Willow are very cross-compatible, and numerous hybrids occur, both naturally and in cultivation. A well-known ornamental example is the weeping willow ("Salix × sepulcralis"), which is a hybrid of Peking willow ("Salix babylonica") from China and white willow ("Salix alba") from Europe. The hybrid cultivar 'Boydii' has gained the Royal Horticultural Society's Award of Garden Merit. Numerous cultivars of "Salix" L. have been developed and named over the centuries. New selections of cultivars with superior technical and ornamental characteristics have been chosen deliberately and applied to various purposes. Most recently, "Salix" has become an important source for bioenergy production and for
Salix babylonica translations): Despite these Biblical references to "willows", whether in Latin or English, the trees growing in Babylon along the Euphrates River in ancient Mesopotamia (modern Iraq) and named "gharab" in early Hebrew, are not willows ("Salix") in either the modern or the classical sense, but the Euphrates poplar "(Populus euphratica)," with willow-like leaves on long, drooping shoots, in the related genus "Populus." Both "Populus" and "Salix" are in the plant family Salicaceae, the willow family. These Babylonian trees are correctly called poplars, not willows, in the New International Version of the "Bible" (English, 1978): Salix babylonica Salix babylonica (Babylon willow