About 400 species mainly in the north-temperate regions but also in higher altitudes of the tropics. Could be pollinated by insects seeking nectar; the hairy seeds are dispersed by wind.
One of the most intricate genera of the plant kingdom, owing to the occurrence of fertile interspecific hybrids and vegetative propogation (by cuttings) which obscure the boundaries of the species.
Literature: Andersson N.J., Monographia Salicum hucusque cognitarum, Kungl. SvenskaVetensk.-Akad. Handl. 6, 1: 1-180 (1867). Camus A. & E.G., Classification des Saules d'Europe & Monographie des Saules de France, 1-2. Paris (1904-1905). Schneider C., Ueber die systematische Gliederung der Gattung Salix, Oesterr. Bot. Zeitschr. 65: 273-278 (1915). Görz R., Salicaceae Asiaticae. I. Brandenburg, 1-23 (1931); II. Repert. Sp. Nov. 32: 387-398 (1933); III. Repert. Sp. Nov. 36: 20-38 (1934).
Forms recorded as Salix australior N. J. Anderss. and Salix subserrata Willd. in the Philistean Plain (Yarkon River) and the Dead Sea Valley, are probably hybrids between Salix acmophylla Boiss. or Salix alba L. and other species. Salix dinsmorei Enander ex Dinsmore in Post, Fl. Syr. Pal. Sin. ed. 2, 2: 529 (1933), recorded in the Upper Galilee, is probably one of them. We have found no species in addition to those dealt with here.
Salix pedicellata Desf. is a Mediterranean tree, growing in Mt. Hermon.
The following intermediate forms (hybrids) have been observed: Salix acmophylla X Salix alba [Plate 28] : Leaves more or less serrulate with slight cover of white hairs when young, later glabrous; stamens 2 or more; capsule mostly short-pedicelled. Common.
Salix acmophylla X Salix babylonica: All leaves glabrous, linear; stamens 2 or more; capsule very short-pedicelled. Rare.
Salix alba X Salix babylonica: Leaves linear, 6-8 times as long as broad, young ones more or less oppressed-pilose, the adult ones glabrous. Rare.
Salix triandra X Salix pseudo-safsaf: Leaves ovate-lanceolate, more or less serrulate, roundish at base, not leathery, nearly glabrous when young, with rather large, persistent stipules; in Jordan Valley and Hula Plain.