The following sections of this BookRags Literature Study Guide is offprint from Gale's For Students Series: Presenting Analysis, Context, and Criticism on Commonly Studied Works: Introduction, Author Biography, Plot Summary, Characters, Themes, Style, Historical Context, Critical Overview, Criticism and Critical Essays, Media Adaptations, Topics for Further Study, Compare & Contrast, What Do I Read Next?, For Further Study, and Sources.
(c)1998-2002; (c)2002 by Gale. Gale is an imprint of The Gale Group, Inc., a division of Thomson Learning, Inc. Gale and Design and Thomson Learning are trademarks used herein under license.
The following sections, if they exist, are offprint from Beacham's Encyclopedia of Popular Fiction: "Social Concerns", "Thematic Overview", "Techniques", "Literary Precedents", "Key Questions", "Related Titles", "Adaptations", "Related Web Sites". (c)1994-2005, by Walton Beacham.
The following sections, if they exist, are offprint from Beacham's Guide to Literature for Young Adults: "About the Author", "Overview", "Setting", "Literary Qualities", "Social Sensitivity", "Topics for Discussion", "Ideas for Reports and Papers". (c)1994-2005, by Walton Beacham.
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Pteridophyta is a division of plants within the classification system that are all vascular in nature and reproduce by the means of spores. The most common examples are ferns, horsetails, and club mosses.
Pteridophytes achieved prominence in the carboniferous period, along with the dinosaurs. At that time, many giant forms of pteridophytes superficially similar to extant species existed. The largest were some 60 ft (20 m) tall, whereas the largest living examples alive today are the giant horsetails Equisetum giganteum which grow up to 15 ft (5 m). The pteridophytes are responsible for many of the coal and oil deposits around the world, and as living organisms, they are popular as decorative plants.
Extant pteridophytes are widely distributed around the world, although their greatest range of diversity can be found in the tropics. They are mostly vascular and terrestrial, with no secondary thickening. They show alternation of generation with the gametophyte form being dominant. The spores are usually produced on the underside of laves or cones, and there is still a great reliance on water for the fertilization process when it occurs.