Mycorrhizal fungi play in both the light and the mud. Part of this thing lives full time inside the plant where light and carbon are packed into lipids and sugars. The other part mines the earth for mineral and organic nutrients.
They also act as the Silk Road for trade between themselves and the plant as they exchange the nutrients for the carbon currencies along it.
In the most fundamental of ways the fungi turned algae into a farmable system. The plants we see today are nothing more than the fungal farmers' design that compels a space to be productive.
