This is distinctive cup fungus occurring at the height of our mushroom season in mid to late summer. In certain years it may be frequent and occasionally the fruit bodies may be rather large (4-5 inches diameter). The interior of the cup is some shade of brown, the exterior white, deeply and extensively ribbed. It is found under mixed conifer, often in rich humus soil and rotted wood.
    No one seems to have determined if it is edible, but it does belong to a group of fungi that contains poisonous species. It's better left in the woods and viewed as yet another unique component of the forest.