Epiphyte

symbiosis

epiphyte, also called air plant, any plant that grows upon another plant or object merely for physical support. Epiphytes have no attachment to the ground or other obvious nutrient source and are not parasitic on the supporting plants. Most epiphytes are found in moist tropical areas, where their ability to grow above ground level provides access to sunlight in dense shaded forests and exploits the nutrients available from leaf and other organic debris that collects high in the tree canopy. The majority of epiphytic plants are angiosperms (flowering plants); they include many species of orchids, tillandsias, and other members of the pineapple family (Bromeliaceae). Mosses, ferns, and liverworts are also common epiphytes and are found in both tropical and temperate regions. While epiphytes are uncommon in arid environments, ball moss (Tillandsia recurvata) is a notable exception and can be found in coastal deserts in Mexico, where it receives moisture from marine fog.

Epiphytes obtain water from rain and water vapour in the air; most absorb water with their roots, though many have specialized leaves that also take in moisture. While some minerals are obtained directly from rain, nutrients are generally absorbed from the debris that collects on the supporting plants. Given their narrow habitat requirements, many epiphytes rely on wind for seed dispersal and have feathery or dustlike seeds. Animal dispersal is also common, and a number of species have edible fruits with seeds that are dispersed by birds and other tree-dwelling animals.