Mushrooms arise when two compatible mycelium (filamentous growth), homokaryotic, in this case, join. In a simpler wording, the mycelium acts similarly to the roots of a tree, yet for a mushroom; they are usually found underground too. Through the junction of two of these mycelia, a diakaryotic mycelium arises and creates fruiting bodies (mushrooms). The mycelium is also the vegetative area of a fungus. In the picture above a mushroom is shown.