Pteridophyta

Pteridophytes, popularly known as ferns and their allies, are a familiar group of vascular plants. They are the most primitive group among vascular plants. They thrived during the Carboniferous Period, some 350 million years ago, when the climate was mild with no significant seasonal fluctuations of temperature. There were luxuriant growths of giant tree ferns, horsetails, and clubmosses in swamp forests. When angiosperms began to proliferate during the Cretaceous Period gymnosperms declined but pteridophytes continued to thrive which still survive today in much greater species diversity than the gymnosperms.