“Some fungi have tens of thousands of mating types, approximately equivalent to our sexes (the record holder is the split gill fungus, Schizophyllum commune, which has more than twenty-three thousand mating types, each of which is sexually compatible with nearly every one of the others). The mycelium of many fungi can fuse with other mycelial networks if they are genetically similar enough, even if they aren’t sexually compatible. Fungal self-identity matters, but it is not always a binary world. Self can shade off into otherness gradually.”