Species
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Nephrolepis exaltata (L.) Schott

Boston Swordfern, Boston fern, Boston fern, Boston sword fern

Climate known 92 photographs Fern or moss
Add one to my plants Sow seed

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

Nephrolepis exaltata, known as the sword fern or Boston fern, is a species of fern in the family Nephrolepidaceae. It is native to the Americas. This evergreen plant can reach as high as 40–90 centimetres (16–35 in), and in extreme cases up to 1.5 metres. It is also known as the Boston sword fern, wild Boston fern, Boston blue bell fern, tuber ladder fern, or fishbone fern.

Text from Wikipedia, “Nephrolepis exaltata”, CC BY-SA 4.0, quoted as written. Kept separate from everything derived here.

About the genus · Nephrolepis

Nephrolepis is a genus of about 30 species of ferns. It is the only genus in the family Nephrolepidaceae, placed in the suborder Aspleniineae of the order Polypodiales in the Pteridophyte Phylogeny Group classification of 2016. Species in this genus include plants commonly referred to as Boston ferns. More on Wikipedia ›

The opening of Wikipedia, “Nephrolepis”, CC BY-SA 4.0, quoted as written.

Family
Nephrolepidaceae
Described by
(L.) Schott
Native to
Hawaii, Arizona, Texas +21
Wild records
788 in range· 429 open

At a glance

Warmest month
29°C
Aug, mean day; nights 24 °C (CHELSA)
Rain
1466mm/yr
12 wet months · peak Aug 193 mm (CHELSA)
Light
25–41DLI
mol/m²/day, winter to summer, open sky (CHELSA shortwave)
In short condensed by rule from the cultivation cards · not written by a person
Grouped as a fern or moss by the genus Nephrolepis, which is reliably one kind of plant (archetype table). Rain rule: a summer growing season, March and May to October in the northern hemisphere (March and May to October at the habitat, northern). Habitat rain 1466 mm a year, wettest August at 193 mm, driest January at 69 mm (habitat calendar, northern hemisphere). Open sky over the habitat: 25 to 41 mol/m²/day. Cold floor 5.3 °C (1st-percentile habitat night, NASA POWER).
Each sentence is one card's own one-line form, written by the same rule as the card (Its year, Rain, Light, Temperature); the note cannot say what a card does not. Months are given for the northern hemisphere (set your site in Settings to change this), and the habitat's own alongside. The cards · the figures.

Also known as Aspidium exaltatum (L.) Schkuhr; Aspidium flagelliferum Roxb. ex Wall.; Nephrodium exaltatum (L.) Desv.; Nephrodium exaltatum (L.) Kunth.

Cultivation

Grouped as a fern or moss by the genus Nephrolepis, 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 summer growing season, March and May to October in the northern hemisphere (March and May to October at the habitat, northern).

This species’ habitat figures, and what two fixed rules read from them.

The rain rule reads a summer growing season: 70% of the year's rain (1073 mm of 1466 mm) falls in March and May to October, warmer than the year (wet-season mean 24.9 °C against a yearly mean of 23.3 °C). Months are the habitat's, northern hemisphere; shifted six months for a southern-hemisphere collection: November to April and 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 1466 mm a year, wettest August at 193 mm, driest January at 69 mm (habitat calendar, northern hemisphere).

This species’ habitat figures, with their source.

1466 mm a year at the habitat, 1073 mm of it March and May to October. Wettest month August at 193 mm, driest January at 69 mm. Across the envelope cells the year's total runs 1151 mm to 2527 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: 25 to 41 mol/m²/day.

This species’ habitat figures, with their source.

Open sky over the habitat: 25 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 19, the highest 90th-percentile month 43).

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 5.3 °C (1st-percentile habitat night, NASA POWER).

This species’ habitat figures, with their source.

Temperature

Coldest: the 1st-percentile night over 44 years at the typical cell is 5.3 °C, the absolute minimum -4.6 °C, 14 frost nights in 44 years (NASA POWER daily minima). Warmest: the 99th-percentile day is 34.1 °C. Monthly means: coldest night 16.8 °C in January (across the envelope cells 10.9 °C to 22.7 °C), warmest day 29.2 °C in August (median year across the envelope cells, CHELSA). Cold floor: 5.3 °C, which is the 1st-percentile night over 44 years at the typical cell (NASA POWER); the archetype table's minimum for a fern or moss, 5 °C, is lower and does not raise it.

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.

Humidity

Relative humidity at the habitat: 61 to 64% 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

Habitat climate through the yearMean day from 23 °C in Jan to 29 °C in Aug; mean night from 17 °C in Jan to 24 °C in Aug. The cold quarter, Dec to Feb, is the three months around the coldest night. 1466 mm of rain a year, most in Aug. The bands show the 10th to 90th percentile across 555 habitat cells. Over 44 years at the typical cell the absolute minimum was -4.6 °C and the 99th-percentile day 34.1 °C; neither is dated to a month. Beneath: daily light integral and relative humidity through the year, each on its own scale.-10°10°20°30°40°frost34.1° 99th-percentile day (undated)-4.6° lowest night in 44 yrs (undated)°C · day and nightcold quarter0100200300400mm rainDLI 25–41RH 61–64 %JanFebMarAprMayJunJulAugSepOctNovDec
day night rain 10th–90th percentile across 555 habitat cells cold quarter: the three months around the coldest night extremes over 44 years at the typical cell, marked at the edge: undated DLI, mol/m²/dayRH %each on its own scale
Figures by month
JanFebMarAprMayJunJulAugSepOctNovDec
Day °C23 / 19–2924 / 20–2925 / 21–2927 / 22–2928 / 22–3129 / 22–3229 / 22–3229 / 23–3229 / 23–3127 / 23–2925 / 22–2824 / 20–28
Night °C17 / 11–2317 / 12–2318 / 14–2319 / 15–2321 / 15–2323 / 14–2523 / 14–2524 / 14–2623 / 16–2521 / 16–2419 / 15–2318 / 12–23
Rain mm69 / 43–26676 / 48–203100 / 53–23177 / 57–229110 / 57–278189 / 38–271171 / 41–248193 / 38–256185 / 57–293125 / 68–31596 / 50–27075 / 40–231
DLI26 / 22–3630 / 26–3734 / 32–3939 / 29–4341 / 25–4338 / 23–4339 / 24–4337 / 28–4232 / 30–3930 / 27–3626 / 22–3625 / 19–35
RH %61 / 58–6861 / 58–6761 / 57–6861 / 56–6962 / 57–6963 / 61–6963 / 61–6964 / 60–6964 / 60–7061 / 60–7061 / 59–7061 / 58–69

Each figure is the median across the 555 grid cells holding the 686 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 1259:1990 (27.025, -80.475). Over 44 years there: absolute minimum -4.6 °C, 1st-percentile night 5.3 °C, 99th-percentile day 34.1 °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 555 distinct grid cells holding the 686 in-range records; extremes and elevation at the typical cell 1259:1990 (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 27.00_-80.625, lapse-corrected +2 m at 6.5 °C/km. Elevation: ETOPO 2022, 10 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 every in-range record's cell, not at the marker.
Openly licensed records inside the range, framed on where they fall.
NativeHawaii, Arizona, Texas, Florida, Louisiana, Mexico Gulf, Costa Rica, Honduras, Nicaragua, Panama, Bahamas, Bermuda, Cuba, Jamaica, Leeward Is. AB Ant, Puerto Rico, Turks-Caicos Is., Bolivia, Colombia, Ecuador, Brazil Northeast, Brazil Southeast, Brazil North, Brazil South· introduced: Portugal, Algeria, Morocco, Azores, Canary Is., Tanzania, St.Helena, India, Queensland, Western Australia, Kermadec Is., Line Is., Tubuai Is., Arkansas
Kew's description“epiphyte” · “subtropical”· quoted from WCVP, RBG Kew (CC BY 4.0); not derived here
Map marker27.532, -82.645 · in the densest population, 266 records (34% of those in range)
Evidence usedThe map marker and the climate envelope rest on all 788 georeferenced records inside the native range; the map shows only the 429 openly licensed ones, which alone would put the marker 161 km away. 350 records outside the range (gardens, roadsides, misidentifications) ignored. 102 in-range records are placed to worse than 10 km and stay on the map but off the climate.
The map markerthe map marker: the openly licensed record nearest the middle of the densest 1° population of the 788 in-range records; it decides nothing.

Photographs

Nephrolepis exaltataNephrolepis exaltataNephrolepis exaltataNephrolepis exaltataNephrolepis exaltataNephrolepis exaltataNephrolepis exaltataNephrolepis exaltata

Photographs: no rights reserved · CC0 (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 Nephrolepis exaltata, most cited first, from OpenAlex (CC0). A mention, not a cultivation source: nothing on this page is drawn from them.

Plasmodesmata and the control of symplastic transport
Alison G. Roberts, Karl Oparka (2003) · Plant Cell & Environment
Antioxidant responses of hyper-accumulator and sensitive fern species to arsenic
Mrittunjai Srivastava, Q. Lena, Nandita Singh, Shraddha Singh (2005) · Journal of Experimental Botany
Evolutionary Conservation of ABA Signaling for Stomatal Closure
Shengguan Cai, Guang Chen, Yuanyuan Wang, Yuqing Huang (2017) · PLANT PHYSIOLOGY
Fungal Planet description sheets: 951–1041
Crous Pw, Wingfield Mj, L. Lombard, Francois Roets (2019) · Persoonia - Molecular Phylogeny and Evolution of Fungi
Bioaccumulation and physiological effects of mercury in Pteris vittata and Nephrolepis exaltata
Jian Chen, Safwan Shiyab, Fengxiang X. Han, David L. Monts (2008) · Ecotoxicology
A study of stomatal mechanics using the cell pressure probe
Peter J. Franks, I.R. Cowan, Graham D. Farquhar (1998) · Plant Cell & Environment
Phytofiltration of Arsenic from Drinking Water Using Arsenic-Hyperaccumulating Ferns
Jianwei Huang, Charissa Y. Poynton, Leon V. Kochian, M. P. Elless (2004) · Environmental Science & Technology
Arsenic chemistry in the rhizosphere of Pteris vittata L. and Nephrolepis exaltata L.
Maria Isidória Silva Gonzaga, Jorge Antônio Gonzaga Santos, Q. Lena (2006) · Environmental Pollution
Spectroscopic Analysis of Arsenic Uptake in Pteris Ferns
E. Terrence Slonecker, Barry Haack, Susan D. Price (2009) · Remote Sensing
Ultrastructural specializations of the cell wall sleeve around plasmodesmata
K. Badelt, Rosemary G. White, Robyn L. Overall, Maret Vesk (1994) · American Journal of Botany

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.

Other Nephrolepis 3 in the reference

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 answered
gbif.occurrences answeredGBIF occurrence download https://doi.org/10.15468/dl.3h4zam
climate answered
wikidata 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: skipped
inat.taxon not asked
inat.photos.wild answeredcarried from build of 2026-09-19; this build: skipped
inat.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 answered
openalex answeredcarried from build of 2026-09-19; this build: skipped

Every upstream is recorded as having answered, reported nothing, or refused. Only “nothing to report” is ever shown as an absence. Records came from 162 datasets via GBIF.org; each carries its own licence.