Marsh Marigold (Caltha palustris). It is in the buttercup family and its other names
include double yellow marigold and Kingscup. It is a delicate but sturdy tundra plant.
There are no petals but five rounded sepals. Caltha means cup and refers to the shape
of the flower. The name from the Middle Ages referred to it as the flower of the Virgin Mary
or Mary's gold and marybud.
It was mentioned by Shakespeare in Cymbelline II.3:
Winking Marybuds begin
To open their golden eyes