Stellaria humifusa; the Saltmarsh Stitchwort is a Stellaria species that grows only on saline soils i.e. beach and coastal saltmarsh areas on Iceland. I am not quite sure about the world-wide distribution of this species, but I know it also can be found on Greenland. It resembles another Stellaria species on Iceland, being St. crassifolia(Fleshy Stitchwort). These two species can be best differentiated by their sepal tips: they are sharpely pointed in the Fleshy Stitchwort but blunt in the Saltmarsh Stitchwort. Also the leaves of the Saltmarsh Stitchwort are more fleshy than those of Fleshy Stitchwort (contrary to what the names may suggest). The pedicels of the Fleshy Stitchwort are ribbed (grooved) on the top, not so in the Saltmarsh Stitchwort. Obviously the saltmarsh stitchwort is found only near sea on salty/brackish soils where the Fleshy Stitchwort grows on fresh-water fed bogs and other moist soils.
It is a member of the Pink family (Caryophyllaceae). The Icelandic name of this species is Lágarfi