From my research I believe this to a Mossy Maple Polypore (Oxyporus populinus), but I have some doubts as it doesn’t have the moss, which typically accompanies a fungus of this type. Oxyporus means “polypore with a sharp, acid taste”; populinus means ” inhabiting poplar (Populus) trees.”, which is odd since it’s mostly found near the base of living maples, not poplars. It’s usually and indicator that the tree is failing (although it could be some considerable time before it actually does). Apparently it’s inedible, but not poisonous.
Lest anyone think that I actually know something about fungi – I don’t. I just browsed the internet until I found something that looked like this and then “googled” the name for additional information. While looking I bumped into Field Guide to Common Macrofungi in Eastern Forests and Their Ecosystem Functions by Michael E. Ostry, Neil A. Anderson, Joseph G. O’Brien. Although hardly “a gripping read”, I was surprised to find that there are many edible, even choice mushrooms growing out there in the woods. Unfortunately it can be difficult to distinguish these from other types, which will probably kill you. It’s probably wise to following the warning on every page of the above field guide: “DO NOT eat any mushroom unless you are absolutely certain of its identity.”