Some pore fungi grow quite large, such as the above, on a tree in Chicago. This is Polyporus squamosus, which gets nearly a foot across (30 cm). This fungus is edible but it's so tough that few mushroom eaters bother with it unless they find very young bodies. The species grows on dead wood. The host tree is living, but it can be seen that the fungus body emerges from a crack in the tree's trunk, so the fungus's hyphae must be coursing through dead wood inside the tree.