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Calypso bulbosa; photograph (c) Dustin Snider, some rights reserved (CC BY) CC BY(c) Dustin Snider, some rights reserved (CC BY) · observed growing wild · 2026-05-31

Calypso bulbosa (L.) Oakes

Fairy-slipper; Fairy-slipper orchid; Venus'-slipper; Venus's slipper

Orchidaceae · Finland, Sweden +55

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Calypso bulbosa, photograph (c) Dustin Snider, some rights reserved (CC BY)Calypso bulbosa, photograph (c) Jared Shorma, some rights reserved (CC BY)Calypso bulbosa, photograph (c) Jared Shorma, some rights reserved (CC BY)Calypso bulbosa, photograph (c) Jared Shorma, some rights reserved (CC BY)Calypso bulbosa, photograph (c) Jared Shorma, some rights reserved (CC BY)Calypso bulbosa, photograph (c) Jared Shorma, some rights reserved (CC BY) 88 photographs ›
Habitat figures
Coldest month, mean nightly low
-8.9°C
Dec at the habitat, not a floor; extremes not used (the weather cell's ground is too far off) CHELSA
Warmest month, mean daily high
21°C
Jul and Aug at the habitat CHELSA
Rain a year (median across the range)
856mm
12 months of 25 mm or more in the median year CHELSA
Open-sky light
6–43DLI
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

Calypso is a genus of orchids containing one species, Calypso bulbosa, known as the calypso orchid, fairy slipper or Venus's slipper. It is a perennial member of the orchid family found in undisturbed northern and montane forests. It has a small pink, purple, pinkish-purple, or red flower accented with a white lip, darker purple spottings, and yellow beard. The genus Calypso takes its name from the Greek signifying concealment, as they tend to favor sheltered areas on conifer forest floors. More on Wikipedia ›

Quoted from Wikipedia, "Calypso bulbosa", CC BY-SA 4.0.

Cultivation

Seasons

The rain rule reads no short rainy season: 70% of the median year's rain (580 mm of 797 mm) takes 8 months, October to January and March to June. Mean temperature moves 21.5 °C between the warmest and coldest month. Months are the habitat's, northern hemisphere; shifted six months for a southern-hemisphere collection: April to July and September to December.

Rain

797 mm in the median year at the habitat, 580 mm of it October to January and March to June. Wettest month November at 89 mm, driest month August at 49 mm. Across the grid cells of the range the year's total runs 552 mm to 1,938 mm, the 10th to 90th percentile of each cell's own year. The median of the cells' own yearly totals, 856 mm, is the year's rain at the top of the page; the 797 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: 6 to 43 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 50).

Warmth and air
Temperature

Monthly means: the coldest month's mean nightly low -8.9 °C in December (across the grid cells of the range -16.2 °C to 3.3 °C), the warmest month's mean daily high 21.3 °C in July (median year across the grid cells of the range, CHELSA). Cold floor: none read. The nearest figure is -8.9 °C, the coldest month's mean nightly low, December, in the median year (CHELSA); a month's mean of its nightly lows is warmer than the nights a floor is read from. The daily extremes were read at a weather cell whose ground is too far above or below the typical spot to correct for, and are not used.

Humidity

Relative humidity at the habitat: 56 to 66% 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. CHELSA monthly means, median year across the grid cells of the range. No cold floor is read without a daily extremes series; the coldest month's mean nightly low named in its sentence is not one. 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 Calypso bulbosa through the yearWarmest months July and August, mean daily high 21 °C; coldest month December, mean nightly low -8.9 °C; 797 mm of rain in the median year (the twelve monthly medians added). Medians across the range, from CHELSA. Habitat months, northern hemisphere.-20°-10°0°10°20°30°frost°C · day and nightcold quarter0100200300400mm rainDLI 6–43RH 56–66%JanFebMarAprMayJunJulAugSepOctNovDec
day night rain medians and 10th–90th percentile across 982 habitat cells, CHELSA cold quarter: the three months around the coldest month's mean nightly low DLI, mol/m²/dayRH %each on its own scale
Figures by month
JanFebMarAprMayJunJulAugSepOctNovDec
Day °C-1 / -9–91 / -8–104 / -3–129 / 3–1514 / 9–1818 / 14–2221 / 17–2721 / 16–2717 / 11–2411 / 4–182 / -4–12-2 / -8–8
Night °C-9 / -16–3-8 / -15–4-5 / -11–5-2 / -6–73 / -1–98 / 4–1111 / 7–1411 / 7–147 / 3–121 / -4–9-5 / -11–6-9 / -16–3
Rain mm79 / 26–29758 / 23–22862 / 30–20960 / 31–13962 / 43–10970 / 31–10651 / 11–11349 / 13–10059 / 24–8274 / 37–16789 / 33–30884 / 27–343
DLI8 / 1–1314 / 4–2023 / 12–2932 / 24–3938 / 32–4641 / 34–4943 / 30–5037 / 22–4428 / 13–3616 / 5–259 / 1–166 / 0–12
RH %66 / 60–7163 / 59–7062 / 57–6559 / 54–6257 / 53–6256 / 53–6157 / 49–6057 / 49–6258 / 51–6461 / 54–6866 / 59–7166 / 60–72

The daily extremes were not used: the correction for elevation, +1011 m, is beyond the 1,000 m either way that a lapse rate is applied over, so the weather cell's ground is other terrain than the typical spot's. So no cold floor is read for this species, and the coldest month's mean nightly low is not taken as one. What that cell gave, so corrected, over 44 years: absolute minimum -34.3 °C, 1st-percentile night -20.8 °C.

How this section is made
Each figure is the median across the 982 grid cells on land that hold in-range records (1527 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 862:1166 (46.875, -121.675). 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 982 distinct grid cells holding 1527 of the 1530 in-range records (3 further cells with records at sea, by the elevation layer, left out); extremes and elevation at the typical cell 862:1166 (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 47.00_-121.875, lapse-corrected +1011 m at 6.5 °C/km. Elevation: ETOPO 2022, 1921 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.
NativeFinland, Sweden, Baltic States, Central European Russia, East European Russia, North European Russia, Northwest European Russia, Buryatiya, Irkutsk, Krasnoyarsk, West Siberia, Yakutskiya, Amur, Khabarovsk, Primorye, Sakhalin, China South-Central, Inner Mongolia, Manchuria, China North-Central, Tibet, Mongolia, Japan, Korea, Aleutian Is., Alaska, Nunavut, Northwest Territories, Yukon, Alberta, British Columbia, Manitoba, Saskatchewan, New Brunswick, Newfoundland, Nova Scotia, Ontario, Prince Edward I., Québec, Colorado, Idaho, Montana, Oregon, Washington, Wyoming, Minnesota, South Dakota, Wisconsin, Maine, Michigan, New Hampshire, New York, Vermont, Arizona, California, Utah, New Mexico · 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 marker48.531, -123.51 · in the densest population, 512 records (29% of those in range)
Kew's description“tuberous geophyte” · “temperate” · quoted from WCVP, RBG Kew (CC BY 4.0); not derived here
Evidence usedThe map marker rests on all 1784 georeferenced records inside the native range; the climate across the range on the 1527 of them in the land cells it reads, of 1530 placed to within 10 km; the map shows only the 690 openly licensed ones, which alone would put the marker 6946 km away. 1 record outside the WCVP native range not used. 254 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 inside the densest 2° block of the 1784 in-range records; it decides nothing. Records outside the native range, living specimens and records marked introduced are not used; which records count.

Photographs

Calypso bulbosa, photograph 1did not loadCalypso bulbosa, photograph 2did not loadCalypso bulbosa, photograph 3did not loadCalypso bulbosa, photograph 4did not loadCalypso bulbosa, photograph 5did not loadCalypso bulbosa, photograph 6did not load

Photographs: (c) Dustin Snider, some rights reserved (CC BY); (c) Jared Shorma, some rights reserved (CC BY) (5).

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

Rumex occidentalis Rumex occidentalis Western dock Photo: CC BY, Urgamal MagsarCanadanthus modestus Canadanthus modestus Great northern aster Photo: CC BY, Barbara BanfieldRibes lacustre Ribes lacustre Swamp currant Photo: CC0, author not statedPinus contorta Pinus contorta Lodgepole pine Photo: CC BY, Adam KamalSpiraea lucida Spiraea lucida Shinyleaf Meadowsweet Photo: CC BY, Caleb CattoLonicera involucrata Lonicera involucrata Bearberry honeysuckle Photo: CC BY, Laura Gaudette

Names & registers

Also known as Calypso borealis; Calypso bulbosa f. bulbosa; Calypsodium boreale; Cymbidium boreale; Cypripedium bulbosum and 7 more. (GBIF Backbone)

GBIFPOWOIPNIWFOWikidataWikipediaiNaturalist

The record

Family
Orchidaceae
Described by
(L.) Oakes
Native to
Finland, Sweden, Baltic States +54
Wild records
1784 in range · 690 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; 11 records within 1 km of a botanic garden, herbarium or zoo left out (8 at a botanic garden or arboretum, 3 at a zoo; 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 47.00_-121.875, lapse-corrected +1011 m at 6.5 °C/km; read, and set aside: the correction for elevation, +1011 m, is beyond the 1,000 m either way that a lapse rate is applied over, so the weather cell's ground is other terrain than the typical spot's, so no cold floor is shown
Wikidata wikidata answeredasked 2026-10-21
Wikipedia wikipedia answeredasked 2026-10-21
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 2026-10-21
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 68 datasets via GBIF.org; each carries its own licence.

Cultifolio

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