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Trillium gracile; photograph (c) Turner Brockman, some rights reserved (CC BY-SA) CC BY-SA(c) Turner Brockman, some rights reserved (CC BY-SA) · observed growing wild · 2026-03-07

Trillium gracile J.D.Freeman

Slender trillium; Graceful trillium; Sabine River wakerobin; Graceful Wakerobin

Melanthiaceae · Texas, Louisiana

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Trillium gracile, photograph (c) Turner Brockman, some rights reserved (CC BY-SA)Trillium gracile, photograph (c) Turner Brockman, some rights reserved (CC BY-SA)Trillium gracile, photograph (c) Turner Brockman, some rights reserved (CC BY-SA)Trillium gracile, photograph (c) Turner Brockman, some rights reserved (CC BY-SA)Trillium gracile, photograph (c) Michelle W. （鍾偉瑋）, some rights reserved (CC BY)Trillium gracile, photograph (c) Turner Brockman, some rights reserved (CC BY-SA) 57 photographs ›
Habitat figures
Cold floor (1 night in 100)
-3.9°C
Record low -12.8 °C in 44 years, at a typical spot in the range NASA POWER
Warmest month, mean daily high
34°C
Aug at the habitat CHELSA
Rain a year (median across the range)
1,415mm
12 months of 25 mm or more in the median year CHELSA
Open-sky light
16–40DLI
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

Trillium gracile, commonly known as the Sabine River wakerobin, slender trillium, or graceful trillium, is a species of flowering plant in the family Melanthiaceae. It is native to the region along the Sabine River in western Louisiana and eastern Texas. It generally grows in mature pine and hardwood forests, and on riverbanks.

Quoted from Wikipedia, "Trillium gracile", 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 no short rainy season: 70% of the median year's rain (1,005 mm of 1,407 mm) takes 8 months, October to March and May to June. Mean temperature moves 18.0 °C between the warmest and coldest month. Months are the habitat's, northern hemisphere; shifted six months for a southern-hemisphere collection: April to September and November to December.

Rain

1,407 mm in the median year at the habitat, 1,005 mm of it October to March and May to June. Wettest month December at 146 mm, driest month August at 91 mm. Across the grid cells of the range the year's total runs 1,376 mm to 1,446 mm, the 10th to 90th percentile of each cell's own year. The median of the cells' own yearly totals, 1,415 mm, is the year's rain at the top of the page; the 1,407 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: 16 to 40 mol/m²/day across the year (daily light integral, median year across the grid cells of the range, CHELSA).

Warmth and air
Temperature

Coldest: the 1st-percentile night over 44 years at a typical spot in the range is -3.9 °C, the absolute minimum -12.8 °C, 846 frost nights in 44 years, 19.2 a year (NASA POWER daily minima). Warmest: the 99th-percentile day is 40.2 °C. Monthly means: the coldest month's mean nightly low 6.3 °C in January (across the grid cells of the range 5.9 °C to 6.6 °C), the warmest month's mean daily high 33.6 °C in August (median year across the grid cells of the range, CHELSA). Cold floor: -3.9 °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: 58 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 -12 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 gracile through the yearWarmest month August, mean daily high 34 °C; coldest month January, mean nightly low 6.3 °C; 1,407 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.-20°-10°0°10°20°30°40°50°frost40.2° 99th-percentile day, NASA POWER-12.8° lowest night in 44 years, NASA POWER°C · day and nightcold quarter050100150200mm rainDLI 16–40RH 58–61%JanFebMarAprMayJunJulAugSepOctNovDec
day night rain medians and 10th–90th percentile across 11 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 °C15 / 15–1618 / 17–1821 / 21–2125 / 25–2629 / 29–3032 / 32–3233 / 33–3334 / 33–3431 / 30–3126 / 26–2621 / 20–2116 / 16–16
Night °C6 / 6–78 / 7–811 / 11–1115 / 15–1520 / 19–2023 / 22–2324 / 24–2424 / 24–2421 / 21–2217 / 16–1712 / 12–128 / 7–8
Rain mm122 / 116–129119 / 112–127115 / 109–123103 / 97–105120 / 116–125133 / 124–151108 / 93–11591 / 82–96100 / 95–107117 / 113–124133 / 126–136146 / 139–149
DLI18 / 18–1822 / 22–2229 / 28–2935 / 35–3638 / 38–3839 / 38–3940 / 39–4037 / 37–3832 / 32–3226 / 26–2619 / 19–2016 / 16–16
RH %60 / 59–6059 / 59–605958 / 58–5960 / 59–6061 / 61–6261 / 60–6260 / 59–605958 / 58–595960 / 59–60
How this section is made
Each figure is the median across the 11 grid cells holding the 12 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 1176:1720 (31.175, -93.975). Over 44 years there: absolute minimum -12.8 °C, 1st-percentile night -3.9 °C, 99th-percentile day 40.2 °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 11 distinct grid cells holding 12 of the 12 in-range records; extremes and elevation at the typical cell 1176:1720 (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 31.00_-93.750, lapse-corrected -12 m at 6.5 °C/km. Elevation: ETOPO 2022, 56 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.
NativeTexas, Louisiana · 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 marker30.931, -94.114 · in the densest population, 131 records (97% 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 135 georeferenced records inside the native range; the climate across the range on the 12 of them placed to within 10 km; the map shows only the 60 openly licensed ones, which alone would put the marker 10 km away. 123 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 135 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 gracile, photograph 1did not loadTrillium gracile, photograph 2did not loadTrillium gracile, photograph 3did not loadTrillium gracile, photograph 4did not loadTrillium gracile, photograph 5did not loadTrillium gracile, photograph 6did not load

Photographs: (c) Turner Brockman, some rights reserved (CC BY-SA) (5); (c) Michelle W. （鍾偉瑋）, some rights reserved (CC BY).

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

Yucca cernua Yucca cernua Nodding Yucca Photo: CC BY, Reid HardinPhysostegia digitalis Physostegia digitalis Finger false dragonhead Photo: CC BY, Laura ClarkEchinacea sanguinea Echinacea sanguinea Sanguine purple-coneflower Photo: CC BY, Cleveland PowellLiatris tenuis Liatris tenuis Gulf blazing star Photo: CC BY, Michelle W. （鍾偉瑋）Silene subciliata Silene subciliata Scarlet catchfly Photo: CC BY, Reid HardinCallirhoe papaver Callirhoe papaver Woodland poppymallow Photo: CC BY, Chet Burrier

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 cernuum Trillium cernuum Whip-poor-will flower Photo: CC BY, Dustin SniderTrillium 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. Raskin all 40 ›

Names & registers

Also known as Trillium gracile f. luteum. (GBIF Backbone)

GBIFPOWOIPNIWFOWikidataWikipediaiNaturalist

The record

Family
Melanthiaceae
Described by
J.D.Freeman
Native to
Texas, Louisiana
Wild records
135 in range · 60 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
Habitat climate climate answeredasked 2026-10-22
Daily extremes (NASA POWER) climate.extremes answeredasked 2026-10-22NASA POWER (MERRA-2) daily 1981–2024, cell 31.00_-93.750, lapse-corrected -12 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 2026-10-22none of the photographs on this page is credited to GBIF: those shown are other sources', and GBIF's were the same photographs or were set aside by the photograph rules
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 14 datasets via GBIF.org; each carries its own licence.

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