A subdivision of the Pteridophyta, which comprises all living and extinct ferns. They arose in the Devonian from the Trimerophytina group of psilophytes and made an important contribution to Carboniferous floras. They are the most advanced, numerous, and varied of the pteridophytes. In most cases they have relatively large, much-divided leaves, and are still significant components of many different plant communities around the globe.
Subjects: Plant Sciences and Forestry.