The ferns are a group of low growing, herbaceous plants that originated in the Devonian period and diversified rapidly in the Carboniferous. They are spore-producing vascular plants, or pteridophytes, and are still evolving to this day. This highly successful group of plants is represented by 12,000 living species found in virtually every habitat throughout the world. The ferns reproduce by releasing large numbers of spores and are reliant on these combining in water to form a new individual. Most ferns have an underground storage stem or rhizome which can branch out to produce more individuals on the surface.
Rhizomes contain water and nutrients allowing ferns to recover quickly after heavy grazing or fire.
It is only the tree ferns that do not have rhizomes. Many of the ferns living in the Carboniferous period are ancestors of the living tropical ferns. They had extensive root systems to maintain stability. Early primitive ferns did not have the flattened leaves that are a characteristic of most types of living fern. The Fact Files, Family Tree and Glossary have been written in consultation with leading palaeontologist Michael Benton, Professor of Vertebrate Palaeontology at the University of Bristol, and represent the latest scientific knowledge about these creatures.