Hydrangea thurnbergii.
Botanical name:
Hydrangea thurnbergii Siebold. Saxifrageae (Hydrangaceae). Tea-Of-Heaven.
Japan. The natives use the dried leaves as a substitute for tea. This tea is called ama-tsja, tea-of-heaven.
Sturtevant's Edible Plants of the World, 1919, was edited by U. P. Hedrick.