As the alternative names of shepherd’s sundial and shepherd’s weather-glass suggest, scarlet pimpernel is well-known for its ability to indicate both the weather and the time of day. The small, bright scarlet flowers open at around 8 am each day, and close at 3 pm. They also close during humid or damp weather (4). This member of the primrose family is a diminutive plant, creeping close to the ground. The egg-shaped leaves are pale green and dotted with black on the undersides (2). The flowers of the subspecies native to Britain (arvensis) are red or pink, but a blue-flowered form (Forma azurea) also occurs, which is often confused with the introduced subspecies blue pimpernel (Anagallis arvensis subsp. foemina) (2). The name pimpernel comes from the Old French pimprenele, the misapplied name of the burnet saxifrage, Pimpinella saxifrage(4).
Scarlet pimpernel is typically an annual or short-lived perennial species (3). It flowers from May to late August and is pollinated by visiting insects, which are attracted by means of bright purple hairs inside the flowers which apparently act as lures (5). When it is ripe, the fruit capsule at the centre of the flower splits open, with the top section hinging backwards to allow the release of the tiny seeds within (4).
This plant was widely used in the past to treat toothache, liver problems, snake bites and kidney inflammation. As the names ‘laughter bringer’ and ‘shepherd’s joy’ indicate, it was also used to reduce bouts of melancholia (4).
This native plant is common and widespread throughout much of Britain, becoming a rare and mainly coastal species further north, particularly in Scotland (2)(3). Elsewhere this species has a very broad global distribution, being found throughout much of the world, except the tropics (2).
Occuring in open habitats and typically a weed of arable areas and gardens, scarlet pimpernel is also found around rabbit warrens, on road verges, sand dunes, heaths, chalk downland and on coastal cliffs (2)(3).
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