[sing. “Aravah”] called by the Torah “Arvei Nachal,” “willows of the brook.” Two branches from this tree make up one of the “Arbaah Minim,” the “Four Species, or Types of Agricultural Produce” which the Jew is commanded by the Torah to hold together and wave in all directions. The symbolism of this act, at least according to one opinion in the Talmud, is to show the supremacy of G-d, its Creator, over Nature.