Pimpernel /(?)/

Pim·per·nel

Pimpernel

n.
  1. A plant of the genus Anagallis, of which one species (Anagallis arvensis) has small flowers, usually scarlet, but sometimes purple, blue, or white, which speedily close at the approach of bad weather. (Bot.)

Phrases & Compounds
Water pimpernel
See Brookweed.