Another way to classify orchids on growth types is ... Epiphytes, Lithophytes and Terrestrials ...
Epiphytes: Orchids which grow in trees are Epiphytes ... The term comes from the Greek words, ipe [meaning on] and phyte [a plant]... Examples Cattleya, Phalaenopsis and Brassia.
Lithophytes: There are also many orchids which do not grow on trees at all, but only on specific kinds of rocks. These plants are called Lithophytes. The term comes from the Greek words, litho [ meaning stone] and phyte [a plant] ... Examples Sophronitis.
Terrestrial: The last major group of orchids are referred to as Terrestrials because they grow in the ground. However, they do not grow in the same soil that most of us understand as potting soil. They grow in humus or leaf litter accumulated on a forest floor. This humus is an extremely open and porous medium which can be duplicated with a fine bark mix in cultivation. Examples Cymbidiums, Papliopedilum.