Orchid stems are also specialized into what are called pseudobulbs. These are basically expanded stems that allow the plant to store excess water and food. The roots of epiphytic (tree-dwelling) orchids have a special outer layer of dead cells called velamen. Because orchids metabolize slowly in order to not outpace their resources, the roots also absorb slowly, meaning that they need help catching water as it passes by. The velamen cells catch and fill with water as it passes by so that the true root (the core of the root structure) has ample time to access as much water as it can. Velamen is silver-white in color, but becomes transparent when wet, so that when the root is wet it turns green as you are able to see through to the inner structures of the root that contain chlorophyll.
The underground tubers of terrestrial orchids [mainly Orchis mascula (early purple orchid)] are ground to a powder and used for cooking, such as in the hot beverage salep or in the Turkish frozen treat dondurma. The name salep has been claimed to come from the Arabic expression ḥasyu al-tha‘lab, "fox testicles", but it appears more likely the name comes directly from the Arabic name saḥlab. The similarity in appearance to testes naturally accounts for salep being considered an aphrodisiac.
The pseudobulb has a smooth surface with lengthwise grooves, and can have different shapes, often conical or oblong. Its size is very variable; in some small species of Bulbophyllum, it is no longer than two millimeters, while in the largest orchid in the world, Grammatophyllum speciosum (giant orchid), it can reach three meters. Some Dendrobium species have long, canelike pseudobulbs with short, rounded leaves over the whole length; some other orchids have hidden or extremely small pseudobulbs, completely included inside the leaves.
The other important use of orchids is their cultivation for the enjoyment of the flowers. Most cultivated orchids are tropical or subtropical, but quite a few that grow in colder climates can be found on the market. Temperate species available at nurseries include Ophrys apifera (bee orchid), Gymnadenia conopsea (fragrant orchid), Anacamptis pyramidalis (pyramidal orchid) and Dactylorhiza fuchsii (common spotted orchid).
These orchids can be planted in orchid bark, moss or a mix (mixes might include bark, small rocks, moss, sponge rock, and even cork). Don’t even think about planting them in the soil. If your orchid is planted in bark you’ll need to water it more often than if it’s planted in moss. The bark will help the water drain with ease where the moss will hold the moisture longer. I prefer the bark or mixes which are predominantly bark because the watering is much easier for me to get right.
The main characteristic of this type of orchid is its very pleasant aroma, which means you will likely smell it even before you see it. The pure white flowers release their scent at night, are frequent bloomers, and can bloom all year long in many places. They are a small but showy type of orchid, and their leaves are long, reed-like in shape, and light green in color. They are also easy to grow and are low-maintenance flowers.
If you just want a quick way to water your orchid without having to transplant the orchid, you can use the ice cube method. Put the equivalent of 1/4 cup (59 ml) of frozen water (usually about three medium ice cubes) on top of the potting mix. Make sure that the ice never comes in contact with the orchid itself - it should only touch the soil. Let the ice cubes melt into the pot. Wait about a week before you do it again. This method is not optimal for the long-term health of the orchid, so only use it as a temporary solution.[2]
Run the orchid under water. The easiest way to water an orchid is to hold it under a faucet and run it under room temperature water. If you have an attachment that allows you to diffuse the water, rather than just running it in one strong stream, that's better for the orchid. Water the orchid this way for a full minute, allowing the water to seep through the pot and come out the holes in the bottom.[3]

Water thoroughly. When you do water, do it like you mean it. Different growers have different rules, but many professional growers turn on their sprinklers for 8 or more minutes. Successful home-growers sometimes dunk their plants, pots and all, into a bucket or sink of water. Some varieties, such as vandas, can be left floating in water for a surprisingly long time. The idea is to make sure the velamen is completely saturated. You want tiny droplets hanging on the roots after watering. This means the plant is completely hydrated.

The orchid plant is also unique in its morphology (form or structure). We can begin with the leaves and work our way down to the roots. The leaves of many orchids in cultivation are unique in that they are specifically designed for water conservation (as is true for almost every orchid structure). They have a heavy waxy leaf coating and specialized stomata (openings through which the leaf “breathes”) that help to prevent water loss during transpiration (the act of the plant “breathing”). Many orchids utilize CAM photosynthesis as well, which in essence means that the plants collect materials during the day and then process them at night.
In the wild, Phalaenopsis are epiphytes and grow on trees in a constantly moist environment. They usually have long flower spikes and therefore look very graceful. These types of flowers have the power to add elegance to the home and brighten up a dull atmosphere, even if your boyfriend leaves his socks on the floor. Phalaenopsis are now widely grown as houseplants. Even though they usually bloom only once or twice a year, their flowers can often last for two to three months. Learn more about Phalaenopsis orchids.

With over 300 species, this type of orchid is well-known but not as common as people think, in part because only a few of the species consist of showy flowers that catch people’s attention. The ones that do, however, come in colors such as yellow with white tips and dark red edges, or dark red with wide white stripes. They contain three separate lobes and beautiful, narrow leaves that perfectly complement the petals.
The Bulbophyllum orchid genus is the largest in the Orchidaceae family, with over 1800 species, making it the third largest genus of plants. (Taxonomists will probably eventually split it into several smaller genera, but with so many types of orchids it's a massive undertaking!) They differ widely in appearance, but all have a single leaf emerging from the top of the pseudobulb, flower stems coming from the bottom of the pseudobulb, and a hinged lip designed to tip insects against the column. Many are pollinated by flies, and stink like dung or rotting carcasses, which is a great conversation starter and gives you bragging rights for putting up with it! (They don't all stink, fortunately.) The rhizomes wander all over the place and often branch freely, so it's easy to grow an impressive specimen.
The term "botanical orchid" loosely denotes those small-flowered, tropical orchids belonging to several genera that do not fit into the "florist" orchid category. A few of these genera contain enormous numbers of species. Some, such as Pleurothallis and Bulbophyllum, contain approximately 1700 and 2000 species, respectively, and are often extremely vegetatively diverse. The primary use of the term is among orchid hobbyists wishing to describe unusual species they grow, though it is also used to distinguish naturally occurring orchid species from horticulturally created hybrids.
Oncidium, perhaps more accurately the oncidium alliance, are a group of plants from South America that span a wide range of habitats. Inside the oncidium alliance there are a number of genera that hybridize freely to create what we call intergeneric oncidium hybrids. These can come in all sorts of shapes and sizes but are generally characterized by large quantities of small to medium flowers borne on a branched stem that generally forms a Christmas-tree shape. The most commonly identified Oncidium are the yellow “dancing lady” type.
Epiphytic orchids, those that grow upon a support, have modified aerial roots that can sometimes be a few meters long. In the older parts of the roots, a modified spongy epidermis, called a velamen, has the function of absorbing humidity. It is made of dead cells and can have a silvery-grey, white or brown appearance. In some orchids, the velamen includes spongy and fibrous bodies near the passage cells, called tilosomes. 

Orchids are an incredibly unique and fascinating group of plants. Many people can identify a Phalaenopsis (moth orchid) or Cattleya (the old corsage orchids), but the question often is asked, “What makes an orchid an orchid?” Orchids have some morphological (physical) traits that make them stand out from other plant families. In orchids, many of their floral parts come in groups of three. There are three sepals, which are the outer petals; these are what you see when you look at an unopened bud. There are also three petals, but in orchids one of the petals has been specialized into a labellum, or lip. This is usually the bottommost petal, and it helps to attract the pollinator to the reproductive organ. In orchids the reproductive organ, known as the column, combines both the male and female parts in one structure.