Polypodium is one type of genus or classification of true ferns. There are numerous species of polypodium ferns. The name polypodium comes from the ancient Greek words polys, which means "many," and podion, which means "foot." This word is used to describe the somewhat foot-like appearance of a fern's rhizomes and root system.
These polypodium ferns, like other types of ferns, are part of a plant family that dates back to the Mesozoic era. Their ancestors were in existence over 360 million years ago. Ferns were already on Earth almost 200 million years before flowering plants even started to exist.
Like most ferns, the polypodium are leafy, flowerless plants that grow in areas where there is moisture. They are vascular plants with well-structured internal vein systems. This vein system is somewhat similar to the vein system of humans in that it provides the plant with its basic needs of water and nutrients throughout its entire body.
Unlike other vascular plants, however, ferns do not reproduce through pollination or by the nurturing of their seeds. Instead, the fern plant reproduces by releasing its spores. These spores are usually quite small and can be plentiful in number. They may be found in colors of black, brown, red, green, or even yellow. Even though they are not very big and can be quite tiny, each spore is capable of producing another fern when the conditions are right.
The polypodium can be found in many parts of the world, including sections of North America, Europe and Asia. Although they are all of the same class, different species can look quite different and have a variety of different frond shapes and sizes. The blade size of these ferns can even vary from 9 inches (22.9 cm) to over 30 inches (76.2 cm) in length.
Most polypodiums do prefer the same type of habitat, however, and many like a rocky area that has moist and slightly acidic, but well-drained, soil. Amorphum, which grow in parts of British Columbia and the western part of North America, are often found growing between the cracks in rocks or on mountain ledges. Scouleri and hesperium are two other polypodium ferns that have adapted to this type of habitat and seem to enjoy growing in these conditions as well.