Saxifraga rivularis; the alpine brook saxifrage is a relative small Saxifrage species that grows almost everywhere on Iceland, but for the southern coastal regions. It is a plant that prefers wet stony habitats. Usually it grows in open area's like mossy riversides.
Apart from the typical (compact) growth-form I also included a photo of a plant that grew in a lava hollow. Because of the darker condition in the hollow the plant is more etiolated (elongated stem-growth) than the normal more compact growth. It is a member of the saxifrage family (Saxifragaceae). The Icelandic name of this species is Lækjasteinbrjótur.