"Mutualism is a subset of symbiosis in which there exists between organisms a prolonged relationship that is interdependent and reciprocally beneficial. (...) In the case of the tree-fungi mutualism, the fungi siphon off carbon that has been produced in the form of glucose by the trees during photosynthesis, by means of chlorophyll that the fungi do not possess. In turn, the trees obtain nutrients such as phosphorus and nitrogen that the fungi have acquired from the soil through which they grow, by means of enzymes that the trees lack. (...) the fungal network also allows plants to distribute resources between trees in a forest: a dying tree might divest its resources into the network to the benefit of the community, for example, or a struggling tree might be supported with extra resources by its neighbours. (...) the network also allows plants to send immune-signalling compounds to one another." Robert MacFarlane, 2019. Underland: a deep time journey. Image by Monica Pinheiro, license CC BY-NC-SA (CC).
