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Hemionitis densa (Brack.) Christenh.

Pteridaceae · Alaska, British Columbia +9

English names not checked: Wikidata's common names were not read for this page.

Photographs not checked iNaturalist and GBIF media were skipped (not asked) when this page was built. Not asked, or not answered, is not "none": nothing here claims there is none. Why the site says it this way.
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Habitat figures
Cold floor (1 night in 100)
-9.9°C
Record low -23.8 °C in 44 years, at a typical spot in the range NASA POWER
Warmest month, mean daily high
25°C
Jul and Aug at the habitat CHELSA
Rain a year (median across the range)
1,469mm
10 months of 25 mm or more in the median year CHELSA
Open-sky light
10–50DLI
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 November to March, with nights below freezing; no growing season read. rain rule, CHELSA
Northern hemisphere unless you set your site. The chart is in the habitat's months.

Summary

Aspidotis densa is a species of fern in the Cheilanthoid subfamily, known by the common name Indian's dream or Serpentine fern or dense lace fern. It is native to the west coast of North America from British Columbia to California and east to the Rocky Mountains in Idaho, Montana, and Wyoming; there is a disjunct population on serpentine soils in Quebec.

Quoted from Wikipedia, "Aspidotis densa", CC BY-SA 4.0; its title is one of this species' older names (GBIF Backbone), which is the proof that the article is this species'.

Cultivation

Seasons

The rain rule reads a rainy season and no growing season: 70% of the median year's rain (1,090 mm of 1,458 mm) falls in November to March, the cooler part of the year, but the mean nightly low is below freezing in February, March, April and January, so the rule reads no growing season from it. Months are the habitat's, northern hemisphere; shifted six months for a southern-hemisphere collection: May to September.

Rain

1,458 mm in the median year at the habitat, 1,090 mm of it November to March. Wettest month December at 257 mm, driest month July at 13 mm. Across the grid cells of the range the year's total runs 860 mm to 2,439 mm, the 10th to 90th percentile of each cell's own year. The median of the cells' own yearly totals, 1,469 mm, is the year's rain at the top of the page; the 1,458 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: 10 to 50 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 5, the highest 90th-percentile month 53).

Warmth and air
Temperature

Coldest: the 1st-percentile night over 44 years at a typical spot in the range is -9.9 °C, the absolute minimum -23.8 °C, 5,170 frost nights in 44 years, 117.5 a year (NASA POWER daily minima). Warmest: the 99th-percentile day is 31.0 °C. Monthly means: the coldest month's mean nightly low -2.7 °C in December (across the grid cells of the range -9.7 °C to 3.3 °C), the warmest month's mean daily high 25.1 °C in July (median year across the grid cells of the range, CHELSA). Cold floor: -9.9 °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: 50 to 62% 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 +186 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.

Climate across the habitat

Habitat months, northern hemisphere

Habitat climate of Hemionitis densa through the yearWarmest months July and August, mean daily high 25 °C; coldest month December, mean nightly low -2.7 °C; 1,458 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, northern hemisphere.-30°-20°-10°0°10°20°30°40°frost31.0° 99th-percentile day, NASA POWER-23.8° lowest night in 44 years, NASA POWER°C · day and nightcold quarter0100200300400500mm rainDLI 10–50RH 50–62%JanFebMarAprMayJunJulAugSepOctNovDec
day night rain medians and 10th–90th percentile across 622 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 °C5 / -1–116 / 0–129 / 3–1412 / 6–1716 / 11–2220 / 16–2725 / 20–3125 / 20–3121 / 17–2815 / 10–218 / 2–144 / -3–10
Night °C-2 / -9–3-2 / -8–4-1 / -6–51 / -4–65 / -1–99 / 4–1212 / 8–1512 / 8–159 / 4–135 / 0–100 / -6–6-3 / -10–3
Rain mm245 / 116–383203 / 88–311174 / 82–287102 / 57–18570 / 42–12535 / 19–10113 / 2–4917 / 4–5233 / 17–8898 / 58–208211 / 112–381257 / 126–433
DLI11 / 6–1617 / 12–2326 / 20–3235 / 29–4142 / 36–4848 / 39–5350 / 41–5344 / 36–4835 / 26–3923 / 15–2813 / 7–1810 / 5–14
RH %62 / 55–6761 / 57–6460 / 56–6458 / 54–6256 / 51–6254 / 46–6150 / 42–6050 / 42–6052 / 44–6156 / 49–6362 / 54–6762 / 56–68
How this section is made
Each figure is the median across the 622 grid cells on land that hold in-range records (1286 records in those cells; 1 more cell holds records but no land by the elevation layer, so those records sit at sea and the cell is 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 922:1155 (43.875, -122.225). Over 44 years there: absolute minimum -23.8 °C, 1st-percentile night -9.9 °C, 99th-percentile day 31.0 °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 622 distinct grid cells holding 1286 of the 1287 in-range records (1 further cell with records at sea, by the elevation layer, left out); extremes and elevation at the typical cell 922:1155 (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 44.00_-122.500, lapse-corrected +186 m at 6.5 °C/km. Elevation: ETOPO 2022, 985 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.

This species has no GBIF key of its own. Its records are GBIF's under the key of the name Kew's World Checklist holds as this plant: 2651595 (Aspidotis densa (Brack.) Lellinger, 1987 records). No name was matched to GBIF; the keys are read from Kew's synonymy. How.

NativeAlaska, British Columbia, Québec, Idaho, Montana, Oregon, Washington, Wyoming, California, Nevada, Utah · 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 marker41.825, -123.783 · in the densest population, 1107 records (72% of those in range)
Kew's description“temperate” · quoted from WCVP, RBG Kew (CC BY 4.0); not derived here
Evidence usedThe map marker rests on all 1548 georeferenced records inside the native range; the climate across the range on the 1286 of them in the land cells it reads, of 1287 placed to within 10 km; the map shows only the 548 openly licensed ones, which alone would put the marker 697 km away. 2 records outside the WCVP native range not used. 261 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.
Other GBIF keysRecords also from GBIF's key 2651595 (Aspidotis densa (Brack.) Lellinger): Kew's file holds it as Aspidotis densa (Brack.) Lellinger (synonym under Hemionitis densa (Brack.) Christenh.); 1,987 records, from GBIF's download.
How this section is made
The map marker: the openly licensed record nearest the middle of the densest 1° population inside the densest 4° block of the 1548 in-range records; it decides nothing. Records outside the native range, living specimens and records marked introduced are not used; which records count.

Photographs

Not checked. iNaturalist and GBIF media were skipped (not asked) when this page was built. Not a statement that none exist.

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

Festuca occidentalis Festuca occidentalis Western fescue Photo: CC BY-SA, Nicholas WeiRibes lobbii Ribes lobbii Gummy gooseberry Photo: CC0, author not stated Anemone grayi Western windflower Heuchera chlorantha Heuchera chlorantha Meadow alumroot Photo: CC BY, jonsenseMitellastra caulescens Mitellastra caulescens Leafy mitrewort Photo: CC BY, Judi SandersLathyrus nevadensis Lathyrus nevadensis Sierra pea Photo: CC BY, J Straka

Other Hemionitis 74 in the reference

Hemionitis acrostica Hemionitis acrostica Pteridaceae Photo: CC BY-SA, Krzysztof Ziarnek, Kenraiz Hemionitis alabamensis Pteridaceae Hemionitis arifolia Pteridaceae Hemionitis aspera Pteridaceae Hemionitis atropurpurea Pteridaceae Hemionitis bonariensis Pteridaceae Hemionitis bradburyi Pteridaceae Hemionitis breweri Pteridaceae Hemionitis bridgesii Pteridaceae Hemionitis calidirupium Pteridaceae Hemionitis californica Pteridaceae Hemionitis calomelanos Pteridaceae all 75 ›

Names & registers

Also known as Aspidotis densa; Cheilanthes densa; Cheilanthes siliquosa; Pellaea densa; Cryptogramma densa and 3 more. (WCVP, RBG Kew)

IPNIPOWOWikidataWFOWikipedia

The record

Family
Pteridaceae
Described by
(Brack.) Christenh.
Native to
Alaska, British Columbia, Québec +8
Wild records
1548 in range · 548 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
Kew's names (WCVP) kew.names answeredas of 2026-06-04Kew's entry Hemionitis densa (Brack.) Christenh. (plant_name_id 3218328), read from Kew's names file
GBIF species record gbif.species not askedGBIF's backbone holds no one accepted species of this name, and a name it holds only as another species' synonym is not taken for this one, so GBIF's records were not asked
GBIF synonyms gbif.synonyms not askedGBIF's backbone holds no one accepted species of this name, and a name it holds only as another species' synonym is not taken for this one, so GBIF's records were not asked
GBIF common names gbif.vernacular not askedGBIF's backbone holds no one accepted species of this name, and a name it holds only as another species' synonym is not taken for this one, so GBIF's records were not asked
WCVP native range wcvp.distribution answeredas of 2026-06-04
GBIF occurrence records gbif.occurrences answeredas of 2026-10-21this species has no GBIF key of its own; its records are read under GBIF's keys for the names Kew's file holds as this plant, never by a name matched; GBIF occurrence download https://doi.org/10.15468/dl.hbdw64, of 2026-10-21; 1987 records of GBIF's key 2651595, Aspidotis densa (Brack.) Lellinger (Kew's file holds it as Aspidotis densa (Brack.) Lellinger (synonym under Hemionitis densa (Brack.) Christenh.)): the GBIF download; 1 record within 1 km of a botanic garden, herbarium or zoo left out (1 at a botanic garden or arboretum; Wikidata's list)
Habitat climate climate answeredasked 2026-10-22
Daily extremes (NASA POWER) climate.extremes answeredasked 2026-10-22NASA POWER (MERRA-2) daily 1981–2024, cell 44.00_-122.500, lapse-corrected +186 m at 6.5 °C/km
Wikidata wikidata answeredasked 2026-10-22found by Kew's IPNI identifier 77182583-1, POWO 77182583-1
Wikipedia wikipedia answeredasked 2026-10-22Wikipedia redirects Hemionitis densa to Aspidotis densa, an older name of this species (Aspidotis densa)
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 not askedGBIF's backbone holds no one accepted species of this name, and a name it holds only as another species' synonym is not taken for this one, so GBIF's records were not asked
Wikimedia Commons commons nothing to reportasked 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 77 datasets via GBIF.org; each carries its own licence.

Cultifolio

Opening your plants…