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 scouleriana Salix scouleriana Salix scouleriana (Scouler's willow; syn. "S. brachystachys" Benth., "S. capreoides" Anderss., "S. flavescens" Nutt., "S. nuttallii" Sarg., "S. stagnalis" Nutt.) is a species of willow native to western North America, from south central Alaska east to western Northwest Territory, central Manitoba, and the Black Hills of South Dakota, and south through the Rocky Mountains to Coahuila, and along the coast through British Columbia, Washington, Oregon, and the Sierra Nevada in California. Other names occasionally used include fire willow, Nuttall willow, mountain willow, and black willow. It is a deciduous shrub or small tree, depending on the environment, usually