Pimpernel
Pimpernel , noun
[French pimprenelle; compare Sp. pimpinela, Italian pimpinella; perh. from Late Latin bipinnella, for bipinnula two-winged, equiv. to Latin bipennis; bis twice + penna feather, wing. Compare Pen a feather.]
(Botany) 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.