26 photographs › At a glance
- Jan, under 5 mm of rain
- Feb, under 5 mm of rain
- Mar
- Apr
- May
- Jun, shaded
- Jul, shaded
- Aug, shaded
- Sep, shaded
- Oct
- Nov
- Dec, under 5 mm of rain
Summary
Costus spectabilis, commonly known as the yellow trumpet, or yellow bell, is an African species of herb; low and perennial, it is found from Sierra Leone to Sudan to as far south as Angola and Zimbabwe.
Quoted from Wikipedia, "Costus spectabilis", CC BY-SA 4.0.
About the genus · Costus
Costus is a genus of herbaceous perennial plants in the family Costaceae, described by Linnaeus in 1753. It is widespread through tropical and subtropical regions of Asia, Africa, and the Americas.
Quoted from Wikipedia, "Costus", CC BY-SA 4.0.
Cultivation
Grouped as a tropical foliage plant, listed under the genus Costus in the archetype table, and Kew describes it as “rhizomatous geophyte”, “seasonally dry tropical”.
Seasons
The rain rule reads a winter growing season: 70% of the median year's rain (803 mm of 1,092 mm) falls in June to September, cooler than the year (wet-season mean 25.1 °C against a yearly mean of 26.7 °C). Months are the habitat's, northern hemisphere; shifted six months for a southern-hemisphere collection: December to March.
Rain
1,092 mm in the median year at the habitat, 803 mm of it June to September. Wettest month August at 252 mm, driest months (2 at 1 mm); 3 months under 5 mm. Across the grid cells of the range the year's total runs 893 mm to 1,541 mm, the 10th to 90th percentile of each cell's own year. The median of the cells' own yearly totals, 1,105 mm, is the year's rain at the top of the page; the 1,092 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: 29 to 42 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 26, the highest 90th-percentile month 44).
Warmth and air
Coldest: the 1st-percentile night over 44 years at a typical spot in the range is 12.1 °C, the absolute minimum 9.0 °C, no frost in 44 years (NASA POWER daily minima). Warmest: the 99th-percentile day is 39.7 °C. Monthly means: the coldest month's mean nightly low 18.8 °C in January (across the grid cells of the range 15.9 °C to 20.7 °C), the warmest month's mean daily high 36.6 °C in March (median year across the grid cells of the range, CHELSA). Cold floor: 12.1 °C, which is the 1st-percentile night over 44 years at a typical spot in the range (NASA POWER).
Relative humidity at the habitat: 36 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. NASA POWER daily minima and maxima over 44 years at a typical spot in the range, lapse-corrected +78 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 Costus in the archetype table, and Kew describes it as “rhizomatous geophyte”, “seasonally dry 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
Mean daily high from 28 °C in Aug to 37 °C in Mar; mean nightly low from 19 °C in Jan and Dec to 24 °C in Apr and May. The cold quarter, Nov to Jan, is the three months around the coldest month's mean nightly low, centred on the 2 months in a row that tie for it. 1,092 mm of rain in the median year (the twelve monthly medians added), the wettest month Aug. The bands show the 10th to 90th percentile across 158 habitat cells. Over 44 years at a typical spot in the range (NASA POWER) the absolute minimum was 9.0 °C and the 99th-percentile day 39.7 °C; neither is dated to a month. 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 | 34 / 27–35 | 36 / 29–37 | 37 / 30–39 | 36 / 29–40 | 33 / 28–38 | 31 / 27–35 | 29 / 26–31 | 28 / 26–29 | 29 / 27–30 | 31 / 28–34 | 33 / 28–36 | 33 / 28–34 |
| Night °C | 19 / 16–21 | 21 / 17–22 | 23 / 18–24 | 24 / 19–27 | 24 / 19–26 | 23 / 18–25 | 22 / 18–23 | 21 / 18–23 | 22 / 18–23 | 22 / 18–23 | 20 / 17–22 | 19 / 16–21 |
| Rain mm | 1 / 0–17 | 3 / 0–36 | 18 / 3–98 | 64 / 24–133 | 118 / 60–165 | 153 / 108–209 | 201 / 125–258 | 252 / 68–306 | 197 / 128–265 | 78 / 33–159 | 6 / 0–53 | 1 / 0–20 |
| DLI | 38 / 34–39 | 41 / 36–42 | 42 / 35–44 | 41 / 34–43 | 38 / 32–41 | 35 / 29–39 | 30 / 26–34 | 29 / 26–32 | 32 / 28–36 | 37 / 31–39 | 38 / 32–40 | 37 / 33–38 |
| RH % | 37 / 33–63 | 36 / 31–63 | 43 / 34–64 | 53 / 44–64 | 59 / 52–65 | 63 / 57–67 | 66 / 61–70 | 67 / 64–71 | 67 / 63–70 | 61 / 54–66 | 47 / 39–64 | 39 / 35–63 |
Records on both sides of the equator: the 45 cells at least 10° south of it have seasons six months apart and are left out, not combined into a year no place has. These figures are across the 158 cells that remain: the 90 at least 10° north and the 68 within 10° of the equator, which stay in either way.
How this section is made
Natural habitat
How this section is made
Photographs
Photographs: author not stated, no rights reserved · CC0 (3); (c) Harriet Baber, some rights reserved (CC BY) (3).
Related
Similar habitat climate The 6 nearest by mean daily high, mean nightly low and rain, month by month. How.
Gardenia ternifolia Powderbark gardenia Photo: CC BY, keesgroenendijk
Afzelia africana African mahogany Photo: CC BY, Zac Peterson
Annona senegalensis Wild custard-apple Photo: CC BY-SA, alanbedfordshaw Cyphostemma cymosum Vitaceae 
Burkea africana False-Ash Photo: CC BY, Matthew Fainman
Parkia biglobosa African locust-bean Photo: CC BY, Lucy Keith-DiagneOther Costus 40 in the reference
Costus afer Spiral-ginger Photo: CC BY, Philippe Hornus
Costus allenii Costaceae Photo: CC BY-SA, David J. Stang
Costus amazonicus Costaceae Photo: CC BY, Dick Culbert from Gibsons, B.C., Canada
Costus arabicus Costaceae Photo: CC BY-SA, Divya Mudappa
Costus atlanticus Costaceae Photo: CC BY, Diogo Luiz
Costus barbatus Costaceae Photo: CC BY, Eduardo Chacón Madrigal
Costus claviger Costaceae Photo: CC BY, thomas_oswald
Costus comosus Red tower ginger Photo: CC BY, Thomas Mesaglio
Costus curvibracteatus Costaceae Photo: CC BY, Ong Jyh Seng
Costus dirzoi Costaceae Photo: CC BY, Alexis López Hernández
Costus dubius Costus Photo: CC BY, Kevin Faccenda all 41 ›Names & registers
Also known as Cadalvena dalzielii; Cadalvena pistiifolia; Cadalvena spectabilis; Costus pistiifolius; Kaempferia spectabilis. (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 2026-10-21
gbif.species answeredasked 2026-10-21gbif.synonyms answeredasked 2026-10-21gbif.vernacular answeredasked 2026-10-21names fetched 2026-10-21wcvp.distribution answeredas of 2026-06-04gbif.occurrences answeredas of 2026-10-21GBIF occurrence download https://doi.org/10.15468/dl.hbdw64, of 2026-10-21climate answeredasked 2026-10-21climate.extremes answeredasked 2026-10-21NASA POWER (MERRA-2) daily 1981–2024, cell 10.50_1.250, lapse-corrected +78 m at 6.5 °C/kmwikidata answeredasked 2026-10-21wikipedia answeredasked 2026-10-21inat.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 2026-10-21commons answeredasked 2026-10-21openalex 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 47 datasets via GBIF.org; each carries its own licence.