Do not eat any mushroom without knowing for sure what type it is. Some are toxic and can make you quite ill or worse. Find someone in your area that knows which are OK to eat.
I always live by the rule of an old gardener I used to know: "If in doubt don't pluck it out." I'd leave the ID to an expert on edible fungi to be on the safe side.
I have eaten thousands of things that I do not even know what they are, my wife is constantly getting after me for that, but I have never been willing to eat a mushroom from the wild. With plants I devised a system for testing things to see if they are edible so far I have never been poisoned, but I am not brave enough to try it with mushrooms. My advice is... don't eat any mushroom unless you bought it at the store or got it from a professional with many years of experience at collecting mushrooms.
http://www.gardenstew.com/about24053.html I remember someone asking about a mushroom a while back and went looking for the thread... I would NEVER eat any mushroom picked from the wild without expert knowledge of what I was picking. My kids have looked for morels before and found a few. they are distinctive and were in the Spring, so I wasn't exactly comfortable or extremely anxious about them, but it was a school project so I let them do it.
I read in a book that, unless you are an expert with IDing mushrooms, stay away from any that have gills. The only ones that are safe are the ones with sponge or with teeth. Even those make me nervous with all of the crazy genetic modifications that scientists are messing with. I still go to the store for mushrooms.
I read an article about two weeks ago where two mushroom scientists whatever the word for them would be discovered three new species of mushroom in a package of sliced mushrooms acquired at the local grocers. The article ended with the scientists saying that there are likely many undocumented mushroom species being sold in stores.