Scientists believe that certain fossils are evidence that giant mushrooms, referred to as Prototaxites, covered the Earth before trees and other land plants became commonplace. It is thought that 420 to 350 million years ago, there were fungi that grew to heights of 24 feet (7.3 m), while any of the few newly evolved trees were no more than about 3 feet (0.9 m) tall. The first Prototaxite fossils were discovered in Canada in 1859, but it wasn’t until about 2007 that it became accepted that the fossils were from giant fungi. Prior to that, there were theories that the fossil was a plant or lichen, or a type of combination of algae and fungus that grows on rocks.
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