Mycelium is ecological connective tissue, the living seam by which much of the world is stitched into relation. In school classrooms children are shown anatomical charts, each depicting different aspects of the human body. One chart reveals the body as a skeleton, another the body as a network of blood vessels, another the nerves, another the muscles. If we made equivalent sets of diagrams to portray ecosystems, one of the layers would show the fungal mycelium that runs through them. We would see sprawling, interlaced webs strung through the soil, through sulfurous sediments hundreds of meters below the surface of the ocean, along coral reefs, through plant and animal bodies both alive and dead, in rubbish dumps, carpets, floorboards, old books in libraries, specks of house dust, and in canvases of old master paintings hanging in museums. According to some estimates, if one teased apart the mycelium found in a gram of soil—about a teaspoon—and laid it end to end, it could stretch anywhere from a hundred meters to ten kilometers. In practice, it is impossible to measure the extent to which mycelium perfuses the Earth’s structures, systems, and inhabitants—its weave is too tight. Mycelium is a way of life that challenges our animal imaginations.

— Entangled Life by Merlin Sheldrake