Polystichum munitum (Kaulf.) C.Presl
Common Sword Fern (EN), Pacific sword fern, Schwert-Schildfarn, Schwertfarn (DE)
Every figure on this page is derived from public data by a stated rule and says its source; nothing here is written by a person or a model, except the Wikipedia passage, which is quoted and marked as such. How it is made.
Summary
Polystichum munitum, the western swordfern, is an evergreen perennial fern native to western North America, where it is one of the most abundant ferns in forested areas. It occurs along the Pacific coast from southeastern Alaska to southern California, and also inland east to southeastern British Columbia, northern Idaho and western Montana, with disjunctive populations in northern British Columbia, Canada; the Black Hills in South Dakota, United States; and Guadalupe Island off of Baja California, Mexico. Western swordfern is known to have locally naturalized in parts of Great Britain and Ireland.
Text from Wikipedia, “Polystichum munitum”, CC BY-SA 4.0, quoted as written. Kept separate from everything derived here.
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 ›
The opening of Wikipedia, “Polystichum”, CC BY-SA 4.0, quoted as written.
At a glance
Also known as Aetopteron munitum (Kaulf.) House; Aspidium munitum Kaulf.; Aspidium munitum var. incisoserratum D.C.Eaton; Aspidium munitum var. nudatum D.C.Eaton; Dryopteris munita (Kaulf.) Kuntze and 15 more.
Cultivation
Grouped as a fern or moss by the genus Polystichum, which is reliably one kind of plant (archetype table). The table supplies one figure for this group, a conventional minimum for the cold floor, and no prose.
Its year Rain rule: a winter growing season, October to March in the northern hemisphere (October to March at the habitat, northern).
This species’ habitat figures, and what two fixed rules read from them.
The rain rule reads a winter growing season: 70% of the year's rain (1183 mm of 1558 mm) falls in October to March, cooler than the year (wet-season mean 6.7 °C against a yearly mean of 10.5 °C). Months are the habitat's, northern hemisphere; shifted six months for a southern-hemisphere collection: April to September.
Read from the median year of CHELSA monthly rainfall and mean temperature across the envelope cells: 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 gives a season to reverse. A reading of the curves, not an observation of the plant.
Rain Habitat rain 1558 mm a year, wettest December at 244 mm, driest July at 27 mm (habitat calendar, northern hemisphere).
This species’ habitat figures, with their source.
1558 mm a year at the habitat, 1183 mm of it October to March. Wettest month December at 244 mm, driest July at 27 mm. Across the envelope cells the year's total runs 898 mm to 2886 mm (10th to 90th percentile of each cell's own year) (median year across the envelope cells, CHELSA; habitat calendar, northern hemisphere).
CHELSA monthly precipitation, median year across the envelope cells. The rain that falls where the species is recorded; nothing about how the plant takes water.
Light Open sky over the habitat: 6 to 41 mol/m²/day.
This species’ habitat figures, with their source.
Open sky over the habitat: 6 to 41 mol/m²/day across the year (daily light integral, median year across the envelope cells, CHELSA; the lowest 10th-percentile month across the cells is 5, the highest 90th-percentile month 50).
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.
Warmth and air Cold floor 5 °C (archetype minimum for a fern or moss, above the -10.0 °C habitat night).
This species’ habitat figures, with their source.
Coldest: the 1st-percentile night over 44 years at the typical cell is -10.0 °C, the absolute minimum -22.9 °C, about 51 frost nights a year (NASA POWER daily minima). Warmest: the 99th-percentile day is 30.9 °C. Monthly means: coldest night 1.7 °C in December (across the envelope cells -2.9 °C to 6.5 °C), warmest day 23.0 °C in August (median year across the envelope cells, CHELSA). Cold floor: 5 °C. The habitat figure, the 1st-percentile night over 44 years at the typical cell (NASA POWER), is -10.0 °C; the archetype table's conventional minimum for a fern or moss (grouped by the genus Polystichum, which is reliably one kind of plant) is 5 °C, which is higher, and the floor rule takes the higher.
NASA POWER daily minima and maxima 1981–2024 at the typical cell, lapse-corrected to its elevation; CHELSA monthly means, median year across the envelope cells, CHELSA. The cold floor is the figure named in its sentence, and the archetype table's group minimum where that is higher. Not a measured survival limit for any plant in a pot.
Relative humidity at the habitat: 59 to 66% across the year (monthly means, median year across the envelope cells, CHELSA). A figure about the air, saying nothing about how the plant takes water.
CHELSA relative humidity, median year across the envelope cells.
The figures the cards read from are in Climate below, and where they came from in Natural habitat.
Climate across the habitat
Figures by month
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Day °C | 7 / 3–12 | 8 / 5–13 | 11 / 7–14 | 13 / 10–16 | 16 / 13–19 | 19 / 15–23 | 23 / 17–27 | 23 / 17–28 | 20 / 16–24 | 15 / 12–19 | 9 / 6–15 | 7 / 2–12 |
| Night °C | 2 / -2–6 | 2 / -2–7 | 4 / -1–7 | 5 / 1–8 | 8 / 5–10 | 11 / 8–12 | 13 / 11–15 | 13 / 11–15 | 12 / 9–13 | 8 / 5–11 | 5 / 0–9 | 2 / -3–7 |
| Rain mm | 227 / 142–412 | 170 / 102–305 | 160 / 98–298 | 113 / 56–218 | 84 / 38–148 | 62 / 10–120 | 27 / 2–72 | 31 / 4–80 | 58 / 9–129 | 139 / 53–313 | 243 / 121–447 | 244 / 150–432 |
| DLI | 7 / 6–14 | 13 / 11–20 | 20 / 19–30 | 29 / 28–39 | 36 / 34–46 | 39 / 36–50 | 41 / 39–50 | 36 / 34–44 | 27 / 25–37 | 15 / 13–26 | 8 / 6–17 | 6 / 5–13 |
| RH % | 65 / 62–69 | 63 / 61–66 | 63 / 61–65 | 61 / 59–64 | 60 / 58–65 | 60 / 57–66 | 59 / 54–67 | 59 / 54–68 | 61 / 56–66 | 63 / 59–66 | 66 / 62–69 | 65 / 61–69 |
Each figure is the median across the 1005 grid cells holding the 1851 in-range records, with the 10th–90th percentile span across those cells after the slash where it differs. Extremes and elevation were read at the typical cell 824:1151 (48.775, -122.425). Over 44 years there: absolute minimum -22.9 °C, 1st-percentile night -10.0 °C, 99th-percentile day 30.9 °C. Normals: CHELSA V2.1 1981–2010 climatology, 0.05° cells (each the mean of ~36 1 km pixels). Envelope: median and 10th–90th percentile of each month across the 1005 distinct grid cells holding the 1851 in-range records; extremes and elevation at the typical cell 824:1151 (its coldest month's mean night nearest the median across cells); its position is the cell centre. Extremes: NASA POWER (MERRA-2) daily 1981–2024, cell 49.00_-122.500, lapse-corrected -54 m at 6.5 °C/km. Elevation: ETOPO 2022, 95 m (cell mean).
Natural habitat
Photographs
Photographs: (c) Jo "Cirque" Stormer, some rights reserved (CC BY) (8).
Photographs: iNaturalist did not answer when this page was built; what is shown came from the sources that did.
Papers naming this species
Works whose title or abstract names Polystichum munitum, most cited first, from OpenAlex (CC0). A mention, not a cultivation source: nothing on this page is drawn from them.
Related
Similar habitat climate the 6 species whose habitat climate is nearest this one's: mean day and night, month by month, and rain on a log scale, in calendar order, so a habitat with the same seasons six months out is far, not near. Nothing else counts: not range, not family.
Mahonia nervosa Cascade Oregon-grape
Tellima grandiflora Fringecup
Heuchera micrantha alumroot
Ribes sanguineum Flowering Currant
Plectritis congesta shortspur seablush
Symphyotrichum subspicatum Douglas asterOther Polystichum 3 in the reference
Polystichum acrostichoides Christmas Fern
Polystichum polyblepharon Japanese Shield-fern
Polystichum setiferum English hedge fern History & registers
Where this page came from built 2026-09-20 · dossier v2 · node
gbif.species answeredcarried from build of 2026-09-19 (offline re-derivation; the backbone was not asked)gbif.synonyms answeredcarried from build of 2026-09-19 (offline re-derivation; the backbone was not asked)gbif.vernacular answeredcarried from build of 2026-09-19 (offline re-derivation; the backbone was not asked)wcvp.distribution answeredgbif.occurrences answeredGBIF occurrence download https://doi.org/10.15468/dl.3h4zamclimate answeredwikidata answeredcarried from build of 2026-09-19 (rederive); that build: carried from build of 2026-09-19 (rederive)wikipedia answeredcarried from build of 2026-09-19; this build: skippedinat.taxon not askedinat.photos.wild answeredcarried from build of 2026-09-19; this build: skippedinat.photos.cultivated nothing to reportcarried from build of 2026-09-19 (rederive); that build: carried from build of 2026-09-19 (rederive)commons nothing to reportcarried from build of 2026-09-19 (rederive); that build: carried from build of 2026-09-19 (rederive)gbif.media answeredopenalex answeredcarried from build of 2026-09-19; this build: skippedEvery upstream is recorded as having answered, reported nothing, or refused. Only “nothing to report” is ever shown as an absence. Records came from 42 datasets via GBIF.org; each carries its own licence.








