Salix arctica

S. arctica is typically a low shrub growing to only 15 centimetres (6 inches) in height, rarely to 25 cm (10 in), although it may reach 50 cm (20 in) in height in the Pacific Northwest. It has round, shiny green leaves 1–4 cm (1⁄2–1+1⁄2 in) long and 6 cm (2+1⁄4 in) broad; they are pubescent, with long, silky, silvery hairs. Like the rest of the willows, Arctic willow is dioecious, with male and female catkins on separate plants. As a result, the plant's appearance varies; the female catkins are red-coloured, while the male catkins are yellow-coloured. Despite its small size, it is a long-lived plant, growing extremely slowly in the severe arctic climate; one in eastern Greenland was found to be 236 years old. Hybrids with Salix arcticola and Salix glauca are known. 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. Its distribution is circumpolar.