free booknotes online
PinkMonkey Online Study Guide-Biology

15.1 Pteridophyta

Pteridophytes are the simplest of the tracheophytes. They were abundant in the geological past. Today, they are best represented by the ferns, although other non-fern pteridophytes are present in lower abundance.

These plants are usually small and herbaceous. They grow well in moist, cool, and shady places where water is readily available.


(a) Distinguishing Characteristics

  1. The life-cycle shows distinct heteromorphic alternation of generations.

  2. Diploid sporophyte generation is predominant.

  3. Sporophyte plant body has true roots, stem and leaves with well developed vascular system.

  4. Asexual reproduction takes place by spores.

  5. Most pteridophytes are homosporous; only a few show heterospory.

  6. Spores are produced in multicellular sporangia after meiosis in spore mother cells.

  7. Gametophyte is haploid, multicellular, green and an independent structure.

  8. Sex organs, antheridia and archegonia are multicellular.

  9. Antherozoids (sperms) are spirally coiled and multi flagellate.

  10. Opening of sex organs and transfer of male gametes to archegonium for fertilization are dependent on water. Further, fertilization takes place inside the archegonium.

Some common examples of microphyllous pteridophytes (i.e., poorly developed leaves) are club mosses (Lycopodium  sp.), and whisk ferns (Psilotum sp.). Examples of megaphyllous (large-leafed) pteridophytes are the ferns Nephrolepis, Osmunda, Pteris, and Salvinia.

[next page]

Table of Contents

15.0 - Introduction
15.1 Pteridophyta : General Account
15.2 Gymnosperms
15.3 Angiosperms : Dicotyledons
15.4 Angiosperms : Monocotyledons
15.5 Vascularization
15.6 Development of seed habit
15.7 Development of Flower and Fruit

Chapter 16





Google
  Web PinkMonkey.com   

All Contents Copyright © PinkMonkey.com
All rights reserved. Further Distribution Is Strictly Prohibited.


About Us
 | Advertising | Contact Us | Privacy Policy | Home Page
This page was last updated: 5/9/2017 9:55:31 AM