Pteris is a well-known fern in Bangladesh. They are called Sun-fern because they grow in the sun. There are about 250 species of Pteris. 16 species are found in Bangladesh. Pteris vittata is the most common in this country. Other species include Pteris longifolia, Pteris cretica, Pteris grandifolia, Pteris palmata etc.

Equisetum is called Horsetail Fern. The branching Equitum looks a lot like a horse’s tail. Hence they are named Horsetail

1. Pteridophyta are green, omnivorous and self-sufficient plants.
2. They are non-flowering and asexual plants.
3. They are mainly sporophyte plants. Sporophytes are large and long lasting.
4. Their body is divided into roots, stems and leaves.
5. Their stems are rhizomes.
6. Their leaves have stomata and chlorophyll. They produce food through the process of photosynthesis.
7. They have vascular bundles. That is, they are vascular plants. Dr. Siddique Publications
8. Their genitalia are multicellular and covered with a sterile sheath.
9. Their male genitalia are called anthoridium and female genitalia are called archegonium.
10. Their sexual reproduction is ogamous in nature. Dr. Siddique Publications
11. Their spermatozoa are multi-flagellated and motile.
12. Their strigametes are immobile and remain inside the archegonium.
13. Their life cycle produces multicellular embryos (the oldest embryos).
14. They are homosporous or heterosporous. That is, they produce microspores and megaspores.
15. Their spore-bearing leaves are called sporophylls.
16. Leaves have rachis. The leaves are arranged in racks.
17. Their gametophyte body is called prothallus.
18. The sporophyte is partially or totally dependent on the gametophyte.
19. There is a clear heteromorphic or asymmetric genealogy in their life cycle.

Aquatic Ferns – Azolla and Salvinia
Smallest Fern – Anogramma
Horsetail- Equisetum
Homozygous – Lycopodium and Dryopteris
Asymmetric – Selaginella and Marsilea
Epiphyte- Selaginella aregana.

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.

1. Increases Soil Fertility: Riccia corpses mix with soil to increase soil fertility. meet the nutrient demands of tropical forests and form the permafrost layer over polar soils.
2. Prevention of soil erosion: It grows on the banks of water bodies and prevents soil erosion.
3. Economic Importance: Moss has no economic importance. But peat moss is economically the most important.
4. Environmental Pollution Index: It acts as an indicator of environmental pollution.
5. Environmental purification: It helps keep the environment clean by absorbing CO2 and releasing O2 in the process of photosynthesis.
6. Research: Rixie was the first land plant. For this reason it is used as a research tool.
7. Corrosion of buildings and walls: It grows on old buildings and walls and causes corrosion.
8. Concepts of evolution: Rexia has characteristics of the first land plants, which helps to understand evolution.

The stages of Riccia’s reproductive system are:
(i) Gamete formation: Male reproductive organs of Riccia are called antheridia and female reproductive organs are called archegonia. Each reproductive mother cell of the antheridium develops into a bi-flagellated spermatozoon. The reproductive mother cell of the archegonium forms the ovule.
(ii) Fertilization: During sexual reproduction, their sperm swim in water and come near the egg. It then fuses with the egg in the presence of water. The union of sperm and egg is called fertilization. Fertilization results in the formation of a zygote.
(iii) Germination: The zygote produced by fertilization germinates to form a simple and spherical sporophyte.

Within the thallus several cup-shaped or flax-shaped female archegonia grow. It consists of two parts. Neck and Abdomen. The neck is slightly curved and consists of few neck duct cells. Abdomen contains an ovary and an abdominal duct cell.

On the surface of the thallus, several stamens antheridia grow. It is round and pear shaped. Inside the antheridium are the sperm mother cells. Two biflagellate spermatozoa are produced from each sperm mother cell.

The area of the thallus where food is deposited or stored is called the storage zone. It is colorless, multicellular, devoid of intercellular spaces and composed of parenchyma cells. This region does not produce food, but stores carbohydrates. Unicellular rhizoids and multicellular scales are produced from this region.