wil'-oz (`arabhim); itea (Le 23:40; Job 40:22; Ps 137:2; Isa 15:7; 44:4)): In all references this tree is mentioned as beside running water. They may all refer to the willow, two varieties of which, Salix fragilis and S. alba, occur commonly in Palestine, or to the closely allied Populus euphratus (also Natural Order Salicaceae), which is even more plentiful, especially on the Jordan and its tributaries. The Brook of the Willows (Isa 15:7) must have been some stream running from Moab to the Jordan or Dead Sea. Popular fancy has associated the willows of Ps 137:2 with the so-called "weeping willow" (Salix babylonica), but though this tree is found today in Palestine, it is an introduction from Japan and cannot have existed "by the waters of Babylon" at the time of the captivity.
E. W. G. Masterman