Pteridophyta

Pteridophyte, also known as vascular cryptogam, is any spore-bearing vascular plant, such as ferns, club mosses, spike mosses, quillworts, horsetails, and whisk ferns. Previously supposed to be of the same evolutionary path, these plants were historically classified as ferns and fern allies and put in the same category Pteridophyta. Despite the fact that contemporary research has demonstrated that the plants are not related, these words are still employed in discussions about lower vascular plants. The Pteridophyte Phylogeny Group (PPG I) identifies two distinct groups of extant lower vascular plants: Polypodiopsida, which includes ferns and horsetails, and Lycopodiopsida, which includes lycophytes.

What are Pteridophytes?

“Pteridophytes are vascular cryptogams with no seeds.” They proliferate by spores and can grow to tree-like heights (3040 feet).”

Ernst Haeckel came up with the term “Pteridophyta” in the year 1866. Pteridophytes are thought to be the earliest terrestrial plants to have a fully developed vascular system. The Greek words “Pteron” and “Phyton” denote feathers and plants, respectively.

Pteridophytes resemble their ancestors in many ways. Pteridophytes, unlike most other members of the Plant Kingdom, reproduce by spores rather than seeds.

Pteridophyta Characteristics 

1. This group’s members are the most basic living vascular plants.
2. A sporophyte is the primary plant body. It is divided into three parts: the root, the stem, and the leaves.
3. Plants (sporophytes) reproduce by sporangia, which create spores. Sporangia can grow on the ventral surface of the leaf or in the leaf axil.
4. Plants can be either homosporous or heterosporous. Sporangium formation can be eusporangiate or leptosporangiate.
5. Spores grow into a multicellular gametophytic entity known as a prothallus, which is a thalloid structure. It is self-sufficient and chlorophyllous. It has antheridia, which are male reproductive organs, and archegonia, which are female reproductive organs. Multicellular and jacketed reproductive organs
6. Because male reproductive units are flagellated and motile, water is required for fertilisation.
7. Seed production does not occur in live pteridophytes.
8. After fertilisation, an embryo grows in situ, and the sporophyte stays connected to the gametophyte until root formation.
9. Plants exhibit obvious generational alternation. The sporophyte and gametophyte are separate organisms.

Life Cycle of Pteridophytes

Pteridophytes display generational alternation. Pteridophyte life cycles comprise an alternating diploid sporophytic generation and haploid gametophyte generation.

• In the life cycle of Pteridophytes, the sporophytic generation is prominent.
• The sporophytic generation is diploid, photosynthetic, and self-contained.
• After meiosis, the sporophyte produces spores within the sporangia.
• The spores germinate and give rise to Prothallus, a gametophyte. The prothallus comes in two varieties: monoecious and dioecious.
• The gametophyte has male sex organs called antheridia and female sex organs called archegonia.
• Many ciliated antherozoids are produced by the antheridium.
• Water is essential throughout the fertilisation process when the antherozoids move to the archegonia.
• The formation of the zygote occurs due to the fertilization of the male and female gametes
• The sporophyte develops from the zygote.
• Both the sporophyte and the gametophyte are morphologically different, self-contained, and free-living organisms.
• Pteridophyta’s life cycle pattern is known as Diplo-haplontic.

Classification of Pteridophytes

Psilophyta (Psilopsida)

• These are the first pteridophytes.
• They don’t have any roots.
• Rhizoids have appeared in place of roots.
• They have spirally organised lateral appendages like scales or leaves.
• They are all homosporous
• They include multiflagellate antherozoids.
• Psilotum is an example

Lycophyta (Lycopsida)

• The plant body is made up of roots, stems, and leaves.
• Their leaves are microphyllous.
• They are either homosporous, like Lycopodium, or heterosporous, like Selaginella.
• These are often referred to as club mosses.
• Lycopodium, Selaginella are examples

Arthrophyta (Sphenopsida)

• The plant body is made up of roots, stems, and leaves.
• They have merged stem’s nodes and internodes.
• They have tiny, scaly leaves that are grouped in whorls at nodes.
• They are often referred to as horsetails.
• The only existing genus in this class is Equisetum.
• They are homosporous in nature.
• Equisetum is an example

Filicophyta (Pteropsida)

• The plant body is made up of roots, stems, and leaves.
• Their leaves are pinnately complex and circinate.
• These can be found in a variety of environments.
• They are homosporous as well as heterosporous.
• They are also referred to as ferns.
• These are the most advanced and biggest group of pteridophytes.
• Pteris and Dryopteris are two examples.

Conclusion 

Pteridophytes are thought to be the earliest terrestrial plants to have a fully developed vascular system. It is divided into three parts: the root, the stem, and the leaves. Sporangia can grow on the ventral surface of the leaf or in the leaf axil. The sporophyte and gametophyte are separate organisms. In the life cycle of Pteridophytes, the sporophytic generation is prominent. The sporophytic generation is diploid, photosynthetic, and self-contained. The spores germinate and give rise to Prothallus, a gametophyte. The prothallus comes in two varieties: monoecious and dioecious. Both the sporophyte and the gametophyte are morphologically different, self-contained, and free-living organisms.