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Lysimachia arvensis; photograph (c) Orzigul Anvarova, some rights reserved (CC BY) CC BY(c) Orzigul Anvarova, some rights reserved (CC BY) · observed growing wild · 2025-06-19

Lysimachia arvensis (L.) U.Manns & Anderb.

Scarlet pimpernel; Poor-man's-weatherglass; Shepherd's-weatherglass; Common Scarlet Pimpernel

Primulaceae · Denmark, Finland +78

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Lysimachia arvensis, photograph (c) Iona Cowell, some rights reserved (CC BY)Lysimachia arvensis, photograph (c) Iona Cowell, some rights reserved (CC BY)Lysimachia arvensis, photograph (c) Orzigul Anvarova, some rights reserved (CC BY)Lysimachia arvensis, photograph (c) Orzigul Anvarova, some rights reserved (CC BY)Lysimachia arvensis, photograph (c) Sophie Cron, some rights reserved (CC BY)Lysimachia arvensis, photograph (c) Jose Gutierrez Higa, some rights reserved (CC BY) 56 photographs ›
Habitat figures
Cold floor (1 night in 100)
2.4°C
Record low -0.8 °C in 44 years, at a typical spot in the range NASA POWER
Warmest month, mean daily high
27°C
Jul and Aug at the habitat CHELSA
Rain a year (median across the range)
684mm
9 months of 25 mm or more in the median year CHELSA
Open-sky light
13–47DLI
Lowest to highest month (DLI) CHELSA
The year in your months, northern hemisphere
  1. Jan
  2. Feb
  3. Mar
  4. Apr
  5. May
  6. Jun
  7. Jul
  8. Aug
  9. Sep
  10. Oct
  11. Nov
  12. Dec
Wet winters: the rain comes October to March, read as a winter growing season. rain rule, CHELSA
Northern hemisphere unless you set your site. The chart is in the habitat's months.

Summary

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.

Quoted from Wikipedia, "Lysimachia arvensis", CC BY-SA 4.0.

About the genus · Lysimachia

Lysimachia is a genus consisting of 182 accepted species of flowering plants traditionally classified in the family Primulaceae. Based on a molecular phylogenetic study it was transferred to the family Myrsinaceae, before this family was later merged into the Primulaceae.

Quoted from Wikipedia, "Lysimachia", CC BY-SA 4.0.

Cultivation

Seasons

The rain rule reads a winter growing season: 70% of the median year's rain (465 mm of 654 mm) falls in October to March, cooler than the year (wet-season mean 13.2 °C against a yearly mean of 16.7 °C). Months are the habitat's, northern hemisphere; shifted six months for a southern-hemisphere collection: April to September.

Rain

654 mm in the median year at the habitat, 465 mm of it October to March. Wettest month December at 100 mm, driest month July at 7 mm. Across the grid cells of the range the year's total runs 171 mm to 1,123 mm, the 10th to 90th percentile of each cell's own year. The median of the cells' own yearly totals, 684 mm, is the year's rain at the top of the page; the 654 mm here is the median year's, the twelve monthly medians added, which the rain rule reads. Habitat calendar, northern hemisphere; median year across the grid cells of the range, CHELSA.

Light

Open sky over the habitat: 13 to 47 mol/m²/day across the year (daily light integral, median year across the grid cells of the range, CHELSA; the lowest 10th-percentile month across the cells is 5, the highest 90th-percentile month 50).

Warmth and air
Temperature

Coldest: the 1st-percentile night over 44 years at a typical spot in the range is 2.4 °C, the absolute minimum -0.8 °C, 3 frost nights in 44 years (NASA POWER daily minima). Warmest: the 99th-percentile day is 41.0 °C. Monthly means: the coldest month's mean nightly low 6.8 °C in January (across the grid cells of the range 2.1 °C to 12.7 °C), the warmest month's mean daily high 26.9 °C in August (median year across the grid cells of the range, CHELSA). Cold floor: 2.4 °C, which is the 1st-percentile night over 44 years at a typical spot in the range (NASA POWER).

Humidity

Relative humidity at the habitat: 60 to 61% across the year (monthly means, median year across the grid cells of the range, CHELSA). A figure about the air, saying nothing about how the plant takes water.

How this section is made

Each card states this species' habitat figures with their sources, and what two fixed rules read from them; nothing here says what the plant does, wants or tolerates. The rules · the terms.

Seasons. Read from the median year of CHELSA monthly rainfall and mean temperature across the grid cells of the range: the rain rule takes the smallest set of months carrying 70% of the rain and calls it winter when its mean is more than half a degree below the year's, summer when more than that above, and neither in between; the temperature rule, used only under 120 mm, names the cooler six months when they are at least a degree cooler than the other six. Months are shifted for the other hemisphere only where the temperature curve moves 4 °C or more and the habitat lies 10° or more from the equator. A reading of the curves, not an observation of the plant.

Rain. CHELSA monthly precipitation, median year across the grid cells of the range. The rain that falls where the species is recorded; nothing about how the plant takes water.

Light. CHELSA shortwave radiation at each envelope cell, a daily-mean flux taken to a daily total and converted at 2.07 mol of PAR per MJ. The sky over the habitat, measured; what reaches a plant under a rock, a shrub or a shade cloth is not.

Temperature. NASA POWER daily minima and maxima over 44 years at a typical spot in the range, lapse-corrected +186 m to its elevation; CHELSA monthly means, median year across the grid cells of the range. The cold floor is the 1st-percentile night named in its sentence. Not a measured survival limit for any plant in a pot.

Humidity. CHELSA relative humidity, median year across the grid cells of the range.

Climate across the habitat

Habitat months, northern hemisphere

Habitat climate of Lysimachia arvensis through the yearWarmest months July and August, mean daily high 27 °C; coldest month January, mean nightly low 6.8 °C; 654 mm of rain in the median year (the twelve monthly medians added). Medians across the range, from CHELSA; the extremes at the edge from NASA POWER. Habitat months, northern hemisphere.-10°0°10°20°30°40°50°frost41.0° 99th-percentile day, NASA POWER-0.8° lowest night in 44 years, NASA POWER°C · day and nightcold quarter050100150200mm rainDLI 13–47RH 60–61%JanFebMarAprMayJunJulAugSepOctNovDec
day night rain medians and 10th–90th percentile across 92 habitat cells, CHELSA cold quarter: the three months around the coldest month's mean nightly low extremes over 44 years at a typical spot in the range, from NASA POWER, marked at the edge, in no month DLI, mol/m²/dayRH %each on its own scale
Figures by month
JanFebMarAprMayJunJulAugSepOctNovDec
Day °C14 / 7–1814 / 7–1816 / 9–2017 / 12–2120 / 16–2424 / 18–3027 / 19–3227 / 20–3224 / 18–2921 / 14–2517 / 11–2215 / 8–19
Night °C7 / 2–137 / 3–139 / 4–1411 / 6–1514 / 9–1717 / 12–2019 / 14–2220 / 15–2318 / 13–2115 / 10–2011 / 6–178 / 3–14
Rain mm73 / 24–13461 / 23–10855 / 20–9253 / 9–9445 / 3–8219 / 1–677 / 1–7117 / 1–7548 / 4–10084 / 16–12592 / 24–140100 / 29–153
DLI16 / 6–2321 / 11–2930 / 18–3738 / 28–4343 / 34–4747 / 37–5047 / 35–5042 / 30–4533 / 21–3923 / 13–3116 / 7–2513 / 5–22
RH %60 / 56–6661 / 56–6560 / 54–6460 / 54–6360 / 54–6460 / 52–6560 / 51–6660 / 52–6660 / 53–6561 / 56–6561 / 57–6661 / 57–67
How this section is made
Each figure is the median across the 92 grid cells on land that hold in-range records (99 records in those cells; 3 more cells hold records but no land by the elevation layer, so those records sit at sea and the cells are left out), with the 10th–90th percentile span across those cells after the slash where it differs. A dash is a month one or more of those cells has no figure for in the grid (a variable CHELSA does not carry there), so no median is taken rather than one over fewer cells. Extremes and elevation were read at a typical spot in the range, cell 1199:4230 (30.025, 31.525). Over 44 years there: absolute minimum -0.8 °C, 1st-percentile night 2.4 °C, 99th-percentile day 41.0 °C. Normals: CHELSA V2.1 1981–2010 climatology, 0.05° cells (each the mean of ~36 1 km pixels). Across the range: median and 10th–90th percentile of each month across the 92 distinct grid cells holding 99 of the 102 in-range records (3 further cells with records at sea, by the elevation layer, left out); extremes and elevation at the typical cell 1199:4230 (its coldest month's mean nightly low nearest the median across cells); its position is the cell centre. Extremes: NASA POWER (MERRA-2) daily 1981–2024, cell 30.00_31.250, lapse-corrected +186 m at 6.5 °C/km. Elevation: ETOPO 2022, 321 m (cell mean).

Natural habitat

Native range as published by WCVP; the marker is where the records are densest and decides nothing: the climate was read across the cells of the in-range records placed well enough to read one, not at the marker.
Openly licensed records inside the range, framed on where they fall.
NativeDenmark, Finland, Great Britain, Ireland, Norway, Sweden, Austria, Belgium, Czechoslovakia, Germany, Hungary, Netherlands, Poland, Switzerland, Baleares, Corse, France, Portugal, Sardegna, Spain, Albania, Bulgaria, Greece, Italy, Kriti, Romania, Sicilia, Turkey-in-Europe, Yugoslavia, Belarus, Baltic States, Krym, Central European Russia, East European Russia, North European Russia, South European Russia, Northwest European Russia, Ukraine, Algeria, Egypt, Libya, Morocco, Tunisia, Western Sahara, Azores, Canary Is., Cape Verde, Madeira, Selvagens, Burundi, Chad, Djibouti, Eritrea, Ethiopia, Socotra, Somalia, Sudan, Kazakhstan, Turkmenistan, Tadzhikistan, Uzbekistan, North Caucasus, Transcaucasus, Afghanistan, Cyprus, East Aegean Is., Iran, Iraq, Lebanon-Syria, Palestine, Sinai, Turkey, Gulf States, Kuwait, Oman, Saudi Arabia, Yemen, Nepal, Pakistan, West Himalaya · introduced: Nigeria, Kenya, Tanzania, Angola, Zimbabwe, Cape Provinces, KwaZulu-Natal, Free State, Northern Provinces, Ascension, St.Helena, Mauritius, Réunion, Primorye, Kirgizistan, China Southeast, Korea, Kazan-retto, Ogasawara-shoto, Taiwan, Assam, Bangladesh, East Himalaya, India, Norfolk Is., New South Wales, Northern Territory, Queensland, South Australia, Tasmania, Victoria, Western Australia, Antipodean Is., Chatham Is., Kermadec Is., New Zealand North, New Zealand South, New Caledonia, Easter Is., Hawaii, Greenland, British Columbia, New Brunswick, Nova Scotia, Ontario, Québec, Colorado, Idaho, Montana, Oregon, Washington, Illinois, Iowa, Kansas, Minnesota, Missouri, Nebraska, Oklahoma, Wisconsin, Connecticut, Indiana, Maine, Massachusetts, Michigan, New Hampshire, New Jersey, New York, Ohio, Pennsylvania, Rhode I., Vermont, West Virginia, Arizona, California, Nevada, Utah, New Mexico, Texas, Alabama, Arkansas, Delaware, Florida, Georgia, Kentucky, Louisiana, Maryland, Mississippi, North Carolina, South Carolina, Tennessee, Virginia, District of Columbia, Mexico Central, Mexico Northeast, Mexico Gulf, Mexico Northwest, Mexico Southwest, Mexico Southeast, Costa Rica, El Salvador, Guatemala, Honduras, Bermuda, Cuba, Dominican Republic, Haiti, Jamaica, Puerto Rico, Venezuela, Bolivia, Colombia, Ecuador, Peru, Brazil Northeast, Brazil Southeast, Brazil South, Argentina Northeast, Argentina South, Argentina Northwest, Chile Central, Chile North, Chile South, Juan Fernández Is., Uruguay, Crozet Is., Tristan da Cunha · regions are the level-3 units of the World Geographical Scheme for Recording Plant Distributions, as Kew's World Checklist records ranges, some under historical names such as Yugoslavia or Czechoslovakia (how).
Map marker38.876, -0.084 · in the densest population, 14 records (13% of those in range)
Kew's description“annual or biennial” · “temperate” · quoted from WCVP, RBG Kew (CC BY 4.0); not derived here
Evidence usedThe map marker rests on all 104 georeferenced records inside the native range; the climate across the range on the 99 of them in the land cells it reads, of 102 placed to within 10 km; the map shows only the 17 openly licensed ones, which alone would put the marker 1328 km away. 690 records outside the WCVP native range not used. 2 in-range records are placed to worse than 10 km, or with no stated accuracy (admitted only as a person's observation to three decimals), and stay on the map but off the climate.
How this section is made
The map marker: the openly licensed record nearest the middle of the densest 1° population of the 104 in-range records; it decides nothing. Records outside the native range, living specimens and records marked introduced are not used; which records count.

Photographs

Lysimachia arvensis, photograph 1did not loadLysimachia arvensis, photograph 2did not loadLysimachia arvensis, photograph 3did not loadLysimachia arvensis, photograph 4did not loadLysimachia arvensis, photograph 5did not loadLysimachia arvensis, photograph 6did not load

Photographs: (c) Iona Cowell, some rights reserved (CC BY) (2); (c) Orzigul Anvarova, some rights reserved (CC BY) (2); (c) Sophie Cron, some rights reserved (CC BY); (c) Jose Gutierrez Higa, some rights reserved (CC BY).

Similar habitat climate The 6 nearest by mean daily high, mean nightly low and rain, month by month. How.

Lobularia maritima Lobularia maritima Sweet alison Photo: CC BY, Vasco Henrique Oliveira FonsecaStachys ocymastrum Stachys ocymastrum Italian hedgenettle Photo: CC BY, Eric LambMalva multiflora Malva multiflora Cretan-hollyhock Photo: CC BY, zebedeugalinhaLathyrus ochrus Lathyrus ochrus Winged vetchling Photo: CC BY-SA, Cesare SandriRuta chalepensis Ruta chalepensis Fringed rue Photo: CC BY, Alessia GuggisbergColchicum filifolium Colchicum filifolium Colchicaceae Photo: CC BY, Augustin Soulard

Other Lysimachia 44 in the reference

Lysimachia asperulifolia Lysimachia asperulifolia Rough-leaf loosestrife Photo: CC BY, agjackson1Lysimachia atropurpurea Lysimachia atropurpurea Primulaceae Photo: CC BY-SA, Alessia GuggisbergLysimachia barystachys Lysimachia barystachys Manchurian yellow loosestrife Photo: CC BY, Violetta DzizyurovaLysimachia borealis Lysimachia borealis Northern starflower Photo: CC BY, Nick KleinschmidtLysimachia candida Lysimachia candida Manipur loosestrife Photo: CC BY, 黄彦豪Lysimachia capillipes Lysimachia capillipes Primulaceae Photo: CC BY, 黃美滿Lysimachia christinae Lysimachia christinae Primulaceae Photo: CC BY-SA, 阿橋 HQLysimachia ciliata Lysimachia ciliata Fringed loosestrife Photo: CC BY, Tom NortonLysimachia clethroides Lysimachia clethroides Gooseneck yellow loosestrife Photo: CC BY-SA, harum.kohLysimachia congestiflora Lysimachia congestiflora Dense-flowered loosestrife Photo: CC BY, Morten RossLysimachia davurica Lysimachia davurica Manchurian yellow loosestrife Photo: CC0, author not statedLysimachia decurrens Lysimachia decurrens Primulaceae Photo: CC BY, Cheng-Te Hsu all 45 ›

Names & registers

Also known as Anagallis arvensis subsp. arvensis; Anagallis arvensis var. arvensis; Anagallis phoenicia. (GBIF Backbone)

GBIFPOWOIPNIWFOWikidataWikipediaiNaturalist

The record

Family
Primulaceae
Described by
(L.) U.Manns & Anderb.
Native to
Denmark, Finland, Great Britain +77
Wild records
104 in range · 17 open

Every figure here is derived from public data by a stated rule and names its source; nothing about this species is written for its page by a person or by AI, apart from the marked, credited quotations. How →

Where this page came from built 2026-10-22
GBIF species record gbif.species answeredasked 2026-10-22
GBIF synonyms gbif.synonyms answeredasked 2026-10-22
GBIF common names gbif.vernacular answeredasked 2026-10-22names fetched 2026-10-22
WCVP native range wcvp.distribution answeredas of 2026-06-04
GBIF occurrence records gbif.occurrences answeredasked 2026-10-22GBIF occurrence search API; 46 records within 1 km of a botanic garden, herbarium or zoo left out (19 at a botanic garden or arboretum, 15 at a herbarium, 12 at a zoo; Wikidata's list)
Habitat climate climate answeredasked 2026-10-22
Daily extremes (NASA POWER) climate.extremes answeredasked 2026-10-22NASA POWER (MERRA-2) daily 1981–2024, cell 30.00_31.250, lapse-corrected +186 m at 6.5 °C/km
Wikidata wikidata answeredasked 2026-10-22
Wikipedia wikipedia answeredasked 2026-10-22
iNaturalist photographs, wild inat.photos.wild answeredasked 2026-10-22from iNaturalist's open data of 2026-09-27: research-grade observations with an open-licence photograph, the 24 whose photographs iNaturalist received last (the open data holds no votes); filled 2026-10-22
iNaturalist photographs, cultivated inat.photos.cultivated not asked
GBIF media gbif.media answeredasked 2026-10-22
OpenAlex papers openalex not askednot yet asked for this reference; a later fill takes the papers from OpenAlex's snapshot

Every source is recorded as having answered, reported nothing, refused, failed, not been asked, or answered twice where one answer is taken (“not taken: two items answered”), and, for a source asked when this page was built, when: the figures are as the source held them that day; a source read from a file (Kew's World Checklist, a GBIF download) says "as of" the file's day instead; a row carried from an earlier build of the page names that build instead. Only “nothing to report” is ever shown as an absence. Records came from 9 datasets via GBIF.org; each carries its own licence.

Cultifolio

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