The orchid family consists of a large number of genera, each with its own unique characteristics. A common characteristic, however, is the basic form of the flower, which consists of three petals surrounded by three sepals -- often in dramatic and contrasting colors and in a variety of shapes and sizes. Although some orchids are native to temperate zones, most orchids tend to prefer a semi-tropical or tropical environment (USDA Zones 9-11) and have epiphytic roots -- meaning they derive moisture and nutrients from the air and support from another plant; few orchids grow in soil. Orchids usually prefer a diurnal temperature fluctuation -- meaning warmer days and cooler nights -- though the absolute temperature range (cool, intermediate or warm) varies by genus and is consistent with their natural habitat. While requiring adequate sunlight for a stunning bloom display, most orchids will not tolerate sustained direct sun.
Many varieties have pseudobulbs, a portion of the stem between leaf nodes that stores water to help sustain the plant through dry periods. Other varieties are monopodial, meaning upward growth is from a single growing point.
There is an exception to almost every general statement one can make about orchids. The family continues to challenge taxonomists.