Abstract
Christmas Island and Macquarie Island are two isolated islands of essentially the same size but providing very different environmental conditions for myxomycetes. The former is located in the tropics and the latter in the subantarctic. Surveys for myxomycetes carried out on Christmas Island in 2017 and Macquarie Island in 1995 yielded a total of 85 species. These data were published in two previous papers, but these papers did not consider the biogeographical distribution of all of the myxomycetes recorded from the two islands. Christmas Island and Macquarie Island share only nine species in common. Two of the 26 species recorded from Macquarie Island and one of the 68 species recorded Christmas Island were new to science.