Tea, botanical name: tea tree? Ketze. Shrub or small tree with hairless shoots. Leaves leathery, oblong or oval, blunt or sharp at the top, wedge-shaped at the base, shiny on the top, hairless or initially pilose on the bottom, serrated at the edge, and glabrous on the petiole. Flowers are white, and stems sometimes grow a little longer.
Sepals broadly ovate to rounded, glabrous, persistent; Petals broadly ovate, slightly articulated at base, glabrous on back, sometimes pubescent; Ovary densely covered with white hairs; Style glabrous. Capsule 3 is spherical or 1-2, with a height of1.1-0/.5cm, and each ball has 1-2 seeds. The flowering period is from June 10 to February of the following year.
Wild species are all over the mountainous areas of the provinces south of the Yangtze River in China. They are small trees with big leaves, usually more than 10 cm long. For a long time, after a lot of cultivation, great changes have taken place in hair and leaf shape. Tea can be used as a beverage, which contains many beneficial ingredients and has health care function.
2065438+0710127 October, the list of carcinogens published by the International Agency for Research on Cancer of the World Health Organization was preliminarily sorted out for reference. Tea is in the list of three types of carcinogens. It is a substance suspected of causing cancer to human beings, and there is no sufficient human or animal data.
Tea culture in China has a long history. According to the literature, early tea may have been used as food. As a special beverage, it should be no later than the Western Han Dynasty. During the Wei, Jin, Southern and Northern Dynasties, tea once became a luxury drink. After the Sui and Tang Dynasties, tea became more popular. From the royal family down to the common people, everyone loved tea, and tasting tea became a fashion. However, it was not until Lu Yu wrote the Tea Classic that tea culture was systematically combed and written.
It is said that tea has been discovered and used in China for at least 4000 years. Around the 5th century, during the Southern and Northern Dynasties, China's tea began to be exported to neighboring countries in Southeast Asia and other parts of Asia. /kloc-in the 20th century, Mongolian caravans came to China to engage in trade, and China brick tea was brought to Central Asia via Siberia. /kloc-tea was brought to Europe by the Dutch in the 0/7th century, and the British brought the fashion of drinking tea to America, Australia and all over the world.