The term Pteridophyta was first coined by Haeckel. Eichler (1883) divided the plant kingdom into Cryptogamia and Phanerogamia. The Cryptogamia was further divided into Thallophyta. Bryophyta and Pteridophyta. Engler (1909) included the Bryophyta and Pteridophyta under Embryophyta. Due to discovery of the fossil plants, the classification of Pteridophytes has undergone …

They are the earliest known vascular plants that originated in the Silurian period (400 million years ago) of the Palaeozoic Era and subsequently diversified and formed the dominant vegetation on earth during Devonian to Permian period. There are controversies regard­ing their origin and evolution. There are two broad theories about …

Telome theory was proposed by Walter Zimmerman (1952, 1965). This theory is based on fossil records and explains the major steps in the evolution of vascular plants. According to this theory, all vascular plants have evolved from simple, leaf-less, root-less and dichotomously branched sterile and fertile axes called telomes which …