Economic Importance

1. They are grown as ornamental plants for their delicate and graceful leaves.
2. Pteridophytes are grown as a soil-binding agent, as they bind the soil even along hill slopes.
3. Equisetum stems have been used for metal polishing and scouring (cleaning of cutlery). Scouring rushes are another name for Equisetum species.
4. Anabaena azollae, a cyanobacterium that fixes nitrogen, coexists symbiotically with the water fern Azolla. It is immunized against paddy fields that act as biological fertilizers.
5. Pteridophytes serve as a valuable source of food for animals, just like other plants. A water fern called Marsilea produces starch in its sporocarps, which is consumed by the tribal peoples.
6. Dryopteris rhizomes are used to make an anthelmintic medication (Male Shield Fern).

R.H Whittaker classified living organisms into five kingdoms based on cell structure, mode of nutrition, reproduction, and phylogenetic relationship. The five kingdoms are Monera, Protista, Fungi, Animalia, and Plantae.

Plant kingdoms have the following characteristics: 

• They are autotrophs, as they make their food by themselves. 
• They reproduce through both sexual and asexual modes (vegetative propagation). 
• They are non-motile. 
• They include multicellular and eukaryotic organisms
• The plant kingdom is further classified into Cryptogams and Phanerogams. 

Cryptogams are plants that reproduce by spores without seeds or flowers, known as cryptogams. Examples are ferns, lichens, algae, etc. They are further classified into Thallophyta, Bryophyta, and Pteridophyte. Phanerogams are seed-bearing plants. They are more advanced than cryptogams. They are further classified into Angiosperms and Gymnosperms. Here is a detailed explanation of Pteridophyta.