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An example collection, so you can see what this page does. Nothing added here is kept: leaving deletes it.
Ruellia foetida; photograph (c) Alexis López Hernández, some rights reserved (CC BY) CC BY(c) Alexis López Hernández, some rights reserved (CC BY) · observed growing wild · 2014-11-21

Ruellia foetida Humb. & Bonpl. ex Willd.

Acanthaceae · Mexico Central, Mexico Northeast +4

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Ruellia foetida, photograph (c) Alexis López Hernández, some rights reserved (CC BY)Ruellia foetida, photograph (c) Alexis López Hernández, some rights reserved (CC BY)Ruellia foetida, photograph (c) Alexis López Hernández, some rights reserved (CC BY)Ruellia foetida, photograph (c) Alexis López Hernández, some rights reserved (CC BY)Ruellia foetida, photograph (c) Alexis López Hernández, some rights reserved (CC BY)Ruellia foetida, photograph (c) Alexis López Hernández, some rights reserved (CC BY) 20 photographs ›
Habitat figures
Cold floor (1 night in 100)
19.0°C
Record low 15.7 °C in 44 years, at a typical spot in the range NASA POWER
Warmest month, mean daily high
30°C
Apr and May at the habitat CHELSA
Rain a year (median across the range)
1,249mm
6 months of 25 mm or more in the median year CHELSA
Open-sky light
31–46DLI
Lowest to highest month (DLI) CHELSA
The year in the habitat's months, not shifted
  1. Jan
  2. Feb
  3. Mar
  4. Apr
  5. May
  6. Jun
  7. Jul
  8. Aug
  9. Sep
  10. Oct
  11. Nov
  12. Dec
A sharp rainy season, June to September (the habitat's months, not shifted), in a year of even temperature. rain rule, CHELSA
Not shifted: the shift rule does not apply to this habitat. The chart is in the habitat's months.

About the genus · Ruellia

Ruellia is a genus of flowering plants commonly known as ruellias or wild petunias. They are not closely related to petunias (Petunia) although both genera belong to the same euasterid clade. The genus was named in honor of Jean Ruelle (1474–1537), herbalist and physician to Francis I of France and translator of several works of Dioscorides.

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

Cultivation

Seasons

The rain rule reads a sharp season: 70% of the median year's rain (974 mm of 1,244 mm) falls in June to September. The temperature curve is flat, 2.8 °C between the warmest and coldest month, so the growing-season rule does not infer a growing season from it. Months are the habitat's, northern hemisphere. The temperature curve moves under 4 °C between the warmest and coldest month, where the shift rule does not apply, so they are not shifted for a collection elsewhere.

Rain

1,244 mm in the median year at the habitat, 974 mm of it June to September. Wettest month September at 284 mm, driest month March at 5 mm. Across the grid cells of the range the year's total runs 909 mm to 1,920 mm, the 10th to 90th percentile of each cell's own year. The median of the cells' own yearly totals, 1,249 mm, is the year's rain at the top of the page; the 1,244 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: 31 to 46 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 24, the highest 90th-percentile month 48).

Warmth and air
Temperature

Coldest: the 1st-percentile night over 44 years at a typical spot in the range is 19.0 °C, the absolute minimum 15.7 °C, no frost in 44 years (NASA POWER daily minima). Warmest: the 99th-percentile day is 35.5 °C. Monthly means: the coldest month's mean nightly low 19.4 °C in February (across the grid cells of the range 14.5 °C to 23.2 °C), the warmest month's mean daily high 30.1 °C in April and May (median year across the grid cells of the range, CHELSA). Cold floor: 19.0 °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 69% 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 -73 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 Ruellia foetida through the yearWarmest months April and May, mean daily high 30 °C; coldest month February, mean nightly low 19.4 °C; 1,244 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.10°15°20°25°30°35°40°35.5° 99th-percentile day, NASA POWER15.7° lowest night in 44 years, NASA POWER°C · day and nightcold quarter0100200300400mm rainDLI 31–46RH 58–69%JanFebMarAprMayJunJulAugSepOctNovDec
day night rain medians and 10th–90th percentile across 105 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 °C28 / 23–3029 / 24–3129 / 26–3230 / 27–3330 / 28–3329 / 27–3129 / 26–3029 / 26–3028 / 26–2928 / 25–2929 / 24–3028 / 23–30
Night °C20 / 14–2319 / 15–2320 / 15–2421 / 17–2522 / 19–2524 / 19–2524 / 18–2524 / 19–2524 / 19–2523 / 18–2522 / 17–2421 / 15–24
Rain mm17 / 5–6110 / 6–495 / 2–429 / 1–4863 / 8–119234 / 112–327219 / 177–343237 / 187–349284 / 227–390132 / 94–21223 / 15–10111 / 6–62
DLI33 / 25–3538 / 29–3943 / 35–4546 / 39–4843 / 40–4736 / 34–3936 / 34–3935 / 33–3731 / 29–3332 / 30–3433 / 26–3431 / 24–33
RH %59 / 54–6658 / 53–6458 / 53–6359 / 52–6361 / 56–6466 / 63–6866 / 63–6967 / 64–7069 / 65–7167 / 62–7064 / 57–6661 / 55–66
How this section is made
Each figure is the median across the 105 grid cells holding the 177 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 1439:1563 (18.025, -101.825). Over 44 years there: absolute minimum 15.7 °C, 1st-percentile night 19.0 °C, 99th-percentile day 35.5 °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 105 distinct grid cells holding 177 of the 177 in-range records; extremes and elevation at the typical cell 1439:1563 (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 18.00_-101.875, lapse-corrected -73 m at 6.5 °C/km. Elevation: ETOPO 2022, 228 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.
NativeMexico Central, Mexico Northeast, Mexico Gulf, Mexico Northwest, Mexico Southwest, Mexico Southeast · 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 marker15.857, -96.005 · in the densest population, 152 records (60% of those in range)
Kew's description“seasonally dry tropical” · quoted from WCVP, RBG Kew (CC BY 4.0); not derived here
Evidence usedThe map marker rests on all 254 georeferenced records inside the native range; the climate across the range on the 177 of them placed to within 10 km; the map shows only the 233 openly licensed ones, which alone would put the marker 1 km away. 2 records outside the WCVP native range not used. 77 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 2° block of the 254 in-range records; it decides nothing. Records outside the native range, living specimens and records marked introduced are not used; which records count.

Photographs

Ruellia foetida, photograph 1did not loadRuellia foetida, photograph 2did not loadRuellia foetida, photograph 3did not loadRuellia foetida, photograph 4did not loadRuellia foetida, photograph 5did not loadRuellia foetida, photograph 6did not load

Photographs: (c) Alexis López Hernández, some rights reserved (CC BY) (6).

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

Acanthocereus fosterianus Acanthocereus fosterianus Cactaceae Photo: CC BY, Carlos Domínguez-RodríguezSalpianthus arenarius Salpianthus arenarius Nyctaginaceae Photo: CC BY, Arturo Benavides MendozaTurnera velutina Turnera velutina Turneraceae Photo: CC BY, Carlos Domínguez-RodríguezBromelia palmeri Bromelia palmeri Bromeliaceae Photo: CC BY, Carlos Domínguez-RodríguezAntigonon flavescens Antigonon flavescens Polygonaceae Photo: CC BY, Carlos Domínguez-RodríguezDiospyros salicifolia Diospyros salicifolia Willow Leaf Persimmon Photo: CC BY, José Javier Barrios Flores

Other Ruellia 37 in the reference

Ruellia affinis Ruellia affinis Acanthaceae Photo: CC BY, B. PhalanRuellia angustiflora Ruellia angustiflora Acanthaceae Photo: CC BY, William Stephens Ruellia angustifolia Acanthaceae Ruellia blechum Ruellia blechum Browne's blechum Photo: CC BY, Guillaume Delaitre Ruellia blumei Acanthaceae Ruellia bourgaei Ruellia bourgaei Acanthaceae Photo: CC0, author not statedRuellia breedlovei Ruellia breedlovei Acanthaceae Photo: CC BY, Neptalí Ramírez MarcialRuellia brevifolia Ruellia brevifolia Tropical wild petunia Photo: CC BY, Zoe Anthony QuestedRuellia californica Ruellia californica Acanthaceae Photo: CC BY, DrepanostomaRuellia caroliniensis Ruellia caroliniensis Carolina wild petunia Photo: CC BY, portulacaRuellia chartacea Ruellia chartacea Peruvian wild petunia Photo: CC BY, Yuri SofronovRuellia ciliatiflora Ruellia ciliatiflora Hairyflower wild petunia Photo: CC BY, Reanne ("Bean") Dunn all 38 ›

Names & registers

Also known as Dipteracanthus foetidus; Dipteracanthus rubicaulis; Ruellia albiflora; Ruellia pulchella; Ruellia rubicaulis. (GBIF Backbone)

GBIFPOWOIPNIWFOWikidataiNaturalist

The record

Family
Acanthaceae
Described by
Humb. & Bonpl. ex Willd.
Native to
Mexico Central, Mexico Northeast, Mexico Gulf +3
Wild records
254 in range · 233 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 18.00_-101.875, lapse-corrected -73 m at 6.5 °C/km
Wikidata wikidata answeredasked 2026-10-22
Wikipedia wikipedia nothing to reportasked 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 33 datasets via GBIF.org; each carries its own licence.

Cultifolio

Opening your plants…