Details
Pteridophytes consist of c. 1200 species of ferns and non-flowering plants. These plants are seedless plants and incapable of transferring the genetic material (DNA) to their offspring using fruits, seeds, and cones. However, these plants produce spores known as sporophylls. The leaves of pteridophytes contain spores on the underside. These spores can cover long distances due to a flexible structure that throws sporangia spores (structure containing spores). Pteridophytes’ anatomical structure is diversified with a wide range of characteristics such as fronds called fronds (these leaves remained coiled until they get matured). The stems are called rhizomes (horizontal) and standard roots with a vascular system for transporting water and food. Their habitat includes terrestrial, aquatic, cold, and humid areas with preferences in tropical regions.
They have a regular alternation between larger asexual sporophytes and mostly inconspicuous, sexual gametophytes, mostly free-living but retained within sporocarps of heterosporous ferns or developed mostly within spore walls of heterosporous lycophytes (Iseotaceae and Selaginellaceae). Sporophytes mostly with roots (absent in Psilotaceae), stems, and leaves, and with well-developed vascular strands. Stems mostly rhizomes, protostelic, siphonostelic, solenostelic, or dictyostelic, sometimes polystelic, some with limited secondary thickening, articulate in Equisetaceae. Leaves microphylls: scalelike or linear with a single vascular strand and a single axillary sporangium, or fronds (megaphylls): with branched vascular strands, lamina often divided, often compound, with many sporangia on abaxial surface, margin, or specialized sporophore, forked and subtending a 3-lobed sporangium in Psilotaceae. Sporangia thick- or thin-walled, homosporous or heterosporous, sessile or stalked, rarely enclosed within sporocarps. Spores trilete or monolete. Gametophytes filamentous or thalloid, autotrophic or mycotrophic. Male gametes (antherozoids) bi or multiflagellate. Female gametophytes (egg cells) borne singly within flask-shaped archegonia.