Orchid, a large family of perennial flowering herbs. Orchids are noted for their beautiful, showy blossoms and for their fragrance. Orchids grow in temperate and tropical regions. Many tropical forms are raised in temperate areas indoors and in greenhouses by orchid fanciers and commercial florists. Many species of orchids—both tropical and temperate—are endangered due to destruction of their habitats.

Orchids have thick, leathery or fleshy leaves. The flowers consist of three sepals and three petals occurring in spikes or branched clusters. One of the petals and one of the sepals usually differ in size, shape, and color from the other two petals and sepals; some are modified into curved spurs or sacs.

Most orchids are pollinated by insects. Frequently, one species of orchid is pollinated by only one species of insect. Many orchid flowers are shaped in such a way that the insects they attract enter the flower in one place and leave by another. The insect is usually attracted by nectar. Some orchids are pollinated by hummingbirds; others are self-pollinated.

An orchid produces thousands of tiny seeds in a capsule below the flower on the flower stalk. The seeds are dispersed by the wind and will not germinate unless they are infected by a fungus. It is not known how the fungus causes the seed to germinate, but each species of orchid is known to require a specific fungus. Orchids are attacked by a few fungus, bacterial, and viral diseases. Snails and flies occasionally damage greenhouse orchids.

Indoor orchid culture is both a business and a hobby. Orchids are raised for sale as corsages and decorative plants. Many persons have successfully raised tropical orchids on window sills of their homes. Some species of orchids can be grown in outdoor gardens. The orchid of most economic importance is the vanilla orchid, the source of vanilla extract.

Types of Orchids
Temperate,

or Hardy, Orchids grow primarily in the north temperate zone. They do best in acid soil, and are usually found in bogs or shaded woodlands. A common genus of temperate orchids is Orchis. The showy orchis is an eastern North American species in this genus. It has 2 to 15 white and lavender flowers on a short stalk that grows between two large, glossy leaves. Each flower is one inch (2.5 cm) long. Other temperate orchids include ladies' tresses; lady's slippers; the dragon's mouth, or arethusa; and the rose pogonia, or snakemouth.

Tropical Orchids

come primarily from the Asian and American tropics. Most of them are epiphytes; that is, they grow on other plants or on rocks, and obtain water from moisture in the air and nutrients from leaves and other organic debris that fall on them. The plants and rocks on which they grow are not a source of nourishment but only support the orchids. These orchids have developed special roots that absorb water from the air, as well as food- and water-storing stems called pseudobulbs.

The most popular of the tropical orchids sold by florists is the large, rose-lilac-colored Cattleya labiata. The large and showy flowers of the genus Cattleya characteristically have a tubular central petal with a flared rim. Native to mountainous areas in the American tropics, they require warm, bright, and humid growing conditions.

Another popular genus, Oncidium, produces drooping clusters of white, yellow, or brown flowers. These plants also come from the American tropics. They have flowers with a wide variety of shapes. One oncidium, the butterfly orchid (so called for the shape of its petals), has striped petals that are yellow and brown, and leaves that are mottled with purple.

Orchids make up the family Orchidaceae. There are between 20,000 and 30,000 species. The showy orchis is Orchis spectabilis. Ladies' tresses make up the genus Spiranthes; lady's slippers, the genus Cypripedium. The dragon's mouth is Arethus bulbosa; rose pogonia, Pogonia ophioglossoides. The butterfly orchid is Oncidium papilio.