Fungi are heterotrophs, which means they require for their nourishment organic compounds synthesized by green plants. Most fungi are saprobes; they feed on dead organic matter, autumn's refuse, and cause its decay. Some fungi, like the amanitas, are parasitical; they take nutrients from a living host.
They are more than nature's recyclers. They are cloaked in myth and magic, icons of our own mortality. "Here is beauty from decay," wrote the naturalist Edwin Way Teale, "a frail and insubstantial form of life, a kind of botanical ectoplasm."