Mycelium

A mycelium may be minute, forming a colony that is too small to see, or may grow to span thousands of acres as in Armillaria.

Plants appear to communicate within an ecosystem using mycelium, the fungal network produced by mycorrhiza fungi.[17] Mycelial networks constitute 20-30% of soil biomass, though traditional biomass measures fail to detect them. Some 83% of plants appear to exhibit mutualistic association with mycelium as an extension of their root systems, with varying levels of reliance.[18] By some estimates, mycelial networks receive up to 10% or more of the photosynthesis output of their host plants.

https://en.m.wikipedia.org/wiki/Mycelium HEIGHT 400 Wikipedia