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Ixora nigricans; photograph madhavan a.p, CC BY, iNaturalist via GBIF CC BYmadhavan a.p, CC BY, iNaturalist via GBIF

Ixora nigricans R.Br. ex Wight & Arn.

Rubiaceae · Assam, Bangladesh +12

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Ixora nigricans, photograph madhavan a.p, CC BY, iNaturalist via GBIFIxora nigricans, photograph madhavan a.p, CC BY, iNaturalist via GBIFIxora nigricans, photograph Siddarth Machado, CC BY, iNaturalist via GBIFIxora nigricans, photograph Siddarth Machado, CC BY, iNaturalist via GBIFIxora nigricans, photograph Siddarth Machado, CC BY, iNaturalist via GBIFIxora nigricans, photograph Siddarth Machado, CC BY, iNaturalist via GBIF 18 photographs ›
Habitat figures
Cold floor (1 night in 100)
13.4°C
Record low 11.3 °C in 44 years, at a typical spot in the range NASA POWER
Warmest month, mean daily high
32°C
Mar and Apr at the habitat CHELSA
Rain a year (median across the range)
3,830mm
9 months of 25 mm or more in the median year CHELSA
Open-sky light
20–42DLI
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 August (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.

Summary

Ixora nigricans, or black ixora, is a plant growing up to a height of 5 metres (16 ft). It is found as common undergrowth in evergreen forests to dry evergreen forests up to 1,900 m (6,230 ft). Black ixora is found in throughout the forests of the Western Ghats of India.

Quoted from Wikipedia, "Ixora nigricans", CC BY-SA 4.0.

About the genus · Ixora

Ixora is a genus of flowering plants in the family Rubiaceae. It is the only genus in the tribe Ixoreae. It consists of tropical evergreen trees and shrubs and holds around 544 species. More on Wikipedia ›

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

Cultivation

Seasons

The rain rule reads a sharp season: 70% of the median year's rain (2,798 mm of 3,808 mm) falls in June to August. The temperature curve is flat, 3.8 °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

3,808 mm in the median year at the habitat, 2,798 mm of it June to August. Wettest month July at 1,169 mm, driest months (2 at 4 mm); 2 months under 5 mm. Across the grid cells of the range the year's total runs 1,980 mm to 5,247 mm, the 10th to 90th percentile of each cell's own year. The median of the cells' own yearly totals, 3,830 mm, is the year's rain at the top of the page; the 3,808 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: 20 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 17, the highest 90th-percentile month 45).

Warmth and air
Temperature

Coldest: the 1st-percentile night over 44 years at a typical spot in the range is 13.4 °C, the absolute minimum 11.3 °C, no frost in 44 years (NASA POWER daily minima). Warmest: the 99th-percentile day is 35.0 °C. Monthly means: the coldest month's mean nightly low 16.1 °C in January (across the grid cells of the range 13.6 °C to 20.2 °C), the warmest month's mean daily high 32.3 °C in March (median year across the grid cells of the range, CHELSA). Cold floor: 13.4 °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: 53 to 79% 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 +359 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 Ixora nigricans through the yearWarmest months March and April, mean daily high 32 °C; coldest month January, mean nightly low 16.1 °C; 3,808 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°35.0° 99th-percentile day, NASA POWER11.3° lowest night in 44 years, NASA POWER°C · day and nightcold quarter0500100015002000mm rainDLI 20–42RH 53–79%JanFebMarAprMayJunJulAugSepOctNovDec
day night rain medians and 10th–90th percentile across 136 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 °C29 / 26–3231 / 28–3332 / 30–3432 / 29–3431 / 27–3326 / 24–2925 / 23–2825 / 23–2826 / 25–2928 / 25–3028 / 25–3128 / 25–31
Night °C16 / 14–2017 / 15–2019 / 17–2221 / 19–2322 / 20–2421 / 19–2421 / 19–2320 / 18–2320 / 18–2320 / 18–2318 / 16–2217 / 14–21
Rain mm4 / 2–324 / 1–4128 / 4–11074 / 16–196162 / 91–286806 / 212–11771169 / 225–1826823 / 185–1227369 / 210–537262 / 180–42290 / 35–29317 / 7–89
DLI36 / 33–3840 / 38–4142 / 40–4341 / 37–4536 / 31–4223 / 21–3020 / 17–3022 / 19–3027 / 26–3231 / 27–3232 / 27–3433 / 29–35
RH %53 / 48–6154 / 46–5958 / 49–6164 / 56–6968 / 62–7378 / 70–8279 / 70–8578 / 70–8474 / 69–7768 / 61–7259 / 52–6854 / 49–63
How this section is made
Each figure is the median across the 136 grid cells holding the 197 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 1614:5141 (9.275, 77.075). Over 44 years there: absolute minimum 11.3 °C, 1st-percentile night 13.4 °C, 99th-percentile day 35.0 °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 136 distinct grid cells holding 197 of the 197 in-range records; extremes and elevation at the typical cell 1614:5141 (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 9.50_76.875, lapse-corrected +359 m at 6.5 °C/km. Elevation: ETOPO 2022, 779 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.
NativeAssam, Bangladesh, East Himalaya, India, Andaman Is., Cambodia, Myanmar, Nicobar Is., Thailand, Vietnam, Jawa, Lesser Sunda Is., Malaya, Sumatera · 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 marker15.042, 74.35 · in the densest population, 129 records (52% of those in range)
Kew's description“shrub or tree” · “wet tropical” · quoted from WCVP, RBG Kew (CC BY 4.0); not derived here
Evidence usedThe map marker rests on all 247 georeferenced records inside the native range; the climate across the range on the 197 of them placed to within 10 km; the map shows only the 231 openly licensed ones, which alone would put the marker 8 km away. 4 records outside the WCVP native range not used. 50 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 247 in-range records; it decides nothing. Records outside the native range, living specimens and records marked introduced are not used; which records count.

Photographs

Ixora nigricans, photograph 1did not loadIxora nigricans, photograph 2did not loadIxora nigricans, photograph 3did not loadIxora nigricans, photograph 4did not loadIxora nigricans, photograph 5did not loadIxora nigricans, photograph 6did not load

Photographs: madhavan a.p, CC BY, iNaturalist via GBIF (2); Siddarth Machado, CC BY, iNaturalist via GBIF (4).

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

Chionanthus mala-elengi Chionanthus mala-elengi Oleaceae Photo: CC BY, madhavan a.pHeptapleurum venulosum Heptapleurum venulosum Araliaceae Photo: CC BY-SA, Dinesh ValkeDendrobium ovatum Dendrobium ovatum Orchidaceae Photo: CC BY, Ashrith GSDysoxylum gotadhora Dysoxylum gotadhora Meliaceae Photo: CC BY, Ahirbudhnyan MLepisanthes tetraphylla Lepisanthes tetraphylla Sapindaceae Photo: CC0, author not statedGomphandra tetrandra Gomphandra tetrandra Stemonuraceae Photo: CC BY-SA, Vinayaraj

Other Ixora 20 in the reference

Ixora borboniae Ixora borboniae Rubiaceae Photo: CC BY-SA, cedric nazeIxora brachiata Ixora brachiata Gorbale Photo: CC0, S.MOREIxora casei Ixora casei Giant red Photo: CC BY, Raúl A. Ruiz M.Ixora chinensis Ixora chinensis Chinese ixora Photo: CC BY, Diogo LuizIxora coccinea Ixora coccinea Rubiaceae Photo: CC BY, Sabarni SarkerIxora congesta Ixora congesta Rubiaceae Photo: CC BY, Michael BerardozziIxora finlaysoniana Ixora finlaysoniana White Jungle Flame Photo: CC BY, Brian Oakes Haiti Hunter Ixora hainanensis Rubiaceae Ixora henryi Rubiaceae Ixora hookeri Ixora hookeri Rubiaceae Photo: CC BY-SA, Steve FitzgeraldIxora javanica Ixora javanica Rubiaceae Photo: CC BY, Samuel LeeIxora macrothyrsa Ixora macrothyrsa Rubiaceae Photo: CC BY, Diogo Luiz all 21 ›

Names & registers

Also known as Ixora acutiflora; Ixora acutifolia; Ixora affinis; Ixora affinis var. plumea; Ixora arguta and 13 more. (GBIF Backbone)

GBIFPOWOIPNIWFOWikidataWikipedia

The record

Family
Rubiaceae
Described by
R.Br. ex Wight & Arn.
Native to
Assam, Bangladesh, East Himalaya +11
Wild records
247 in range · 231 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; 1 record within 1 km of a botanic garden, herbarium or zoo left out (1 at a herbarium; 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 9.50_76.875, lapse-corrected +359 m at 6.5 °C/km
Wikidata wikidata answeredasked 2026-10-22IPNI and POWO linked by Kew's number for Ixora nigricans R.Br. ex Wight & Arn. (the item's: IPNI 754258-1, POWO 754259-1)
Wikipedia wikipedia answeredasked 2026-10-22
iNaturalist taxon inat.taxon not asked
iNaturalist photographs, wild inat.photos.wild not asked
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 24 datasets via GBIF.org; each carries its own licence.

Cultifolio

Opening your plants…