The association is often very specific, with the heterotrophic plants only associating with selected fungus partners, including Russulaceae.
2.
Some Russulaceae are associated with myco-heterotrophic plants of the Ericaceae subfamily Monotropoideae, forming " monotropoid mycorrhiza ".
3.
This is an epiparasitic relationship, where the heterotrophic plant ultimately derives its carbon from the primary, ectomycorrhizal plant partner of the fungus.