Shelf mushrooms are easily identifiable because they grow like shelves on rotting trees and fallen logs.
The Jack Lantern is poisonous, but the others are considered a viable food source. They really don't taste very good, however and are leathery.
The main thing then, is to know what the Jack O' Lantern looks like. It does have a 3-8 inch stalk, but grown at base of stumps and buried roots of deciduous trees, and is saffon to yellow-orange.