When did ferns first appear in Earth’s history?

Ferns first appeared in Earth’s history during the Devonian Period, which began approximately 419.2 million years ago, when fossils exhibiting fernlike characteristics began to emerge in the geologic record.1

While some paleobotanists have historically identified specific fossils as potential ancestors—such as Archaeopteris or Protopteridium—the earliest "true" ferns are generally considered to have arisen during the Carboniferous Period, with some evidence suggesting they may have appeared as early as the Devonian. By the Triassic Period, several modern fern families were already well established, though the majority of species belonging to modern families did not undergo significant diversification until the Cretaceous Period.1