I am fairly sure this is Agaricus
but as to species I am having a hard time
Is this Agaricus subrutiliescens (see Trudell book page 191)
Growing on duff in a suburban area

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Sava said:
Unfortunately, Elmer, it's not likely we have A. subrutilescens here. That species is found in the woods and I haven't seen it fruit so massively. Almost certainly, this is a bad yellow stainer, I don't know the species name. If there are any fresh mushrooms there, you can check that it stains yellow when you rub the cap, and it should also have an uninviting chemical odor



















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