Saxifraga oppositifolia is a cushion or mat-forming alpine plant with bright pink flowers that occurs in tundra, gravelly areas, fellfields and talus across the mountainous regions of Denali. Plants reach up to 3 cm tall, from highly branched, trailing stems. The vegetative part of the plant is formed of many narrow stems densely covered with clasping, scale-like leaves. On close inspection the leathery leaves are placed opposite to each other, unusual in the genus Saxifraga. Above the mat, the plant produces flowers on several stems identical to the sterile ones, with solitary flowers on each stalk. The five petals are hot pink to lilac (rarely white) and 5-12 mm long, above green-purplish hairy sepals, 2-3.5 mm long. Flowers have 10 stamens and 2 fused carpels. Fruits are two-beaked capsules. Saxifraga oppositifolia can't be mistaken for any other member of its genus, but could be confused for other pink-flowered cushion-forming alpine plants. Look for the tight basal rosettes of leaves and the two fused carpels inside the flower.
Purple mountain saxifrage flowers early season (Hulten 1968).
Saxifraga oppositifolia is monoecious with bisexual flowers. Flowers are slightly protogynous—the stigmas becoming receptive to pollen before the anthers of the same flower develop (Savile 1972). Flowers are showy and produce nectar to attract insects, primarily flies and bees. In an experiment in Ellesmere Island, Northwest Territories by Kevan (1979), flowers are predominately outcrossed, and insect visitation was high. Flowers excluded from pollinators did set fruit, indicating some level of auto-deposition and self-compatibility, but selfed flowers produced far fewer seeds. The fruit is a dry capsule, which splits to disperse many small seeds.
Saxifraga oppositifolia is a wide-ranging circumpolar arctic-alpine species complex. This species occurs widely in arctic and alpine areas of North America, occurring across Canada, reaching the Pacific Northwest, and the Rocky Mountains in Colorado in the west, and also occurring in a few locations in New York and Vermont. In Alaska, S. oppositifolia is widespread across the mountainous regions, including the southeastern panhandle and Kodiak Island, and also occurs in coastal tundra on the North Slope. In Denali, this species occurs across alpine areas, primarily north of the Alaska Range crest, but also in widely scattered sites south of the crest.
Though its lowest recorded elevation from the park is 213 m, purple mountain saxifrage is overwhelmingly found at high altitudes. The average elevation is 1274 m, and the highest 1787. This species generally is found on south facing slopes, and almost always on a moderate incline (12-28 degrees).