Scientific American Magazine has an interesting story about the spread of terrestrial plants during the Early Devonian Period. A paper in the journal Science Advances looked at the origin of lichens. Did they appear before or after the rise of vascular plants? Lichens, which are a composite organism resulting from a symbiotic relationship between a fungus and an alga or cyanobacterium, may have lead the way for terrestrial plants by helping prepare the ground so the plants could absorb vital soil nutrients.

Around 410 million years ago, terrestrial life was relatively simple. There were no forests or prairies—land was largely dominated by slimy microbial mats. The types of plants that would eventually give rise to trees and flowers had only just evolved and would take another several million years to fully flourish and diversify.

A new discovery is rewriting the story of how these vascular plants, as they are called, spread onto land. Researchers may have finally resolved a debate about an enigmatic but widespread fossil called Spongiophyton: it seems to have been a strange life-form called a lichen that may have helped pave the way for plants to thrive on land.