In general, orchids are divided into categories which are based on their different growth habits. Three common categories of orchids are 1) Epiphytes, 2) Lithophytes and 3) Terrestrials.
EPIPHYTES
Epiphytes are typically considered “air plants” or plants that attach themselves to other plants or trees, or rocks, etc. Epiphyte Orchids specifically, are orchids that have been able to adapt to the tropical climates by clinging to tree limbs and branches so that they may expose themselves to light and air. The name Epiphytes is derived from the term epi which means on or above and phyte which means plant. Contrary to modern discussions, orchids are not necessarily parasitic just because they grow on tree limbs and branches. Epiphytes usually have roots which dangle in the air and can sometimes be up to a few meters long. These roots have a spongy white layer of cells called velamen which protect the inner tissues of the roots and also aids in the absorption of water. Epiphytic orchids usually get nutrients from mineral dust, animal droppings and other collected humus on the surface to which they cling. Many Cattleya and the popular Phaleonopsis orchids are considered epiphytic orchids.
LITHOPHYTES
Lithophytes are generally considered plants that grow on rocks. Lithophyte orchids that are mainly located in the tropical regions of the world. You may find them covering the trunks of trees or in cracks and crannys in mossy rocks. The orchids get nutrition from the moss and absorb as much as they can. They also get nutrition from humus and eroded soil that may cover the rocks and trunks of trees. Part of the LIthophyte called a pseudobulb is used for storage of nutrients so that they may survive in extended dry periods. A pseudobulb The lithophyte also uses its thick green leaves to store nutrients for later use in dry periods.
TERRESTRIALS
Terrestrial means that which grows in the ground. Terrestrial Orchids may be found in a larger variety of climates including cooler and warmer tropical areas. Terrestrial orchids grow in the ground and thrive in the soil. Most of these types of orchids have a symbiotic relationship with a special type of fungus that invades the cells in the outer layers of the roots and provide the orchid with the nutrients it needs to survive and aids in seed germination. Without this fungus many terrestrial orchids would not survive. This symbiotic relationship between the fungus and the orchid is call mycorrhiza. Many Cymbidiums orchids are considered terrestrial orchids.
Very interesting. I’m getting into orchids and I love your website. Thanks for the great information.