Features of Ferns in Biology

There are more than 12,000 species of ferns.

Ferns are the largest group of nonflowering vascular plants, with about 12,000 different species on earth today. They are also an ancient plant; 400-million-year-old leaf impressions of ferns have been discovered, although most of those species are now extinct. Many types of ferns exist, each with distinct features, but also with many common features.

Appearance

To understand the biology of a fern, it's important to understand its parts. Fern leaves are called fronds. Fronds are megaphylls, meaning they have a large network of veins. The leaves coil into the shape of a shepherd's crook.The stems of most ferns are creeping rootstock known as rhizomes. They grow horizontally under or just above the ground. Tree ferns can have long, trunk-like stems. Roots are typically simple, thin and wiry.

Life Cycle

The sporangia, or spore cases, are the beginnings of a fern. They stay on the underside of fern leaves The sporangia dry out, and eventually burst, sending spores into the air. Some spores land in a suitable place for growth, settle and grow into a prothallus. The prothallus is where fertilization that creates a fern takes place. Sperm on one side of the plant swim through water in the plant to the other side, where there are eggs. The fertilized eggs eventually grow into a fern plant.

Places Found

Ferns are found in many environments, and adapt easily. Biologically, they make up a tough species. They can live anywhere -- from a desert environment to under the water. Typically, however, they thrive in a jungle environment where there is plentiful water. Approximately two thirds of today's ferns are found in jungle environments.

Biological Importance

Not only are ferns important to today's landscapers and gardeners because of their pleasing looks, but their biological makeup also has historic and economic importance as well. Approximately 300 million years ago, fern forests covered much of the world. As the ferns died in the swampy environment, the heavy amounts of water kept them from decomposing properly. Instead, the ferns became peat, which, when covered in sediment and compressed, became coal that we use today.

References

• Britannica: Fern -- General Features
• Cliffs Notes: Plant Biology: Phylum Pterophyta
• The Open Door: The Pteridophytes: Ferns and Horsetails