The Collaborative International Dictionary
Valonia \Va*lo"ni*a\, n. [It. vallonia, vallonea, fr. NGr. balania`, balanidia`, the holm oak, bala`ni, balani`di, an acorn, Gr. ba`lanos.]
The acorn cup of two kinds of oak ( Quercus macrolepis, and Quercus vallonea) found in Eastern Europe. It contains abundance of tannin, and is much used by tanners and dyers.
[Perhaps named from its resemblance to an acorn.] (Bot.) A genus of marine green alg[ae], in which the whole frond consists of a single oval or cylindrical cell, often an inch in length.
Wikipedia
Quercus macrolepis, the Valonia oak, is a tree in the family Fagaceae.
It is found in the Southern Mediterranean, in the Balkans including the Greek Islands, in Morocco, and in Turkey.