Boletopsis nothofagi is endemic to New Zealand and has a mycorrhizal association with red beech (Nothofagus fusca).

It is unknown when exactly the fungus forms its fruit body, but it has so far been found solely in May, during autumn in the Southern Hemisphere.

The two authors chose the epithet nothofagi based on the characteristic of the fungus as mycorrhizal symbiont of Nothofagus fusca.

The cap, when viewed under a microscope, is clearly differentiated and consists of a cutis, a layer of oriented hyphae lying radially.

These areas are in Rimutaka Forest Park near Wellington, and Saint Arnaud in the northern part of the South Island.

These locations are relatively far away from each other and isolated, which, together with its absence in the rest of New Zealand, makes it unlikely that the species is a recent import.

B. nothofagi has been found exclusively in N. fusca forests spread through New Zealand below 37° S. The fungus forms a mycorrhizal association with the trees of N. fusca, in which the hyphae of the fungal mycelium wrap around the roots of the tree and penetrate the cortex, but not its cells.

Subsequently, B. nothofagi takes over the function of the root hair and directs water and soil nutrients to the tree.

[4] Little is known about the habitat requirements – such as humidity, temperature, soil composition and water content – of B. nothofagi.

The tree species prefers lowlands and hills along river valleys and usually grows on nutrient-rich, well-drained soil.

[6] According to Cooper and Leonard, the fact that Boletopsis nothofagi was only found 200 years after the European settlement of New Zealand illustrates the rarity of this species, although it is also possible that the late discovery was caused by rare or infrequent fructification.

Although no data on population trends or historical distribution of the fungus exists, Cooper and Leonard consider the species in accordance to the New Zealand Threat Classification System as "naturally uncommon".