In general the arbuscular mycorrhizal (AM) symbiosis is characterized by low specificity. AM fungi are able to colonize roots of different plant species simultaneously, and individual plants are generally growing with many different AM fungi. However, for several mycoheterotrophic plant species extreme specificity towards very narrow lineages of AM fungi has been reported. But because these mycoheterotrophic plants are often extremely rare and restricted to tropical rainforests it is challenging to study their myccorrhizal symbionts over a wide geographic range. In this study I analyze the population genetics, mycorrhizal communities, and vegetation preferrences of Thismia in temperate Australia and New Zealand.