I have read that Acaena Novae-zelandiae, which we locally call Buzzy, was used by the early European settlers in Tassie instead of tea..... apparantly when the stock of food ran out, experimentation began using the leaves for tea. I am not sure whether they dired them or used them fresh.... I am drying some at the moment to try, but the fresh are a little ropey at the moment.... I don't know if they contain caffeine... I intend to try it shortly, so will be interesting.