THE discovery of tiny fragments of land plants that date back 450 million years has prompted a re-evaluation of even older fossils. The conclusion is that plants first colonised the land around 50 million years earlier than we thought.
Until now, the earliest conclusive evidence of land plants consisted of tiny branching structures found in rocks in Wales, dated to around 425 million years ago. But many rocks laid down during the previous 50 million years contain spores that cannot be identified with certainty. Some palaeobiologists argued that the spores came from primitive land plants such as liverworts, while others…
