Rumex arcticus is a tall perennial herb in the buckwheat family (Polygonaceae) with highly reduced reddish flowers. This species occurs in wet meadows across the park from the lowlands well into alpine areas. Plants grow 0.3-1 m tall from a stout rhizome. Stems are typically reddish (and often the entire plant may have a reddish tinge), and are longitudinally ribbed. Leaves can vary from dark green to red-edged or entirely red. Basal leaves are fleshy, long-petioled, and oblong to lanceolate in shape. The stem leaves are alternate, acute and narrow. The inflorescence is a terminal, open, branched raceme of small reduced flowers. Flowers have highly reduced tepals, also reddish. Fruits are winged seeds, 1-2 mm tall. This species looks similar to the related Rumex acetosa ssp. alpestris, but its leaves are oblong, not hastate.
Rumex arcticus is perennial and deciduous and greens up after snow melt. Flowering happens in mid-summer.
This plant is monoecious with bisexual flowers. Flowers are likely wind-pollinated. The fruits are achenes with three winged margins, also wind-dispersed.
The leaves and stem of Rumex arcticus are edible, either raw or cooked. Leaves make a good addition to salad. It is used extensively by Alaska's indigenous peoples and often preserved for winter use. rhizomatous root is usually boiled and mixed with seal oil or added to stews. Leaves and stems are separately boiled in water to make green and red drinks, similar to lemonade. This root has been used as a tonic, laxative and to treat gastrointestinal problems (Garibaldi 1999). The stem can be used to relieve the sting from mosquito bites or stinging nettles.
Rumex arcticus is an amphi-Beringian species with an arctic-alpine distribution. In North America, it ranges from Alaska eastward into Yukon, Nunavut, and the Canadian arctic islands, and southward into British Columbia, Alberta and Manitoba. Rumex arcticus occurs widely across Alaska, except it is rare in the southeastern panhandle. In Denali, this species occurs in suitable wetland habitat park wide on both sides of the Alaska Range.
Rumex arcticus grows at elevations between 185 m and 1312 m, with an average plot elevation of 750 m. This species shows no strong preference in site aspect. It prefers low angled sites with an average plot slope of 5 degrees.