Camellia (pronounced or ) is a genus of flowering plants in the family Theaceae. They are found in tropical and subtropical areas in eastern and southern Asia, from the Himalayas east to Japan and Indonesia. There are more than 220 described species; almost all are found in southern China and Indochina except species C. lanceolata which can be found in west of the Malesia region. Camellias are popular ornamental, tea, and woody-oil plants cultivated worldwide for centuries. Over 26,000 cultivars, with more than 51,000 cultivar names, including synonyms, have been registered or published. Of economic importance in East Asia, Southeast Asia, and the Indian subcontinent, leaves of C. sinensis are processed to create the popular beverage tea. The ornamental C. japonica, C. sasanqua and their hybrids are the source of hundreds of garden cultivars. C. oleifera produces tea seed oil, used in cooking and cosmetics.

Taxonomy

The genus was named by Linnaeus after the Jesuit botanist Georg Joseph Kamel, who worked in the Philippines and described one of its species (although Linnaeus did not refer to Kamel's account when discussing the genus).

Botany

Camellias are evergreen shrubs or small trees up to 20 m tall. Their leaves are alternately arranged, simple, thick, serrated, and usually glossy.

Flowers and fruit

Their flowers are usually large and conspicuous, one to 12 cm in diameter, with five to nine petals in naturally occurring species of camellias. The colors of the flowers vary from white through pink colors to red; truly yellow flowers are found only in South China and Vietnam. Tea varieties are always white-flowered. Camellia flowers throughout the genus are characterized by a dense bouquet of conspicuous yellow stamens, often contrasting with the petal colors. Some research has shown that the colour of petals in some species' flowers indicate their size and how they are pollinated; species with red or yellow flowers are pollinated by sunbirds whereas species with white flowers are smaller in diameter and are pollinated by bees. The fruit of camellia plants is a dry capsule, sometimes subdivided into up to five compartments. Each compartment contains up to eight seeds.

Growth

The various species of camellia plants are generally well-adapted to acid soils rich in humus, and most species do not grow well on chalky soil or other calcium-rich soils. Most species of camellias also require a large amount of water, either from natural rainfall or from irrigation, and the plants will not tolerate droughts. However, some of the more unusual camellias – typically species from karst soils in Vietnam – can grow without too much water. Camellia plants usually have a rapid growth rate. Typically, they will grow about 30 cm per year until mature – however, this varies depending on their variety and geographical location.

Ecology

Camellia plants are used as food plants by the larvae of some Lepidoptera species. Leaves of Camellia japonica are susceptible to the fungal parasite Mycelia sterile (see below for the significance), mycelia sterile PF1022 produces a metabolite named PF1022A that is used to produce emodepside, an anthelmintic drug. Due to habitat destruction, several camellias have become rare in their natural range. One of these is the aforementioned C. reticulata, grown commercially in thousands for horticulture and oil production but rare enough in its natural range to be considered a threatened species.

Use by humans

Camellia sinensis, the tea plant, is of major commercial importance because tea is made from its leaves. The species C. sinensis is the product of many generations of selective breeding to bring out desirable qualities for tea. However, many other camellias can be used to produce a similar beverage. For example, tea made from C. sasanqua leaves is popular in some parts of Japan. Seeds of C. oleifera, C. japonica, and, to a lesser extent, other species such as C. crapnelliana, C. reticulata, C. sasanqua and C. sinensis as well are pressed to make tea seed oil, a sweet seasoning and cooking oil special to East Asia. It is the most important cooking oil for hundreds of millions of people, particularly in southern China. Camellia oil is commonly used to clean and protect the blades of cutting instruments. Camellia oil pressed from seeds of C. japonica, also called tsubaki oil or tsubaki-abura (椿油) in Japanese, has been traditionally used in Japan for hair care. C. japonica plant is used to prepare traditional antiinflammatory medicines.

History

Fossil record

The earliest fossil record of Camellia are the leaves of †C. abensis from the upper Eocene of Japan, †C. abchasica from the lower Oligocene of Bulgaria and †C. multiforma from the lower Oligocene of Washington, United States.

Garden history

Camellias were cultivated in the gardens of China for centuries before they were seen in Europe. The German botanist Engelbert Kaempfer reported that the "Japan Rose", as he called it, grew wild in woodland and hedgerow, but that many superior varieties had been selected for gardens. Europeans' earliest views of camellias must have been their representations in Chinese painted wallpapers, where they were often represented growing in porcelain pots. The first living camellias seen in England were a single red and a single white, grown and flowered in his garden at Thorndon Hall, Essex, by Robert James, Lord Petre, among the keenest gardeners of his generation, in 1739. His gardener James Gordon was the first to introduce camellias to commerce, from the nurseries he established after Lord Petre's untimely death in 1743, at Mile End, Essex, near London. With the expansion of the tea trade in the later 18th century, new varieties began to be seen in England, imported through the British East India Company. The Company's John Slater was responsible for the first of the new camellias, double ones, in white and a striped red, imported in 1792. Further camellias imported in the East Indiamen were associated with the patrons whose gardeners grew them: a double red for Sir Robert Preston in 1794 and the pale pink named "Lady Hume's Blush" for Amelia, the lady of Sir Abraham Hume of Wormleybury, Hertfordshire (1806). The camellia was imported from England to America in 1797 when Colonel John Stevens brought the flower as part of an effort to grow attractions within Elysian Fields in Hoboken, New Jersey. By 1819, twenty-five camellias had bloomed in England; that year the first monograph appeared, Samuel Curtis's, A Monograph on the Genus Camellia, whose five handsome folio colored illustrations have usually been removed from the slender text and framed. Though they did not flower for over a decade, camellias that set seed rewarded their growers with a wealth of new varieties. By the 1840s, the camellia was at the height of its fashion as the luxury flower. The Parisian courtesan Marie Duplessis, who died young in 1847, inspired Dumas' La Dame aux camélias and Verdi's La Traviata. The fashionable imbricated formality of prized camellias was an element in their decline, replaced by the new hothouse orchid. Their revival after World War I as woodland shrubs for mild climates has been paralleled by the rise in popularity of Camellia sasanqua.

Modern cultivars

The tea camellia, C. sinensis, has been selected by many commercial cultivars for the taste of its leaves once processed into tea leaves. Today, camellias are grown as ornamental plants for their flowers; about 3,000 cultivars and hybrids have been selected, many with double or semi-double flowers. C. japonica is the most prominent species in cultivation, with over 2,000 named cultivars. Next are C. reticulata with over 400 named cultivars, and C. sasanqua with over 300 named cultivars. Popular hybrids include C. × hiemalis (C. japonica × C. sasanqua) and C. × williamsii (C. japonica × C. saluenensis). Some varieties can grow considerably, up to 100 m², though more compact cultivars are available. They are frequently planted in woodland settings alongside other calcifuges, such as rhododendrons. They are particularly associated with areas of high soil acidity, such as Cornwall and Devon in the UK. They are highly valued for their very early flowering, often among the first flowers to appear in the late winter. Late frosts can damage the flower buds, resulting in misshapen flowers. There is a great variety of flower forms:

AGM cultivars

The following hybrid cultivars have gained the Royal Horticultural Society's Award of Garden Merit:

Species

Plants of the World Online currently includes: synonym Camellia rusticana – snow camellia C. chrysantha, C. nitidissima – yellow camellia

Cultural significance

The Camellia family of plants in popular culture.