Dim sum various mixtures of flowers with green tea, black tea or oolong tea. Flowers used include jasmine, gardenia, magnolia, grapefruit flower, sweet-scented osmanthus and rose. There are strict rules about the proportion of flowers to tea. Jasmine tea is the most popular type of scented tea, and is often the most popular type of tea served at yum cha establishments. The above teas are produced in most of China. Chinese tea bushes ("Camellia sinensis") are cultivated in the mountain areas of tropical and subtropical regions or wherever there is a proper climate, sufficient humidity, adequate sunshine and fertile soil. Chinese tea
Camellia sinensis there is no high-quality evidence that tea confers significant benefits. In clinical research over the early 21st century, tea has been studied extensively for its potential to lower the risk of human diseases, but none of this research is conclusive as of 2017. Caffeine is a molecule produced in "Camellia sinensis" and functions as a secondary metabolite. 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" differs from other caffeine producing plants such as coffee or guyausa. Analysis of the pathway was carried out