Celandine

A close-up of a pair of flowers of a Greater Celandine (Chelidonium majus) plant.

Chelidonium majus, commonly known as the greater celandine or tetterwort (in America, the latter refers to Sanguinaria canadensis), is the only species in the genus Chelidonium, family Papaveraceae. The greater celandine is native to Europe and the Mediterranean basin. It is also widespread in North America, having been brought there by settlers as a herbal remedy for skin problems such as warts as early as 1672.
It is considered to be a poisonous plant and is listed as such by the Canadian Poisonous Plants Information System.