The identity of Porphyra columbina (Bangiales, Rhodophyta) originally described from the New Zealand subantarctic islands

Porphyra columbina Mont. (Bangiales, Rhodophyta) was collected in 1840 from the Auckland Islands in the New Zealand subantarctic region. This name has been applied to bladed Bangiales exhibiting a wide range of morphological forms, and found throughout the New Zealand region and in much of the southern hemisphere, particularly in Australia and Chile. By using morphological and anatomical characters as well as nSSU and rbcL sequence data, Montagne's description of P. columbina is re-examined in the light of recent collections from the New Zealand region and the Southern Ocean. We conclude that P. columbina is primarily distributed in cold temperate conditions, including the Auckland, Campbell, Antipodes, Chatham and Falkland Islands, and is only rarely present on mainland New Zealand. Specimens from the type locality and other subantarctic locations have a rosette to ovate growth form and are typically less than 5 cm in height/width, with specimens from more northern locations including some ribbon-like growth forms. Thalli are purple to grey, bleaching golden green. Mature specimens have a distinctly spotted appearance, with conspicuous large, purple-red clusters of phyllospores and golden marginal areas of spermatangia. Five unique rbcL haplotypes, differing by 1-6 substitutions, were obtained from 26 specimens, with the most common haplotype found in specimens from the Auckland, Campbell and the Falkland Islands.