I assume that the mushroom gets eaten by an animal. If that's not the answer you're looking for.. my apologies.
The evolution of molecular biology has made possible to establish a new classification of all organisms according to their DNA, and it's called phylogenetic classification.This classification groups living beings according to their kinship, established according to anatomical, physiological and behavioral criteria and especially genetic, based on the similarity of genes between species.
This made it possible to discover kinship ties between species of which there is no suspicion of any morphological link between them, something which the old classification (the traditional classification) was incapable of doing (and this proves the importance of the DNA and genes in organisms classification.
Nucleus
Hope this helps *smiles*