Fungi come in many shapes and sizes, ranging from single-celled yeasts and molds to enormous underground networks that can stretch for miles. They differ from plants in that they cannot produce their own food and instead consume and break down dead or living organisms. Fungi spread through tiny spores carried by wind and rain or through networks of underground hyphae. They are found virtually everywhere and play important roles in decomposition as well as having uses like leavening bread and brewing beer. The largest known fungus covers 2,200 acres in Oregon.