Fungi are fascinating, tasty, and critically important. Once considered part of the plant kingdom, they are now classified in their own biological domain, the fungi, separate from plants, animals, and bacteria. A major difference is that fungi have cell walls-- like plants --but contain chitin-- like mollusks --unlike plant cell walls which contain cellulose. Without the fungal symbiosis with plants called a mychorrhiza, Life on Earth would not have evolved. This fungal-root ...