puffball mushroom growing in my backyard. Several of them come up every autumn in my backyard by one particular tree. I had been throwing the mushrooms away because I assumed they were poisonous. I finally looked up what type of mushroom I had and it sure looks like a giant puffball which is good eats when it is a little younger than this one. Jo, my native american neighbor confirmed that this was a giant puffball. She gathers and eats them every year. Wikipedia says they are making some new type of cancer medication out of these type of mushrooms and I have seen them sold on the internet for an interesting amount of money for culinary purposes. I may not have a green thumb but I can't slow these fungi down or kill them even if I try. They come up every autumn like clock work.