Between fungi of the same species
Many fungi are sexual and must mate to reproduce. They send out pheromones and “sniff” out those of others, and then they grow toward those that seem attractive (based on whatever it is fungi are attracted to). Whenever two mycelia meet, they communicate to negotiate their relationship, which can range from fusion (to form a reproductive or nonreproductive partnership) to indifference to physical exclusion and even chemical antagonism. Each mated mycelium negotiates the physical dynamics of fusion, and of life in partnership thereafter.