Trillium luteum, Great Smoky Mountains, Cosby, TN, US

Trillium luteum (Muhl.) Harb.

Lemon-scented Trillium, Lemon-scented Wakerobin, Wax Toadshade, Wax Wakerobin

Climate known 35 photographs

Every figure on this page is derived from public data by a stated rule and says its source; nothing here is written by a person or a model, except the Wikipedia passage, which is quoted and marked as such. How it is made.

Summary

Trillium luteum, the yellow trillium or yellow wakerobin, is a species of flowering plant in the bunchflower family Melanthiaceae. It is a member of the Trillium cuneatum complex, a closely related group of sessile-flowered trilliums. The species is endemic to the southeastern United States, especially in and around the Great Smoky Mountains of eastern Tennessee and western North Carolina.

Text from Wikipedia, “Trillium luteum”, CC BY-SA 4.0, quoted as written. Kept separate from everything derived here.

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.

Text from Wikipedia, “Trillium”, CC BY-SA 4.0, quoted as written.

Family

Melanthiaceae

Described by

(Muhl.) Harb.

Native to

Alabama, Georgia, Kentucky +2

Wild records

1262 in range· 259 open

At a glance

Warmest month

30°C

Jul, mean day; nights 20 °C (CHELSA)

Rain

1375mm/yr

12 wet months · peak Feb 136 mm (CHELSA)

Light

14–39DLI

mol/m²/day, winter to summer, open sky (CHELSA shortwave)

In short condensed by rule from the cultivation cards · not written by a person

Rain rule: no season, 70% of the rain takes 8 months (December to July in the northern hemisphere). Habitat rain 1375 mm a year, wettest February at 136 mm, driest October at 79 mm (habitat calendar, northern hemisphere). Open sky over the habitat: 14 to 39 mol/m²/day. Cold floor -10.2 °C (1st-percentile habitat night, NASA POWER).

Each sentence is one card's own one-line form, written by the same rule as the card (Its year, Rain, Light, Temperature); the note cannot say what a card does not. Months are given for the northern hemisphere (set your site in Settings to change this), and the habitat's own alongside. The cards · the figures.

Also known as Trillium cuneatum var. luteum (Muhl.) H.E.Ahles; Trillium hugeri f. flavum Peattie; Trillium sessile f. luteum (Muhl.) Peattie; Trillium sessile var. luteum Muhl.; Trillium underwoodii var. luteum (Muhl.) J.F.Macbr. and 1 more.

Cultivation

Its year Rain rule: no season, 70% of the rain takes 8 months (December to July in the northern hemisphere).

This species’ habitat figures, and what two fixed rules read from them.

The rain rule reads no season: 70% of the year's rain (989 mm of 1375 mm) takes 8 months, December to July. Mean temperature moves 21.7 °C between the warmest and coldest month. Months are the habitat's, northern hemisphere; shifted six months for a southern-hemisphere collection: June to January.

Read from the median year of CHELSA monthly rainfall and mean temperature across the envelope cells: 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 gives a season to reverse. A reading of the curves, not an observation of the plant.

Rain Habitat rain 1375 mm a year, wettest February at 136 mm, driest October at 79 mm (habitat calendar, northern hemisphere).

This species’ habitat figures, with their source.

1375 mm a year at the habitat, 989 mm of it December to July. Wettest month February at 136 mm, driest October at 79 mm. Across the envelope cells the year's total runs 1206 mm to 1648 mm (10th to 90th percentile of each cell's own year) (median year across the envelope cells, CHELSA; habitat calendar, northern hemisphere).

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

Light Open sky over the habitat: 14 to 39 mol/m²/day.

This species’ habitat figures, with their source.

Open sky over the habitat: 14 to 39 mol/m²/day across the year (daily light integral, median year across the envelope cells, CHELSA; the lowest 10th-percentile month across the cells is 13, the highest 90th-percentile month 40).

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.

Warmth and air Cold floor -10.2 °C (1st-percentile habitat night, NASA POWER).

This species’ habitat figures, with their source.

Temperature

Coldest: the 1st-percentile night over 44 years at the typical cell is -10.2 °C, the absolute minimum -24.7 °C, about 64 frost nights a year (NASA POWER daily minima). Warmest: the 99th-percentile day is 35.2 °C. Monthly means: coldest night -1.0 °C in January (across the envelope cells -2.7 °C to 0.7 °C), warmest day 29.5 °C in July (median year across the envelope cells, CHELSA). Cold floor: -10.2 °C, which is the 1st-percentile night over 44 years at the typical cell (NASA POWER).

NASA POWER daily minima and maxima 1981–2024 at the typical cell, lapse-corrected to its elevation; CHELSA monthly means, median year across the envelope cells, CHELSA. The cold floor is the figure named in its sentence. Not a measured survival limit for any plant in a pot.

Humidity

Relative humidity at the habitat: 56 to 61% across the year (monthly means, median year across the envelope cells, CHELSA). A figure about the air, saying nothing about how the plant takes water.

CHELSA relative humidity, median year across the envelope cells.

The figures the cards read from are in Climate below, and where they came from in Natural habitat.

Climate across the habitat

day night rain 10th–90th percentile across 384 habitat cells cold quarter: the three months around the coldest night extremes over 44 years at the typical cell, marked at the edge: undated DLI, mol/m²/dayRH %each on its own scale

Figures by month

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Day °C	8 / 7–10	10 / 9–12	15 / 13–17	20 / 18–21	24 / 22–26	28 / 25–29	30 / 27–31	29 / 26–31	26 / 23–27	20 / 18–22	15 / 13–16	9 / 8–11
Night °C	-1 / -3–1	1 / -1–2	4 / 2–6	9 / 7–10	14 / 11–15	18 / 16–19	20 / 18–22	20 / 17–21	16 / 14–18	10 / 9–12	5 / 4–7	1 / -1–2
Rain mm	130 / 98–157	136 / 102–167	123 / 109–148	111 / 97–132	115 / 101–138	115 / 104–145	127 / 114–155	102 / 83–124	96 / 81–117	79 / 65–98	109 / 89–133	132 / 103–161
DLI	16 / 14–17	20 / 19–21	28 / 27–29	35 / 34–36	38 / 37–39	39 / 39–40	38 / 37–38	35 / 34–36	29 / 29–30	24 / 23–25	17 / 16–18	14 / 13–15
RH %	58 / 58–59	57 / 57–58	56 / 55–57	56 / 55–57	59 / 57–60	60 / 59–62	61 / 60–63	61 / 59–63	60 / 58–62	58 / 57–59	58 / 57–59	59 / 58–60

Each figure is the median across the 384 grid cells holding the 1104 in-range records, with the 10th–90th percentile span across those cells after the slash where it differs. Extremes and elevation were read at the typical cell 1085:1924 (35.725, -83.775). Over 44 years there: absolute minimum -24.7 °C, 1st-percentile night -10.2 °C, 99th-percentile day 35.2 °C. Normals: CHELSA V2.1 1981–2010 climatology, 0.05° cells (each the mean of ~36 1 km pixels). Envelope: median and 10th–90th percentile of each month across the 384 distinct grid cells holding the 1104 in-range records; extremes and elevation at the typical cell 1085:1924 (its coldest month's mean night nearest the median across cells); its position is the cell centre. Extremes: NASA POWER (MERRA-2) daily 1981–2024, cell 35.50_-83.750, lapse-corrected -310 m at 6.5 °C/km. Elevation: ETOPO 2022, 432 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 every in-range record's cell, not at the marker.

Openly licensed records inside the range, framed on where they fall.

NativeAlabama, Georgia, Kentucky, North Carolina, Tennessee· introduced: Maryland

Kew's description“rhizomatous geophyte” · “temperate”· quoted from WCVP, RBG Kew (CC BY 4.0); not derived here

Map marker35.678, -83.766 · in the densest population, 1091 records (86% of those in range)

Evidence usedThe map marker and the climate envelope rest on all 1262 georeferenced records inside the native range; the map shows only the 259 openly licensed ones, which alone would put the marker 1 km away. 215 records outside the range (gardens, roadsides, misidentifications) ignored. 158 in-range records are placed to worse than 10 km and stay on the map but off the climate.

The map markerthe map marker: the openly licensed record nearest the middle of the densest 1° population of the 1262 in-range records; it decides nothing.

Photographs

Photographs: (c) Will Kuhn, some rights reserved (CC BY) (2); (c) Niki Robertson, some rights reserved (CC BY); (c) Dan Vickers, some rights reserved (CC BY); (c) Natalie Lemanski, some rights reserved (CC BY-SA); (c) Alaina Krakowiak, some rights reserved (CC BY); no rights reserved · CC0; (c) Asher P Higgins, some rights reserved (CC BY).

Photographs: iNaturalist did not answer when this page was built; what is shown came from the sources that did.

Papers naming this species

Works whose title or abstract names Trillium luteum, most cited first, from OpenAlex (CC0). A mention, not a cultivation source: nothing on this page is drawn from them.

Tennessee's Forests, 2004

Christopher M. Oswalt, Sonja N. Oswalt, Tony G. Johnson, James L. Chamberlain (2009)

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