Known as Camellia sinensis, tea is an evergreen plant of the Camellia family. All teas (except for some herbals) are made from this plant.
The processing method and the tea’s country of origin determine the tea varietal. All teas contain caffeine, except herbal (legally called Tisane teas) and decaffeinated teas.

Processing
Green Tea: green tea is made by simply steaming and then drying the tea leaves.

Oolong Tea: sometimes called “red” tea, this tea is partially fermented before drying. The fermentation process causes the tea’s color to be darker, and causes more varying flavors.

Black Tea: Black tea is a 100% fermented, tea leaf.

Origin
Indian Teas: India is the origin for Assam and Darjeeling teas. Assam teas are known for their robust, full-body, whereas Darjeelings are slightly more delicate and flowery.

Ceylon: Ceylon is the old-fashioned name for Sri Lanka. A common tea from this area is the Orange Pekoe, which indicates the size of the tea leaf rather than the flavor or color Orange.

Chinese Teas: Chinese teas are quite varied. They vary from Lapsang Souchong which is a black tea with a smoky, distinctive flavor, to the popular Young Hyson, which is a green tea.

Japanese Teas: Japanese green teas are, in general, the most delicate.