Anthyllis vulneraria; the Kidney Vetch is legume species that is only common in the south-western Iceland (Reykjanes peninsula - south-east of Reykjavik - and Mossveltveit - just north of Reykjavik). It grows on dry nutrient-poor soils. I found this species to thrive on thermally warm soils at Gunnuhver. This thermally hot area lies in the extreme southwest point of the Reykjanes district. Recently though, (>2010's) it has appeared in a very different region, being Loðmundarfjörður in South-eastern Iceland. Here it has become very common along the jeep-track that leads into this richly vegetated valley from where it also settles on the slopes along this fjord valley. Strangely enough, in this fjord also the Blue Mountain-heath (Phyllodoce coerulea), which elsewhere is only found in the north of Iceland. Why this remote valley is home (or rather has become home) to these species who elsewhere grow in totally different regions of Iceland is unknown. The Kidney Vetch is such a characteristic plant that it can't be confused. The pinnate leaves normally have a large top leaflet and small or no side leaflets. The plant trails over the ground. In thicker vegetation often only the large leaflets are visible (see photo). Near inflorescences, though, the leaflets are more or less equal. The (yellow with red spots) flowers are arranged like clovers and typically have may hairs in between. The flowers are pea-flower shaped (family trait). Icelandic Kidney Vetch is regarded to be the subspecies borealis of Anthyllis vulneraria
It is a member of the pea family (Fabaceae, formerly known as Papillionaceae). The Icelandic name of this species is Gullkollur.