Tea
Tea is basically the dried and processed leaves of only one species of plant called camellia sinensis. Interestingly enough, herbal teas or herbal infusions are not really teas, but simply dried leaves and/or flowers from various other plants and herbs. Sometimes, teas can also be flavored with oils or scented with flower petals during the processing stage. They can also be combined with fruits and spices. 
Types of Tea
White Tea
- The      least processed
 - Taste      like fresh leaves or grass
 - Lower      amount of caffeine
 - Highest      antioxidant properties
 
- minimal      oxidation
 - closer      to white tea, taste like fresh leaves or grass
 - Lower      amount of caffeine
 - Highest      antioxidant properties
 
Oolong Tea(wu long)
- Between      green & black tea
 - Partially      oxidized
 
Black Tea
- Highest      caffeine
 - Not      much antioxidant
 - Full      oxidation
 
Chai Tea
Black tea with spices, milk and sugar
Flavored / Scented Tea
Tea with flower petals /blossoms, herbs or fruit peel.
Examples:
Flower Tea: 
- rose, chamomile, lavender,      jasmine, Chrysanthemum, osmanthus, ginseng flower, honeysuckle flower,      carnation etc
 
Herbal Tea:
- Leaf:      lemongrass, French verbena, mint
 - Seed:      fennel, cardamom, pumpkin seed
 - Bark:      slippery elm, cinnamon, willow bark
 - Root:      chicory, ginger, turmeric
 - Fruit:      apple, peach, blueberry