Fun with fungi reminds me of Ghostbusters.
Estimates on spores range from 400 million to one billion years old. At first I thought the small age would effect coal formation, but Steve is right, they would not. Things like deforestation might.
There is the possibiity that ocean fungi, a pedecessor of land fungi with spores with thicker walls, could make fungi a bit older.

Which came first bacteria or fungi? The smart money is on germs.

I live on the oldest mountain chain on Earth. The Atlantic rift divided the Adirondacks in a way that the other end is in Scotland. We probably share fungi deep in the Earth.
Robo I have more questions than answers and always have.
Wondering is wonderful. The envitable is enevitable and g iven entropy and assumptions everything we think we know will change.