The abundance of green ferns is the first thing that strikes our attention. Pteridophytes include ferns like this. Pteridophyta, often known as vascular cryptogams, has around 12000 species on the planet. The only non-flowering seedless plants with circulatory tissues are pteridophytes. Psilophyta, Lycophyta, Arthrophyta, and Filicophyta are the four primary classes of Pteridophyta.
Pteridophyta is known as “cryptogams” because, unlike most other members of the Plant Kingdom, they reproduce through spores rather than seeds. Pteridophyta includes ferns, horsetails, and lycophytes.
Pteridophyta
“Pteridophytes are vascular cryptogams with no seeds. They reproduce via spores and can grow to tree-like heights of 30 to 40 feet”.
In the year 1866, Ernst Haeckel coined the name “Pteridophyta.” Pteridophytes are the first land plants to have a fully established vascular system. The Greek words “pteron” and “phyton” refer to feathers and plants, respectively.
Characteristics of Pteridophyta
There are the following Key Characteristics of Pteridophyta:
Primal Terrestrial Plants
It is a hypothesis that life began in the seas and evolved to dry land during millions of years of evolution. Pteridophyta, on the other hand, is a primitive terrestrial plant that has evolved.
Plant Body
The fundamental plant body is the sporophyte. It’s broken down further into stems, roots, and leaves.
Stems
The majority of the branches are herbaceous, but some are woody. A monopodial stem or a dichotomous branching stem could be used for the branches.
Roots
Roots are small and sprout along the rhizomes by mistake.
Leaves
Leaves come in three varieties: scale, small sessile, and huge petiolate compound.
Vascular Tissues
The vascular tissues have a good amount of development. The xylem is mostly made up of tracheids, and there are no xylem vessels. Sieve cells, phloem parenchyma, and companion cells are all present in the phloem.
Classification of Pteridophyta
Generally, there are the following four types of Classification
- Psilophyta
- Lycophyta
- Arthrophyta
- Filicophyta
Psilophyta
- The most basic pteridophytes are these.
- They are free of roots.
- Rhizoids have taken the place of roots.
- They have spirally arranged lateral appendages like scales or leaves.
- They are homosporous.
- They have multiflagellate antherozoids, for example.
- Examples: Psilotum
Lycophyta (Lycopsida)
- Roots, stems, and leaves make up the plant body.
- Their leaves are microphyllous.
- They are heterosporous in Selaginella or homosporous in Lycopodium.
- Club mosses are another name for these mosses.
- Lycopodium and Selaginella are two examples.
Arthrophyta (Sphenopsida)
- Roots, stems, and leaves make up the plant body.
- They’ve connected the stem’s nodes and internodes.
- They have tiny, scaly leaves that are grouped in whorls at nodes.
- Horsetails are another name for them.
- The only extant genus in this class is Equisetum.
- They are homosporous.
- Equisetum is an example.
Filicophyta (Pteropsida)
- Roots, stems, and leaves make up the plant body.
- Their leaves are pinnately complex and circinate.
- They can be found in a variety of environments.
- They are heterosporous as well as homosporous.
- They’re also called ferns.
- The largest group of pteridophytes and the most developed.
- Pteris and Dryopteris are two examples.
Vascular Plant
Pteridophyta has well-developed circulatory tissues. Tracheids make up the xylem, while sieve cells and phloem parenchyma make up the phloem. The tissue, however, is devoid of xylem vessels and phloem companion cells.
Sporangia in Sporophytes
Sporophylls, which are leaf-like structures, look after sporangia in sporophytes. The tip of the leaves curls inwards to protect the fragile growing zones. Furthermore, spores are created within the sporangia. Sporophylls can also form cones or strobili, which are compact structures.
Formation of Spores
In the sporangia, spores are generated. The spores can be found in a variety of places.
Homosporous refers to the production of only one type of spore.
Heterosporous refers to the fact that two types of spores are formed.
Multicellular Sex Organs
The sex organs of Pteridophyta are multicellular. The male sex organ is antheridia, while the female sex organ is archegonia. The prothallus carries the sexual organs. A prothallus is a tiny gametophyte that emerges from spores after they have germinated.
Alternation of Generation
It can be proven by looking for sporophyte and gametophyte generations in them. The dominant sporophyte uses meiosis to produce spores. In the gametophyte generation, mitosis creates gametes. The life cycle of Pteridophytes and other plants is known as the alternation of generations.
Life Cycle of Pteridophyta
Pteridophyta exhibits generational alternation. Pteridophytes have a life cycle that is similar to that of seed-bearing plants; however, unlike mosses and seed plants, they have distinct and free-living generations of haploid gametophyte and diploid sporophyte. The following is a summary of a Pteridophyta (fern) life cycle:
- Since they are flowerless and seedless, Pteridophyta reproduces by spores.
- At first, spores are released into the atmosphere.
- Spores develop into haploid gametophytes with both male and female sex organs in the shape of a heart.
- As soon as the immature gametophyte grows, the sex organs become active.
- In ferns, the male reproductive organ (antheridium) produces sperm, while the female reproductive organ (archegonium) produces eggs.
Conclusion
In a word, we can state that Pteridophyta is one of the oldest plant families on the planet. They can only be found in terrestrial environments. They’re also known as one of the first “real” plants to adapt to land life. They are also the earliest terrestrial plants to have a fully developed vascular system. Ferns are a type of pteridophyte that can be found in abundance all around us. Habitat, plant body, stem, roots, leaves, vascular tissues, and reproduction are all characteristics of Pteridophyta.