What type of mushroom is growing on my elm stump?
You have submitted a beautiful picture! It shows what I think is the fruiting body of Polyporus squamosus. The fungus is a Basidiomycete polypore fungus that can grow saprophytically (on dead wood) or cause a white rot or heart rot of trees. It is commonly found associated with hardwood trees such as maple, perhaps where one had been cut down. It produces a sizable fruting body with scales on the top, pores underneath, and is sturdy, not fragile. Most polypores become tough with age, so it would not be edible. I do not recommend eating any mushrooms or fruiting bodies you find unless you are absolutely sure you have it identified by an expert as an edible type.