Pteridophytes – Class 11 | Chapter – 3 | Short Notes Series PDF

Pteridophytes are the first terrestrial vascular plants. Carolus Linnaeus classified them under the group cryptogamae.These are vascular plants with differentiated parts like roots, leaves, and stems. They are further classified into Psilopsida, Lycopsida, Sphenopsida, Filicopsida.

Characteristics of Pteridophytes

  • They contain the vascular system. However, companion cells, xylem vessels, and sieve tubes are absent.
  • They have leaf-like appendages that extend the sporangia of the plant. These appendages are called sporophylls.
  • They reproduce by the following methods:
    • The mother cells undergo meiosis to produce spores, which germinates to produce thallus.
    • Sexual reproduction in water conditions, where male organs called antheridia and female organs called archegonia fertilizes

Life Cycle of Pteridophytes

Pteridophytes show alternation of generations. Their life cycle is similar to seed-bearing plants, however, the pteridophytes differ from mosses and seed plants as both haploid gametophyte and diploid sporophyte generations are independent and free-living. The sexuality of pteridophytic gametophytes can be classified as follows:

  1. Dioicous: the individual gametophyte is either a male producing antheridia and sperm or a female producing archegonia and egg cells.
  2. Monoicous: every individual gametophyte may produce both antheridia and archegonia and it can function both as a male as well as a female.
  3. Protandrous: the antheridia matures before the archegonia.
  4. Protogynous: the archegonia matures before the antheridia.

Classification of Pteridophytes

Pteridophyta is classified into four main classes:

Psilopsida

  • They are the most primitive.
  • The stem is photosynthetic and dichotomously branched.
  • Rhizoids are present.
  • Leaves are mostly absent.
  • The sporophyte is homosporous synangium.
  • Examples- Psilotum and Tmesipteris.

Lycopsida

  • They are commonly known as club moss.
  • Well-differentiated plant body with adventitious root, stem, rhizophores and leaves.
  • The sporophyte is homosporous or heterosporous.
  • Examples- Selaginella, Lycopodium.

Sphenopsida

  • Commonly known as horsetail.
  • Well-differentiated plant body with roots arising from nodes of the underground rhizome, stem and scaly leaves.
  • Homosporous, sporangia are borne on strobili.
  • Examples- Equisetum.

Pteropsida

  • Commonly known as a fern.
  • Well-differentiated plant body with roots, stem and leaves.
  • The sporophyte is homosporous or heterosporous.
  • Antherozoids are multiflagellate.
  • Examples- Pteris, Dryopteris, Adiantum

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By Team Learning Mantras