Tea

Tea leaves are harvested from Camellia sinensis plant. Different kinds of tea are made by different processing, harvesting from different varieties of the plant or the age of the leaves.
Blending means mixing with either other ingredients or with different types of tea.
Major producers are India, China, Sri Lanka, Kenya, Indonesia and Turkey.
Fermentation means oxidation in tea. The leaves are turning black and starch is degrading to sugar.
The most oxidized is black tea. Due to this processing, it's also the poorest in antioxidants. On the other hand, it can be stored for the longest time and that's why it was the only tea known to Europe in past.
Less oxidized is oolong tea. Green the least, white tea isn't oxidized at all.
Pu-erh is made from older leaves and is really fermented (so here, bacteria are really at work).
Earl Grey is black tea blended with bergamot (a citrus fruit).
Touareg is green tea blended with mentha.
Genmaicha is green tea blended with roasted rice.