Mushroom

Fungi are a kingdom of multicellular heterotrophs. They feed primarily on decomposing plant material, aided by their ability to produce cellulose. The body of the mushroom is called mycelium and its individual parts are microscopic. Since the body of the mushroom is usually dispersed over a relatively large area it is rarely noticed. In nature some species of mushrooms may have a body that spreads over hundreds of square miles. Mushrooms are fungi, and are usually placed in a Kingdom of their own apart from plants and animals. Mushrooms contain no chlorophyll and most are considered sacrophytes. That is, they obtain their nutrition from metabolizing non living organic matter. This means they break down and "eat" dead plants, like your compost pile does.

The body of the mushroom stores nutrients and other essential compounds, and when enough material is stored and the conditions are right they start to fruit - produce mushrooms.