common name for the family Theaceae, comprising a group of mostly woody flowering plants, and for one of its genera, CAMELLIA, (q.v.). The family, which contains about 600 species placed in 28 genera, is distributed through tropical and subtropical areas, but most species occur in eastern Asia and South America. Horticulturally important members of the family include Camellia (especially C. japonica), Gordonia, and Stewartia.

The tea family is a member of the order Theales, comprising nearly 3500 species placed in 18 families. SAINT-JOHN'S-WORT, (q.v.), Hypericum, is in the family Clusiaceae, as are the fruits mammee apple, Mammea americana, and the MANGOSTEEN, (q.v.), Garcinia mangostana. The KIWI FRUIT, (q.v.), Actinidia chinensis, is a member of the family Actinidiaceae. Other families of the order are important sources of timber.

Characteristics of the Order.

The order Theales is primarily tropical in distribution, centered in southeastern Asia, with few temperate members. Most members are evergreen trees with broad, simple, resin-containing leaves, although a few climbers and herbs occur. The flowers usually have four or five free, or unfused, sepals (outer flower whorls) and petals (inner floral whorls) and are radially symmetrical. The numerous stamens (male floral organs) are fused either into a ring, as in Camellia, or into distinct bundles, as in Saint-John's-wort. When the stamens are united into a ring, the petals are often joined to the ring, as in Camellia. The ovary (female floral organ) is superior; that is, the sepals, petals, and stamens are produced from its base.

The most important source of timber in the order is the family Dipterocarpaceae, which dominates the rain forests of Malaysia and is also a source of useful resins. This family contains more than 500 species. Members of the family produce a characteristic two-winged fruit, which is distributed by the wind; the wings are formed by persistent sepals.

Plants in the order Theales are members of the class Magnoliopsida (see DICOTS,) in the division Magnoliophyta (see ANGIOSPERM

The Beverage.

The tea plant itself is C. sinensis, a native of Southeast Asia. The tea brewed from the dried leaves of this plant has been drunk in China since perhaps the 28th century bc and certainly since the 10th century bc, from which time written records of its use survive. It was first brought to Europe by the Dutch in the early 17th century ad. Introduced into Britain in 1657, it quickly overtook coffee to become the principal beverage of the British Isles. Tea was introduced to North America by early settlers but was heavily taxed by the British, eventually resulting in the well-known Boston Tea Party of 1773; it has never competed successfully with coffee as the staple beverage in the U.S. Tea is drunk by about half of the world's population.

Leaf buds and young leaves are used in making tea, the age of the leaves determining the taste and name of the particular commercial variety. Thus, orange pekoe is made from the youngest leaves, and souchong from the fourth leaves. After picking, the leaves either are dried immediately and completely to produce green teas, such as pan-fired, basket-fired, hyson, and gunpowder, or are partially dried and then allowed to ferment to produce various kinds of black teas, such as orange pekoe, pekoe, congou, and souchong. Oolong tea is partially fired and then steamed, thus being intermediate between green and black teas. After being sorted, all grades of tea are packed in foil-lined chests to prevent the absorption of unpleasant odors or the loss of aroma during shipment. In China, tea is sometimes allowed to absorb the scent from various flowers; JASMINE (q.v.) is a particular favorite.

Tea is an aromatic stimulant, containing various polyphenols, essential oils, and caffeine. The concentration of caffeine in tea ranges from 2.5 to 4.5 percent, as contrasted to an average concentration of about 1.5 percent in coffee.

Pests.

The tea plant is attacked by several injurious insects, the most important of which is the fagot worm. The tea borer, which is the larva of a cossid moth, Zeuzera coffeae, attacks the stems and branches of the tea plant. Several species of scale insects (see SCALE INSECT,) in Aspidiotus, the genus containing the San Jose scale, attack the tea plant; A. theae is especially destructive to the young plant. Several mites (see MITE,) also feed on it, including a red spider, Tetranychus bimaculatus, and the yellow tea mite, Acarus translucens, which destroys the buds.

Production.

World production of tea exceeded 2.6 million metric tons annually in the mid-1990s. The principal tea-growing countries were India, China, Kenya, and Sri Lanka.        M.R.C., MARSHALL R. CROSBY, Ph.D.

For further information on this topic, see the Bibliography, sections 452. Plants, 592. Horticulture.