Mycorrhizal fungi play an essential role in orchid establishment. Mycorrhizal fungi are also an important factor that governs orchid distribution. This study will focus on multiple Australian orchid genera which form orchid mycorrhizal associations with the fungus Serendipita. I investigated continent-wide phylogeny and biogeographical patterns of distribution for Serendipita in Australia as well as the ability of orchid species in utilizing a range of given fungi during germination. In this talk, I will explore the diversity of Serendipita lineages associated with studied orchid genera and whether fungal specialization correlates with orchid rarity. Further, I will discuss whether the differences of Serendipita lineages in inducing orchid seed germination implies differences in nutrient utilization capacity of the fungi. Lastly, given the remarkable diversity of Serendipita lineages found in Australia, I am describing seven new species of Serendipita, adding to limited described species globally. My project will contribute to understanding biodiversity in a cryptic and ecologically important group of soil fungi as well as to gain a better understanding in terms of natural and landscape management in the future for the terrestrial orchid ecosystem.