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Lysimachia arvensis, syn. Anagallis arvensis, commonly known as scarlet pimpernel, red pimpernel, red chickweed, poor man's barometer, poor man's weather-glass, shepherd's weather glass or shepherd's clock, is a species of low-growing annual plant with brightly coloured flowers, most often scarlet but also bright blue and sometimes pink. The native range of the species is Europe and Western Asia and North Africa. The species has been distributed widely by humans, either deliberately as an ornamental flower or accidentally. L. 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.

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 [1400–50], derived from Middle French , from Old French , and ultimately from Vulgar Latin ( 'pepper' + '-ine' + diminutive suffix).

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

Description

When found as a summer annual, the scarlet pimpernel has a low-growing creeping habit, but as a winter annual, it forms a half-rosette with an upright stem. It has weak sprawling stems with square cross-section growing to about long. They bear bright green, soft, ovate sessile leaves in opposite pairs. The orange, red or blue, radially symmetric flowers, about in diameter, are produced singly in the leaf axils from spring to autumn. The petal margins are somewhat crenate and have small glandular hairs. The stamens have and therefore attract a variety of pollinators, especially flies, but the flowers are also capable of autopollination. The dehiscent capsule fruits ripen from August to October in the northern hemisphere. The weight of the fruiting body bends the stem, and the seeds are transported by the wind or rain. Blue-flowered plants (treated as L. arvensis f. azurea by some sources) are common in some areas, such as the Mediterranean region, and should not be confused with the related blue pimpernel, Lysimachia foemina. In 2007, a molecular phylogenetic study showed that Lysimachia foemina is more closely related to Lysimachia monelli than to Lysimachia arvensis, and should be treated as a separate species (all three species were then placed in Anagallis). The species has a diploid chromosome count of 2n=40.

Scarlet pimpernel flowers open only when the sun shines, and even close in overcast conditions.

Scarlet pimpernel has a wide variety of flower colours, which may be treated as forms, although not by Plants of the World Online which does not accept any subdivisions. Sufficiently high doses proved fatal. Less specifically the herb has been reported as being toxic to poultry and rabbits, and the seed to birds.

Lysimachia arvensis is insecticidal, or at least is repellent to some insects, possibly by virtue of its pungent essential oil which has a characteristic smell. Taken by mouth, experimental doses of the liquid in humans caused twenty-four hours of intense nausea, headache and bodily pain. Some people also experience dermatitis from contact with the leaf. Reports from Australia state that when grain crops have been infested by the weed, chaff that contains much of the material becomes unpalatable to stock as fodder. When grazing in pasture, livestock usually leave the plant alone, but when they do nonetheless eat significant quantities, they suffer diuretic and narcotic effects sufficiently intense to justify regarding the plant as poisonous. Among other possible glycosides, also a member of the subfamily Myrsinoideae.

The plant contains tanning agents, bitters, and the proteolytic enzyme primverase.

Antibacterial tests of the green parts failed to show any encouraging positive effect.

The Scarlet Pimpernel is the alias of Sir Percy Blakeney in the novel of the same name by Baroness Emma Orczy and its numerous film and musical adaptations.

The fictional flower Elanor is said to be a little enlarged version of pimpernel, according to one of J. R. R. Tolkien's letters. The flower appears in The Lord of the Rings: Fellowship of the Ring, The Lord of the Rings: Return of the King, and in Unfinished Tales.

References

Sources

  • Harvey Wickes Felter and John Uri Lloyd (1898) King's American Dispensatory.
  • Connecticut Botanical Society: Anagallis arvensis
  • USDA Plants Profile: Anagallis arvensis
  • Ploi - Plant Care Guide: Anagallis arvensis