Salix arctica is a creeping dwarf willow with ovate leaves and erect, long catkins that occurs widely in the mountainous regions of Denali, common in dry tundra and rocky areas. This species is highly variable, 3-15 cm tall with thick, hairless branches. Leaves are 3-7 cm long, have entire margins, and are dark green above and pale beneath with a silky 'beard' at the tip. Stipules are absent. Willows are dioecious (that is, separate plants produce either male or female flowers), the flowers highly reduced and borne in catkins evolved for wind pollination. Female catkins appear with the leaves, born on leafy branchlets, and appear wooly due to beard hairs on the brown bracts. Catkins are relatively long compared to the dwarf size of the plant, 3-7 cm. Fruits are 2-valved hairy capsules, splitting open to release seeds with tufts of long hairs. This species can be distinguished from other common dwarf willows in the park by the pale underside of the leaf and the beard of hairs at the tip of the leaf.
Leaves and catkins develop together and generally appear early-mid-June.
Salix arctica is dioecious, and insect and wind pollinated. Seeds have attached hairs to aid in wind dissemination. Plants also spread vegetatively.
Collett (2004) documented a variety of insects that utilize S. arctica including gall-formers such as: Rabdophaga salicis, Pontania sp., and eriophyid mites, and skeletonizing beetles from the Chrysomelid family. This species is the host plant for at least two butterflies: the Dingy Fritillary Boloria improba, and the Arctic Orange Colias hecia (Scott 1986).
Like all willows, the fresh bark of S. arctica contains salicin, a precursor to aspirin and has traditionally been used as pain and fever reliever. Leaves and young twigs are edible.
Salix arctica is a circumpolar species with an arctic-alpine distribution, ranging from northern Eurasia across Alaska to the Canadian Arctic to Greenland, and Fennoscandia. In North America, S. arctica ranges down the west coast and Rocky Mountains into the Pacific Northwest, and occurs in the Maritime provinces in eastern Canada. In Alaska, this species is common throughout the hills and mountains statewide. In Denali, S. arctica is also common in the mountains on both sides of the Alaska Range.
Salix arctica is an alpine species that can be found at elevations from 274 m to 1710 m, with an average plot elevation of 1080 m. This species shows a slight preference for north-facing slopes. It is more commonly found on steeper (>20 degrees) slopes.