Kingdoms Planate and Animalia: Gymnospermae (Gymnos: Naked, Sperma: Seed)

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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 Showing Pinus Sp

Image shwoing Cycas sp. with its parts.

Image Showing Cycas Sp

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