Camellia sinensis

Camellia sinensis, the tea plant, is the species of plant whose leaves and leaf buds are used to make tea. It is in the genus "Camellia". 
White tea, green tea, oolong, pu-erh tea and black tea all come from this species. They are processed differently, so they have different levels of oxidation. Kukicha (twig tea) is also harvested from "Camellia sinensis", but uses twigs and stems rather than leaves.