Kingdoms Planate and Animalia: Gymnospermae (Gymnos: Naked, Sperma: Seed) (For CBSE, ICSE, IAS, NET, NRA 2022)

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Gymnospermae (Gymnos: Naked, Sperma: Seed)

  • Gymnospermae are plants with naked seeds. They are the most primitive and simple seed plants. The seeds produced by these plants are naked and are not enclosed within fruits.
  • Usually perennial, evergreen and woody plants. They were dominant on earth during Jurassic period – the age of Dinosaurs.
  • Gymnosperms include the two groups: Cycadae, e. g. Cycas and Coniferae, e. g. Pinus, Cedrus, Ginkgo etc.
  • The livings gymnosperms are woody, evergreen perennials grow as trees or shrubs.
  • Leaves may be dimorphic i.e.. 2 types, foliage and scale leaves.
  • Gymnosperms are xerophytes in nature due to presence of thick bark, thick hypodermis, thick cuticle, scales leaves, sunken stomata, transfusion tissue, etc.
  • Vascular bundles in stem are arranged in a ring and show secondary growth.
  • The gymnosperms are heterosporous, means 2 types of spores produced i.e.. haploid microspores and megaspores. Microspores produced within micro-sporangia while megaspores produce within megasporongia (nucellus) of ovules. Both types of sporangia are formed on sporophylls (microsporophylls and megasporophylls) .
  • Pollination is anemophilous (by wind) .
  • Endosperm or female gametophyte formed before fertilization and is always haploid.
  • Cotyledons 2 (in Cycas) or many (in Pinus 2 - 14) .
  • Wood is manoxylic (in Cycas) or Pycnoxylic (in Pinus) .

Some Common Gymnosperms Are

  • Pine (Pinus) , Red Wood (Sequoia) , Juniper (Juniperus) , Cedar (Cedrus) . Many gymnosperms yield timber, resins, turpentine, and many other products like the dry fruit chilgoza.
Image Showing Pinus Sp. With Male and Female Cones, Scale Le …
Image Shwoing Cycas Sp. With Its Parts

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