Ferns are non-flowering plants that help to prevent erosion. According to the New York Botanical Garden there are about 10,400 species of true ferns. They can be terrestrial plants, found in woods and other moist, shady areas, or epiphytes, attaching themselves to trees in the rainforest and living off organic debris. Their size varies from towering tree ferns to tiny, floating aquatic plants.
Parts of Ferns
A simple description of a fern might be: a plant with fronds that are attached to rhizomes. The frond is the leaf of the fern and the rhizome is a stem like a root but with a variety of purposes. Most rhizomes grow and spread underground and many have actual roots growing from them. The rhizomes hold soil in place as they spread out. They are vascular, which means they transport nutrients throughout the plant through tubular structures. Fronds grow from the rhizome on a stem or stipe. The differences in the fronds, stipes and rhizomes help to identify different species of ferns.
Fern fronds range from 15 feet long in tree ferns to less than half an inch in floating aquatic ferns. The fronds roll out from a leaf bud as they develop and, in the species where it is visible, the curled leaf bud is called a crozier. In some ferns, the fiddlehead, or crozier, is considered an edible delicacy. The frilly or fan-like spread of leaves that distinguishes most ferns is called a pinnate frond; the individual leaves are known as pinnae.
Ferns don't reproduce by seed. Instead they have spores. Spores can be located on the underside of the fronds. Very often, they are clusters of small brown dots that hold the microscopic reproductive structure of the plant. Ferns are referred to as cryptograms from the Greek "kryptos" and "gamia" which means "hidden marriage." The spores are released when they are ready and are scattered by the wind. They develop a self-contained reproductive vessel with eggs and sperm in it. If there is sufficient moisture for the sperm to swim to the eggs, a new plant is formed. Before the development of microscopes, which reveal the secrets of fern reproduction, people believed that the fern had magical properties. Because they couldn't see how it reproduced without seeds or bulbs, they thought ferns could go invisible and spring up at will. So, even Shakespeare wrote about ferns as the ingredient used to give people the power of invisibility.
Ferns love shade and need moisture. The water makes it possible for them to reproduce because it is a conduit for the plant's sperm to reach its eggs. About 70 percent of ferns are found in tropical regions and the giant tree ferns grow in tropical rainforests. Temperate climate ferns tend to grow in woodlands where they are protected and shaded by the trees.