Epiphytes are a group of plants that do not grow in the soil. Instead, they use trees and other large plants for support, so that they can reach the light in their normal habitat - rain forests and the like.
A range of popular plants, such as many orchids are true epiphytes as are the popular 'air plants', Urn Plants and other Bromeliads. Many ferns and mosses are also epiphytic.
They do not normally harm their host plants - simply hitch a lift to somewhere they can get to the light.
Habitat Most epiphytic plants live in rain forest habitats or similar, where the humidity levels are high, and the light at ground level is low. A quick look at any Epiphyte will show you that it is not capable of growing to the great height needed in rain forest conditions to reach the life-giving light source.
However, most areas of the world have areas that are suitable habitat for a wide range of epiphytic plants. Here in the UK for instance, such woodlands exist in areas - particularly to the west - such as South Wales and even Cornwall. These areas have high annual rainfall, and are home to numerous ferns and mosses, which attach themselves to trees in order to take themselves further up the 'light chain'!
The image below, shows a group of Epiphytic ferns and mosses on trees in a cloud forest range.
Some epiphytic plants use their climbing skills to clamber up tall trees. Vines and 'climbers' such as many of the Philodendrons anchor themselves to the soil at the base of a tree, then clamber up through the branches to the all important light source.
Water and food collection by Epiphytes
Most Epiphytes collect rainwater by channelling the falling water into tightly arranged whorls of leaves which then 'guide' the water down into a tight basal 'water' tank' of leaves at their base. Typical are the urn plants, but many other epiphytic plants will also be seen to do the same by their leaf formation - orchids, upon close inspection, will be seen to channel falling rain in to the base of their stems and hence into a tangles group of aerial roots. This tangles root system will also collect falling debris from their host tree. This in turn, rots down and provides the plant with all important nutrition.
The aerial roots on many Epiphytes are capable of absorbing water from the damp atmosphere. Some Epiphytes will also have swollen bulb-like stems in which they can store the water.
Water collected in the 'reservoir' of the Urn Plants - Aechmeas other Bromeliads - soon becomes a nitrogen-rich food store as insects and other dust debris are washed down and eventually decompose - releasing the store of 'liquid fertilizer ' to the plant as and when it requires it.
Clever things these Epiphytes!