Pteridophytes

Pteron-feather

phyton- plants

Pteridophytes are the plants having feather-like a leaf. They are also known as vascular cryptogams i.e. non-flowering plants with conducting tissue xylem and phloem. They are seedless vascular plants, primitive vascular plants. There are about 400 living and fossil genera and 1050 species in the world. In Nepal, there are about 383 species.

General characteristics

• They are mostly found in moist, shady and terrestrial habitat. Some of them are aquatic. Eg; Azolla. Some of them are epiphyte. Eg; Drynaria. They are mostly herbaceous and few are trees. Eg; Cyathea.
• The sporophytic plant is dominant and differentiated into root, stem, and leaf. Sporophyte reproduces by the formation of spores and spores are produced in the sporangium. Sporangia are aggregated in sorus.
• The plant may be homosporous or may be heterosporous.
• Spores develop into gametophyte known as prothallus. Prothallus develops from homospores are monoecious. Prothallus developing from heterosporous are dioecious.
• Antheridium is male reproductive organ. Archegonium is female reproductive organ. Antherozoid is multi-flagellated.
• Water is necessary for fertilization. A zygote is the final product of fertilization. The zygote develops into the embryo and then into the sporophyte.
• There is the distinct alternate of generation seen in the lifecycle of Pteridophyta.
• In xylem vessel is absent and in phloem companion cell is absent.