The roots of the orchid are different from those of other plants, consisting of a special sponge-like layer of tissues called velamen that covers up the true roots inside. This special sheathing acts as a moisture collecting device while protecting the roots underneath from direct sunlight. The orchid's green leaves play the actual role of food manufacturing. Orchids are epiphytes, that is the roots' main duty is to grasp and cling to other larger structures such as trees, without in any way harming or taking away food from the host, unlike a parasitic plant. Some orchids have roots that go into the ground like most other plants, while others even find unusual places to grow such as in the crevices of rocks on the side of a cliff.
Orchids are monocotyledonous plants and have two different types of growth structures.
The new shoots will collect and replenish the old ones with food, Orchids that grow in this fashion are, for instance, Dendrobiurn chrysotoxum , and so on. The flowers are what clearly distinguish one orchid from another. Some bear large flowers of bright hues, and some have smaller or even tiny little flowers of softer tones. They may flower singly or in small groups of two or three per stem. Others will bloom in a big cluster or a bunch with some standing up on an erect stem and yet others bending down in a flowing cluster.