mycorrhizal network

 The underground web of fungal threads connecting the roots of trees and plants across a forest floor. The fungi colonize the root tips of trees, extending outward through the soil in filaments called mycelium, linking tree to tree in a network that can span acres. Through this network, trees exchange carbon, water, nitrogen, phosphorus, and chemical signals. The relationship is mutualistic — trees give the fungi sugars from photosynthesis; fungi give trees access to water and nutrients the roots alone couldn't reach.