Koenigia islandica; The Iceland-purslane is a small annual plant on Iceland. It grows in areas with sparse vegetation. In the highlands I noticed this plant is often fount in hollows around stones created by wind or water action around the stone. Apperantly the hollow around the stone gives the necessary protection. Characteristic are the red stems, the glossy green little leaves and the minute flowers.
It is a member of the dock family (Polygonaceae)