One adaption in orchids can be found among the epidendrums. The species E. falcatum retains all its weight in the thick, heavy leaves. The root system is not numerous, but s-ong enough to hold a heavy plant firmly in its place on a tree. The pseudobulbs are merely short stems which support the long, spears-lriaped leaves which, rough and hard, will withstand a harsh environment. They are the main source of food supply for the plant.
Only occasionally is a single old leaf shed, their lifespan being for many years. The plant grows from a downward-creeping rhizome and the large green flower emerges from inside the base of the leaf. In cultivation the pendent habit should be retained and regular spraying essential.
All orchids produce roots. There are basically two kinds: aerial and underground. The root structure of orchids is peculiar to them, and all their roots are of a uniform thickness which does not increase with age. The roots will branch, in some species freely. All consist of a central wiry thread which is surrounded by the fleshy, moisture- retaining, part which in turn is coated by the white papery covering, the velamen, which grows as the root extends, leaving only the green growing tip exposed.
Epiphytic sympodial orchids produce their roots from the base of the leading growth at some stage during the young growth's development, and will give it a tremendous boost with a fresh food supply.
In cultivation these roots can he aerial or underground depending upon the angle at which they are produced. Some may grow horizontally and remain as aerial roots until they come into contact with compost when they will grow into it to become terrestrial.
A small group of orchids consist merely of a small crown from which bursts a mass of tangled roots. These species, among them the genus Microcoelia, have roots which produce chlorophyll.