The word Pteridophyta is formed from the Greek word Pteron meaning wing or Phyton meaning plant. Pteridophyta means winged plants. Non-flowering plants that have vascular bundles in their bodies and are divided into roots, stems and leaves are called pteridophytes. The division of Pteridophytes is called Pteridophyta. They are also called vascular cryptogams because they have vascular bundles in their bodies. They are the most underdeveloped of the vascular plants. Pteridophyta evolved from Bryophyta. They originated in the Devonian period, 360-408 million years ago. They were most widespread during the Carboniferous period, 286-360 million years ago. Most Pteridophyta are terrestrial. Some species are aquatic or parasitoid. 400 million years ago pteridophyta first dominated the land. Currently there are 11,023 species of 400 genera in the world. 195 species of 41 genera are found in Bangladesh.