Salix arctica (Arctic Willow) is a tiny creeping willow (family Salicaceae). It is adapted to survive in harsh Arctic and subarctic environments, and has a circumpolar distribution round the Arctic Ocean. It grows in tundra and rocky moorland, and is the northernmost woody plant in the world, occurring far above the tree line up 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. It is typically a low shrub growing to only 1-15 centimeter (0.39-5.9 inches) in height (rarely to 25 centimeter (9.8 inches) high), however in the Pacific Northwest it may reach 50 centimeter (20 inches) in height, and has round, shiny green leaves 1-4 centimeter (0.39-1.6 inches) long and broad, rarely up to 8 centimeters (3.1 inches) long and 6 centimeter (2.4 inches) broad; they are hairy, 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.