Mycorrhizal fungi are so prolific that their mycelium makes up between a third and a half of the living mass of soils. The numbers are astronomical. Globally, the total length of mycorrhizal hyphae in the top ten centimeters of soil is around half the width of our galaxy (4.5 × 1017 kilometers of hyphae, versus 9.5 × 1017 kilometers of space).
