Ranunculus ficaria or Ficaria verna, commonly known as lesser celandine or pilewort, is a low-growing, hairless perennial flowering plant in the buttercup family Ranunculaceae.
It is native to central Europe, North Africa and the Caucasus.
The plant is poisonous if ingested raw and potentially fatal to grazing animals and livestock such as horses, cattle, and sheep. For these reasons, several US states have banned the plant or listed it as a noxious weed. It contains the toxin protoanemonin. The leaves need only a quick blanch to destroy the protoanemonin, as does drying.
It prefers bare, damp ground and is considered by horticulturalists in the United Kingdom as a persistent garden weed.
Emerging in late winter with flowers appearing March through May, its appearance across the landscape is regarded by many as a harbinger of spring.