Fungi are largely made up of a network of long, microscopic, thread-like filaments that grow in the soil or on decaying organic matter. Some kinds of fungus produce fruiting bodies that rise out of the ground in the form of mushrooms—short-lived, spore-producing structures designed to release spores for the next generation, and then decay. As a decomposer, fungus is a vitally important aspect of the diverse, natural world of Point Reyes National Seashore, where there are over 450 known species of microfungi, with many more still to be found. They are found in all types of park habitats, from Bishop pine forests to coast live oak woodlands, meadows to sand dunes. In Muir Woods, over 200 different species of fungi live in the old-growth forest and the surrounding hillsides.