To All,
After water, tea is the most widely consumed drink in the world. In fact, one authority makes the to me incredible claim that worldwide more tea is consumed that all other manufactured beverages combined [M&M, p. 32]; this includes coffee, chocolate, sodas, and alcoholic beverages. Tea, while not a fruit, is derived from a plant product, so it falls within the domain of the Fruit Explorer. This e-mail only covers tea made from the leaves of the tea plant; it does not cover herbal tea, which is made from various other plants, and it does not cover tea made from the twigs and stems of the tea plant.
The drink tea is made from the leaves of the tea plant, Camellia sinensis, which is in the family Theaceae, which is often called the tea family. This plant is variously called the tea bush, tea shrub, and tea tree; we will call it the tea bush. As you would guess from the genus of the tea plant, this family (and genus) includes the ornamental, flowering shrub camellia (see pictures).
Tea comes from two subspecies, namely Chinese tea (C. sinensis sinensis) and Indian tea (C.sinensis assamica) [Weinberg and Bealer, p. 246]. (Splitters separate these into two different species; as always, I side with the lumpers, as explained in the e-mail of 24 Jul 2014. There are some differences between these two subspecies, but I will not go into them.) The first tea, which was drunk perhaps 3000 years ago, was Chinese tea.Indian tea comes in three main categories named after the region where it is grown: Assam, Darjeeling, and Nilgiri. (Assam is in far northeast India; it is to the east of Bangladesh. Darjeeling is north of Bangladesh and right between Nepal and Bhutan. The Nilgiri Hills are in southwest India.)
The tea plant can grow to a height of more than 50 feet, where the record is a tea tree in China that is 108 feet tall [Weinberg and Bealer, p. 249. The cultivated plant, however, is usually pruned to create a flat-topped plant at waist height to facilitate harvesting [Weinberg and Bealer, p. 250]; this flat top is called a plucking table [Pradeepkumar et al., p. 707-711]. The plant can be grown at altitudes up to about 4900 feet; higher altitudes are preferred since the plant grows more slowly and acquires more flavor [Weinberg and Bealer, p. 249]. The tea plant requires about 50 inches of rain per year. I have not been able to find pictures of a full-grown tea plant or of an individual tea bush. Below are pictures of tea bushes on plantations; the first picture is of a plantation in Kerala, India.
The dark, shiny green leaves are anywhere from 1.5 to 6 inches long and 0,75 to 2 inches wide. Plucking is the term used to describe the picking of the leaves. You can watch this short video of women plucking; if you find this relaxing, many such videos can be found on YouTube. The ideal is that they pluck the last two leaves on each shoot as well as the bud at the end of the shoot. (This is the apical bud that represents the growing tip of the plant.) You can see this two-leaves-and-a-bud structure in the pictures below.
A skilled worker plucks a set of leaves every second or so all day long. The proper way to pluck is by snapping the wrist; twisting or pinching the leaves results in a lower quality tea [Pradeepkumar et al., p. 724]. The young leaves are plucked since properties of the tea depend on the age of the leaves, and the young leaves and bud produce the best tea. Older leaves are left on the bush not only because they are coarser and less flavorful but also so they can photosynthesize and fuel further growth. The plucking is repeated every week or two since new leaves grow and the planter wants them to be harvested when young. Each new batch of leaves is called a flush. For more detail on plucking, consult Pradeepkumar et al., [pp. 711-13, and the Ten Commandments of Plucking on p. 723] or the Tea Research Institute of Sri Lanka [pp. 1-5]. The last photograph shows my sister in China picking tea leaves. It took her about half an hour to pick enough to earn a pair of sandals.
One of the effects of plucking and pruning is, by removing leaves, to stimulate the growth of the desirable new leaves. James Norwood Pratt dramatically describes this process from the point of view of the tea bush [quoted in Weinberg and Bealer, p. 250]:
Constant pruning and plucking keeps the bush desperately striving for full tree-hood and perpetually producing new leaves and buds.... The poor tea bush is kept in this state of unrelieved anxiety from about age 2 to something over 50, when its yield begins to decrease, and, to avoid labor and sorrow, it's uprooted and replaced. It dies without once having been allowed to flower and seed. [Ellipsis in Weinberg and Bealer]
The tea plant can be propagated by seeds, as seen in this video, or by cuttings, as seen in this video. In short, use seeds to generate genetic diversity since cross-pollination is needed to produce seeds; use cuttings to lock in desirable genetics since this generates a clone. (I have found a mention of grafting, but details have eluded me [Clowes, p. 143].) If you want to grow your own seeds, harvest them from special stands of plants that contain desirable cultivars [Pradeepkumar et al., p. 693]. Tea flowers, which are self-incompatible, are pollinated by a small insect with a short flying range; it is necessary to separate seed plants from ordinary plants by at least ten meters to prevent undesired cross-pollination [Clowes, pp. 140, 143, Pradeepkumar et al., p. 693]. Once the seedlings come up, here is a video that shows how to transplant them. Here are some pictures of seeds.
- A tea plant with an immature, green seed still on the plant.
- A tea plant, where the shell on top still holds a mature seed and the shell on bottom is empty since the mature seed has already fallen out.
- A handful of tea seeds.
(I have been unable to find out exactly what pollinates tea. This lack of attention that the literature gives to pollination probably stems from the fact that it is the leaves rather than the fruit that are harvested from the tea plant. Clowes [p. 143] says, "...pollen was transported by several flies of Diptera spp." "Diptera" just means they are flies, and "spp." is an abbreviation for species. Pradeepkumar et al. [p. 693] says, "Pollination is caused by a pserphid, a small insect havings short flying range." Here "pserphid" is short for the family pserphidae. (In zoology the rule is that a family name ends in -ae, and the -ae is often dropped when no confusion can result. This is why a member of the family Hominidae is called a hominid. Recall that the convention is different in botany, where a family name ends in -aceae (e-mail of 12 Jun 2015).) Google, Bing, and my insect books have failed to turn up any kind of pserphid. Perhaps the author means "syrphid" instead of "pserphid." The syrphids are called the hoverflies and occur just about everywhere. I once netted one beside my trash can. Identifying pserphid with syrphid is an appealing conjecture since syrphids are known to be important pollinators worldwide and since they prefer yellow and white flowers, but it is still no more than a very shaky conjecture. In sum, I am forced to leave unanswered the question of what pollinates the tea plant.)
[Continued in Part 2]
[Continued in Part 2]
