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Cerastium arcticum; photograph Ingvild Riska, CC BY, iNaturalist via GBIF CC BYIngvild Riska, CC BY, iNaturalist via GBIF

Cerastium arcticum Lange

Arctic Mouse-ear; Arctic mouse-ear chickweed; Arctic chickweed

Caryophyllaceae · Svalbard, West Siberia +5

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Cerastium arcticum, photograph Ingvild Riska, CC BY, iNaturalist via GBIFCerastium arcticum, photograph Cees Bronger, CC BY, via GBIFCerastium arcticum, photograph Cees Bronger, CC BY, via GBIFCerastium arcticum, photograph anasacuta, CC BY, iNaturalist via GBIFCerastium arcticum, photograph William Stephens, CC BY, iNaturalist via GBIFCerastium arcticum, photograph William Stephens, CC BY, iNaturalist via GBIF 24 photographs ›
Habitat figures
Cold floor (1 night in 100)
-27.9°C
Record low -39.5 °C in 44 years, at a typical spot in the range NASA POWER
Warmest month, mean daily high
4°C
Jul at the habitat CHELSA
Rain a year (median across the range)
531mm
11 months of 25 mm or more in the median year CHELSA
Open-sky light
0–40DLI
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
Rain spread: 70% of the median year's rain takes 8 months, so no short rainy season. rain rule, CHELSA
Northern hemisphere unless you set your site. The chart is in the habitat's months.

Summary

Cerastium arcticum, the Arctic mouse-ear chickweed or Arctic mouse-ear, is a flower found in parts of western and southern Greenland, Baffin Island, Labrador, Iceland, Faroe Islands, Scotland, Norway and Svalbard.

Quoted from Wikipedia, "Cerastium arcticum", CC BY-SA 4.0.

About the genus · Cerastium

Cerastium is a genus of annual, winter annual, or perennial flowering plants belonging to the family Caryophyllaceae. They are commonly called mouse-ears or mouse-ear chickweeds. There are 214 accepted species, found nearly worldwide but with the greatest concentration in the northern temperate regions. More on Wikipedia ›

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

Cultivation

Seasons

The rain rule reads no short rainy season: 70% of the median year's rain (415 mm of 540 mm) takes 8 months, August to March. Mean temperature moves 19.8 °C between the warmest and coldest month. Months are the habitat's, northern hemisphere; shifted six months for a southern-hemisphere collection: February to September.

Rain

540 mm in the median year at the habitat, 415 mm of it August to March. Wettest months (2 at 56 mm), driest month May at 23 mm. Across the grid cells of the range the year's total runs 388 mm to 815 mm, the 10th to 90th percentile of each cell's own year. The median of the cells' own yearly totals, 531 mm, is the year's rain at the top of the page; the 540 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: 0 to 40 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 0, the highest 90th-percentile month 45).

Warmth and air
Temperature

Coldest: the 1st-percentile night over 44 years at a typical spot in the range is -27.9 °C, the absolute minimum -39.5 °C, 13,519 frost nights in 44 years, 307.3 a year (NASA POWER daily minima). Warmest: the 99th-percentile day is 4.2 °C. Monthly means: the coldest month's mean nightly low -18.9 °C in February (across the grid cells of the range -23.0 °C to -11.1 °C), the warmest month's mean daily high 3.9 °C in July (median year across the grid cells of the range, CHELSA). Cold floor: -27.9 °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: 67 to 71% 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 -26 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 Cerastium arcticum through the yearWarmest month July, mean daily high 4 °C; coldest month February, mean nightly low -18.9 °C; 540 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.-50°-40°-30°-20°-10°0°10°frost4.2° 99th-percentile day, NASA POWER-39.5° lowest night in 44 years, NASA POWER°C · day and nightcold quarter0255075100mm rainDLI 0–40RH 67–71%JanFebMarAprMayJunJulAugSepOctNovDec
day night rain medians and 10th–90th percentile across 512 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 °C-14 / -17–-7-14 / -18–-8-14 / -17–-7-11 / -13–-5-4 / -5–-11 / 0–34 / 2–63 / 1–50 / -2–2-6 / -9–-2-9 / -12–-4-13 / -16–-6
Night °C-18 / -22–-11-19 / -23–-11-18 / -22–-11-15 / -18–-8-7 / -8–-3-1 / -2–12 / 0–41 / -1–3-3 / -5–0-10 / -13–-5-14 / -17–-7-17 / -21–-10
Rain mm55 / 39–8652 / 34–7750 / 32–8036 / 25–5623 / 17–3928 / 19–4138 / 25–5946 / 32–7656 / 36–9647 / 32–7753 / 39–7756 / 41–80
DLI00 / 0–15 / 4–720 / 16–2336 / 29–3940 / 34–4531 / 25–3718 / 16–227 / 5–91 / 0–200
RH %68 / 62–7468 / 62–7469 / 62–7567 / 62–7267 / 62–7069 / 64–7270 / 63–7571 / 65–7469 / 65–7367 / 62–7367 / 62–7368 / 61–74
How this section is made
Each figure is the median across the 512 grid cells on land that hold in-range records (764 records in those cells; 26 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 201:3972 (79.925, 18.625). Over 44 years there: absolute minimum -39.5 °C, 1st-percentile night -27.9 °C, 99th-percentile day 4.2 °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 512 distinct grid cells holding 764 of the 798 in-range records (26 further cells with records at sea, by the elevation layer, left out); extremes and elevation at the typical cell 201:3972 (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 80.00_18.750, lapse-corrected -26 m at 6.5 °C/km. Elevation: ETOPO 2022, 128 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.
NativeSvalbard, West Siberia, Greenland, Nunavut, Northwest Territories, Labrador, Québec · 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 marker78.217, 15.631 · in the densest population, 359 records (32% of those in range)
Kew's description“subshrub” · “temperate” · quoted from WCVP, RBG Kew (CC BY 4.0); not derived here
Evidence usedThe map marker rests on all 1127 georeferenced records inside the native range; the climate across the range on the 764 of them in the land cells it reads, of 798 placed to within 10 km; the map shows only the 1060 openly licensed ones, which alone would put the marker in the same place. 382 records outside the WCVP native range not used. 329 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 1127 in-range records; it decides nothing. Records outside the native range, living specimens and records marked introduced are not used; which records count.

Photographs

Cerastium arcticum, photograph 1did not loadCerastium arcticum, photograph 2did not loadCerastium arcticum, photograph 3did not loadCerastium arcticum, photograph 4did not loadCerastium arcticum, photograph 5did not loadCerastium arcticum, photograph 6did not load

Photographs: Ingvild Riska, CC BY, iNaturalist via GBIF; Cees Bronger, CC BY, via GBIF (2); anasacuta, CC BY, iNaturalist via GBIF; William Stephens, CC BY, iNaturalist via GBIF (2).

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

Ranunculus sulphureus Ranunculus sulphureus Ranunculaceae Photo: CC BY, desertnaturalistCochlearia groenlandica Cochlearia groenlandica Danish scurvygrass Photo: CC BY, Ida B D JacobsenPotentilla hyparctica Potentilla hyparctica Arctic cinquefoil Photo: CC BY, Johnathan CampbellAlopecurus magellanicus Alopecurus magellanicus Alpine foxtail Photo: CC BY, EstebanMHBoechera holboellii Boechera holboellii Holboell's rockcress Photo: CC BY, Ida B D JacobsenDraba alpina Draba alpina Alpine draba Photo: CC BY, desertnaturalist

Other Cerastium 26 in the reference

Cerastium alpinum Cerastium alpinum Alpine mouse-ear Photo: CC BY, Denys Vynokurov Cerastium argenteum Caryophyllaceae Cerastium arvense Cerastium arvense Field mouse-ear Photo: CC0, author not statedCerastium banaticum Cerastium banaticum Caryophyllaceae Photo: CC BY-SA, Krzysztof Ziarnek, KenraizCerastium biebersteinii Cerastium biebersteinii Snow-in-summer Photo: CC BY, Sergey CherkasovCerastium brachypetalum Cerastium brachypetalum Grey mouse-ear Photo: CC BY, Eric WeissgerberCerastium candidissimum Cerastium candidissimum Greek Snow-In-Summer Photo: CC BY, Pantazi KaterinaCerastium davuricum Cerastium davuricum Caryophyllaceae Photo: CC BY, ivansemenkovCerastium decalvans Cerastium decalvans Caryophyllaceae Photo: CC0, Mirko UbovićCerastium elongatum Cerastium elongatum Caryophyllaceae Photo: CC BY, Jared ShormaCerastium fontanum Cerastium fontanum Common mouse-ear Photo: CC0, author not statedCerastium gibraltaricum Cerastium gibraltaricum Gibraltar chickweed Photo: CC BY-SA, jlblancopastor all 27 ›

Names & registers

Also known as Cerastium alpinum var. procerum; Cerastium alpinum var. uniflorum; Cerastium arcticum subsp. hyperboreum; Cerastium arcticum subsp. procerum; Cerastium arcticum subsp. vestitum and 5 more. (GBIF Backbone)

GBIFPOWOIPNIWFOWikidataWikipedia

The record

Family
Caryophyllaceae
Described by
Lange
Native to
Svalbard, West Siberia, Greenland +4
Wild records
1127 in range · 1060 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 2026-10-21
GBIF species record gbif.species answeredasked 2026-10-21
GBIF synonyms gbif.synonyms answeredasked 2026-10-21
GBIF common names gbif.vernacular answeredasked 2026-10-21names fetched 2026-10-21
WCVP native range wcvp.distribution answeredas of 2026-06-04
GBIF occurrence records gbif.occurrences answeredas of 2026-10-21GBIF occurrence download https://doi.org/10.15468/dl.hbdw64, of 2026-10-21; 5 records within 1 km of a botanic garden, herbarium or zoo left out (5 at a botanic garden or arboretum; Wikidata's list)
Habitat climate climate answeredasked 2026-10-21
Daily extremes (NASA POWER) climate.extremes answeredasked 2026-10-21NASA POWER (MERRA-2) daily 1981–2024, cell 80.00_18.750, lapse-corrected -26 m at 6.5 °C/km
Wikidata wikidata answeredasked 2026-10-21
Wikipedia wikipedia answeredasked 2026-10-21
iNaturalist taxon inat.taxon not asked
iNaturalist photographs, wild inat.photos.wild not asked
iNaturalist photographs, cultivated inat.photos.cultivated not asked
GBIF media gbif.media answeredasked 2026-10-21
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 50 datasets via GBIF.org; each carries its own licence.

Cultifolio

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