Epiphytes are the special kind of plants which do not grow on soil like the normal plants do. The term epiphyte comes from the Greek word ‘epi’ meaning ‘upon’ and ‘phyton’ meaning ‘plant’. Epiphytic plants are also termed “air plants” because they do not root in soil. These plants usually grow on other plants (trees) or sometimes on surfaces like walls and buildings. The epiphytes growing on other plants neither affect their host in a bad way (although their attachment roots and weight can slowly tumble them or cause other damage) nor do no derive their nutrition from them. They use their host for physical support only. Most commonly found epiphytes are mosses, ferns, cacti, orchids and bromeliads. Parasitic and semi-parasitic plants growing on other plants are not termed true epiphytes.
Most of the epiphytes are found in damp tropical areas like rainforests and temperate areas. Many types of mosses, liverworts, lichens, and algae are found in temperate zones while ferns, cacti, orchids, and bromeliads grow in tropics. About one third of all ferns and 70 percent of orchids are epiphytes. Epiphytes grow most readily in cracks, grooves, crannies, and pockets where organic debris collects, which helps them in initial growth. They grow high above the ground level, on tall trees, where it can receive better sunlight than the lower shady areas. They produce their own energy from photosynthesis and obtain moisture and nutrients from the air and organic debris accumulating around it.
These plants usually have feathery or dust-like seeds which can be easily dispersed by wind. Others bear edible fruits with seeds that are dispersed by birds and other tree-dwelling animals. They are very well adapted with specialized or modified structures to survive in harsh conditions. Plants like Orchids have roots with large surface area which facilitates faster and better absorption of water and nutrients. Their stems also have pseudobulbs which stores nutrients and water for drier periods. They produce very large number of tiny seeds with balloon-like seed coat which are dispersed over large areas by wind. This way they are well-adapted to canopy life.