''Camellia sinensis'' is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of evergreen

shrub A shrub or bush is a small to medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees by their multiple ...

or small

tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, e.g., including only woody plants with secondary growth, only ...

in the

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

family

Theaceae Theaceae (), the tea family, is a family of flowering plants comprising shrubs and trees, including the economically important tea plant, and the ornamental camellias. It can be described as having from seven to 40 genera, depending on the sour ...

. Its leaves, leaf buds, and stems can be used to produce

tea Tea is an aromatic beverage prepared by pouring hot or boiling water over cured or fresh leaves of '' Camellia sinensis'', an evergreen shrub native to East Asia which probably originated in the borderlands of south-western China and nor ...

. Common names include tea plant, tea shrub, and tea tree (unrelated to '' Melaleuca alternifolia'', the source of

tea tree oil Tea tree oil, also known as melaleuca oil, is an essential oil with a fresh, camphoraceous odour and a colour that ranges from pale yellow to nearly colourless and clear. It is derived from the leaves of the tea tree, '' Melaleuca alternif ...

, or the genus ''

Leptospermum ''Leptospermum'' is a genus of shrubs and small trees in the myrtle family Myrtaceae commonly known as tea trees, although this name is sometimes also used for some species of ''Melaleuca''. Most species are endemic to Australia, with the greate ...

'' commonly called tea tree).

White tea White tea may refer to one of several styles of tea which generally feature young or minimally processed leaves of the ''Camellia sinensis'' plant. Currently there is no generally accepted definition of white tea and very little international ...

, yellow tea,

green tea Green tea is a type of tea made from the leaves and buds of the '' Camellia sinensis'' that have not undergone the withering and oxidation process that creates oolong teas and black teas. Green tea originated in China in the late 1st millenn ...

oolong Oolong or Wulong (, ; ; , "black dragon" tea) is a traditional semi-oxidized Chinese tea (''Camellia sinensis)'' produced through a process that includes withering the leaves under strong sun and allowing some Enzymatic oxidation, oxidation to ...

, dark tea (which includes pu-erh tea) and

black tea Black tea (also literally translated as red tea from various East Asian languages) is a type of tea that is more tea processing, oxidized than oolong, yellow tea, yellow, white tea, white, and green tea, green teas. Black tea is generally st ...

are all harvested from two of the five varieties which form the main crops now grown, ''C. sinensis'' var. ''sinensis'' and ''C. s.'' var. ''assamica'', but are processed differently to attain varying levels of

oxidation Redox ( , , reduction–oxidation or oxidation–reduction) is a type of chemical reaction in which the oxidation states of the reactants change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is ...

with black tea being the most oxidized and white being the least. Kukicha (

twig A twig is a thin, often short, branch of a tree or Bush (plant), bush. The buds on the twig are an important diagnostic characteristic, as are the abscission scars where the leaves have fallen away. The color, texture, and patterning of the t ...

tea) is also harvested from ''C. sinensis'', but uses twigs and stems rather than leaves.

Description

''Camellia sinensis'' is native to

East Asia East Asia is a geocultural region of Asia. It includes China, Japan, Mongolia, North Korea, South Korea, and Taiwan, plus two special administrative regions of China, Hong Kong and Macau. The economies of Economy of China, China, Economy of Ja ...

, the

Indian Subcontinent The Indian subcontinent is a physiographic region of Asia below the Himalayas which projects into the Indian Ocean between the Bay of Bengal to the east and the Arabian Sea to the west. It is now divided between Bangladesh, India, and Pakista ...

, and

Southeast Asia Southeast Asia is the geographical United Nations geoscheme for Asia#South-eastern Asia, southeastern region of Asia, consisting of the regions that are situated south of China, east of the Indian subcontinent, and northwest of the Mainland Au ...

, but it is today cultivated all around the world in tropical and subtropical regions. It is an evergreen

or small

that is usually trimmed to below when cultivated for its leaves. It has a strong

taproot A taproot is a large, central, and dominant root from which other roots sprout laterally. Typically a taproot is somewhat straight and very thick, is tapering in shape, and grows directly downward. In some plants, such as the carrot, the taproot ...

. The flowers are yellow-white, in diameter, with seven or eight petals. Flower of Tea plant

The seeds of ''C. sinensis'' and '' C. oleifera'' can be pressed to yield tea oil, a sweetish seasoning and cooking oil that should not be confused with

, an

essential oil An essential oil is a concentrated hydrophobic liquid containing volatile (easily evaporated at normal temperatures) chemical compounds from plants. Essential oils are also known as volatile oils, ethereal oils, aetheroleum, or simply as the ...

that is used for medical and cosmetic purposes, and originates from the leaves of a different plant. The leaves are long and broad. Fresh leaves contain about 4%

caffeine Caffeine is a central nervous system (CNS) stimulant of the methylxanthine chemical classification, class and is the most commonly consumed Psychoactive drug, psychoactive substance globally. It is mainly used for its eugeroic (wakefulness pr ...

, as well as related compounds including

theobromine Theobromine, also known as xantheose, is the principal alkaloid of ''Theobroma cacao'' (cacao plant). Theobromine is slightly water-soluble (330 mg/L) with a bitter taste. In industry, theobromine is used as an additive and precursor to ...

. The young, light-green leaves are preferably harvested for tea production when they have short, white hairs on the underside. Older leaves are deeper green. Different leaf ages produce differing tea qualities, since their chemical compositions are different. Usually, the tip (bud) and the first two to three leaves are harvested for processing. This hand picking is repeated every one to two weeks. In 2017, Chinese scientists sequenced the genome of ''C. s.'' var. ''assamica''. It contains about three billion base pairs, which was larger than most plants previously sequenced.

Taxonomy

Linnaeus did not consider this plant a ''Camellia'' but placed it in a separate genus ''Thea''. Then in 1818, Robert Sweet merged the two genera, selecting ''Camellia'' for the merged genus, and shifted all the former ''Thea'' species to that genus. The name ''sinensis'' means "from China" in

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

. The generic name ''Camellia'' is taken from the Latinized name of Rev. Georg Kamel, SJ (1661–1706), a

Moravia Moravia ( ; ) is a historical region in the eastern Czech Republic, roughly encompassing its territory within the Danube River's drainage basin. It is one of three historical Czech lands, with Bohemia and Czech Silesia. The medieval and early ...

n-born

Jesuit The Society of Jesus (; abbreviation: S.J. or SJ), also known as the Jesuit Order or the Jesuits ( ; ), is a religious order (Catholic), religious order of clerics regular of pontifical right for men in the Catholic Church headquartered in Rom ...

lay brother, pharmacist, and missionary to the

Philippines The Philippines, officially the Republic of the Philippines, is an Archipelagic state, archipelagic country in Southeast Asia. Located in the western Pacific Ocean, it consists of List of islands of the Philippines, 7,641 islands, with a tot ...

. Five varieties of ''Camellia sinensis'' are accepted: The Cambodia type tea ("''C. assamica'' subsp. ''lasiocalyx''") was originally considered a type of Assam tea. However, later genetic work showed that it is a hybrid between Chinese small leaf tea and Assam tea. Tea plants are native to East Asia, and probably originated in the borderlands of north Burma and southwestern China. * Chinese (small leaf) tea 'C. sinensis'' var. ''sinensis''* Chinese Western Yunnan Assam (large leaf) tea 'C. sinensis'' var. ''assamica''* Indian Assam (large leaf) tea 'C. sinensis'' var. ''assamica''* Chinese Southern Yunnan Assam (large leaf) tea 'C. sinensis'' var. ''assamica'' Chinese (small leaf) tea may have originated in southern China possibly with hybridization of unknown wild tea relatives. However, since no wild populations of this tea are known, the precise location of its origin is speculative. Given their genetic differences forming distinct

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

s, Chinese Assam type tea (''C. s.'' var. ''assamica'') may have two different parentages – one being found in southern

Yunnan Yunnan; is an inland Provinces of China, province in Southwestern China. The province spans approximately and has a population of 47.2 million (as of 2020). The capital of the province is Kunming. The province borders the Chinese provinces ...

(

Xishuangbanna Xishuangbanna, sometimes shortened to Banna, is one of the eight autonomous prefectures of Yunnan Province. The autonomous prefecture for Dai people is in the extreme south of Yunnan province, China, bordering both Myanmar and Laos. Xishuangbanna ...

, Pu'er City) and the other in western Yunnan ( Lincang, Baoshan). Many types of Southern Yunnan Assam tea have been hybridized with the closely related species ''

Camellia taliensis ''Camellia taliensis'' (also known as Yunnan large leaf varietal tea, wild tea, Dali tea, Yunnan broad tea, Fried egg plant and others; 大理茶) is a small species of evergreen shrub whose leaves and leaf buds are used to produce tea. It is o ...

''. Unlike Southern Yunnan Assam tea, Western Yunnan Assam tea shares many genetic similarities with Indian Assam type tea (also ''C. s.'' var. ''assamica''). Thus, Western Yunnan Assam tea and Indian Assam tea both may have originated from the same parent plant in the area where southwestern China, Indo-Burma, and Tibet meet. However, as the Indian Assam tea shares no

haplotype A haplotype (haploid genotype) is a group of alleles in an organism that are inherited together from a single parent. Many organisms contain genetic material (DNA) which is inherited from two parents. Normally these organisms have their DNA orga ...

s with Western Yunnan Assam tea, Indian Assam tea is likely to have originated from an independent domestication. Some Indian Assam tea appears to have hybridized with the species '' Camellia pubicosta''. Assuming a generation of 12 years, Chinese small leaf tea is estimated to have diverged from Assam tea around 22,000 years ago; this divergence would correspond to the last glacial maximum, while Chinese Assam tea and Indian Assam tea diverged 2,800 years ago. Chinese small leaf type tea was introduced into India in 1836 by the British and some Indian Assam type tea (e.g. Darjeeling tea) appear to be genetic hybrids of Chinese small leaf type tea, native Indian Assam, and possibly also closely related wild tea species.

Cultivars

Hundreds, if not thousands of

cultivar A cultivar is a kind of Horticulture, cultivated plant that people have selected for desired phenotypic trait, traits and which retains those traits when Plant propagation, propagated. Methods used to propagate cultivars include division, root a ...

s of ''C. sinensis'' are known. Some Japanese cultivars include: * Benifuuki * Fushun * Kanayamidori * Meiryoku * Saemidori * Okumidori * Yabukita

Cultivation

''Camellia sinensis'' is mainly cultivated in tropical and subtropical climates, in areas with at least 127 cm (50 in) of rainfall a year. Tea plants prefer a rich and moist growing location in full to part sun, and can be grown in

hardiness zone A hardiness zone is a geographic area defined as having a certain average annual minimum temperature, a factor relevant to the survival of many plants. In some systems other statistics are included in the calculations. The original and most widely ...

s 7–9. However, species is commercially cultivated from the equator to as far north as

Scotland Scotland is a Countries of the United Kingdom, country that is part of the United Kingdom. It contains nearly one-third of the United Kingdom's land area, consisting of the northern part of the island of Great Britain and more than 790 adjac ...

, with the northernmost tea plantation at 59°N latitude on Shapinsay in the

Orkney Orkney (), also known as the Orkney Islands, is an archipelago off the north coast of mainland Scotland. The plural name the Orkneys is also sometimes used, but locals now consider it outdated. Part of the Northern Isles along with Shetland, ...

Islands. Many high quality teas are grown at high elevations, up to , as the plants grow more slowly and acquire more flavour. Tea plants will grow into a tree if left undisturbed, but cultivated plants are pruned to waist height for ease of plucking. Two principal varieties are used, the small-leaved Chinese variety plant (''C. s.'' var. ''sinensis'') and the large-leaved Assamese plant (''C. s.'' var. ''assamica''), used mainly for black tea. Tea trees can remain productive for many years.

Chinese teas

The Chinese plant is a small-leafed bush with multiple stems that reaches a height of some . It is native to southeast China. The first tea plant variety to be discovered, recorded, and used to produce tea dates back 3,000 years ago; it yields some of the most popular teas. ''C. s.'' var. ''waldenae'' was considered a different species, ''C. waldenae'' by SY Hu, but it was later identified as a variety of ''C. sinensis''. This variety is commonly called Waldenae Camellia; it is grown on Sunset Peak and Tai Mo Shan in

Hong Kong Hong Kong)., Legally Hong Kong, China in international treaties and organizations. is a special administrative region of China. With 7.5 million residents in a territory, Hong Kong is the fourth most densely populated region in the wor ...

, and also occurs in

Guangxi Guangxi,; officially the Guangxi Zhuang Autonomous Region, is an Autonomous regions of China, autonomous region of the China, People's Republic of China, located in South China and bordering Vietnam (Hà Giang Province, Hà Giang, Cao Bằn ...

province.

Indian teas

Three main kinds of tea are produced in India: *

Assam Assam (, , ) is a state in Northeast India, northeastern India, south of the eastern Himalayas along the Brahmaputra Valley, Brahmaputra and Barak River valleys. Assam covers an area of . It is the second largest state in Northeast India, nor ...

, from ''C. s.'' var. ''assamica'', comes from the near sea-level heavily forested northeastern section of India, the state of

. Tea from here is rich and full-bodied. The first tea estate in India was established in Assam in 1837. Teas are manufactured in either the ''orthodox'' process or the " crush, tear, curl" (CTC) process. *

Darjeeling Darjeeling (, , ) is a city in the northernmost region of the States and union territories of India, Indian state of West Bengal. Located in the Eastern Himalayas, it has an average elevation of . To the west of Darjeeling lies the Koshi Pr ...

, from ''C. s.'' var. ''sinensis'', is from the cool and wet

highland region, tucked in the foothills of the

Himalayas The Himalayas, or Himalaya ( ), is a mountain range in Asia, separating the plains of the Indian subcontinent from the Tibetan Plateau. The range has some of the Earth's highest peaks, including the highest, Mount Everest. More than list of h ...

. Tea plantations could be at altitudes as high as . The tea is delicately flavoured, and considered to be one of the finest teas in the world. The Darjeeling plantations have three distinct harvests, termed 'flushes', and the tea produced from each flush has a unique flavour. First (spring) flush teas are light and aromatic, while the second (summer) flush produces tea with a bit more bite. The third, or autumn flush gives a tea that is lesser in quality. * Nilgiri is from a southern region of India almost as high as Darjeeling. Grown at elevations between , Nilgiri teas are subtle and rather gentle, and are frequently blended with other, more robust teas. Camellia sinensis-fruto

Pests and diseases

Tea leaves are eaten by some

herbivore A herbivore is an animal anatomically and physiologically evolved to feed on plants, especially upon vascular tissues such as foliage, fruits or seeds, as the main component of its diet. These more broadly also encompass animals that eat ...

s, such as the

caterpillar Caterpillars ( ) are the larval stage of members of the order Lepidoptera (the insect order comprising butterflies and moths). As with most common names, the application of the word is arbitrary, since the larvae of sawflies (suborder ...

s of the willow beauty (''Peribatodes rhomboidaria''), a geometer moth.

Health effects

Green tea has been consumed for health purposes for thousands of years and is currently promoted for various health benefits though scientific studies show mixed results, with some evidence suggesting modest effects in certain populations; the United States

Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respo ...

has approved a specific green tea extract ointment for treating genital warts. Black tea is rated by the Natural Medicines Comprehensive Database of

Natural Standard Natural Standard is an international research collaboration that systematic review, systematically reviews scientific evidence on complementary and alternative medicine. Together with the faculty of Harvard Medical School, Natural Standard provid ...

as likely effective for improving mental alertness, possibly effective for conditions like low blood pressure,

heart attack A myocardial infarction (MI), commonly known as a heart attack, occurs when Ischemia, blood flow decreases or stops in one of the coronary arteries of the heart, causing infarction (tissue death) to the heart muscle. The most common symptom ...

risk,

osteoporosis Osteoporosis is a systemic skeletal disorder characterized by low bone mass, micro-architectural deterioration of bone tissue leading to more porous bone, and consequent increase in Bone fracture, fracture risk. It is the most common reason f ...

, ovarian cancer, and Parkinson’s disease, possibly ineffective for various cancers and

diabetes Diabetes mellitus, commonly known as diabetes, is a group of common endocrine diseases characterized by sustained high blood sugar levels. Diabetes is due to either the pancreas not producing enough of the hormone insulin, or the cells of th ...

, and lacks sufficient evidence for other uses.

Biosynthesis of caffeine

Caffeine Caffeine is a central nervous system (CNS) stimulant of the methylxanthine chemical classification, class and is the most commonly consumed Psychoactive drug, psychoactive substance globally. It is mainly used for its eugeroic (wakefulness pr ...

, a molecule produced in ''C. sinensis'', functions as a

secondary metabolite Secondary metabolites, also called ''specialised metabolites'', ''secondary products'', or ''natural products'', are organic compounds produced by any lifeform, e.g. bacteria, archaea, fungi, animals, or plants, which are not directly involved ...

and acts as a natural

pesticide Pesticides are substances that are used to control pests. They include herbicides, insecticides, nematicides, fungicides, and many others (see table). The most common of these are herbicides, which account for approximately 50% of all p ...

: it can paralyze and kill herbivorous insects feeding on the plant. Caffeine is a purine alkaloid and its biosynthesis occurs in young tea leaves and is regulated by several enzymes. The biosynthetic pathway in ''C. sinensis'' is similar to other caffeine-producing plants such as

coffee Coffee is a beverage brewed from roasted, ground coffee beans. Darkly colored, bitter, and slightly acidic, coffee has a stimulating effect on humans, primarily due to its caffeine content, but decaffeinated coffee is also commercially a ...

or guayusa. Analysis of the pathway was carried out by harvesting young leaves and using reverse transcription PCR to analyze the genes encoding the major enzymes involved in synthesizing caffeine. The gene ''TCS1'' encodes caffeine synthase. Younger leaves feature high concentrations of TCS1 transcripts, allowing more caffeine to be synthesized during this time. Dephosphorylation of xanthosine-5'-monophosphate into xanthosine is the committed step for the xanthosines entering the beginning of the most common pathway. A sequence of reactions turns xanthosine (9β--ribofuranosylxanthine) into 7-methylxanthosine, then 7-methylxanthine, then

(3,7-dimethylxanthine), and finally into caffeine (1,3,7-trimethylxanthine). Caffeine synthesis in c

Primary green tea catechins

File:(+)-Gallocatechin.svg, (–)- Epigallocatechin File:Epigallocatechin gallate structure.svg, (–)-

Epigallocatechin gallate Epigallocatechin gallate (EGCG), also known as epigallocatechin-3-gallate, is the ester of epigallocatechin and gallic acid, and is a type of catechin. EGCG – the most abundant catechin in tea – is a polyphenol under basic research for it ...

File:Epicatechin gallate.svg, (–)- Epicatechin gallate File:(–)-Epicatechin.svg, (–)- Epicatechin

References

External links

*
Camellia sinensis
' from

Purdue University Purdue University is a Public university#United States, public Land-grant university, land-grant research university in West Lafayette, Indiana, United States, and the flagship campus of the Purdue University system. The university was founded ...

The International Camellia Society
* Plant Cultures

Jac.OxfordJournals.org
The effect of a component of tea (''Camellia sinensis'') on methicillin resistance in ''Staphylococcus''.
Suns.Ars-Grin.gov
List of Chemicals in ''Camellia sinensis'' (Dr. Duke's Databases) {{Authority control sinensis Medicinal plants Medicinal plants of Asia Tea Plants used in traditional Chinese medicine Caffeine Plants described in 1753 Taxa named by Carl Linnaeus Flora of Assam (region)