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Adiantum formosum; photograph (c) Bryce Watts-Parker, some rights reserved (CC BY) CC BY(c) Bryce Watts-Parker, some rights reserved (CC BY) · observed growing wild · 2026-09-11

Adiantum formosum R.Br.

Pteridaceae · New South Wales, Queensland +2 · listed by its genus as a fern or moss

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Adiantum formosum, photograph (c) Bryce Watts-Parker, some rights reserved (CC BY)Adiantum formosum, photograph (c) Bryce Watts-Parker, some rights reserved (CC BY)Adiantum formosum, photograph (c) Bryce Watts-Parker, some rights reserved (CC BY)Adiantum formosum, photograph (c) Bryce Watts-Parker, some rights reserved (CC BY)Adiantum formosum, photograph (c) Bryce Watts-Parker, some rights reserved (CC BY)Adiantum formosum, photograph (c) Bryce Watts-Parker, some rights reserved (CC BY) 60 photographs ›
Habitat figures
Cold floor (1 night in 100)
3.9°C
Record low 0.6 °C in 44 years, at a typical spot in the range NASA POWER
Warmest month, mean daily high
26°C
Jan at the habitat CHELSA
Rain a year (median across the range)
1,124mm
12 months of 25 mm or more in the median year CHELSA
Open-sky light
17–41DLI
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 May to November (November to May at the habitat), 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

Adiantum formosum, known as the giant maidenhair or black stem maidenhair is a fern found in Australia and New Zealand. It was one of the many species authored by Scottish botanist Robert Brown, appearing in his 1810 work Prodromus Florae Novae Hollandiae et Insulae Van Diemen. Its species name is the Latin adjective formosus "handsome" or "beautiful".

Quoted from Wikipedia, "Adiantum formosum", CC BY-SA 4.0.

About the genus · Adiantum

Adiantum, the maidenhair fern, is a genus of about 250 species of ferns in the subfamily Vittarioideae of the family Pteridaceae, though some researchers place it in its own family, Adiantaceae. The genus name comes from Greek, meaning "unwetted", referring to the fronds' ability to shed water without becoming wet.

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

Cultivation

Grouped as a fern or moss, listed under the genus Adiantum in the archetype table, and Kew describes it as “perennial”.

Seasons

The rain rule reads a summer growing season: 70% of the median year's rain (775 mm of 1,099 mm) falls in November to May, warmer than the year (wet-season mean 18.9 °C against a yearly mean of 16.4 °C). Months are the habitat's, southern hemisphere; shifted six months for a northern-hemisphere collection: May to November.

Rain

1,099 mm in the median year at the habitat, 775 mm of it November to May. Wettest month February at 147 mm, driest month August at 53 mm. Across the grid cells of the range the year's total runs 846 mm to 1,481 mm, the 10th to 90th percentile of each cell's own year. The median of the cells' own yearly totals, 1,124 mm, is the year's rain at the top of the page; the 1,099 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: 17 to 41 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 15, the highest 90th-percentile month 43).

Warmth and air
Temperature

Coldest: the 1st-percentile night over 44 years at a typical spot in the range is 3.9 °C, the absolute minimum 0.6 °C, no frost in 44 years (NASA POWER daily minima). Warmest: the 99th-percentile day is 38.3 °C. Monthly means: the coldest month's mean nightly low 5.8 °C in July (across the grid cells of the range 3.0 °C to 9.9 °C), the warmest month's mean daily high 26.2 °C in January (median year across the grid cells of the range, CHELSA). Cold floor: 3.9 °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 63% 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 -223 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 Adiantum in the archetype table, and Kew describes it as “perennial”. 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, southern hemisphere

Habitat climate of Adiantum formosum through the yearWarmest month January, mean daily high 26 °C; coldest month July, mean nightly low 5.8 °C; 1,099 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, southern hemisphere.-10°0°10°20°30°40°frost38.3° 99th-percentile day, NASA POWER0.6° lowest night in 44 years, NASA POWER°C · day and nightcold quarter050100150200250mm rainDLI 17–41RH 56–63%JanFebMarAprMayJunJulAugSepOctNovDec
day night rain medians and 10th–90th percentile across 891 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 °C26 / 24–2825 / 23–2724 / 22–2521 / 19–2318 / 15–2016 / 13–1815 / 12–1817 / 14–1920 / 17–2322 / 19–2524 / 21–2625 / 23–28
Night °C17 / 14–2017 / 14–2016 / 13–1913 / 10–1610 / 7–147 / 4–116 / 3–107 / 4–119 / 6–1312 / 9–1514 / 11–1716 / 13–19
Rain mm112 / 76–171147 / 100–214112 / 70–18098 / 63–14587 / 59–12776 / 50–11457 / 40–8353 / 38–7255 / 39–7083 / 68–104108 / 85–138111 / 83–162
DLI40 / 39–4235 / 34–3731 / 30–3225 / 23–2719 / 17–2217 / 15–2019 / 17–2225 / 23–2832 / 30–3537 / 36–3940 / 39–4141 / 40–43
RH %62 / 59–6463 / 61–6663 / 60–6562 / 60–6461 / 59–6360 / 58–6258 / 56–6156 / 55–5856 / 54–5857 / 55–5960 / 57–6261 / 58–63
How this section is made
Each figure is the median across the 891 grid cells on land that hold in-range records (1678 records in those cells; 3 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 2442:6639 (-32.125, 151.975). Over 44 years there: absolute minimum 0.6 °C, 1st-percentile night 3.9 °C, 99th-percentile day 38.3 °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 891 distinct grid cells holding 1678 of the 1681 in-range records (3 further cells with records at sea, by the elevation layer, left out); extremes and elevation at the typical cell 2442:6639 (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 -32.00_151.875, lapse-corrected -223 m at 6.5 °C/km. Elevation: ETOPO 2022, 173 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.
NativeNew South Wales, Queensland, Victoria, New Zealand North · introduced: Tanzania, Nansei-shoto, India, Sri Lanka · 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-32.682, 151.384 · in the densest population, 1123 records (64% of those in range)
Kew's description“perennial” · “subtropical” · quoted from WCVP, RBG Kew (CC BY 4.0); not derived here
Evidence usedThe map marker rests on all 1749 georeferenced records inside the native range; the climate across the range on the 1678 of them in the land cells it reads, of 1681 placed to within 10 km; the map shows only the 1515 openly licensed ones, which alone would put the marker 2 km away. 6 records outside the WCVP native range not used. 68 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 1749 in-range records; it decides nothing. Records outside the native range, living specimens and records marked introduced are not used; which records count.

Photographs

Adiantum formosum, photograph 1did not loadAdiantum formosum, photograph 2did not loadAdiantum formosum, photograph 3did not loadAdiantum formosum, photograph 4did not loadAdiantum formosum, photograph 5did not loadAdiantum formosum, photograph 6did not load

Photographs: (c) Bryce Watts-Parker, some rights reserved (CC BY) (6).

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

Eucalyptus saligna Eucalyptus saligna Sydney blue gum Photo: CC BY, Petra HollandAlectryon subcinereus Alectryon subcinereus Bird's eye Photo: CC BY-SA, Greg TasneyDendrobium speciosum Dendrobium speciosum Rock-lily Photo: CC BY, Petra HollandEhretia acuminata Ehretia acuminata Kodo wood Photo: CC BY-SA, Greg TasneyStenocarpus salignus Stenocarpus salignus Killarney beefwood Photo: CC BY, Petra HollandLastreopsis decomposita Lastreopsis decomposita Trim Shield Fern Photo: CC0, author not stated

Other Adiantum 42 in the reference

Adiantum aethiopicum Adiantum aethiopicum Pteridaceae Photo: CC BY, Ian RainbowAdiantum aleuticum Adiantum aleuticum Aleutian maidenhair fern Photo: CC BY, John BrewAdiantum amplum Adiantum amplum Pteridaceae Photo: CC BY, Alexis López HernándezAdiantum anceps Adiantum anceps Double edge maidenhair Photo: CC0, author not statedAdiantum andicola Adiantum andicola Pteridaceae Photo: CC BY, Juan Cruzado CortésAdiantum atroviride Adiantum atroviride Pteridaceae Photo: CC BY-SA, Greg TasneyAdiantum capillus-veneris Adiantum capillus-veneris Maidenhair fern Photo: CC BY, zebedeugalinhaAdiantum caudatum Adiantum caudatum Tailed maidenhair Photo: CC BY, 林正文Adiantum chilense Adiantum chilense Chilean Maidenhair Fern Photo: CC0, author not statedAdiantum concinnum Adiantum concinnum Polished maidenhair Photo: CC BY, Carlos Domínguez-RodríguezAdiantum cunninghamii Adiantum cunninghamii Cunningham's maidenhair Photo: CC BY, Hannah Rogers Adiantum curvatum Pteridaceae all 43 ›

Names & registers

Also known as Adiantum formosum var. leptophyllum. (GBIF Backbone)

GBIFPOWOIPNIWFOWikidataWikipediaiNaturalist

The record

Family
Pteridaceae
Described by
R.Br.
Native to
New South Wales, Queensland, Victoria +1
Wild records
1749 in range · 1515 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 2026-10-21
GBIF species record gbif.species answeredasked 2026-10-21
GBIF synonyms gbif.synonyms answeredasked 2026-10-21
GBIF common names gbif.vernacular answeredasked 2026-10-21names fetched 2026-10-21
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; 30 records within 1 km of a botanic garden, herbarium or zoo left out (20 at a botanic garden or arboretum, 3 at a herbarium, 7 at a zoo; Wikidata's list)
Habitat climate climate answeredasked 2026-10-21
Daily extremes (NASA POWER) climate.extremes answeredasked 2026-10-21NASA POWER (MERRA-2) daily 1981–2024, cell -32.00_151.875, lapse-corrected -223 m at 6.5 °C/km
Wikidata wikidata answeredasked 2026-10-21found by its label; its IPNI identifier 17010270-1 is Kew's for Adiantum formosum R.Br.
Wikipedia wikipedia answeredasked 2026-10-21
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 2026-10-21
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 32 datasets via GBIF.org; each carries its own licence.

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