Pimpernel, a sprawling herb with many small, five-pointed flowers. It also is called poor man's weatherglass, because the flowers close in cloudy weather. In the United States it is a common weed in sandy, waste places. The scarlet, or common, pimpernel has scarlet, purplish, or white flowers and oval leaves. The flaxleaf pimpernel has blue flowers with a reddish tinge and narrow leaves.

The pimpernel belongs to the primrose family, Primulaceae. The scarlet pimpernel is Anagallis arvensis; flaxleaf, A. linifolia.