Lygodium is a genus of plants that belongs to the fern family, consisting of about 40 species of climbing fern. These plants have fronds, which are the branch and leaf structure of all ferns. Lygodium is indigenous to tropical regions across the globe, such as southeast Asia, Japan, and China. Other species are also found in the southeastern parts of the United States.
These plants have fronds that are flexible but do not coil around a supporting structure while they are growing. This characteristic results in the frond’s formation of individual vines. Depending on the species of Lygodium, the length of the fronds can reach from 10 to 40 feet (3 to 12 m).
The spores of Lygodium plants are typically spread by the wind. People and animals that come into contact with the ferns can also help spread their spores. Machinery and equipment used in agriculture and commercial forest operations facilitate the distribution of the spores to wider areas as well.
One species of the genus, Lygodium microphyllum, also known as the old world climbing fern, is capable of re-sprouting from anywhere, even along its leaf. It is this characteristic that gave this type of climbing fern a reputation for being an invasive plant. When given a reasonable length of time, it can cover the natural vegetation of hundreds of acres.
Each leaflet of Lygodium plants produces spores, and after they have been dried in the sun some people use these spores in herbal medicine. The medication is then prepared by wrapping the spores in a cloth and then boiling it in water as a decoction. Others use the alternative method of placing the spores in a strainer after boiling. This is used as a form of treatment for urinary ailments, such as frequent urination and turbid urine. It is also believed to relieve sore throats and common colds.
As of 2010, some Lygodium plants were considered a problem in parts of the world because they have covered large areas of trees and plants. Some authorities on these types of plants have estimated that they can multiply 12 times over a period of 10 years. The dense growth of Lygodium plants can serve as fire hazards because small fires on the ground often reach the trees by way of these climbing ferns. This situation often poses great concern to those who have the responsibility of caring for and managing forest areas.