Lysimachia arvensis

Blue form

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

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 Template:Lang [1400–50], derived from Middle French Template:Lang, from Old French Template:Lang, and ultimately from Vulgar Latin Template:Lang (Template:Lang 'pepper' + Template:Lang '-ine' + Template:Lang 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 Template:Convert long. They bear bright green, soft, ovate sessile leaves in opposite pairs. The orange, red or blue, radially symmetric flowers, about Template:Convert 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 Template:Clarification needed span 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).<ref name="manns2007">Template:Cite journal</ref> The species has a diploid chromosome count of 2n=40.<ref>Template:Cite book</ref>

Scarlet pimpernel flowers open only when the sun shines, and even close in overcast conditions.<ref name="ct-botanical-society" /> This habit leads to names such as "shepherd's weather glass". It has been observed along the verges of salted roads, creating a broad red band along the roadside.<ref name=Doerr>Template:Cite book</ref>

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.<ref name=POWO_77100386-1/> The petals of the type arvensis are bright red to minium-coloured; carnea is deep peach; lilacina is lilac; pallida is white; and azurea is blue. The blue form can be difficult to distinguish from L. foemina, but the petal margins are diagnostic: whereas L. foemina has clearly irregular petal margins with only 5 to 15 glandular hairs, L. arvensis f. azurea has 50 to 70 hairs on only slightly irregular margins.Template:Citation needed

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  Flower close up
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  L. arvensis f. azurea together with a colour variant closer to f. carnea
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  L. arvensis f. azurea. The glandular hairs on the petal margins, at least 50 in this example, are clearly visible in the enlarged photo.
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  Purple form
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  Fruits and seeds of Lysimachia arvensis

Medical and agricultural significance

Lysimachia arvensis is generally unwelcome as a cosmopolitan invasive species; it is harmfully toxic in several respects and accordingly undesirable in pastures. The plant is acrid and bitter, and grazing livestock generally avoid eating it except in conditions of overgrazing or grazing of unsatisfying stubble. Experimental feeding of the plant material to various animals, such as horses and dogs, caused gastroenteritis.<ref name= "WattPP">Watt, John Mitchell; Breyer-Brandwijk, Maria Gerdina: The Medicinal and Poisonous Plants of Southern and Eastern Africa 2nd ed Pub. E & S Livingstone 1962</ref> Sufficiently high doses proved fatal.<ref name="Long1917">Template:Cite book</ref> Less specifically the herb has been reported as being toxic to poultry and rabbits, and the seed to birds.<ref name= "WattPP"/>

Lysimachia arvensis is less often used in folk medicine worldwide than where it has long been familiar in its countries of origin. In various countries however, the plant material has been applied externally to slow-healing ulcers and wounds. It also has been applied as an expectorant and as a remedy for pruritus, rheumatism, haemorrhoids, rabies, leprosy, and snake-bite. Lysimachia has been used in treatment of non-specified types of phthisis, and of kidney-related conditions such as dropsy and chronic nephritis. It was used as an antidepressant in ancient Greece, and to treat various mental disorders in European folk medicine, leading to the German name Template:Lang (Template:Lang meaning 'fool, cuckoo' and Template:Lang meaning 'heal'). Generally however, documented evidence for clinical efficacy is lacking. Lysimachia arvensis is traditionally known by pharmacists as Arvensis Herba.<ref>The Edinburgh New Dispensatory, Andrew Duncan (the Younger), Bell & Bradfute, 1813, p 278</ref>

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.<ref name="Long1917"/> Reportedly an Indian practice of expelling leeches from dog nostrils can lead to fatal results if the animal swallows the fluid.<ref name= "WattPP"/>

The herb and its seed contain saponins, which could explain why fresh material is strongly haemolytic.<ref>Podolak I, Galanty A, Sobolewska D. Saponins as cytotoxic agents: a review. Phytochemistry Reviews. 2010;9(3):425-474. Template:Doi [1]</ref> Among other possible glycosides,<ref name="Long1917"/> the root yields the triterpenoid glycoside cyclamin<ref name= "WattPP"/> which is highly toxic and occurs in Cyclamen species,<ref name= "vWvHvO">Template:Cite book</ref> also a member of the subfamily Myrsinoideae.<ref name="SHARMA2011">Template:Cite book</ref>

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

Antibacterial tests of the green parts failed to show any encouraging positive effect.<ref name="WattPP" />

In literature

Scarlet pimpernel (Template:Transliteration in Tamil) is one of the two flowers mentioned in the Template:Transliteration.<ref>Template:Cite web</ref>

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.<ref>Template:Cite book</ref> The flower appears in The Lord of the Rings: Fellowship of the Ring,<ref>Template:Cite book</ref> The Lord of the Rings: Return of the King,<ref>Template:Cite book</ref> and in Unfinished Tales.<ref>Template:Cite book</ref>

Sources

• Template:Cite book
• Harvey Wickes Felter and John Uri Lloyd (1898) King's American Dispensatory.
• Template:Cite journal

External links

• Connecticut Botanical Society: Anagallis arvensis Template:Webarchive
• USDA Plants Profile: Anagallis arvensis
• Ploi - Plant Care Guide: Anagallis arvensis