Silene acaulis, moss campion, is a small mountain-dwelling wildflower that is common all over the high arctic and the higher mountains of Europe and North America (Alps, Carpathians, Urals, Pyrenees, British Isles, Faroe Islands, Rocky Mountains, Spitsbergen).
It is densely tufted, forming domed cushions composed of long shoots with four or five small green leaves at their apex and many remnants of old leaves below. The cushion has a solid, very long taproot. The leaves are narrow with short stiff hairs on the margin. Numerous pink (rarely white) flowers, seldom more than one on each shoot; the petals are distinctly longer than the calyx. S. acaulis displays "compass flowering", developing flowers on the southfacing part of the cushion first, later on the north side. It has a long flowering season. It grows mainly in dry, gravelly localities, but also in damper places. With the cushions it produces its own, warmer climate with high temperatures inside, when the sun shines.