Over 90% of plant species have mycorrhizal relationships with fungi, via their roots. Such relationships tend to be symbiotic, to sustain the relationship: fungi obtain sugars and shelter, and help the plants to obtain minerals, nutrients and water. The mycelia are very fine and spread well beyond the root zone, sometimes several hundred metres, increasing plant access to available nutrients. A few mycorrhizal relationships are parasitic.
Fungi can grow on the inside (endomycorrhizal), or on the outside of roots (ectomycorrhizal). The ‘endos’ are a bit like our gut biome, and can help plants cope with extreme environments; ‘ectos’ are the most familiar, because we can see them without a microscope.
Fungi are at work in permaculture systems everywhere, and we can benefit from understanding the roles they play, and working with those. There are many guilds that we can create which incorporate fungi, and this area of study is evolving rapidly.
Not all mycorrhizal fungi form edible mushrooms, but some of the most recognisable and sought-after mushrooms are mycorrhizal: