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Sphaeropteris robusta; photograph (c) ian_mcallan, some rights reserved (CC BY) CC BY(c) ian_mcallan, some rights reserved (CC BY) · observed growing wild · 2019-08-15

Sphaeropteris robusta (Holttum) R.M.Tryon

Cyatheaceae · Norfolk Is.

Cited as Kew's World Checklist cites it, Sphaeropteris robusta (Holttum) R.M.Tryon: GBIF's backbone key for this page carries the name with another author, (C.Moore ex Watts) R.M.Tryon.

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Sphaeropteris robusta, photograph (c) ian_mcallan, some rights reserved (CC BY)Sphaeropteris robusta, photograph (c) Leon Perrie, some rights reserved (CC BY)Sphaeropteris robusta, photograph (c) Leon Perrie, some rights reserved (CC BY)Sphaeropteris robusta, photograph (c) naturewatchwidow, some rights reserved (CC BY)Sphaeropteris robusta, photograph (c) naturewatchwidow, some rights reserved (CC BY)Sphaeropteris robusta, photograph Krzysztof Ziarnek, Kenraiz, CC BY-SA 4.0, via Wikimedia Commons 16 photographs ›
Habitat figuresfrom few records
Coldest month, mean nightly low
15.8°C
Aug at the habitat, not a floor; extremes not used (sea cell) CHELSA
Warmest month, mean daily high
23°C
Jan and Feb at the habitat CHELSA
Rain a year (median across the range)
1,604mm
12 months of 25 mm or more in the median year CHELSA
Open-sky light
16–44DLI
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
Rain spread: 70% of the median year's rain takes 8 months, so no short rainy season. rain rule, CHELSA
Northern hemisphere unless you set your site. The chart is in the habitat's months.

From few records: 24 records in 3 grid cells. The records.

Summary

Sphaeropteris robusta, synonym Cyathea robusta, is a fern in the family Cyatheaceae. The specific epithet alludes to its robust habit.

Quoted from Wikipedia, "Sphaeropteris robusta", CC BY-SA 4.0.

About the genus · Sphaeropteris

Sphaeropteris is a genus of tree ferns in the family Cyatheaceae. It has been treated as a subgenus within the genus Cyathea, but is accepted in the Pteridophyte Phylogeny Group classification of 2016.

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

Cultivation

Seasons

The rain rule reads no short rainy season: 70% of the median year's rain (1,145 mm of 1,604 mm) takes 8 months, January to July and September. Mean temperature moves 6.0 °C between the warmest and coldest month. Months are the habitat's, southern hemisphere; shifted six months for a northern-hemisphere collection: July to January and March.

Rain

1,604 mm in the median year at the habitat, 1,145 mm of it January to July and September. Wettest month April at 175 mm, driest month October at 111 mm. Across the grid cells of the range the year's total runs 1,309 mm to 1,610 mm, the 10th to 90th percentile of each cell's own year. The median of the cells' own yearly totals, 1,604 mm, is the year's rain at the top of the page; the 1,604 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: 16 to 44 mol/m²/day across the year (daily light integral, median year across the grid cells of the range, CHELSA).

Warmth and air
Temperature

Monthly means: the coldest month's mean nightly low 15.8 °C in August (across the grid cells of the range 15.6 °C to 16.0 °C), the warmest month's mean daily high 23.2 °C in February (median year across the grid cells of the range, CHELSA). Cold floor: none read. The nearest figure is 15.8 °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 that is mostly sea and are not used.

Humidity

Relative humidity at the habitat: 55 to 60% 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

From few records: this habitat climate is read from 24 records in 3 grid cells; a page says so under 12 records or 5 cells, and shows the figures as read.

Habitat months, southern hemisphere

Habitat climate of Sphaeropteris robusta through the yearWarmest months January and February, mean daily high 23 °C; coldest month August, mean nightly low 15.8 °C; 1,604 mm of rain in the median year (the twelve monthly medians added). Medians across the range, from CHELSA. Habitat months, southern hemisphere.10°15°20°25°°C · day and nightcold quarter050100150200mm rainDLI 16–44RH 55–60%JanFebMarAprMayJunJulAugSepOctNovDec
day night rain medians and 10th–90th percentile across 3 habitat cells, CHELSA cold quarter: the three months around the coldest month's mean nightly low DLI, mol/m²/dayRH %each on its own scale
Figures by month
JanFebMarAprMayJunJulAugSepOctNovDec
Day °C23 / 23–2323 / 23–2322 / 22–2321 / 21–2120 / 20–2019 / 18–1918 / 18–1817 / 17–1818 / 18–1819 / 19–1920 / 20–2022 / 21–22
Night °C22 / 21–2222 / 22–2221 / 21–2120 / 20–2019 / 18–1917 / 17–1716 / 16–1616 / 16–1617 / 16–1717 / 17–1719 / 18–1920 / 20–20
Rain mm120 / 90–120122 / 97–122122 / 100–123175 / 129–175161 / 127–161174 / 139–175154 / 134–156115 / 105–116117 / 99–118111 / 79–111117 / 99–118116 / 109–116
DLI44 / 44–4439 / 39–4033 / 33–3426 / 25–2719 / 19–2016 / 16–1717 / 17–1823 / 23–2431 / 31–3238 / 38–3842 / 42–4244 / 44–44
RH %60 / 60–6260 / 59–6258 / 58–6058 / 57–6057 / 56–5856 / 55–5856 / 55–5755 / 55–5758 / 57–5858 / 57–5959 / 59–6060 / 60–62

The daily extremes were read at a NASA POWER cell that is 0% land: neither it nor the next candidates whose coldest month's mean nightly low is within 2 °C of the median across cells sit in a POWER cell that is mostly land, and the rule reads a cold floor only from a cell that is mostly land, so none is read for this species. Nor is the coldest month's mean nightly low taken as one: it is a mean of a month's lows, not its coldest night. What that cell gave over 44 years: absolute minimum 13.1 °C, 1st-percentile night 15.0 °C, 99th-percentile day 24.9 °C.

How this section is made
Each figure is the median across the 3 grid cells on land that hold in-range records (24 records in those cells; 1 more cell holds records but no land by the elevation layer, so those records sit at sea and the cell is 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 2430:6781 (-31.525, 159.075). 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 3 distinct grid cells holding 24 of the 25 in-range records (1 further cell with records at sea, by the elevation layer, left out); extremes and elevation at the typical cell 2430:6781 (its coldest month's mean nightly low nearest the median across cells, though its NASA POWER cell is only 0% land and none of the 2 next candidates within 2 °C of the median was mostly land); its position is the cell centre. Extremes: NASA POWER (MERRA-2) daily 1981–2024, cell -31.50_159.375, lapse-corrected +16 m at 6.5 °C/km. Elevation: ETOPO 2022, 16 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.
NativeNorfolk Is. · 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 marker-31.567, 159.083 · in the densest population, 29 records (97% of those in range)
Kew's description“wet tropical” · quoted from WCVP, RBG Kew (CC BY 4.0); not derived here
Evidence usedThe map marker rests on all 30 georeferenced records inside the native range; the climate across the range on the 24 of them in the land cells it reads, of 25 placed to within 10 km; the map shows only the 28 openly licensed ones, which alone would put the marker in the same place. 1 record outside the WCVP native range not used. 5 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 of the 30 in-range records; it decides nothing. Records outside the native range, living specimens and records marked introduced are not used; which records count.

Photographs

Sphaeropteris robusta, photograph 1did not loadSphaeropteris robusta, photograph 2did not loadSphaeropteris robusta, photograph 3did not loadSphaeropteris robusta, photograph 4did not loadSphaeropteris robusta, photograph 5did not loadSphaeropteris robusta, photograph 6did not load

Photographs: (c) ian_mcallan, some rights reserved (CC BY); (c) Leon Perrie, some rights reserved (CC BY) (2); (c) naturewatchwidow, some rights reserved (CC BY) (2); Krzysztof Ziarnek, Kenraiz, CC BY-SA 4.0, via Wikimedia Commons.

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

Dianella intermedia Dianella intermedia Asphodelaceae Photo: CC BY, Leon PerrieHowea forsteriana Howea forsteriana Sentry palm Photo: CC BY, William HarlandPouzolzia australis Pouzolzia australis Kermadec Nettle Tree Photo: CC BY, John BarklaMetrosideros kermadecensis Metrosideros kermadecensis Pohutukawa Photo: CC0, author not statedRhopalostylis baueri Rhopalostylis baueri Kermadec Five Finger Photo: CC0, author not statedSphaeropteris excelsa Sphaeropteris excelsa Norfolk tree fern Photo: CC0, author not stated

Other Sphaeropteris 11 in the reference

Sphaeropteris atrox Cyatheaceae Sphaeropteris brunoniana Cyatheaceae Sphaeropteris cooperi Sphaeropteris cooperi Scaly tree fern Photo: CC BY, Kevin FaccendaSphaeropteris excelsa Sphaeropteris excelsa Norfolk tree fern Photo: CC0, author not stated Sphaeropteris felina Cyatheaceae Sphaeropteris glauca Sphaeropteris glauca Cyatheaceae Photo: CC BY, Fabian BrambachSphaeropteris intermedia Sphaeropteris intermedia Cyatheaceae Photo: CC BY, Irisa HudsonSphaeropteris lunulata Sphaeropteris lunulata Balabala Photo: CC BY, Cheng-Wei CHENSphaeropteris medullaris Sphaeropteris medullaris Black tree fern Photo: CC BY-SA, Tony WillsSphaeropteris quindiuensis Sphaeropteris quindiuensis Cyatheaceae Photo: CC BY, Dick Culbert from Gibsons, B.C., CanadaSphaeropteris tomentosissima Sphaeropteris tomentosissima Cyatheaceae Photo: CC BY-SA, Magnus Manske

Names & registers

Also known as Alsophila robusta; Alsophila robusta var. norfolkiana; Cyathea robusta; Sphaeropteris robusta var. norfolkiana. (GBIF Backbone)

GBIFPOWOIPNIWFOWikidataWikipediaiNaturalist

The record

Family
Cyatheaceae
Described by
(Holttum) R.M.Tryon
Native to
Norfolk Is.
Wild records
30 in range · 28 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 2026-10-22GBIF's key 5529544 is Sphaeropteris robusta (C.Moore ex Watts) R.M.Tryon; the page links Kew's Sphaeropteris robusta (Holttum) R.M.Tryon, and the name is cited as Kew cites it
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; 3 records within 1 km of a botanic garden, herbarium or zoo left out (3 at a botanic garden or arboretum; 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 -31.50_159.375, lapse-corrected +16 m at 6.5 °C/km; read, and set aside: NASA POWER's cell is mostly sea (0% land), so no cold floor is shown
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 2026-10-22none 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
Wikimedia Commons commons 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 8 datasets via GBIF.org; each carries its own licence.

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