Salix babylonica a gold-yellow in autumn. The flowers are arranged in catkins produced early in the spring; it is dioecious, with the male and female catkins on separate trees. "Salix babylonica" was described and named scientifically by Carolus Linnaeus in 1736, who knew the species as the pendulous-branched ("weeping") variant then recently introduced into the Clifford garden in Hartekamp in The Netherlands. Early Chinese cultivar selections include the original weeping willow, "Salix babylonica" 'Pendula', in which the branches and twigs are strongly pendulous, which was presumably spread along ancient trade routes. These distinctive trees were subsequently introduced into England from Aleppo in
Salix fragilis frequently with the type. It is a smaller shrubby tree, rarely exceeding tall, with completely hairless leaves up to 9 cm long and 2–3 cm broad. According to some botanists, it is a distinct species (treated as "Salix decipiens" Hoffm.), with, in this view, "S. fragilis" then being a hybrid between "S. decipiens" and "S. alba". Some other botanists regard "S. decipiens" as itself being a hybrid between "S. fragilis" and "S. triandra". Little evidence supports either of these suggestions. It readily forms natural hybrids with white willow "S. alba" in Europe and Asia, the hybrid being named "Salix" ×