Thimbleweed (Anemone spp) is a collection of perennial herbs which come in a variety of different colors and presentations. They are often used in rock gardens and also sold often in flower stores as a cute flower.
All parts of the Anemone plant is poisonous. It contains protoanemonin, which causes intense pain and inflammation of the mouth with blistering, ulceration, and profuse salivation. There is sometimes central nervous system involvement.