Multiple names: underground network, mycorrhizal network, common mycorrhizal network (CMN). Refers to belowground networks made up of mycelium and mycorrhizal fungal hyphae. These hyphae form expansive networks throughout the soil, with a single network forming connections with multiple different individual trees and plants, creating a vast exchange system which moves water, nutrients, and carbon between the plant and fungal symbiotic trading partners. These partnerships exist with nearly 80% of plant species. A single teaspoon of healthy soil can contain up to one hundred meters of mycorrhizal hyphae.