Orchid flowers come in many shapes and colors. Their numerous fanciful names come from their resemblance to moths (Phalaenopsis), butterflies (Oncidium papilio), spiders (Arachnis), bees (Ophrys), slipper or moccasins(Paphiopedilum or cypripedium), or dancing ladies (Oncidium).
Orchid leaves are simple leaves with parallel veins. They are not made up of lobes or leaflets. The leaves may be terete (pencil-like), semi-terete, quarter-terete, strap-leaf or plicate, and are very variable in size. The structure of the leaves corresponds to the specific habitat of the plant.
Orchids that grow in sunlight or very dry area, have thick, leathery leaves and the laminas are covered by a waxy cuticle, to reduce water loss. Those grow on shady area have long, thin leaves.
Most plants have leaves that are thicker, smooth, and V-shaped in cross-section. These thick and fleshy leaves are called conduplicate. Some orchids have plicate leaves that are thin with many lengthwise pleats. A number of orchids have long, thin, cylindrical leaves (may be grooved) called terete.
The leaves of most orchids are perennial, and can last for a few years. Those with plicate leaves shed their leaves annually and develop new leaves together with new pseudobulbs.
The roots of epiphytic and climbing orchids are one of their most striking characteristics. The roots are roughly of the same diameter throughout their length, and there is no tap root. The exposed roots are covered in a silvery gray coat called velamen, which darken with age. The velamen is a spongy and absorbent layers of dead cells. The root tip is rather green and can photosynthesize. The root will attach to any suitable surface, such as a branch, and cannot be pulled away without damaging it. When the roots are no longer exposed, they become pale and swollen and are easily rot if they get water-logged.
Roots are important to epiphytic orchids, as these orchids grow high above ground and need a good support. The roots can travel a few meters along the branch.
There are several orchid species which are depending on their green roots to produce their food, as they are leafless. Their stems are merely stumps to hold the flowers.
Terrestrial and lithophytic orchids usually have hairy roots, and are more tolerant of damp conditions, but they still need good drainage.
Pseudobulbs are tough, swollen stems whose main functions are to store food and water for the orchid plants. Pseudobulbs come in all shapes and sizes. In horn Dendrobium, the pseudobulbs are long, vertical canes of up to 1.5 m long, and are dangling pendulous rods in the nobile Dendrobium. The pseudobulbs are round and fat in Epidendrum and Spathoglottis , and flat and wrinkled in the mature bulbs of Oncidium.
The pseudobulbs enables the orchid plants to withstand periods of drought. In some orchids, the pseudobulbs are buried deep in the ground and these plants are capable of surviving bush fires.