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 matsudana this character is variable in many willows (e.g. crack willow "Salix fragilis" can have either one or two), so even this difference may not be a meaningful species distinction. Chinese willow has been introduced into many areas as an ornamental tree, including Australia, Europe and North America. A particularly popular cultivar of this species is "Salix matsudana" 'Tortuosa', the "Corkscrew willow" (also known as the Hankow willow, curly willow, dragon's claw, or globe willow), in which the branches and twigs grow in a spiral, twisting manner. As a result of the ornamental shape of the branches and twigs, this cultivar