Jiaogulan, also known by the botanical name gynostemma pentaphyllum, is a wild-growing herb found in the mountains of Southwestern China.
It contains no caffeine, and can be thought of as calming and clarifying. It is said to have adaptogenic properties similar to that of ginseng.
Taste-wise, it is sweet up front and slightly nutty, with a touch of earthy bitterness.
It can be prepared similar to how one might prepare sheng pu-erh maocha: using water of around 195f, do a quick rinse to awaken the leaves, then steep quickly and pour, adding to the steeping time with each successive infusion. If a decent amout of tea is used (more than 5g per 100ml), you can start by just pouring the water over the tea, then pouring it off.
A very nice hot beverage for those times when the effects of caffeine aren't desired.