Tea leaves come from the Camellia sinensis which is a species of evergreen shrub or small tree whose leaves and leaf buds are used to produce tea.
Two main varieties are grown: Camellia sinensis sinensis for Chinese teas, and Camellia sinensis assamica for Indian Assam teas
White tea, yellow tea, green tea, oolong, pu-erh tea and black tea are all harvested from one or the other, but are processed differently to attain varying levels of oxidation. Kukicha (twig tea) is also harvested from Camellia sinensis, but uses twigs and stems rather than leaves.
White tea has had minimal processing and has not been left to oxidise so it retains all its natural antioxidants but does not have as much flavour or colour.
Green tea has very little oxidation, which is halted by pan-frying the tea leaves, this helps to bring out the flavour and allows the caffeine to develop, giving the tea a grassy and earthy taste but with a sweet note.
Black tea has been fully fermented, which blackens the tea leaves and causes the formation of caffeine and tannins. It generally possesses the most robust flavour and highest level of caffeine, but the least amount of antioxidants.
Rooibos is also called red tea or red bush tea, is a South African tea made like a black tea but it contains no caffeine. This tea has a sweet malty taste and is full of antioxidants.
Tisanes are herb based teas, which can be blended with fruits, flowers and spices, they are brewed like tea but traditionally taken with honey to sweeten.