Overview
Lemon juice being used in tea is probably an Asian invention. It can be seen in many, many tisanes and when it is used in tea, it can be used to make a refreshing drink, like lemon wheels on the side of your glass of iced black tea in Hong Kong, which is not a garnish. It is known as Dong Ling Cha. You are supposed to mash the slices to extract the flavor. Also, there is Southern Sweet Tea, which is basically just really sweet iced tea with a lemon twist, common in the American South.