillata (sensu Abbott 1999: 69) should retain its specietal status pending future more definitive molecular proof to the contrary or in accord with that placement. [Antoine N'Yeurt]