Epiphyte

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Near Orosí, Costa Rica

Epiphytes on a tree near Santa Elena in Costa Rica

An example of an epiphyte assemblage of orchids and bromeliads in a garden setting in Hawaii

A Epiphyte is any plant that grows upon or attached to another living plant. The term is from the Greek epi- (meaning 'upon') and phyton (meaning 'plant'). These plants are sometimes called "air plants" because they do not root in soil. However, there are many aquatic species of algae, including seaweeds, that are epiphytes on other aquatic plants (seaweeds or aquatic angiosperms).

Epiphytes usually derive only physical support and not nutrition from their host, though they may sometimes damage the host. Parasitic and semiparasitic plants growing on other plants (mistletoe is well known) are not epiphytes.

An epiphyte uses photosynthesis for energy and (where non-aquatic) obtains moisture from the air or from dampness (rain and cloud moisture) on the surface of its host. Roots may develop primarily for attachment, and specialized structures (for example, cups and scales) may be used to collect or hold moisture.

Epiphytes attached to their hosts high in the canopy have an advantage over herbs restricted to the ground where there is less light and herbivores may be more active.

Epiphytes are also important to certain animals that may live in their water reservoirs, such some types of frogs and arthropods.

The best-known epiphytes include mosses, lichens, orchids, and bromeliads (such as Spanish moss of the genus Tillandsia), but epiphytes may be found in every major group of the plant kingdom. Assemblages of large epiphytes occur most abundantly in moist tropical forests, but mosses and lichens occur as epiphytes in almost any environment with trees.

Some epiphytes are large trees that begin their lives high in the forest canopy. Over decades they send roots down the trunk of a host tree eventually overpowering and replaceing it. The Rata of New zealand is an example of this, epiphytes that end up as free standing trees are also called Hemiphytes.

In Europe there are no dedicated epiphytes using roots, although grass, small bushes or small trees may grow on the branches of other plants.

The first important monograph on epiphyte ecology was written by A.F.W. Schimper (Die epiphytische Vegetation Amerikas, 1888).

Epiphyte is one of the subdivisions of the Raunkiær system.