55 photographs › At a glance
- Jan
- Feb
- Mar
- Apr, under 5 mm of rain
- May
- Jun, shaded
- Jul, shaded
- Aug, shaded
- Sep, shaded
- Oct
- Nov
- Dec
Summary
Pilosocereus alensis, the Sonoran old man cactus, is a species of cactus native to Western Mexico, from Sonora south to Jalisco. The hairs protect the flower buds. Flowers open at night in June and give off the odor of ammonia, attracting bats for pollination.
Quoted from Wikipedia, "Pilosocereus alensis", CC BY-SA 4.0.
Cultivation
Seasons
The rain rule reads a summer growing season: 70% of the median year's rain (697 mm of 874 mm) falls in June to September, warmer than the year (wet-season mean 26.3 °C against a yearly mean of 23.3 °C). Months are the habitat's, northern hemisphere; shifted six months for a southern-hemisphere collection: December to March.
Rain
874 mm in the median year at the habitat, 697 mm of it June to September. Wettest month July at 225 mm, driest month April at 4 mm; 1 month under 5 mm. Across the grid cells of the range the year's total runs 689 mm to 1,104 mm, the 10th to 90th percentile of each cell's own year. The median of the cells' own yearly totals, 874 mm, is the year's rain at the top of the page; the 874 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: 27 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 25, the highest 90th-percentile month 51).
Warmth and air
Coldest: the 1st-percentile night over 44 years at a typical spot in the range is 8.8 °C, the absolute minimum 3.8 °C, no frost in 44 years (NASA POWER daily minima). Warmest: the 99th-percentile day is 39.0 °C. Monthly means: the coldest month's mean nightly low 11.5 °C in January (across the grid cells of the range 7.2 °C to 17.4 °C), the warmest month's mean daily high 33.3 °C in May (median year across the grid cells of the range, CHELSA). Cold floor: 8.8 °C, which is the 1st-percentile night over 44 years at a typical spot in the range (NASA POWER).
Relative humidity at the habitat: 48 to 66% 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 +37 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 26 °C in Jan and Dec to 33 °C in May and Jun; mean nightly low from 12 °C in Jan, Feb and Dec to 22 °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. 874 mm of rain in the median year (the twelve monthly medians added), the wettest month Jul. The bands show the 10th to 90th percentile across 158 habitat cells. Over 44 years at a typical spot in the range (NASA POWER) the absolute minimum was 3.8 °C and the 99th-percentile day 39.0 °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 | 26 / 22–28 | 27 / 23–30 | 29 / 25–32 | 31 / 28–34 | 33 / 29–35 | 33 / 29–36 | 31 / 26–33 | 30 / 26–32 | 30 / 26–32 | 29 / 26–31 | 28 / 24–30 | 26 / 22–28 |
| Night °C | 12 / 7–17 | 12 / 8–17 | 13 / 9–18 | 16 / 11–20 | 19 / 14–22 | 21 / 17–24 | 22 / 16–25 | 22 / 16–25 | 21 / 16–24 | 18 / 14–22 | 15 / 10–20 | 12 / 8–18 |
| Rain mm | 30 / 16–48 | 14 / 8–26 | 6 / 3–16 | 4 / 2–10 | 8 / 2–26 | 95 / 33–174 | 225 / 162–300 | 212 / 144–255 | 165 / 111–244 | 69 / 40–100 | 25 / 10–37 | 21 / 5–45 |
| DLI | 29 / 26–33 | 35 / 32–38 | 43 / 41–45 | 48 / 47–49 | 50 / 46–51 | 42 / 37–47 | 36 / 33–40 | 36 / 33–39 | 33 / 30–37 | 33 / 32–35 | 31 / 28–34 | 27 / 25–31 |
| RH % | 53 / 48–58 | 51 / 47–57 | 50 / 44–55 | 48 / 42–54 | 50 / 43–57 | 57 / 49–63 | 64 / 59–67 | 66 / 60–69 | 65 / 59–70 | 60 / 52–67 | 54 / 49–61 | 53 / 49–59 |
How this section is made
Natural habitat
How this section is made
Photographs
Photographs: (c) Manuel Nicolás Madrigal Pérez, some rights reserved (CC BY); (c) Adrian Bojorquez, some rights reserved (CC BY-SA) (5).
Related
Similar habitat climate The 6 nearest by mean daily high, mean nightly low and rain, month by month. How.
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Agave ornithobroma Asparagaceae Photo: CC0, author not stated
Agave microceps Compact Thread-leaf Century Plant Photo: CC0, author not stated
Solanum grayi Solanaceae Photo: CC BY, Gustavo ZaRo
Randia echinocarpa Rubiaceae Photo: CC BY, Xavier Alejandro Caratachea Navarro
Vitex pyramidata Lamiaceae Photo: CC BY-SA, Christian FrancoOther Pilosocereus 20 in the reference
Pilosocereus armatus Cactaceae Photo: CC BY, Alex Doyle
Pilosocereus arrabidae Cactaceae Photo: CC0, author not stated
Pilosocereus azulensis Cactaceae Photo: CC BY, Peter A. Mansfeld
Pilosocereus brasiliensis Cactaceae Photo: CC BY, fmunoz
Pilosocereus catingicola Cactaceae Photo: CC0, author not stated
Pilosocereus chrysacanthus Cactaceae Photo: CC BY, Alexis López Hernández
Pilosocereus chrysostele Cactaceae Photo: CC BY, stephen
Pilosocereus collinsii Cactaceae Photo: CC BY, Carlos Domínguez-Rodríguez
Pilosocereus curtisii Cactaceae Photo: CC BY, Jose Luis Leon de la Luz
Pilosocereus fulvilanatus Cactaceae Photo: CC BY, B. Phalan
Pilosocereus gaumeri Cactaceae Photo: CC BY, Oscar Orlando Vazquez Piña
Pilosocereus lanuginosus Cactaceae Photo: CC BY, Laura Gaudette all 21 ›Names & registers
Also known as Cephalocereus alensis; Cephalocereus guerreronis; Cereus alensis; Pilocereus alensis; Pilocereus guerreronis and 1 more. (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 2026-10-22
gbif.species answeredasked 2026-10-22gbif.synonyms answeredasked 2026-10-22gbif.vernacular answeredasked 2026-10-22names fetched 2026-10-22wcvp.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; 2 records within 1 km of a botanic garden, herbarium or zoo left out (2 at a botanic garden or arboretum; Wikidata's list)climate answeredasked 2026-10-22climate.extremes answeredasked 2026-10-22NASA POWER (MERRA-2) daily 1981–2024, cell 24.50_-106.875, lapse-corrected +37 m at 6.5 °C/kmwikidata answeredasked 2026-10-22wikipedia answeredasked 2026-10-22inat.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 2026-10-22openalex 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 18 datasets via GBIF.org; each carries its own licence.