Ranunculus hyperboreus; The Arctic buttercup is a peculiar buttercup species. First it has three sepals (calyx leaves) and three petals (corolla leaves). this is very unusual for dicotolydons in general. This feature immediately distiguishes them from all other buttercups. Also the sepals are light-colored, resembling petals. The petals are light-yellow to, but can also seem to be almost white under certain light conditions. Although the distribution over Iceland of the arctic buttercup is fairly wide spread, the species is usually found at or around (hot) springs. Apperently it seems that it requires rich iron feed from spring water.
It is a member of the buttercup family (Ranunculaceae). The Icelandic name of this species is Sefbrúða.