A mycorrhiza is a symbiotic association between a green plant and a fungus.
The plant makes organic molecules such as sugars by photosynthesis and supplies them to
the fungus, and the fungus supplies to the plant water and mineral nutrients, such as phosphorus,
taken from the soil.
These symbioses are characterized by movement of nutrients – carbon flows to the
fungus and inorganic nutrients move to the plant, thereby providing a critical linkage
between the plant root and soil.