A garden on the north side of the house has two old aspen trunks, which look lovely among the lilies of the valley in the summer. In the winter, they looked a little bare until they started growing a nice crop of decorations. The decorations are conks, a type of shelf or bracket fungus:
Like other mushrooms, the mycelium break down the structure of the wood, starting the process of returning the stump to earth; unlike other mushrooms, they have no stem. And unlike the mushrooms that grow in our yard, conks are very tough and difficult to cut. They provide a tiny, almost invisible microsystem for mites and spiders. Some shelf fungi are ground and used as teas or herbal medicines, but I don't think conks fall in that category.