Ferns and horsetails are living fossils in that they are from the earliest forms of plant life on earth. They are vascular plants which prefer moist, shady environments, and reproduce via airborne spores or underground rhizomes. Ferns and horsetails are a monophyletic group, and the closest living relatives to seed bearing plants.
Class: Polypodiopsida (Ferns)
Ferns are a very ancient family of plants, and have been around for some 360 million years, since the Mesozoic Era.They existed on the planet some 200 million years before the evolution of flowering plants. Ferns are vascular plants which mainly grow in moist, shady environments under the protective canopy of trees, such as in woods and forests, or near streams or in ditches. They do not have seeds or flowers, but reproduce by spores, and go through an intermediate stage called a gametophyte.
Class: Equisetopsida (Horsetails)
The horsetails are now represented by only one genus Equisetum, and are amongst the oldest plants on earth. Fossils have been discovered in coal beds of tree-sized horsetails which grew in great and vast forests dating back to the Paleozoic Era, some hundreds of millions of years ago. It is from these ancient forests that coal was formed, and is mined today as fossil fuel.
Horsetails produce spores in cone-like structures. The spores develop into underground prothalli which produce new plants in the same manner as fern prothalli do. They also spread via tuber-like rhizomes beneath the earth.They are unwelcome in pastures due to their high levels of silica in their tissues, which are poisonous to cows and sheep, and other livestock.
They are called horsetails due to their branched structure which can resemble a horse’s tail.