Species
+

Iris cristata Aiton

crested iris, crested iris, dwarf crested iris, ᎤᏍᎦᎢ

Climate known 64 photographs Bulb, tuber or caudex
Add one to my plants Sow seed

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

Iris cristata is a species in the genus Iris, and is part of the subgenus of Limniris. It is a rhizomatous perennial plant, endemic to the eastern United States. It has pale lavender flowers with a white patch and orange or yellow crest. It is a close relative to Iris lacustris, the only other crested iris native to North America. More on Wikipedia ›

The opening of Wikipedia, “Iris cristata”, CC BY-SA 4.0, quoted as written. Kept separate from everything derived here.

Family
Iridaceae
Described by
Aiton
Native to
Illinois, Iowa, Missouri +17
Wild records
1825 in range· 372 open

At a glance

Warmest month
30°C
Jul, mean day; nights 20 °C (CHELSA)
Rain
1324mm/yr
12 wet months · peak Jul 125 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
Grouped as a bulb, tuber or caudex by the genus Iris, which is reliably one kind of plant (archetype table). Rain rule: no season, 70% of the rain takes 9 months (November to July in the northern hemisphere). Habitat rain 1324 mm a year, wettest July at 125 mm, driest October at 89 mm (habitat calendar, northern hemisphere). Open sky over the habitat: 14 to 39 mol/m²/day. Cold floor -10.9 °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 Evansia cristata (Aiton) Klatt; Iris cristata var. alba Dykes; Iris glumacea Raf.; Iris glumacea var. angustifolia Raf.; Iris odorata Pers. and 2 more.

Cultivation

Grouped as a bulb, tuber or caudex by the genus Iris, which is reliably one kind of plant (archetype table). The table holds no figure for this group, which spans too much for one minimum; the cold floor is the habitat's alone, and no prose comes from the table.

Its year Rain rule: no season, 70% of the rain takes 9 months (November 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 (1029 mm of 1324 mm) takes 9 months, November to July. Mean temperature moves 22.2 °C between the warmest and coldest month. Months are the habitat's, northern hemisphere; shifted six months for a southern-hemisphere collection: May 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 1324 mm a year, wettest July at 125 mm, driest October at 89 mm (habitat calendar, northern hemisphere).

This species’ habitat figures, with their source.

1324 mm a year at the habitat, 1029 mm of it November to July. Wettest month July at 125 mm, driest October at 89 mm. Across the envelope cells the year's total runs 1129 mm to 1634 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 12, the highest 90th-percentile month 41).

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 -10.9 °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 -10.9 °C, the absolute minimum -23.0 °C, about 83 frost nights a year (NASA POWER daily minima). Warmest: the 99th-percentile day is 35.2 °C. Monthly means: coldest night -1.3 °C in January (across the envelope cells -3.8 °C to 1.1 °C), warmest day 29.6 °C in July (median year across the envelope cells, CHELSA). Cold floor: -10.9 °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 60% 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 8 °C in Jan to 30 °C in Jul; mean night from -1 °C in Jan to 20 °C in Jul. The cold quarter, Dec to Feb, is the three months around the coldest night. 1324 mm of rain a year, most in Jul. The bands show the 10th to 90th percentile across 1002 habitat cells. Over 44 years at the typical cell the absolute minimum was -23.0 °C and the 99th-percentile day 35.2 °C; neither is dated to a month. Beneath: daily light integral and relative humidity through the year, each on its own scale.-30°-20°-10°10°20°30°40°frost35.2° 99th-percentile day (undated)-23.0° lowest night in 44 yrs (undated)°C · day and nightcold quarter050100150200mm rainDLI 14–39RH 56–60 %JanFebMarAprMayJunJulAugSepOctNovDec
day night rain 10th–90th percentile across 1002 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 °C8 / 5–1010 / 7–1315 / 12–1719 / 17–2224 / 21–2628 / 25–3030 / 27–3229 / 26–3126 / 23–2820 / 18–2214 / 12–169 / 6–11
Night °C-1 / -4–10 / -3–34 / 1–79 / 6–1113 / 11–1618 / 15–2020 / 17–2220 / 17–2216 / 14–1810 / 8–135 / 3–70 / -2–3
Rain mm104 / 80–151110 / 76–159119 / 98–148111 / 89–135122 / 98–149114 / 101–142125 / 104–153104 / 83–136102 / 82–13089 / 72–122107 / 82–135117 / 85–158
DLI16 / 14–1721 / 19–2228 / 26–2935 / 33–3638 / 37–3939 / 39–4038 / 37–4135 / 34–3729 / 28–3124 / 22–2517 / 15–1814 / 12–15
RH %58 / 57–5957 / 56–5856 / 55–5756 / 54–5759 / 57–6060 / 58–6260 / 58–6360 / 58–6359 / 57–6258 / 57–5958 / 57–5959 / 57–60

Each figure is the median across the 1002 grid cells holding the 1657 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 1083:1926 (35.825, -83.675). Over 44 years there: absolute minimum -23.0 °C, 1st-percentile night -10.9 °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 1002 distinct grid cells holding the 1657 in-range records; extremes and elevation at the typical cell 1083:1926 (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 36.00_-83.750, lapse-corrected +52 m at 6.5 °C/km. Elevation: ETOPO 2022, 476 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.
NativeIllinois, Iowa, Missouri, Oklahoma, Indiana, New York, Ohio, Pennsylvania, West Virginia, Alabama, Arkansas, Georgia, Kentucky, Maryland, Mississippi, North Carolina, South Carolina, Tennessee, Virginia, District of Columbia
Kew's description“rhizomatous geophyte” · “temperate”· quoted from WCVP, RBG Kew (CC BY 4.0); not derived here
Map marker35.689, -83.396 · in the densest population, 707 records (39% of those in range)
Evidence usedThe map marker and the climate envelope rest on all 1825 georeferenced records inside the native range; the map shows only the 372 openly licensed ones, which alone would put the marker 15 km away. 7 records outside the range (gardens, roadsides, misidentifications) ignored. 168 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 1825 in-range records; it decides nothing.

Photographs

Iris cristataIris cristataIris cristataIris cristataIris cristataIris cristataIris cristataIris cristata

Photographs: (c) Michael J. Papay, some rights reserved (CC BY) (2); no rights reserved · CC0; (c) er-birds, some rights reserved (CC BY) (2); (c) Jacob Weston, some rights reserved (CC BY); (c) cwwood, some rights reserved (CC BY-SA) (2).

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

Isozyme diversity in Iris Cristata and the threatened glacial endemic I. Lacustris (Iridaceae)
Gary L. Hannan, Michael W. Orick (2000) · American Journal of Botany
Isolation and structure determination of three epoxidized iridals from Iris cristata
L. Taillet, J.‐P. BONFILS, F-J. Marner, Yves Sauvaire (1999) · Phytochemistry
The Ligneous Flora of Rich Mountain, Arkansas and Oklahoma
Ernest J Palmer (1924) · Journal of the Arnold Arboretum
Flowering Phenology: Trends Over 32 Years in a Common Garden
J. Dan Pittillo, Beverly Collins (2010) · Southeastern Naturalist
Occurrence Download
GBIF.Org User (2023) · Global Biodiversity Information Facility
Hardy plants : spring 1932 /
Shreve Farm., Ralph W. Shreve, Henry G. Gilbert Nursery and Seed Trade Catalog Collection., Ralph W. Shreve (Firm) (1932)
Occurrence Download
GBIF.org User (2026) · Global Biodiversity Information Facility
Occurrence Download
GBIF.org User (2026) · Global Biodiversity Information Facility
Occurrence Download
GBIF.org User (2026) · Global Biodiversity Information Facility

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 Iris 16 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: filled 2026-09-20
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 43 datasets via GBIF.org; each carries its own licence.