




85 photographs › At a glance
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- Dec, shaded
Summary
Bromus sitchenis, the Alaska brome, is a perennial grass native to the North Pacific coast of North America, in woods and banks from Alaska to Oregon. It can grow up to 1.8 m tall, but is often shorter. Leaf blades are elongate, 7–12 mm wide, and as much as 35 cm long. Spikelets 2.5 to 3.5 cm long with between 6 and 12 flowers, awn is 5 to 10 mm long.
Quoted from Wikipedia, "Bromus sitchensis", CC BY-SA 4.0.
Cultivation
Seasons
The rain rule reads a winter growing season: 70% of the median year's rain (1,050 mm of 1,364 mm) falls in October to March, cooler than the year (wet-season mean 7.2 °C against a yearly mean of 11.0 °C). Months are the habitat's, northern hemisphere; shifted six months for a southern-hemisphere collection: April to September.
Rain
1,364 mm in the median year at the habitat, 1,050 mm of it October to March. Wettest month December at 229 mm, driest month July at 17 mm. Across the grid cells of the range the year's total runs 527 mm to 2,820 mm, the 10th to 90th percentile of each cell's own year. The median of the cells' own yearly totals, 1,335 mm, is the year's rain at the top of the page; the 1,364 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: 7 to 45 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
Coldest: the 1st-percentile night over 44 years at a typical spot in the range is -3.6 °C, the absolute minimum -16.6 °C, 1,147 frost nights in 44 years, 26.1 a year (NASA POWER daily minima). Warmest: the 99th-percentile day is 32.1 °C. Monthly means: the coldest month's mean nightly low 1.6 °C in December (across the grid cells of the range -3.6 °C to 7.7 °C), the warmest month's mean daily high 23.8 °C in August (median year across the grid cells of the range, CHELSA). Cold floor: -3.6 °C, which is the 1st-percentile night over 44 years at a typical spot in the range (NASA POWER).
Relative humidity at the habitat: 59 to 65% 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 -150 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
Mean daily high from 8 °C in Jan and Dec to 24 °C in Aug; mean nightly low from 2 °C in Jan, Feb and Dec to 13 °C in Jul and Aug. The cold quarter, Dec to Feb, is the three months around the coldest month's mean nightly low, centred on the 3 months in a row that tie for it. 1,364 mm of rain in the median year (the twelve monthly medians added), the wettest month Dec. The bands show the 10th to 90th percentile across 108 habitat cells. Over 44 years at a typical spot in the range (NASA POWER) the absolute minimum was -16.6 °C and the 99th-percentile day 32.1 °C; neither is dated to a month. Beneath: daily light integral and relative humidity through the year, each on its own scale.
Figures by month
| Figure | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Day °C | 8 / 2–14 | 10 / 3–15 | 12 / 5–16 | 14 / 8–17 | 17 / 11–20 | 20 / 14–23 | 23 / 16–28 | 24 / 17–28 | 21 / 15–25 | 17 / 11–21 | 11 / 5–17 | 8 / 2–15 |
| Night °C | 2 / -4–8 | 2 / -3–8 | 4 / -2–9 | 5 / 0–10 | 8 / 3–12 | 11 / 5–14 | 13 / 9–16 | 13 / 9–16 | 12 / 8–15 | 8 / 4–13 | 5 / -1–10 | 2 / -4–8 |
| Rain mm | 201 / 106–391 | 157 / 92–303 | 141 / 76–290 | 99 / 35–216 | 75 / 11–149 | 54 / 2–120 | 17 / 1–67 | 23 / 1–66 | 46 / 6–120 | 109 / 27–243 | 213 / 64–433 | 229 / 92–424 |
| DLI | 8 / 7–19 | 14 / 12–24 | 21 / 19–34 | 30 / 28–43 | 36 / 34–50 | 40 / 36–53 | 45 / 39–52 | 40 / 35–48 | 30 / 26–40 | 18 / 14–30 | 9 / 7–21 | 7 / 5–17 |
| RH % | 64 / 59–68 | 63 / 59–66 | 63 / 59–65 | 62 / 58–64 | 61 / 57–66 | 60 / 56–67 | 59 / 53–69 | 59 / 53–69 | 60 / 53–67 | 62 / 56–66 | 65 / 58–68 | 64 / 58–68 |
How this section is made
Natural habitat
How this section is made
Photographs
Photographs: (c) Matt Berger, some rights reserved (CC BY) (6).
Related
Similar habitat climate The 6 nearest by mean daily high, mean nightly low and rain, month by month. How.
Lupinus rivularis Riverbank lupine Photo: CC BY, Harry Podschwit
Marah oregana Western wild cucumber Photo: CC0, author not stated
Acer macrophyllum Oregon maple Photo: CC BY-SA, Rand Workman
Oemleria cerasiformis Osoberry Photo: CC BY, Gavin Slater
Rubus ursinus California blackberry Photo: CC BY-SA, benned-h
Ribes sanguineum Flowering currant Photo: CC0, author not statedOther Bromus 30 in the reference
Bromus arenarius Australian brome Photo: CC BY, swainsona1
Bromus arvensis Field brome Photo: CC BY, Наталья Пикалова
Bromus benekenii Lesser Hairy-brome Photo: CC BY, Vladimír Fuka
Bromus briziformis Rattlesnake brome Photo: CC0, author not stated
Bromus carinatus California brome Photo: CC BY, Milan Chytrý
Bromus catharticus Rescue grass Photo: CC0, author not stated
Bromus ciliatus Fringed brome Photo: CC BY, kursic
Bromus commutatus Meadow brome Photo: CC BY, Наталья Пикалова
Bromus diandrus Great brome Photo: CC BY, zebedeugalinha
Bromus erectus Upright brome Photo: CC BY, Vladimír FukaNames & registers
Also known as Bromus willdenowii; Ceratochloa sitchensis. (GBIF Backbone)
The record
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 2026-10-21
gbif.species answeredasked 2026-10-21gbif.synonyms answeredasked 2026-10-21gbif.vernacular answeredasked 2026-10-21names fetched 2026-10-21wcvp.distribution answeredas of 2026-06-04gbif.occurrences answeredas of 2026-10-21GBIF occurrence download https://doi.org/10.15468/dl.hbdw64, of 2026-10-21; 59 records within 1 km of a botanic garden, herbarium or zoo left out (23 at a botanic garden or arboretum, 4 at a herbarium, 32 at a zoo; Wikidata's list)climate answeredasked 2026-10-21climate.extremes answeredasked 2026-10-21NASA POWER (MERRA-2) daily 1981–2024, cell 44.50_-123.125, lapse-corrected -150 m at 6.5 °C/kmwikidata answeredasked 2026-10-21IPNI and POWO linked by Kew's number for Bromus sitchensis Trin. (the item's: IPNI 394118-1, POWO 30105543-2)wikipedia answeredasked 2026-10-21inat.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 2026-10-22inat.photos.cultivated not askedgbif.media answeredasked 2026-10-21openalex not askednot yet asked for this reference; a later fill takes the papers from OpenAlex's snapshotEvery 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 110 datasets via GBIF.org; each carries its own licence.






