True tea is an agricultural product produced from the leaves, buds and/or stems of the Camellia Sinensis family of plants only.  While there are many different sub-species/varietals/cultivars of Camellia Sinensis used in the production of tea, at the most basic level, the methods used in processing the leaves after harvest determines what type of tea is produced. 

"Herbal Teas" or "tisanes" are comprised of roots, fruit, bark, leaves, seeds, etc of plants other than Camellia Sinensis and should not technically be referred to as "tea."

Chinese Tea Info

Japanese Tea Info