Species
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Ilex glabra (L.) A.Gray

Appalachian tea, Appalachian-tea, Bitter Gallberry, Canadian winterberry

Climate known 81 photographs
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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

Ilex glabra, also known as Appalachian tea, evergreen winterberry, Canadian winterberry, gallberry, inkberry, dye-leaves and houx galbre, is a species of evergreen holly native to the coastal plain of eastern North America, from coastal Nova Scotia to Florida and west to Louisiana where it is most commonly found in sandy woods and peripheries of swamps and bogs. Ilex glabra is often found in landscapes of the middle and lower East Coast of the United States. It normally is cultivated as an evergreen shrub in USDA zones 6 to 10.

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

About the genus · Ilex

Ilex or holly is a genus of over 570 species of flowering plants in the family Aquifoliaceae, and the only living genus in that family. Ilex has the most species of any woody dioecious angiosperm genus. The species are evergreen or deciduous trees, shrubs, and climbers from tropics to temperate zones worldwide. More on Wikipedia ›

The opening of Wikipedia, “Holly”, CC BY-SA 4.0, quoted as written.

Family
Aquifoliaceae
Described by
(L.) A.Gray
Native to
Nova Scotia, Connecticut, Maine +18
Wild records
1792 in range· 414 open

At a glance

Warmest month
31°C
Jul, mean day; nights 23 °C (CHELSA)
Rain
1382mm/yr
12 wet months · peak Aug 179 mm (CHELSA)
Light
18–40DLI
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 (March, May to October and December in the northern hemisphere). Habitat rain 1382 mm a year, wettest August at 179 mm, driest April at 84 mm (habitat calendar, northern hemisphere). Open sky over the habitat: 18 to 40 mol/m²/day. Cold floor -4.2 °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 Ennepta myricoides Raf.; Ilex glabra f. leucocarpa F.W.Woods; Ilex glabra var. austrina Ashe; Prinos glaber L.; Winterlia glabra (L.) C.Koch and 2 more.

Cultivation

Its year Rain rule: no season, 70% of the rain takes 8 months (March, May to October and December 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 (1035 mm of 1382 mm) takes 8 months, March, May to October and December. Mean temperature moves 16.6 °C between the warmest and coldest month. Months are the habitat's, northern hemisphere; shifted six months for a southern-hemisphere collection: November to April, June and September.

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 1382 mm a year, wettest August at 179 mm, driest April at 84 mm (habitat calendar, northern hemisphere).

This species’ habitat figures, with their source.

1382 mm a year at the habitat, 1035 mm of it March, May to October and December. Wettest month August at 179 mm, driest April at 84 mm. Across the envelope cells the year's total runs 1180 mm to 1640 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: 18 to 40 mol/m²/day.

This species’ habitat figures, with their source.

Open sky over the habitat: 18 to 40 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 11, the highest 90th-percentile month 42).

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 -4.2 °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 -4.2 °C, the absolute minimum -11.0 °C, about 18 frost nights a year (NASA POWER daily minima). Warmest: the 99th-percentile day is 38.5 °C. Monthly means: coldest night 6.8 °C in January (across the envelope cells -3.1 °C to 13.1 °C), warmest day 30.9 °C in July (median year across the envelope cells, CHELSA). Cold floor: -4.2 °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: 57 to 64% 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

Habitat climate through the yearMean day from 16 °C in Jan to 31 °C in Jul; mean night from 7 °C in Jan to 23 °C in Jul. The cold quarter, Dec to Feb, is the three months around the coldest night. 1382 mm of rain a year, most in Aug. The bands show the 10th to 90th percentile across 955 habitat cells. Over 44 years at the typical cell the absolute minimum was -11.0 °C and the 99th-percentile day 38.5 °C; neither is dated to a month. Beneath: daily light integral and relative humidity through the year, each on its own scale.-20°-10°10°20°30°40°frost38.5° 99th-percentile day (undated)-11.0° lowest night in 44 yrs (undated)°C · day and nightcold quarter050100150200250mm rainDLI 18–40RH 57–64 %JanFebMarAprMayJunJulAugSepOctNovDec
day night rain 10th–90th percentile across 955 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
JanFebMarAprMayJunJulAugSepOctNovDec
Day °C16 / 3–2217 / 4–2321 / 7–2524 / 11–2728 / 16–3030 / 22–3231 / 25–3230 / 25–3229 / 21–3025 / 16–2821 / 11–2517 / 6–23
Night °C7 / -3–138 / -2–1411 / 1–1614 / 5–1818 / 10–2222 / 16–2423 / 19–2523 / 19–2521 / 16–2417 / 10–2112 / 5–188 / -0–15
Rain mm90 / 56–13587 / 68–139110 / 93–15284 / 63–12192 / 67–122153 / 98–214169 / 99–209179 / 103–218143 / 95–19595 / 78–12586 / 52–12194 / 57–138
DLI19 / 13–2224 / 19–2731 / 26–3338 / 33–4040 / 37–4239 / 37–4138 / 37–4035 / 34–3730 / 28–3226 / 21–2821 / 13–2318 / 11–20
RH %58 / 56–5958 / 56–5957 / 55–6057 / 55–6059 / 57–6262 / 59–6463 / 59–6564 / 60–6562 / 59–6459 / 57–6158 / 57–5958 / 57–59

Each figure is the median across the 955 grid cells holding the 1611 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 1194:1903 (30.275, -84.825). Over 44 years there: absolute minimum -11.0 °C, 1st-percentile night -4.2 °C, 99th-percentile day 38.5 °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 955 distinct grid cells holding the 1611 in-range records; extremes and elevation at the typical cell 1194:1903 (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 30.50_-85.000, lapse-corrected -20 m at 6.5 °C/km. Elevation: ETOPO 2022, 26 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.
NativeNova Scotia, Connecticut, Maine, Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, Rhode I., Texas, Alabama, Arkansas, Delaware, Florida, Georgia, Louisiana, Maryland, Mississippi, North Carolina, South Carolina, Virginia
Kew's description“shrub” · “temperate”· quoted from WCVP, RBG Kew (CC BY 4.0); not derived here
Map marker28.443, -81.542 · in the densest population, 544 records (30% of those in range)
Evidence usedThe map marker and the climate envelope rest on all 1792 georeferenced records inside the native range; the map shows only the 414 openly licensed ones, which alone would put the marker 41 km away. 6 records outside the range (gardens, roadsides, misidentifications) ignored. 181 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 1792 in-range records; it decides nothing.

Photographs

Ilex glabraIlex glabraIlex glabraIlex glabraIlex glabraIlex glabraIlex glabraIlex glabra

Photographs: (c) Douglas Goldman, some rights reserved (CC BY-SA) (8).

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 Ilex glabra, most cited first, from OpenAlex (CC0). A mention, not a cultivation source: nothing on this page is drawn from them.

Flammability of native understory species in pine flatwood and hardwood hammock ecosystems and implications for the wildland–urban interface
Anna L. Behm, Mary L. Duryea, Alan J. Long, Wayne C. Zipperer (2004) · International Journal of Wildland Fire
Vegetation and habitat conditions in Western Head Bog, a southern Nova Scotian plateau bog
A. W. H. Damman, Joseph J. Dowhan (1981) · Canadian Journal of Botany
Identification and characterisation of the phenolics of Ilex glabra L. Gray (Aquifoliaceae) leaves by liquid chromatography tandem mass spectrometry
Rakesh Jaiswal, Elias A. Halabi, Mohamed Gamaleldin Elsadig Karar, Nikolai Kuhnert (2014) · Phytochemistry
A place in space,
Paul A. Keddy (2001) · American Journal of Botany
Fuel Consumption Models for Pine Flatwoods Fuel Types in the Southeastern United States
Clinton S. Wright (2013) · Southern Journal of Applied Forestry
Biology and behavior of a seasonally aquatic bee, Perdita (Alloperdita) floridensis Timberlake (Hymenoptera: Andrenidae: Panurginae)
Björn Nordén, Karl V. Krombein, Mark Deyrup, Jayanthi P. Edirisinghe (2003) · Journal of the Kansas Entomological Society
Changes in a Flatwoods Site Following Intensive Preparation
Robert P. Schultz, Lawrence P. Wilhite (1974) · Forest Science

Similar habitat climate the 6 species whose habitat climate is nearest this one's: mean day and night, month by month, and rain on a log scale, in calendar order, so a habitat with the same seasons six months out is far, not near. Nothing else counts: not range, not family.

Other Ilex 9 in the reference

History & registers

Where this page came from built 2026-09-20 · dossier v2 · node
gbif.species answeredcarried from build of 2026-09-19 (offline re-derivation; the backbone was not asked)
gbif.synonyms answeredcarried from build of 2026-09-19 (offline re-derivation; the backbone was not asked)
gbif.vernacular answeredcarried from build of 2026-09-19 (offline re-derivation; the backbone was not asked)
wcvp.distribution answered
gbif.occurrences answeredGBIF occurrence download https://doi.org/10.15468/dl.3h4zam
climate answered
wikidata answeredcarried from build of 2026-09-19 (rederive); that build: carried from build of 2026-09-19 (rederive)
wikipedia answeredcarried from build of 2026-09-19; this build: skipped
inat.taxon not asked
inat.photos.wild answeredcarried from build of 2026-09-19; this build: skipped
inat.photos.cultivated nothing to reportcarried from build of 2026-09-19 (rederive); that build: carried from build of 2026-09-19 (rederive)
commons nothing to reportcarried from build of 2026-09-19 (rederive); that build: carried from build of 2026-09-19 (rederive)
gbif.media answered
openalex answeredcarried from build of 2026-09-19; this build: skipped

Every upstream is recorded as having answered, reported nothing, or refused. Only “nothing to report” is ever shown as an absence. Records came from 60 datasets via GBIF.org; each carries its own licence.