A fern is a member of a group of vascular plants that reproduce via spores and have neither seeds nor flowers.
They belong to the lower vascular plant division Pteridophyta, having leaves usually with branching vein systems.
There are about 10,560 known species of fern.
Ferns are some of the oldest plants in the world. They first appear in the fossil record about 360 million years ago in the late Devonian period, but many of the current families and species did not appear until roughly 145 million years ago in the early Cretaceous, after flowering plants came to dominate many environments.
Ferns are distributed throughout the world, including tropical, temperate, and Arctic environments, although most species are located in tropical regions.
There are four particular types of habitats that ferns are found in: moist, shady forests; crevices in rock faces, especially when sheltered from the full sun; acid wetlands including bogs and swamps; and tropical trees, where many species are epiphytes.
Lifespan of fern depends on the species. Some types of ferns can live up to 100 years.
In size alone they range from minute filmy plants only 2 to 3 milometers (0.08 to 0.12 inch) tall to huge tree ferns 10 to 25 meters (30 to 80 feet) in height.
Just like other plants, ferns have roots, stems, and leaves. These parts, however, have names that are specific to ferns. These terms are important to know when identifying ferns.
Rhizome: This part of the plant is responsible for producing roots, which take up nutrients and water from the soil. Fern rhizomes can be very thin and creeping, or thick and stocky. Often times the shape of the rhizome is indicative of the growth form of the fern. Ferns that grow in a crown formation, with all fronds emerging from a single central point, tend to have stockier rhizomes, whereas ferns that send up single fronds from multiple places tend to have creeping rhizomes.
Stalk, Stipe, or Stem: This is the part of the fern that connects the root of the plant to the blade, or the leafy part of the plant. Its function is almost entirely support, however it may also be photosynthetic.
Frond, Leaf, or Blade: This is the part of the frond which bears leaflets or pinnae. This part of the plant is responsible for performing photosynthesis. New leaves typically expand by the unrolling of a tight spiral called a “crozier” or “fiddlehead fern.”
Leaflets or Pinnae: These are the parts of the frond that are fully divided from the stalk of the frond. Some but not all fern fronds are divided into pinnae. Further divisions in the frond are called pinnules, where the leaflets are further divided into smaller leaves that are connected to the branched stem of the pinna.
Axis or Rachis: This is the part of the fern stem that is touching the fern’s leaflets. Essentially, it’s the part of the stem that touches the leafy portion of the frond.
As mentioned above ferns do not produce seeds, they are grown from spores. They are produced in specialized organs — the spore cases, or sporangia. Spores usualy look like small dots on the undersides of the fronds. Fern plants can drop millions of spores onto the ground, but only the few that find ideal conditions will grow.
Ferns are not as important economically as seed plants but have considerable importance in some societies.
Some ferns are used for food, including the fiddleheads of Pteridium aquilinum (bracken), Matteuccia struthiopteris (ostrich fern), and Osmundastrum cinnamomeum (cinnamon fern).
Ferns make lovely houseplants, but the humidity in homes is often too low for some ferns to thrive. This is especially true in the winter when the heat is on.
The study of ferns and other pteridophytes is called pteridology. A pteridologist is a specialist in the study of pteridophytes in a broader sense that includes the more distantly related lycophytes.
Fern-Fever was a craze for ferns. Victorian decorative arts presented the fern motif in pottery, glass, metal, textiles, wood, printed paper, and sculpture, with ferns “appearing on everything from christening presents to gravestones and memorials”.
Ferns figure in folklore, for example in legends about mythical flowers or seeds.
In Slavic folklore, ferns are believed to bloom once a year, during the Ivan Kupala night. Although alleged to be exceedingly difficult to find, anyone who sees a “fern flower” is thought to be guaranteed to be happy and rich for the rest of their life.
Similarly, Finnish tradition holds that one who finds the “seed” of a fern in bloom on Midsummer night will, by possession of it, be guided and be able to travel invisibly to the locations where eternally blazing Will o’ the wisps called aarnivalkea mark the spot of hidden treasure. These spots are protected by a spell that prevents anyone but the fern-seed holder from ever knowing their locations.
The book Where the Red Fern Grows has elicited many questions about the mythical “red fern” named in the book. There is no such known plant, although there has been speculation that the Oblique grape-fern, Sceptridium dissectum, could be referred to here, because it is known to appear on disturbed sites and its fronds may redden over the winter.