Somebody came across this blog after searching “the biggest mushroom species Ontario”. I wonder if that person was looking for the mushrooms the grew the largest or the ones there are most examples of in the province. If the question was meant to be what is the largest, then I guess I have to ask, do you mean the largest organism or the largest fruit? I suspect the honey mushroom (Armillaria mellea) might be the largest organism and perhaps the giant puffball (Calvatia gigantea) the largest fruit. Any other guesses? Now if the question was about the most common fungi in the province, I couldn’t begin to guess. For all I know it could be some kind of resupinate or slime mold. Who knows?