A pimpernel is a small wild plant that usually has red flowers.
pimpernel in British English
(ˈpɪmpəˌnɛl, -nəl)
noun
1.
any of several plants of the primulaceous genus Anagallis, such as the scarlet pimpernel, typically having small star-shaped flowers
2.
any of several similar and related plants, such as Lysimachia nemorum (yellow pimpernel)
Word origin
C15: from Old French pimpernelle, ultimately from Latin piperpepper; compare Old English pipeneale
pimpernel in American English
(ˈpɪmpərˌnɛl; ˈpɪmpərnəl)
noun
any of a genus (Anagallis) of plants of the primrose family, esp. the scarlet pimpernel (A. arvensis), with red, white, or blue, starlike flowers which close in bad weather
Word origin
ME pympernelle < OFr piprenelle < LL pimpinella, an herb with medicinal uses, prob. altered < *piperinella, ult. < L piper, pepper: its fruit resembles small peppercorns