The family Orchidaceae, popularly known as orchids, are perennial herbs that are found on every continent in the world except Antarctica. Orchids are monocotyledons which evolved from primitive monocots that also gave rise to lilies and amaryllis. As orchids developed, they became a very large family of about 650 genera and perhaps 20,000 or more species, more than any other family of plants. They mate across species easily, and there are probably 200,000 or more hybrids in existence today. Orchid species might be terrestrial (growing in earth), epiphytic (growing on another living plant), or less commonly saprophytic (subsisting on decomposing material). They tend to be epiphytes in tropical and subtropical forests, terrestrial in temperate and arctic regions. Although orchids are not a food crop, one Central American orchid yields the fragrant and delicious vanilla bean.
Orchid stamens and pistils are fused together into one structure, and the plants are prized for the resulting beautiful flowers. Typically, these flowers have three petals and three petal-like sepals, the middle one of which (the lip or labellum) is swollen and covered with pollen to attract insects. Apparently orchid flowers, which vary widely in shape and size, are specialized to attract local insects; for example, the huge African waxflower, which has a labellum over a foot long, is pollinated by a moth with an equally long tongue. These specific adaptations help explain the wide variation in orchid flowers.
Of the many many species of orchids, cultivators focus on a mere handful, and they tend to be hybrids of tropical epiphytes. Although orchids have a reputation as being difficult to grow, most people could cultivate at least one type, for there is such variation in ideal conditions that one is bound to suit your home environment. In general, epiphytic orchids prefer conditions that mimic their home environment on branches near the tops of tropical canopies: gently moving, rather than stagnant, air; shaded light rather than glaring sun; a porous, organic growth medium; and daily misting with pure water - distilled or pure rainwater is best. Beyond this, they are a varied lot, and some like cool temperatures, some warm; most prefer humid air, but some tolerate dry. Provided that the orchid is in its ideal conditions, it should grow easily, but what exactly those conditions are for each species is best found out by conferring with an orchid afficionado. Because orchid growers tend to become quite passionate about their hobby, it shouldn't be too difficult to find them in your area and pump them for information. Or check out one of the many orchid lovers' websites, including:
http://www.orchidweb.com/index.asp
http://www.canadianorchidcongress.ca/
http://www.orchid.org.uk/contents.htm