Decaffeination this trait could be bred into other coffee plants by crossing them with "C. charrieriana", or an equivalent effect could be achieved by knocking out the gene for caffeine synthase in normal coffee plants. Tea may also be decaffeinated, usually by using processes analogous to the direct method or the CO process, as described above. The process of oxidizing tea leaves to create black tea ("red" in Chinese tea culture) or oolong tea leaves from green leaves does not affect the amount of caffeine in the tea, though tea-plant subspecies (i.e., "Camellia sinensis sinensis" vs. "Camellia sinensis assamica") may differ
Camellia sinensis Asia, but it is today cultivated across the world in tropical and subtropical regions. Camellia sinensis is an evergreen shrub or small tree that is usually trimmed to below when cultivated for its leaves. It has a strong taproot. The flowers are yellow-white, in diameter, with 7 to 8 petals. The seeds of "Camellia sinensis" and "Camellia oleifera" can be pressed to yield tea oil, a sweetish seasoning and cooking oil that should not be confused with tea tree oil, an essential oil that is used for medical and cosmetic purposes, and originates from the leaves of a different plant.