Lianas are vinelike plants that grow in the rain forest and require some type of support to grow toward the canopy of the forest, where more light occurs. Lianas play an important role in rain forests, where they make up about 20 percent of the woody plants. Besides helping form bridges between different plants in the canopy, lianas also provide flower and fruits for wildlife and form important walkways for a variety of animals.
More than 2,500 species of vines from about 90 families of lianas thrive in the canopy of the rain forest. The plants range from small vines to gigantic lianas that appear as thick as tree trunks. Some of the vines grow to more than 3,000 feet in length.
One of the best-known families of liana plants, the rattan (Rhapis humilis blume), is used in furniture, ropes and baskets. The rattan also produces large fruits that primates prefer.
The scraped-off bark of another type of liana, the garlic liana (Mansoa alliaceae), is used to alleviate colds and fever after it's cooked in water. A steam bath of the leaves of the garlic liana also helps with arthritis pain and fever.
When cooked in water, the red wood of the cat nail liana (Uncaria tomentosa) makes a liquid that treats asthma, stomach ulcers, and bladder and kidney diseases.
Very few plants grow at ground level in the rain forest because the area receives only 1 percent to 2 percent of available sunlight. Liana, however, becomes rooted in the soil at ground level as a small shrub. The plant then uses the trees or other nearby vegetation to climb to the canopy, using its triangular leaves to cling to its host. Because the plants stay rooted in the ground, they take no resources from the trees except support.
One way to tell lianas apart from the trees and shrubs it grows on requires testing the stiffness of the plant's stems. While trees and shrubs feature flexible young twigs and branches as well as stiffer, older growth, liana grows differently. Its newest growth tends to be stiff while the old growth at the base of the stem tends to be more flexible.
The web of woody liana vines provides a variety of animals with mobility across the rain-forest canopy. Some animals, such as sloths and spider monkeys, rarely touch the ground, using lianas and other trees and plants to get them from one place to another. Lemurs also rely on trees with liana wrapped around them as preferred nesting sites.