Pteridophyte, << TEHR uh duh fyt or tuh RIHD uh `fyt,` >> is one of a large and important group of plants that are simpler in their structures than flowering plants. The name pteridophyte means fern plant. Not all the pteridophytes are ferns, but ferns are the best known of the group.
The pteridophytes lack flowers, but they have many of the same tissues and habits that flowering plants have. Their organs are distinctly divided into roots, stems, and leaves, as those of flowering plants are.
Instead of reproducing by seeds as flowering plants do, the pteridophytes multiply by means of very small bodies called spores (see Spore ). These spores do not result from flowers, but grow on special parts of the plant in little capsules. The spore capsules of ferns are the roundish brown specks on the back of certain of the fern leaves. When the spores drift away and begin to develop, they produce small plants quite different from the ferns. After a time these small plants give rise to young ferns, which grow and produce another generation of spores. This process is known as alternation of generations (see Alternation of generations ).
Other plants that belong to the pteridophyte group include horsetails, club mosses, and ground pines. These pteridophytes have a life history that is similar to that of the ferns.
Millions of years ago the pteridophytes were among the largest and most common kinds of plants. Many of the world’s coal deposits contain large amounts of pteridophyte remains. Fossil records show that many pteridophytes reached the size of large trees. But present-day kinds, except the tree ferns of the tropics, are small, nonwoody herbs.
