All true teas come from one single plant, Camellia Sinensis. Any other plant that calls itself a “tea” is, in fact, a poser! So it is a good thing that plants don’t call themselves anything! Ha ha ha! ๐
The different types of true teas, which include green, white, yellow, oolong, Pu-erh and red/black, all come from this one plant. The differences are in how the plant is processed and turned into dried teas leaves that we use to make our beloved beverage of choice.
In its most general form, tea processing involves different manners and degree of oxidation of the leaves, stopping the oxidation, forming the tea and drying it.
The above quote comes from the current (as of 02 January in the year 2012 AD) Wikipedia article on Tea Processing, which is a great overview of the processing of different types of teas. I cannot better explain the process to you in my own words, so I will leave you this link so you can read it yourself. It is recommended reading for the beginning tea lover!
I will leave you to your reading. Right now, I think I’m going to go enjoy a nice cup of Jasmine tea…