From around 420 to 350 million years ago, when land plants were still the relatively new kids on the evolutionary block and “the tallest trees stood just a few feet high,” giant spires of life poked from the Earth. “The ancient organism boasted trunks up to 24 feet (8 meters) high and as wide as three feet (one meter),” said National Geographic in 2007. With the help of a fossil dug up in Saudi Arabia scientists finally figured out what the giant creature was: a fungus. (We think.)
The towering fungus spires would have stood out against a landscape scarce of such giants, said New Scientist in 2007.
“A 6-metre fungus would be odd enough in the modern world, but at least we are used to trees quite a bit bigger,” says Boyce. “Plants at that time were a few feet tall, invertebrate animals were small, and there were no terrestrial vertebrates. This fossil would have been all the more striking in such a diminutive landscape.”