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Polystichum drepanum; photograph El Funcionario, CC BY-SA 4.0, via Wikimedia Commons CC BY-SAEl Funcionario, CC BY-SA 4.0, via Wikimedia Commons

Polystichum drepanum (Sw.) C.Presl

Madeira Shield-Fern

Dryopteridaceae · Madeira · listed by its genus as a fern or moss

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Polystichum drepanum, photograph author not stated, no rights reservedPolystichum drepanum, photograph author not stated, no rights reservedPolystichum drepanum, photograph author not stated, no rights reservedPolystichum drepanum, photograph This illustration was made by Citron, CC BY-SA 3.0, via Wikimedia CommonsPolystichum drepanum, photograph El Funcionario, CC BY-SA 4.0, via Wikimedia CommonsPolystichum drepanum, photograph El Funcionario, CC BY-SA 4.0, via Wikimedia Commons 9 photographs ›
Habitat figures
Coldest month, mean nightly low
11.5°C
Feb at the habitat, not a floor; extremes not used (sea cell) CHELSA
Warmest month, mean daily high
23°C
Aug at the habitat CHELSA
Rain a year (median across the range)
2,203mm
11 months of 25 mm or more in the median year CHELSA
Open-sky light
15–47DLI
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 winters: the rain comes October to March, read as a winter growing season. rain rule, CHELSA
Northern hemisphere unless you set your site. The chart is in the habitat's months.

Summary

Polystichum drepanum, also known as Madeira shield-fern, is a species of fern in the Dryopteridaceae family.

Quoted from Wikipedia, "Polystichum drepanum", CC BY-SA 4.0.

About the genus · Polystichum

Polystichum is a genus of ferns in the family Dryopteridaceae, subfamily Dryopteridoideae, according to the Pteridophyte Phylogeny Group classification of 2016. The genus has about 500 species and has a cosmopolitan distribution. The highest diversity is in eastern Asia, with about 208 species in China alone; the region from Mexico to Brazil has at least 100 additional species; Africa, North America, and Europe have much lower diversity. More on Wikipedia ›

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

Cultivation

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

Seasons

The rain rule reads a winter growing season: 70% of the median year's rain (1,692 mm of 2,212 mm) falls in October to March, cooler than the year (wet-season mean 14.8 °C against a yearly mean of 16.3 °C). Months are the habitat's, northern hemisphere; shifted six months for a southern-hemisphere collection: April to September.

Rain

2,212 mm in the median year at the habitat, 1,692 mm of it October to March. Wettest month December at 382 mm, driest month July at 21 mm. Across the grid cells of the range the year's total runs 1,820 mm to 2,580 mm, the 10th to 90th percentile of each cell's own year. The median of the cells' own yearly totals, 2,203 mm, is the year's rain at the top of the page; the 2,212 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: 15 to 47 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 13, the highest 90th-percentile month 47).

Warmth and air
Temperature

Monthly means: the coldest month's mean nightly low 11.5 °C in February (across the grid cells of the range 8.9 °C to 13.2 °C), the warmest month's mean daily high 22.9 °C in August (median year across the grid cells of the range, CHELSA). Cold floor: none read. The nearest figure is 11.5 °C, the coldest month's mean nightly low, February, 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: 63 to 66% 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.

Group. Listed under the genus Polystichum 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, northern hemisphere

Habitat climate of Polystichum drepanum through the yearWarmest month August, mean daily high 23 °C; coldest month February, mean nightly low 11.5 °C; 2,212 mm of rain in the median year (the twelve monthly medians added). Medians across the range, from CHELSA. Habitat months, northern hemisphere.5°10°15°20°25°°C · day and nightcold quarter0100200300400500mm rainDLI 15–47RH 63–66%JanFebMarAprMayJunJulAugSepOctNovDec
day night rain medians and 10th–90th percentile across 14 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 °C15 / 12–1614 / 12–1615 / 13–1715 / 13–1717 / 15–1820 / 19–2122 / 22–2323 / 22–2322 / 20–2319 / 17–2117 / 14–1916 / 13–17
Night °C12 / 9–1412 / 9–1312 / 10–1412 / 10–1414 / 11–1516 / 15–1718 / 18–1819 / 18–2018 / 16–2017 / 14–1815 / 12–1713 / 10–15
Rain mm258 / 211–301265 / 219–308218 / 188–259183 / 150–220107 / 91–12857 / 51–6721 / 15–2228 / 21–29124 / 106–143260 / 213–301309 / 246–362382 / 292–457
DLI17 / 15–2123 / 21–2731 / 29–3537 / 36–3942 / 42–4345 / 45–4647 / 46–4742 / 41–4434 / 32–3725 / 23–2918 / 16–2315 / 13–20
RH %65 / 62–6664 / 63–6563 / 60–6464 / 62–6565 / 63–6664 / 61–6663 / 56–6564 / 59–6564 / 63–6666 / 64–6865 / 63–6666 / 63–68

The daily extremes were read at a NASA POWER cell that is 12% 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 7.9 °C, 1st-percentile night 11.1 °C, 99th-percentile day 23.3 °C.

How this section is made
Each figure is the median across the 14 grid cells holding the 15 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 1146:3260 (32.675, -16.975). 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 14 distinct grid cells holding 15 of the 15 in-range records; extremes and elevation at the typical cell 1146:3260 (its coldest month's mean nightly low nearest the median across cells, though its NASA POWER cell is only 12% land and none of the 9 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 32.50_-16.875, lapse-corrected +366 m at 6.5 °C/km. Elevation: ETOPO 2022, 494 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.
NativeMadeira · 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 marker32.75, -17 · in the densest population, 24 records (100% 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 24 georeferenced records inside the native range; the climate across the range on the 15 of them placed to within 10 km; the map shows only the 8 openly licensed ones, which alone would put the marker 1 km away. 3 records outside the WCVP native range not used. 9 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 24 in-range records; it decides nothing. Records outside the native range, living specimens and records marked introduced are not used; which records count.

Photographs

Polystichum drepanum, photograph 1did not loadPolystichum drepanum, photograph 2did not loadPolystichum drepanum, photograph 3did not loadPolystichum drepanum, photograph 4did not loadPolystichum drepanum, photograph 5did not loadPolystichum drepanum, photograph 6did not load

Photographs: author not stated, no rights reserved · CC0 (3); This illustration was made by Citron, CC BY-SA 3.0, via Wikimedia Commons; El Funcionario, CC BY-SA 4.0, via Wikimedia Commons (2).

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

Hedera maderensis Hedera maderensis Araliaceae Photo: CC0, author not statedTeucrium betonicum Teucrium betonicum Betony Photo: CC BY, Vítor JorgeSonchus pinnatus Sonchus pinnatus Wing-leaved Sow-thistle Photo: CC BY, Vítor JorgeConvolvulus massonii Convolvulus massonii Madeira Morning Glory Photo: CC BY, Vítor JorgeErysimum bicolor Erysimum bicolor Brassicaceae Photo: CC BY, Vítor JorgeSibthorpia peregrina Sibthorpia peregrina Madeira Moneywort Photo: CC0, author not stated

Other Polystichum 43 in the reference

Polystichum acrostichoides Polystichum acrostichoides Christmas fern Photo: CC BY, Michael J. PapayPolystichum aculeatum Polystichum aculeatum Hard shield-fern Photo: CC BY, Daniel BuczkiewiczPolystichum andersonii Polystichum andersonii Anderson's holly fern Photo: CC BY, Matt BergerPolystichum andinum Polystichum andinum Dryopteridaceae Photo: CC BY, Constanza Vargas VillegasPolystichum × bicknellii Polystichum × bicknellii Dryopteridaceae Photo: CC BY, Sean Frederick TuckPolystichum braunii Polystichum braunii Braun's holly fern Photo: CC BY, Oleg Kosterin Polystichum calderonense Monte Guilarte holly fern Polystichum dracomontanum Polystichum dracomontanum Dryopteridaceae Photo: CC0, author not stated Polystichum × dycei Dryopteridaceae Polystichum falcinellum Polystichum falcinellum Madeira Sword-Fern Photo: CC BY, K.P. Polystichum grandifrons Dryopteridaceae Polystichum hancockii Polystichum hancockii Dryopteridaceae Photo: CC BY, Jacy Chen all 44 ›

Names & registers

Also known as Aspidium drepanum; Phegopteris drepanum; Polypodium drepanum. (GBIF Backbone)

GBIFPOWOIPNIWFOWikidataWikipediaiNaturalist

The record

Family
Dryopteridaceae
Described by
(Sw.) C.Presl
Native to
Madeira
Wild records
24 in range · 8 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
Habitat climate climate answeredasked 2026-10-22
Daily extremes (NASA POWER) climate.extremes answeredasked 2026-10-22NASA POWER (MERRA-2) daily 1981–2024, cell 32.50_-16.875, lapse-corrected +366 m at 6.5 °C/km; read, and set aside: NASA POWER's cell is mostly sea (12% 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 10 datasets via GBIF.org; each carries its own licence.

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