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 arctica Salix arctica Salix arctica, the arctic willow, is a tiny creeping willow (family Salicaceae). It is adapted to survive in Arctic conditions, specifically tundras. The arctic willow grows in tundra and rocky moorland, and is the northernmost woody plant in the world, occurring far above the tree line to the northern limit of land on the north coast of Greenland. It also occurs further south in North America on high-altitude alpine tundra, south to the Sierra Nevada in California and the Rocky Mountains in New Mexico, and in Asia to Xinjiang in China. "S. arctica" is typically a low shrub