Any tree or shrub of the genus Salix. Willows and poplars are numerous in Palestine. In all regions the white willow (Salix alba) and the Euphrates poplar (Populus Euphratica) occur with great frequency, while the crack-willow (Salix fragilis) and the white poplar (Populus alba) are also common. On the banks of the Jordan and in the valleys of the Dead Sea grow the Salix safsaf and its variety, the Salix hierochuntica. The following species also occur, although less frequently: black willow (Salix nigricans) at Amanus, near Beirut; French willow (Salix triandra) at Al-Zib; Salix alba, var. latifolia, near Beirut and the Dead Sea; var. integrifolia near 'Ainṭab; goat-willow (Salix caprea) on Lebanon; Salix alba, var. Libanotica; Salix pedicellata near Damascus and in Cœle-Syria; black poplar (Populus nigra); weeping willow (Salix Babylonica); and Lombardy poplar (Populus pyramidalis). The "willows" of the Bible (, Isa. xv. 7, xliv. 4, and Ps. cxxxvii. 2; , Lev. xxiii. 40 and Job xl. 22) were the Euphrates poplars, although the Mishnah interprets as "willows," despite the Talmudic traces that the willow had previously been termed (comp.Ezek. xvil. 5). (Gen. xxx. 37; Hos, iv. 13; the of the Targum) is not the officinal storax (Styrax officinalis), but the white poplar (Populus alba). See Plants.
The Feast of Tabernacles requires, according to the Bible, "willows of the brook," the Karaites and recent exegetes regarding this as applying to the booths themselves, while rabbinical tradition refers it to the accessory decorations for the festival. One tannaitic tradition seems to show that the Biblical "willow of the brook" had leaves serrate like a sickle, while the variety with leaves dentate like a saw was rejected. Another tannaitic tradition, however, states that may be used only when they have red twigs and lanceolate leaves, they being unavailable if they have white twigs and round leaves. Babli combines these traditions, and identifies the former of the two varieties of willow with the , while the useless willow is the (Euphrates poplar). The tannaitic description of the corresponds to the trembling poplar, or aspen (Populus tremula), and even more closely to the Salix safsaf, or the French willow (Salix triandra). Still another variety is the , a willow with red twigs and an oblong, sickle-shaped leaf, probably the white willow (Salix alba), and which answers to the tannaitic requirements.
The ruling of Babli concerning the available varieties of the willow was naturally adopted by the codifiers, such as Maimonides. Joseph Caro, however, followed by Mordecai Jaffe, dissented, claiming that the usage was at variance with the phraseology of the Halakah, since all willow twigs are green, although they become red after sufficient exposure to the sun, so that it is inadmissible to reject twigs because they are green, and not red.
In addition to the species of willow unavailable in themselves, twigs were forbidden which had been placed under the ban, or which had been stolen or cut, or had become dry, though twigs whose leaves had partly fallen or withered might be used. Willows were also used independently on the Feast of Tabernacles as a shield for the altar, and were carried in the processions which took place daily, or, after the destruction of the Temple, on the seventh day, the "willow of the brook" receiving the name of "hosanna" from the processional shout.
Willow twigs were used for weaving baskets and similar utensils, peeled twigs being employed for the finer grades; while the wood of the willow and poplar was made into troughs, etc. The galls on the leaves of the willow served to dye veils, and the cotton of the seeds of the female willow and poplar was made into an inferior grade of lamp-wick.
The Haggadah is concerned with the willow only so far as it forms part of the festal bush, in which the "willow of the brook" symbolizes: (1) God; (2) the impious and the ignorant of Israel, who have neither righteousness nor knowledge, as the willow has neither taste nor smell; (3) Joseph and Rachel, who, like the willow, faded before the rest; (4) the Sanhedrin, the pair of twigs typifying the two secretaries; (5) the mouth, on account of the labiate leaves. All four trees symbolize the beneficence of the rain which they cause; they fulfil their purpose when two fragrant and two scentless varieties of trees are combined. These metaphors are repeated frequently in synagogal poetry and in homiletic literature, with little change or addition, even in modern times.