Long before flowering plants, before the dinosaurs walked the Earth (during the Triassic Period 245 million years ago), ferns were well established. The end of the late Devonian Period (about 360 million years ago) was the era that gave rise to the ferns.

As ferns began to proliferate, they helped in the breakdown of the Earth's rocky crust, the formation of soil, and the decrease of CO2 in the atmosphere. These things in turn led to the Late Devonian extinction, and the cooling of the Earth from its previous greenhouse state.