Ferns are among the more easily recognized plants. Most species have leaves or fronds that are subdivided into many smaller leaflets. Many ferns grow in cool, shady forests. The geological record indicates that ferns have grown on Earth for at least 400 million years. Ferns do not reproduce by shedding seeds from the green leaves.
Some ferns reproduce by spore and by producing rhizomes.
Oak fern , some Maidenhair ferns, and Bracken grow rhizomes. Rhizomes allow the plant to form sizeable colonies. Like all plants, ferns produce oxygen and collect carbon dioxide from the atmosphere and provide food and shelter for other organisms. Ferns also produce soil and reduce soil erosion, creating an ecosystem for other plants to grow. Some ferns, like the Ostrich fern , are harvested as food.