Peter Kalm: Conversation with Franklin
Esther Louise Larsen, trans., “Pehr Kalm’s Report on the Characteristics and Uses of the American Walnut Tree Which is Called Hickory," Agricultural History, XIX (1945), 55-64.

[Hickory Tea.] Mr. Benjamin Franklin, a man now famous in the political world, told me that at different times he had drunk tea cooked from the leaves of the hickory with the bitter nuts. The leaves are collected early in the spring when they have just come out but have not yet had time to become large. They are then dried and used as tea. Mr. Franklin said that of all the species used for tea in North America, next to the real tea from China, he had in his estimation not found any as palatable and agreeable as this.

[1778; p. 59]
622912 = 004-062b.html