Example ⟳ +
An example collection, so you can see what this page does. Nothing added here is kept: leaving deletes it.
Ruellia inundata; photograph (c) Andrea Gantzer, some rights reserved (CC BY) CC BY(c) Andrea Gantzer, some rights reserved (CC BY) · observed growing wild · 2026-03-03

Ruellia inundata Kunth

Slender ruellia

Acanthaceae · Mexico Central, Mexico Northeast +14 · listed by its genus as a tropical foliage plant

Add one to my plants
Sow seed
Ruellia inundata, photograph (c) Jennifer Alondra, some rights reserved (CC BY)Ruellia inundata, photograph (c) Deby Gómez, some rights reserved (CC BY)Ruellia inundata, photograph (c) Andrea Gantzer, some rights reserved (CC BY)Ruellia inundata, photograph (c) Andrea Gantzer, some rights reserved (CC BY)Ruellia inundata, photograph (c) Francisco Emilio Roldán Velasco, some rights reserved (CC BY)Ruellia inundata, photograph (c) Francisco Emilio Roldán Velasco, some rights reserved (CC BY) 76 photographs ›
Habitat figures
Cold floor (1 night in 100)
14.9°C
Record low 9.9 °C in 44 years, at a typical spot in the range NASA POWER
Warmest month, mean daily high
32°C
Apr and May at the habitat CHELSA
Rain a year (median across the range)
1,170mm
8 months of 25 mm or more in the median year CHELSA
Open-sky light
28–43DLI
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
Wet summers: the rain comes June to September, read as a summer growing season. rain rule, CHELSA
Northern hemisphere unless you set your site. The chart is in the habitat's months.

Summary

Ruellia inundata is a subshrub plant, in the genus Ruellia, family Acanthaceae and is a perennial herbaceous plant first described by the German botanist Carl Sigismund Kunth.

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

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

Grouped as a tropical foliage plant, listed under the genus Ruellia in the archetype table, and Kew describes it as “subshrub”, “wet tropical”.

Seasons

The rain rule reads a summer growing season: 70% of the median year's rain (806 mm of 1,146 mm) falls in June to September, warmer than the year (wet-season mean 26.8 °C against a yearly mean of 25.5 °C). Months are the habitat's, northern hemisphere; shifted six months for a southern-hemisphere collection: December to March.

Rain

1,146 mm in the median year at the habitat, 806 mm of it June to September. Wettest month September at 223 mm, driest month March at 12 mm. Across the grid cells of the range the year's total runs 817 mm to 1,900 mm, the 10th to 90th percentile of each cell's own year. The median of the cells' own yearly totals, 1,170 mm, is the year's rain at the top of the page; the 1,146 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: 28 to 43 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 14.9 °C, the absolute minimum 9.9 °C, no frost in 44 years (NASA POWER daily minima). Warmest: the 99th-percentile day is 39.4 °C. Monthly means: the coldest month's mean nightly low 18.7 °C in January (across the grid cells of the range 13.6 °C to 22.3 °C), the warmest month's mean daily high 32.1 °C in May (median year across the grid cells of the range, CHELSA). Cold floor: 14.9 °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: 56 to 66% 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 +35 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.

Group. Listed under the genus Ruellia in the archetype table, and Kew describes it as “subshrub”, “wet tropical”. A group is taken only where Kew's description of the species agrees with the table's listing. The table gives no figure and no prose; the cold floor is the habitat's alone.

Climate across the habitat

Habitat months, northern hemisphere

Habitat climate of Ruellia inundata through the yearWarmest months April and May, mean daily high 32 °C; coldest month January, mean nightly low 18.7 °C; 1,146 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.5°10°15°20°25°30°35°40°45°39.4° 99th-percentile day, NASA POWER9.9° lowest night in 44 years, NASA POWER°C · day and nightcold quarter0100200300400mm rainDLI 28–43RH 56–66%JanFebMarAprMayJunJulAugSepOctNovDec
day night rain medians and 10th–90th percentile across 523 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 / 24–3029 / 26–3130 / 27–3332 / 29–3532 / 28–3630 / 27–3430 / 27–3430 / 27–3429 / 26–3329 / 25–3128 / 25–3028 / 24–30
Night °C19 / 14–2219 / 14–2320 / 15–2322 / 17–2423 / 19–2523 / 19–2523 / 19–2523 / 19–2523 / 19–2522 / 18–2421 / 16–2319 / 14–23
Rain mm26 / 3–4613 / 5–3412 / 4–3724 / 2–5084 / 11–221196 / 119–301185 / 142–285202 / 146–302223 / 159–354120 / 66–27439 / 15–10222 / 5–60
DLI30 / 25–3535 / 30–3941 / 35–4443 / 39–4841 / 37–4737 / 32–4138 / 33–4137 / 33–4033 / 29–3631 / 28–3429 / 26–3428 / 24–33
RH %59 / 52–6457 / 51–6356 / 50–6157 / 49–6159 / 51–6564 / 57–6964 / 59–6964 / 60–6966 / 62–7164 / 59–7061 / 55–6760 / 54–66
How this section is made
Each figure is the median across the 523 grid cells on land that hold in-range records (743 records in those cells; 5 more cells hold records but no land by the elevation layer, so those records sit at sea and the cells are left out), 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 1429:1563 (18.525, -101.825). Over 44 years there: absolute minimum 9.9 °C, 1st-percentile night 14.9 °C, 99th-percentile day 39.4 °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 523 distinct grid cells holding 743 of the 749 in-range records (5 further cells with records at sea, by the elevation layer, left out); extremes and elevation at the typical cell 1429:1563 (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 18.50_-101.875, lapse-corrected +35 m at 6.5 °C/km. Elevation: ETOPO 2022, 531 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, Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, Panama, Netherlands Antilles, Venezuela, Colombia, Ecuador · 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 marker16.6, -93.55 · in the densest population, 717 records (56% of those in range)
Kew's description“subshrub” · “wet tropical” · quoted from WCVP, RBG Kew (CC BY 4.0); not derived here
Evidence usedThe map marker rests on all 1282 georeferenced records inside the native range; the climate across the range on the 743 of them in the land cells it reads, of 749 placed to within 10 km; the map shows only the 1008 openly licensed ones, which alone would put the marker 42 km away. 119 records outside the WCVP native range not used. 533 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 4° block of the 1282 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 inundata, photograph 1did not loadRuellia inundata, photograph 2did not loadRuellia inundata, photograph 3did not loadRuellia inundata, photograph 4did not loadRuellia inundata, photograph 5did not loadRuellia inundata, photograph 6did not load

Photographs: (c) Jennifer Alondra, some rights reserved (CC BY); (c) Deby Gómez, some rights reserved (CC BY); (c) Andrea Gantzer, some rights reserved (CC BY) (2); (c) Francisco Emilio Roldán Velasco, some rights reserved (CC BY) (2).

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

Rauvolfia tetraphylla Rauvolfia tetraphylla Milkbush Photo: CC BY, nasuaPorophyllum punctatum Porophyllum punctatum Asteraceae Photo: CC0, author not statedSenna atomaria Senna atomaria Flor de San Jose Photo: CC BY, Jose Luis Leon de la LuzSemialarium mexicanum Semialarium mexicanum Celastraceae Photo: CC BY, Carlos Domínguez-RodríguezCoccoloba barbadensis Coccoloba barbadensis Polygonaceae Photo: CC BY, Douglas Caro LopezMesosphaerum suaveolens Mesosphaerum suaveolens Pignut Photo: CC BY, Rohit Naniwadekar

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 Aphragmia haenkei; Aphragmia inundata; Dipteracanthus haenkei; Ruellia albicans; Ruellia albicaulis and 1 more. (GBIF Backbone)

Kew accepts as species of their own Ruellia galeottii: older names in GBIF's record of this species that Kew's World Checklist accepts as other species. (WCVP, RBG Kew, file of 2026-06-04)

GBIFPOWOIPNIWFOWikidataWikipediaiNaturalist

The record

Family
Acanthaceae
Described by
Kunth
Native to
Mexico Central, Mexico Northeast, Mexico Gulf +13
Wild records
1282 in range · 1008 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; 13 records within 1 km of a botanic garden, herbarium or zoo left out (8 at a botanic garden or arboretum, 2 at a herbarium, 3 at a zoo; Wikidata's list)
Habitat climate climate answeredasked 2026-10-22
Daily extremes (NASA POWER) climate.extremes answeredasked 2026-10-22NASA POWER (MERRA-2) daily 1981–2024, cell 18.50_-101.875, lapse-corrected +35 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 2026-10-22
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 104 datasets via GBIF.org; each carries its own licence.

Cultifolio

Opening your plants…