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Trillium cernuum; photograph (c) Dustin Snider, some rights reserved (CC BY) CC BY(c) Dustin Snider, some rights reserved (CC BY) · observed growing wild · 2026-06-02

Trillium cernuum L.

Whip-poor-will flower; Nodding trillium; Nodding wakerobin

Melanthiaceae · Manitoba, Saskatchewan +29

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Trillium cernuum, photograph (c) Dustin Snider, some rights reserved (CC BY)Trillium cernuum, photograph (c) brendanboyd, some rights reserved (CC BY)Trillium cernuum, photograph (c) brendanboyd, some rights reserved (CC BY)Trillium cernuum, photograph author not stated, no rights reservedTrillium cernuum, photograph (c) Jenn (McPhee) Dyson, some rights reserved (CC BY)Trillium cernuum, photograph (c) naturalist charlie, some rights reserved (CC BY) 72 photographs ›
Habitat figures
Cold floor (1 night in 100)
-26.2°C
Record low -35.6 °C in 44 years, at a typical spot in the range NASA POWER
Warmest month, mean daily high
24°C
Jul and Aug at the habitat CHELSA
Rain a year (median across the range)
886mm
12 months of 25 mm or more in the median year CHELSA
Open-sky light
8–39DLI
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 summers: the rain comes April to October, read as a summer growing season. rain rule, CHELSA
Northern hemisphere unless you set your site. The chart is in the habitat's months.

Summary

Trillium cernuum is a species of flowering plant in the bunchflower family Melanthiaceae. The specific epithet cernuum means "drooping, curving forwards, facing downwards", a distinctive habit of its flower. It is commonly called nodding trillium or nodding wakerobin (not to be confused with Trillium flexipes) since the flower is invariably found nodding beneath the leaves. It is sometimes referred to as the northern nodding trillium to distinguish from Trillium rugelii, a similar nodding species native to the southern Appalachian Mountains. More on Wikipedia ›

Quoted from Wikipedia, "Trillium cernuum", CC BY-SA 4.0.

About the genus · Trillium

Trillium is a genus of about fifty flowering plant species in the family Melanthiaceae. Trillium species are native to temperate regions of North America and Asia, with the greatest diversity of species found in the southern Appalachian Mountains in the southeastern United States.

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

Cultivation

Seasons

The rain rule reads a summer growing season: 70% of the median year's rain (642 mm of 914 mm) falls in April to October, warmer than the year (wet-season mean 13.3 °C against a yearly mean of 5.6 °C). Months are the habitat's, northern hemisphere; shifted six months for a southern-hemisphere collection: October to April.

Rain

914 mm in the median year at the habitat, 642 mm of it April to October. Wettest month June at 103 mm, driest month February at 41 mm. Across the grid cells of the range the year's total runs 713 mm to 1,323 mm, the 10th to 90th percentile of each cell's own year. The median of the cells' own yearly totals, 886 mm, is the year's rain at the top of the page; the 914 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: 8 to 39 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 6, the highest 90th-percentile month 42).

Warmth and air
Temperature

Coldest: the 1st-percentile night over 44 years at a typical spot in the range is -26.2 °C, the absolute minimum -35.6 °C, 7,734 frost nights in 44 years, 175.8 a year (NASA POWER daily minima). Warmest: the 99th-percentile day is 28.5 °C. Monthly means: the coldest month's mean nightly low -13.6 °C in January (across the grid cells of the range -18.7 °C to -7.8 °C), the warmest month's mean daily high 24.3 °C in July (median year across the grid cells of the range, CHELSA). Cold floor: -26.2 °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: 56 to 65% 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 -289 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 Trillium cernuum through the yearWarmest months July and August, mean daily high 24 °C; coldest month January, mean nightly low -13.6 °C; 914 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.-40°-20°0°20°40°frost28.5° 99th-percentile day, NASA POWER-35.6° lowest night in 44 years, NASA POWER°C · day and nightcold quarter0255075100125mm rainDLI 8–39RH 56–65%JanFebMarAprMayJunJulAugSepOctNovDec
day night rain medians and 10th–90th percentile across 1010 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-6 / -10–1-4 / -8–22 / -1–79 / 5–1417 / 11–2022 / 17–2524 / 21–2824 / 21–2719 / 17–2212 / 9–155 / 1–9-3 / -7–3
Night °C-14 / -19–-8-12 / -16–-7-7 / -10–-30 / -2–46 / 4–1013 / 10–1516 / 14–1816 / 14–1812 / 10–146 / 3–8-1 / -5–2-9 / -14–-3
Rain mm51 / 21–10541 / 18–9550 / 31–11371 / 49–11086 / 71–107103 / 83–121100 / 80–11593 / 80–11799 / 81–11690 / 65–12571 / 38–12559 / 26–120
DLI10 / 9–1317 / 16–1925 / 24–2732 / 30–3437 / 35–3939 / 37–4239 / 36–4133 / 31–3525 / 23–2716 / 14–1910 / 8–138 / 6–11
RH %65 / 59–6863 / 57–6559 / 56–6256 / 54–6056 / 55–6059 / 57–6159 / 57–6260 / 58–6260 / 58–6260 / 58–6261 / 59–6464 / 59–69
How this section is made
Each figure is the median across the 1010 grid cells holding the 1392 in-range records, 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 833:2305 (48.325, -64.725). Over 44 years there: absolute minimum -35.6 °C, 1st-percentile night -26.2 °C, 99th-percentile day 28.5 °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 1010 distinct grid cells holding 1392 of the 1392 in-range records; extremes and elevation at the typical cell 833:2305 (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 48.50_-65.000, lapse-corrected -289 m at 6.5 °C/km. Elevation: ETOPO 2022, 21 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.
NativeManitoba, Saskatchewan, New Brunswick, Newfoundland, Nova Scotia, Ontario, Prince Edward I., Québec, Illinois, Iowa, Minnesota, North Dakota, South Dakota, Wisconsin, Connecticut, Indiana, Maine, Massachusetts, Michigan, New Hampshire, New Jersey, New York, Ohio, Pennsylvania, Rhode I., Vermont, West Virginia, Delaware, Maryland, Virginia, District of Columbia · 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 marker46.699, -92.231 · in the densest population, 907 records (50% of those in range)
Kew's description“rhizomatous geophyte” · “temperate” · quoted from WCVP, RBG Kew (CC BY 4.0); not derived here
Evidence usedThe map marker rests on all 1808 georeferenced records inside the native range; the climate across the range on the 1392 of them placed to within 10 km; the map shows only the 492 openly licensed ones, which alone would put the marker 211 km away. 5 records outside the WCVP native range not used. 416 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 4° block of the 1808 in-range records; it decides nothing. Records outside the native range, living specimens and records marked introduced are not used; which records count.

Photographs

Trillium cernuum, photograph 1did not loadTrillium cernuum, photograph 2did not loadTrillium cernuum, photograph 3did not loadTrillium cernuum, photograph 4did not loadTrillium cernuum, photograph 5did not loadTrillium cernuum, photograph 6did not load

Photographs: (c) Dustin Snider, some rights reserved (CC BY); (c) brendanboyd, some rights reserved (CC BY) (2); author not stated, no rights reserved · CC0; (c) Jenn (McPhee) Dyson, some rights reserved (CC BY); (c) naturalist charlie, some rights reserved (CC BY).

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

Solidago hispida Solidago hispida Hairy goldenrod Photo: CC BY, Jenn (McPhee) DysonPinus banksiana Pinus banksiana Jack pine Photo: CC BY, Nathan AaronNuphar × rubrodisca Nuphar × rubrodisca Red-disk yellow pond-lily Photo: CC BY, Quinten WiegersmaLonicera hirsuta Lonicera hirsuta Hairy honeysuckle Photo: CC0, author not statedLonicera oblongifolia Lonicera oblongifolia Swamp fly honeysuckle Photo: CC BY, Dustin SniderHypericum fraseri Hypericum fraseri Hypericaceae Photo: CC BY-SA, Michael Wolf

Other Trillium 39 in the reference

Trillium albidum Trillium albidum Giant white wakerobin Photo: CC0, author not statedTrillium angustipetalum Trillium angustipetalum Narrowpetal wakerobin Photo: CC BY, Barry Langdon-LassagneTrillium apetalon Trillium apetalon Melanthiaceae Photo: CC BY, Kristof ZyskowskiTrillium camschatcense Trillium camschatcense Kamchatka trillium Photo: CC BY, Kristof ZyskowskiTrillium catesbaei Trillium catesbaei Bashful wakerobin Photo: CC BY, willingardenTrillium chloropetalum Trillium chloropetalum Giant trillium Photo: CC0, author not statedTrillium cuneatum Trillium cuneatum Little sweet Betsy Photo: CC BY, Joseph FeltsTrillium decipiens Trillium decipiens Chattahoochee River wakerobin Photo: CC BY, Brandon CorderTrillium decumbens Trillium decumbens Decumbent Trillium Photo: CC BY-SA, Turner BrockmanTrillium discolor Trillium discolor Mottled wakerobin Photo: CC BY, Rachel StepekTrillium erectum Trillium erectum Red trillium Photo: CC BY, Evan M. RaskinTrillium flexipes Trillium flexipes Drooping trillium Photo: CC BY, Chris Stahl all 40 ›

Names & registers

Also known as Trillium cernuum f. billingtonii; Trillium cernuum f. cernuum; Trillium cernuum f. lalondei; Trillium cernuum f. marginatum; Trillium cernuum f. tangerae and 12 more. (GBIF Backbone)

GBIFPOWOIPNIWFOWikidataWikipediaiNaturalist

The record

Family
Melanthiaceae
Described by
L.
Native to
Manitoba, Saskatchewan, New Brunswick +28
Wild records
1808 in range · 492 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 answeredas of 2026-10-21GBIF occurrence download https://doi.org/10.15468/dl.hbdw64, of 2026-10-21; 31 records within 1 km of a botanic garden, herbarium or zoo left out (14 at a botanic garden or arboretum, 4 at a herbarium, 13 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 48.50_-65.000, lapse-corrected -289 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 54 datasets via GBIF.org; each carries its own licence.

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