21 photographs › At a glance
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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 summer growing season: 70% of the median year's rain (427 mm of 562 mm) falls in January to April, warmer than the year (wet-season mean 24.7 °C against a yearly mean of 22.6 °C). Months are the habitat's, southern hemisphere. The habitat lies within 10° of the equator, where the shift rule does not apply, so they are not shifted for a collection elsewhere.
Rain
562 mm in the median year at the habitat, 427 mm of it January to April. Wettest month March at 134 mm, driest month August at 5 mm. Across the grid cells of the range the year's total runs 249 mm to 1,271 mm, the 10th to 90th percentile of each cell's own year. The median of the cells' own yearly totals, 583 mm, is the year's rain at the top of the page; the 562 mm here is the median year's, the twelve monthly medians added, which the rain rule reads. Habitat calendar, southern hemisphere; median year across the grid cells of the range, CHELSA.
Light
Open sky over the habitat: 31 to 40 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 44).
Warmth and air
Monthly means: the coldest month's mean nightly low 16.7 °C in August (across the grid cells of the range 13.8 °C to 21.1 °C), the warmest month's mean daily high 27.9 °C in March (median year across the grid cells of the range, CHELSA). Cold floor: none read. The nearest figure is 16.7 °C, the coldest month's mean nightly low, August, in the median year (CHELSA); a month's mean of its nightly lows is warmer than the nights a floor is read from. The daily extremes were read at a weather cell whose ground is too far above or below the typical spot to correct for, and are not used.
Relative humidity at the habitat: 62 to 67% 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. CHELSA monthly means, median year across the grid cells of the range. No cold floor is read without a daily extremes series; the coldest month's mean nightly low named in its sentence is not one. 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, southern hemisphere
Mean daily high from 25 °C in Jul and Aug to 28 °C in Feb, Mar and Apr; mean nightly low from 17 °C in Jul, Aug and Sep to 22 °C in Feb and Mar. The cold quarter, Jul to Sep, is the three months around the coldest month's mean nightly low, centred on the 3 months in a row that tie for it. 562 mm of rain in the median year (the twelve monthly medians added), the wettest month Mar. The bands show the 10th to 90th percentile across 56 habitat cells. Beneath: daily light integral and relative humidity through the year, each on its own scale.
Figures by month
| Figure | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Day °C | 27 / 21–30 | 28 / 21–29 | 28 / 21–30 | 28 / 21–29 | 27 / 22–28 | 26 / 22–27 | 25 / 22–27 | 25 / 22–27 | 26 / 22–28 | 26 / 22–28 | 26 / 22–28 | 27 / 22–29 |
| Night °C | 21 / 15–24 | 22 / 15–24 | 22 / 15–25 | 21 / 15–24 | 19 / 14–23 | 18 / 14–22 | 17 / 13–22 | 17 / 14–21 | 17 / 14–21 | 18 / 14–21 | 18 / 14–22 | 19 / 15–23 |
| Rain mm | 85 / 31–170 | 125 / 47–288 | 134 / 78–318 | 83 / 34–193 | 37 / 11–71 | 13 / 4–36 | 6 / 2–23 | 5 / 1–13 | 8 / 2–25 | 10 / 3–42 | 19 / 6–43 | 37 / 13–80 |
| DLI | 34 / 25–38 | 32 / 26–35 | 33 / 28–36 | 32 / 28–36 | 32 / 26–36 | 31 / 24–35 | 32 / 25–36 | 36 / 28–39 | 38 / 29–41 | 39 / 29–43 | 40 / 30–44 | 37 / 27–42 |
| RH % | 66 / 62–68 | 67 / 63–70 | 66 / 62–70 | 66 / 62–71 | 65 / 59–69 | 64 / 56–68 | 63 / 54–67 | 62 / 53–67 | 62 / 56–67 | 63 / 58–67 | 62 / 58–67 | 63 / 60–68 |
The daily extremes were not used: the record low, 18.1 °C, is warmer than the coldest month's mean nightly low across the range, 16.7 °C, which no night series of the habitat can give. So no cold floor is read for this species, and the coldest month's mean nightly low is not taken as one. What that cell gave, so corrected, over 44 years: absolute minimum 18.1 °C, 1st-percentile night 20.2 °C.
How this section is made
Natural habitat
How this section is made
Photographs
Photographs: (c) Connor Connolly-Moyls, some rights reserved (CC BY) (2); (c) portioid, some rights reserved (CC BY); (c) Ingvild Riska, some rights reserved (CC BY) (2); (c) Paúl Gonzáles, some rights reserved (CC BY).
Related
Similar habitat climate The 6 nearest by mean daily high, mean nightly low and rain, month by month. How.
Solanum pimpinellifolium Currant tomato Photo: CC BY, Raúl A. Ruiz M. Morisonia scabrida Capparaceae 
Haageocereus versicolor Cactaceae Photo: CC BY, Paúl Gonzáles
Bougainvillea peruviana Nyctaginaceae Photo: CC BY, Connor Connolly-Moyls
Zelenkoa onusta Orchidaceae Photo: CC BY-SA, Dalton Holland Baptista
Tillandsia espinosae Bromeliaceae Photo: CC BY-SA, Eduardo Dios AlemánOther Ruellia 37 in the reference
Ruellia affinis Acanthaceae Photo: CC BY, B. Phalan
Ruellia angustiflora Acanthaceae Photo: CC BY, William Stephens Ruellia angustifolia Acanthaceae 
Ruellia blechum Browne's blechum Photo: CC BY, Guillaume Delaitre Ruellia blumei Acanthaceae 
Ruellia bourgaei Acanthaceae Photo: CC0, author not stated
Ruellia breedlovei Acanthaceae Photo: CC BY, Neptalí Ramírez Marcial
Ruellia brevifolia Tropical wild petunia Photo: CC BY, Zoe Anthony Quested
Ruellia californica Acanthaceae Photo: CC BY, Drepanostoma
Ruellia caroliniensis Carolina wild petunia Photo: CC BY, portulaca
Ruellia chartacea Peruvian wild petunia Photo: CC BY, Yuri Sofronov
Ruellia ciliatiflora Hairyflower wild petunia Photo: CC BY, Reanne ("Bean") Dunn all 38 ›Names & registers
Also known as Aphragmia floribunda; Aphragmia rotundifolia; Dipteracanthus floribundus; Dipteracanthus viscidus. (GBIF Backbone)
The record
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 answeredasked 2026-10-22gbif.synonyms answeredasked 2026-10-22gbif.vernacular answeredasked 2026-10-22names fetched 2026-10-22wcvp.distribution answeredas of 2026-06-04gbif.occurrences answeredas of 2026-10-21GBIF occurrence download https://doi.org/10.15468/dl.hbdw64, of 2026-10-21; 5 records within 1 km of a botanic garden, herbarium or zoo left out (5 at a herbarium; Wikidata's list)climate answeredasked 2026-10-22climate.extremes answeredasked 2026-10-22NASA POWER (MERRA-2) daily 1981–2024, cell -5.00_-80.000, lapse-corrected -964 m at 6.5 °C/km; read, and set aside: the record low, 18.1 °C, is warmer than the coldest month's mean nightly low across the range, 16.7 °C, which no night series of the habitat can give, so no cold floor is shownwikidata answeredasked 2026-10-22wikipedia nothing to reportasked 2026-10-22inat.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 2026-10-22inat.photos.cultivated not askedgbif.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 rulesopenalex not askednot yet asked for this reference; a later fill takes the papers from OpenAlex's snapshotEvery 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 15 datasets via GBIF.org; each carries its own licence.