— This article by Jerry Cates was first published on 23 October 2015, and revised last on 2 April 2016. © Budsinthenews Vol. 6:10(13).
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The tea plant (Camellia sinensis)
The tea plant (Camellia sinensis), an evergreen shrub or small tree, is native to Southeast Asia, East Asia, and the Indian Subcontinent. Today it is found around the world, primarily in tropical and subtropical climes. Often it is cultivated for its leaves which are used to make the beverage we call tea.
The seeds of Camellia sinensis and a close relative, the oil-seed Camellia (Camellia oleifera) yield a sweet cooking oil commonly known as tea oil. Tea oil should not be confused with the pungent tea tree oil, derived from leaves of the tea tree (Melaleuca alternifolia), used in medicines and cosmetics.
Tea plant leaves — 4–15 cm (1.6–5.9 in) in length and 2–5 cm (0.79–1.97 in) wide — are light green when young, with short white hairs on their ventral surfaces. The young, light green leaves are preferred for making tea. The leaves contain caffeine and a number of related compounds including theobromine and a specific group of catechins found in higher concentrations in tea leaves than in most other botanicals. Catechins constitute about 25% of the dry mass of a fresh tea leaf. Chinese green tea leaves contain almost six times the concentrations of these catechins compared to the black tea leaves most commonly favored by Western cultures. White tea leaves, which are processed and oxidized the least, have even greater concentrations of these catechins.
The average person worldwide is familiar with the aromatic beverage prepared by pouring hot or boiling water over cured leaves of the tea plant. That drink is — excepting only unadulterated water itself — the most widely consumed beverage in the world. Many types of tea are recognized, including Chinese green (Oolong) teas produced according to traditional Chinese methodology, White, and Darjeeling (black) plus a slew of other Western black teas, most of which are graded according to the Orange Pekoe leaf grading system.
The custom of making and drinking tea originated in southwestern China, where it was originally used for medicinal purposes.
NOTE: Due to the important Chinese origins of this plant, it is appropriate to take a moment to consider the way the Chinese referred to it in writing. The Han character for tea is 茶 (pronounced chá in Mandarin); that character is synonymous with 茗 (pron. míng in Mandarin, and ming in Cantonese), to the point that the combination of both characters (茗茶, pronounced míng chá in Mandarin) signifies “good tea.” 茶 is a nine stroke pictogram that was derived from the archaic form 荼, pron. tu, and having the meaning of a bitter plant; note that the two characters are almost identical, except that the archaic version has 10 strokes, with an added cross stroke in the 8th position (the character is written from the top left, downward). Bitterness in Chinese, as in typical Western languages, characterizes both a taste and an emotion, as the character 苦 (pron. ku) demonstrates; 苦 means bitter, painful, or hard (difficult), and shares the first three strokes with 茶, the Chinese word for tea; this latter character stands both for the tea plant and the beverage made from its leaves. In earlier times 茶 also was used to define a moment, i.e., the amount of time it takes to drink a cup of tea.
During the Golden Age of the Chinese Tang dynasty (618-907 C.E.) tea drinking became widespread in China. The custom soon was exported to other East Asian countries. It was introduced to the West during the 16th century by Portuguese priests and merchants. The British, who made tea drinking fashionable in the West during the 17th century, started large-scale production and commercialization of the plant in India, effectively bypassing the monopoly on tea trade that had previously been enforced by the Chinese.
The British also introduced a new methodology in tea processing, resulting in what we call black tea today. That process (sometimes erroneously called fermentation, as no fermentation takes place) involved a more thorough oxidation and drying of the tea leaves. This was done to add shelf life, enabling shipping of the processed tea leaves without rotting or mildewing enroute. It also modulated the astringent notes common to green teas, giving the tea brewed from black tea leaves a reddish hue and a more subtle flavor, but also neutralized some of the natural antioxidants in the leaves.
Green tea catechins are comprised of four major epicatechin derivatives; namely, epicatechin, epigallocatechin, epicatechin gallate, and epigallocatechin gallate. Of these, the latter — epigallocatehin gallate — accounts for more than 40% of the total content.
Other natural components in tea leaves include the three flavonoids kaempferol, quercetin, and myricetin. More myricetin is contained in tea and its extracts than in most other plants. Some authorities believe that the high concentration of myricetin is responsible for much of the bioactivity of tea and its extracts.
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Taxonomy:
- Domain: Eukaryota (yew-carr-ee-OH-tah) — from the Greek prefix ευ (yew) = good, well, pleasing + καρυον (khar-yone) = a nut/nucleus, thus organisms whose cells contain a nucleus and other organelles within membranes.
- (unranked): Bikonta Cavalier-Smith, 1993 (bye-KOHN-tuh) — from the Latin bis = twice/double + the Greek κοντος = a punting pole; those eukaryotic organisms within the subgroups Apusozoa, Rhizaria, Excavata, Archaeplastida, or Chromalveolata.
- (unranked): Archaeplastida Adl et al., 2005 (ahr-kee-PLASS-tih-duh) — from the Greek αρχαιος (AHR-kee-ose) = ancient/antiquated + πλασις (PLAS-iss) = a moulding + Anglo Saxon tid = time; a major group of eukaryotes, comprised of the red algae (Rhodophyta), the green algae, and the land plants along with the freshwater unicellular algae known as glaucophytes.
- Kingdom/Regnum: Plantae Copeland, 1956 (PLAN-tee) or Viridiplantae Cavalier-Smith, 1881 (veer-id-eye-PLAN-tee) — from the Latin planta = a green twig; the plant kingdom, consisting of multi-cellular green plants, i.e., whose cells have cellulose within their cell walls and have primary chloroplasts derived from endosymbiosis with cyanobacteria containing chlorophylls a and b and lack phycobilins..
- (unranked): Streptophyta Jeffrey 1967 (strepp-toh-PHY-tuh) — from στρεπτος (STREP-tose) = (easily) twisted, pliant + φυτον (PHU-tawn) = a plant/tree; the land plants and the green algal group Charophyta.
- Subkingdom: Embryophyta Engler, 1892 (imm-bree-oh-FYE-tuh) — from the Greek εμβρυον (EMM-bree-yon) + φυτον (PHU-tawn) = a plant/tree; green plants, informally known as land plants because most are terrestrial rather than aquatic, while the related green algae are primarily aquatic;
- (unranked): Angiosperms (AN-gee-oh-spurms)/Magnoliophyta Cronquist (mag-NOH-lee-oh-fye-tuh) — from the Greek αγγειον (AUGG-ee-awn) = a vessel/pail/reservoir + σπερμα (SPUR-mah) = a seed; the flowering plants, distinguished from the gymnosperms by having flowers, endosperm within the seeds, and the production of fruits that contain the seeds;
- (unranked): Eudicots (YEW-dee-kotts) — from the Greek prefix ευ (yew) = good, well, pleasing + δι (die/dee) = two/double + κοτυληδων (cott-ee-LEE-dun) = a cup-shaped hollow; a monophyletic clade of flowering plants previously known as tricolpates or non-magnoliid dicots, to emphasize the evolutionary divergence of tricolpat dicots from earlier, less specialized dicots; close relationships are presumed among flowering plants with tricolpate pollen grains (the grains have three colpi, or elongated apertures or furrows in the pollen grain paralleling the polar axis);
- (unranked): Asterids (ASS-turr-iddz) — from the Greek αστηρ (ASS-turr) = a star/meteor + the Latin suffix -idus (EE-duss) = indicative of having the nature of; one of the two most species group of eudicots (which have inflorescences having the appearance of a meteor or shooting star), the other being the rosids;
- Order: Ericales Bercht. & J. Presl (ay-ree-KAL-ees) — a diverse order comprised of some 8,000 species, in 23 families of trees, shrubs, lianas and herbs;
- Family: Theaceae D. Don (tee-ACE-ee-uh) — a family of flowering shrubs and trees, comprised of seven to 40 genera, and characterized by simple leaves that are alternate spiral to distichial, serrated, and glossy. Most are evergreens, but two genera are deciduous. The toothed margins are generally associated with a characteristic Theoid leaf tooth crowned by a glandular, deciduous tip. Flowers in this family are generally pink or white, large and showy, and strongly scented. The calyx has five or more sepals, which persist into the fruiting stage. The corolla is five-merous, only rarely numerous. Multistaminate, usually with 20-100+ stamens, either free or adnate to the base of the corolla, and distinguished by the presence of pseudopollen. Pseudopollen, produced from connective cells, is thickened in rib-like or circular forms. Ovary often hairy, narrowing gradually into a branched or cleft style. Typical carpels are opposite from the petals, though in Camellia they are opposite the sepals. Fruits are loculicidal capsules, indehiscent baccate fruits, or pomes. Seeds are few, sometimes winged, in some genera encased in fleshy tissue, in others unwinged and nude.
- Genus: Camellia L. (kah-MEEL-ee-yuh) — a genus of flowering plants native to eastern and southern Asia, comprised of 100–300 described species and some 3,000 hybrids. Linnaeus coined the generic name in honor of the Jesuit botanist Georg Joseph Kamel, who worked in the Philippines, despite the fact Kamel had never described any of the plants in this genus. In China camellias are described as cháhuā (茶花), or “tea flower.” In Japan they are called tsubaki (椿); in Korea, dongbaek-kkot (동백꽃); and in Vietnam hoa trà or hoa chè.
- Species: C. sinensis (seyn-ENN-sus) — the tea plant, a botanical of major commercial importance because of the tea that is popular worldwide that is made from its leaves. The species C. sinensis has been subjected to many centuries of selective breeding, conducted for the express purpose of bringing out those qualities considered specially desirable for the brewing of tea.
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References:
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