Black tea remains inconclusive. Black tea Black tea is a type of tea that is more oxidized than oolong, green, and white teas. Black tea is generally stronger in flavour than the less oxidized teas. All four types are made from leaves of the shrub (or small tree) "Camellia sinensis." Two principal varieties of the species are used – the small-leaved Chinese variety plant ("C. sinensis" var. "sinensis"), used for most other types of teas, and the large-leaved Assamese plant ("C. sinensis" var. "assamica"), which was traditionally mainly used for black tea, although in recent years some green and white teas have
Camellia sinensis pairs which was larger than most plants previously sequenced. "Camellia sinensis" is mainly cultivated in tropical and subtropical climates, in areas with at least 127 cm (50 inches) of rainfall a year. Tea plants prefer a rich and moist growing location in full to part sun, and can be grown in hardiness zones 7 – 9. However, the clonal one is commercially cultivated from the equator to as far north as Cornwall and Scotland on the UK mainland. Many high quality teas are grown at high elevations, up to , as the plants grow more slowly and acquire more flavour.