This is referred to as Lepiota rachodes in David Arora's ATtRPaM and MD, but Vellinga's research since seems to indicate it is more closely related to Chlorophyllum. I think it has actually gone through being called Macrolepiota at some point since it was even a Lepiota. Anyway I'm curious to hear if anyone thinks there's any chance whatsoever these are poisonous :), they look like the edible kind to me due to size, white spore print, and orange/red staining flesh.