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Dryopteris koidzumiana; photograph ゆうき315, CC BY-SA 4.0, via Wikimedia Commons CC BY-SAゆうき315, CC BY-SA 4.0, via Wikimedia Commons

Dryopteris koidzumiana Tagawa

Dryopteridaceae · Japan, Nansei-shoto · listed by its genus as a fern or moss

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Habitat figures
Coldest month, mean nightly low
12.2°C
Jan at the habitat, not a floor; extremes not used (sea cell) CHELSA
Warmest month, mean daily high
28°C
Jul and Aug at the habitat CHELSA
Rain a year (median across the range)
3,696mm
12 months of 25 mm or more in the median year CHELSA
Open-sky light
15–38DLI
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.

About the genus · Dryopteris

Dryopteris, commonly called the wood ferns, male ferns, or buckler ferns, is a fern genus in the family Dryopteridaceae, subfamily Dryopteridoideae, according to the Pteridophyte Phylogeny Group classification of 2016 (PPG I). There are about 300-400 species in the genus. The species are distributed in Asia, the Americas, Europe, Africa, and the Pacific islands, with the highest diversity in eastern Asia. More on Wikipedia ›

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

Cultivation

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

Seasons

The rain rule reads no short rainy season: 70% of the median year's rain (2,896 mm of 3,784 mm) takes 8 months, March to October. Mean temperature moves 13.5 °C between the warmest and coldest month. Months are the habitat's, northern hemisphere; shifted six months for a southern-hemisphere collection: September to April.

Rain

3,784 mm in the median year at the habitat, 2,896 mm of it March to October. Wettest month June at 652 mm, driest month December at 202 mm. Across the grid cells of the range the year's total runs 2,715 mm to 5,252 mm, the 10th to 90th percentile of each cell's own year. The median of the cells' own yearly totals, 3,696 mm, is the year's rain at the top of the page; the 3,784 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 38 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 41).

Warmth and air
Temperature

Monthly means: the coldest month's mean nightly low 12.2 °C in January (across the grid cells of the range 9.9 °C to 14.6 °C), the warmest month's mean daily high 27.8 °C in August (median year across the grid cells of the range, CHELSA). Cold floor: none read. The nearest figure is 12.2 °C, the coldest month's mean nightly low, January, 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: 56 to 70% 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 Dryopteris 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 Dryopteris koidzumiana through the yearWarmest months July and August, mean daily high 28 °C; coldest month January, mean nightly low 12.2 °C; 3,784 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°30°°C · day and nightcold quarter02004006008001000mm rainDLI 15–38RH 56–70%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 / 13–1715 / 13–1717 / 15–1920 / 18–2123 / 21–2325 / 24–2628 / 26–2828 / 27–2827 / 25–2724 / 22–2520 / 19–2217 / 15–18
Night °C12 / 10–1512 / 10–1514 / 12–1617 / 16–1920 / 19–2223 / 22–2426 / 25–2726 / 25–2725 / 24–2622 / 20–2318 / 16–2014 / 12–16
Rain mm236 / 151–308218 / 167–316334 / 216–512340 / 246–504363 / 272–523652 / 358–913283 / 187–374294 / 241–336359 / 254–472271 / 225–348232 / 171–360202 / 143–295
DLI15 / 13–1619 / 17–2025 / 22–2531 / 29–3133 / 33–3431 / 30–3438 / 38–4137 / 35–3831 / 29–3325 / 23–2618 / 16–1915 / 13–16
RH %56 / 54–6157 / 55–6259 / 56–6361 / 58–6564 / 60–6870 / 66–7570 / 67–7368 / 65–7266 / 62–6960 / 57–6458 / 55–6256 / 54–60

The daily extremes were read at a NASA POWER cell that is 28% 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 5.7 °C, 1st-percentile night 10.5 °C, 99th-percentile day 29.1 °C.

How this section is made
Each figure is the median across the 14 grid cells on land that hold in-range records (18 records in those cells; 4 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 1234:6186 (28.275, 129.325). 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 18 of the 22 in-range records (4 further cells with records at sea, by the elevation layer, left out); extremes and elevation at the typical cell 1234:6186 (its coldest month's mean nightly low nearest the median across cells, though its NASA POWER cell is only 28% land and none of the 8 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 28.50_129.375, lapse-corrected +215 m at 6.5 °C/km. Elevation: ETOPO 2022, 235 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.
NativeJapan, Nansei-shoto · 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 marker26.764, 128.206 · in the densest population, 32 records (65% 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 49 georeferenced records inside the native range; the climate across the range on the 18 of them in the land cells it reads, of 22 placed to within 10 km; the map shows only the 46 openly licensed ones, which alone would put the marker 1 km away. 27 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 49 in-range records; it decides nothing. Records outside the native range, living specimens and records marked introduced are not used; which records count.

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

Rhododendron tashiroi Rhododendron tashiroi Ericaceae Photo: CC BY, Takaaki HattoriCinnamomum daphnoides Cinnamomum daphnoides Lauraceae Photo: CC0, author not statedRhododendron eriocarpum Rhododendron eriocarpum Ericaceae Photo: CC BY, Forest & Kim StarrSmilax sebeana Smilax sebeana Smilacaceae Photo: CC0, author not statedGastrochilus japonicus Gastrochilus japonicus Tamra gastrochilus Photo: CC BY, M108tDiplazium lobatum Diplazium lobatum Athyriaceae Photo: CC BY, Yu-Chang Chen

Other Dryopteris 75 in the reference

Dryopteris aemula Dryopteris aemula Hay-scented Buckler-fern Photo: CC BY, Rocco LieghioDryopteris affinis Dryopteris affinis Scaly male fern Photo: CC0, pondbobDryopteris aitoniana Dryopteris aitoniana Madeira Buckler-fern Photo: CC BY, Sam J. Thomas Dryopteris × ambroseae Dryopteridaceae Dryopteris amurensis Dryopteris amurensis Amur wood fern Photo: CC BY, Violetta DzizyurovaDryopteris ardechensis Dryopteris ardechensis Cévennes Male-fern Photo: CC BY-SA, Chérif-Jacques AllaliDryopteris arguta Dryopteris arguta Coastal wood fern Photo: CC BY, Matt Berger Dryopteris assamensis Dryopteridaceae Dryopteris atrata Dryopteris atrata Shaggy shield fern Photo: CC BY, Jacy ChenDryopteris × australis Dryopteris × australis Woodfern Photo: CC BY-SA, lejones417Dryopteris bissetiana Dryopteris bissetiana Mountain buckler fern Photo: CC BY, Yoshihiro TokueDryopteris blanfordii Dryopteris blanfordii Dryopteridaceae Photo: Public domain, Stickpen all 76 ›

Names & registers

Also known as Dryopteris erythrosora var. koidzumiana. (GBIF Backbone)

GBIFPOWOIPNIWFOWikidata

The record

Family
Dryopteridaceae
Described by
Tagawa
Native to
Japan, Nansei-shoto
Wild records
49 in range · 46 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 28.50_129.375, lapse-corrected +215 m at 6.5 °C/km; read, and set aside: NASA POWER's cell is mostly sea (28% land), so no cold floor is shown
Wikidata wikidata answeredasked 2026-10-22
Wikipedia wikipedia nothing to reportasked 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 nothing to reportasked 2026-10-22
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 14 datasets via GBIF.org; each carries its own licence.

Cultifolio

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