Anagallis arvensis

Scarlet pimpernel
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Clade:	Asterids
Order:	Ericales
Family:	Primulaceae
Genus:	Anagallis
Species:	A. arvensis
Binomial name
Anagallis arvensis L.
Synonyms
Lysimachia arvensis (L.) U.Manns & Anderb.

Anagallis arvensis (syn. Lysimachia arvensis), commonly known as the scarlet pimpernel, red pimpernel, red chickweed, poor man's barometer, poor man's weather-glass,^[1] shepherd's weather glass or shepherd's clock, is a species of low-growing annual plant with brightly coloured flowers,^[2] most often scarlet but also bright blue and sometimes pink. The native range of the species is Europe and Western Asia and North Africa.^[3] The species has been distributed widely by humans, either deliberately as an ornamental flower or accidentally.^[4] A. arvensis is now naturalised almost worldwide, with a range that encompasses the Americas, Central and East Asia, the Indian Subcontinent, Malesia, the Pacific Islands, Australasia and Southern Africa.^[5][6][7]

Traditionally included in the primrose family Primulaceae, the genus Anagallis was placed in the family Myrsinaceae^[8] until that family in turn was included in Primulaceae in the APG III system. The genus Anagallis is included in Lysimachia by some authors.^[9]

This common European plant is generally considered a weed and is an indicator of light soils, though it grows opportunistically in clay soils as well. The origin of the name pimpernel comes from late Middle English pympernele [1400–50], derived from Middle French pimprenelle, from Old French piprenelle, and ultimately from Vulgar Latin *piperīnella (piper 'pepper' + -īn- '-ine' + -ella diminutive suffix).

The flower serves as the emblem of the fictional hero the Scarlet Pimpernel.