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Berkheya radula; photograph (c) Stefan Wolmarans, some rights reserved (CC BY) CC BY(c) Stefan Wolmarans, some rights reserved (CC BY) · observed growing wild · 2025-12-19

Berkheya radula (Harv.) De Wild.

Asteraceae · Zimbabwe, Botswana +4

Cited as Kew's World Checklist cites it, Berkheya radula (Harv.) De Wild.: GBIF's backbone key for this page carries the name with another author, (Harv.) Burtt Davy.

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Berkheya radula, photograph (c) Hildegard Klein, some rights reserved (CC BY)Berkheya radula, photograph (c) Hildegard Klein, some rights reserved (CC BY)Berkheya radula, photograph (c) alanbedfordshaw, some rights reserved (CC BY-SA)Berkheya radula, photograph (c) alanbedfordshaw, some rights reserved (CC BY-SA)Berkheya radula, photograph (c) Stefan Wolmarans, some rights reserved (CC BY)Berkheya radula, photograph (c) Stefan Wolmarans, some rights reserved (CC BY) 70 photographs ›
Habitat figures
Cold floor (1 night in 100)
-1.0°C
Record low -5.3 °C in 44 years, at a typical spot in the range NASA POWER
Warmest month, mean daily high
27°C
Jan at the habitat CHELSA
Rain a year (median across the range)
668mm
7 months of 25 mm or more in the median year CHELSA
Open-sky light
25–45DLI
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 summers: the rain comes May to September (November to March at the habitat), read as a summer growing season. rain rule, CHELSA
Northern hemisphere unless you set your site. The chart is in the habitat's months.

Cultivation

Seasons

The rain rule reads a summer growing season: 70% of the median year's rain (508 mm of 665 mm) falls in November to March, warmer than the year (wet-season mean 20.6 °C against a yearly mean of 16.9 °C). Months are the habitat's, southern hemisphere; shifted six months for a northern-hemisphere collection: May to September.

Rain

665 mm in the median year at the habitat, 508 mm of it November to March. Wettest month January at 120 mm, driest month July at 3 mm; 1 month under 5 mm. Across the grid cells of the range the year's total runs 589 mm to 743 mm, the 10th to 90th percentile of each cell's own year. The median of the cells' own yearly totals, 668 mm, is the year's rain at the top of the page; the 665 mm here is the median year's, the twelve monthly medians added, which the rain rule reads. Habitat calendar, southern hemisphere; median year across the grid cells of the range, CHELSA.

Light

Open sky over the habitat: 25 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 24, the highest 90th-percentile month 47).

Warmth and air
Temperature

Coldest: the 1st-percentile night over 44 years at a typical spot in the range is -1.0 °C, the absolute minimum -5.3 °C, 339 frost nights in 44 years, 7.7 a year (NASA POWER daily minima). Warmest: the 99th-percentile day is 34.2 °C. Monthly means: the coldest month's mean nightly low 3.5 °C in July (across the grid cells of the range 2.3 °C to 5.6 °C), the warmest month's mean daily high 26.5 °C in January (median year across the grid cells of the range, CHELSA). Cold floor: -1.0 °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: 47 to 57% 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 -7 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, southern hemisphere

Habitat climate of Berkheya radula through the yearWarmest month January, mean daily high 27 °C; coldest month July, mean nightly low 3.5 °C; 665 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, southern hemisphere.-10°0°10°20°30°40°frost34.2° 99th-percentile day, NASA POWER-5.3° lowest night in 44 years, NASA POWER°C · day and nightcold quarter0255075100125150mm rainDLI 25–45RH 47–57%JanFebMarAprMayJunJulAugSepOctNovDec
day night rain medians and 10th–90th percentile across 168 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 °C27 / 25–2926 / 24–2825 / 23–2723 / 21–2420 / 19–2218 / 16–1918 / 17–1921 / 20–2225 / 23–2626 / 24–2726 / 24–2826 / 25–29
Night °C16 / 14–1816 / 14–1714 / 13–1611 / 10–137 / 6–94 / 3–64 / 2–66 / 5–810 / 9–1212 / 11–1414 / 12–1615 / 14–17
Rain mm120 / 106–13396 / 82–11187 / 77–9636 / 32–4114 / 11–188 / 6–103 / 2–48 / 5–1218 / 14–2370 / 54–8190 / 73–106115 / 100–132
DLI43 / 43–4541 / 40–4236 / 36–3731 / 31–3228 / 27–2825 / 24–2627 / 26–2732 / 31–3239 / 38–3941 / 41–4342 / 42–4545 / 44–47
RH %57 / 54–5957 / 55–5957 / 55–5854 / 53–5651 / 50–5251 / 50–5249 / 48–5047 / 46–4947 / 45–4851 / 49–5354 / 51–5656 / 53–58
How this section is made
Each figure is the median across the 168 grid cells holding the 360 in-range records, 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 2321:4162 (-26.075, 28.125). Over 44 years there: absolute minimum -5.3 °C, 1st-percentile night -1.0 °C, 99th-percentile day 34.2 °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 168 distinct grid cells holding 360 of the 360 in-range records; extremes and elevation at the typical cell 2321:4162 (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 -26.00_28.125, lapse-corrected -7 m at 6.5 °C/km. Elevation: ETOPO 2022, 1531 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.
NativeZimbabwe, Botswana, Cape Provinces, Free State, Swaziland, Northern Provinces · 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 marker-25.774, 28.292 · in the densest population, 369 records (84% of those in range)
Kew's description“subtropical” · quoted from WCVP, RBG Kew (CC BY 4.0); not derived here
Evidence usedThe map marker rests on all 439 georeferenced records inside the native range; the climate across the range on the 360 of them placed to within 10 km; the map shows only the 139 openly licensed ones, which alone would put the marker 12 km away. 1 record outside the WCVP native range not used. 79 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.
How this section is made
The map marker: the openly licensed record nearest the middle of the densest 1° population of the 439 in-range records; it decides nothing. Records outside the native range, living specimens and records marked introduced are not used; which records count.

Photographs

Berkheya radula, photograph 1did not loadBerkheya radula, photograph 2did not loadBerkheya radula, photograph 3did not loadBerkheya radula, photograph 4did not loadBerkheya radula, photograph 5did not loadBerkheya radula, photograph 6did not load

Photographs: (c) Hildegard Klein, some rights reserved (CC BY) (2); (c) alanbedfordshaw, some rights reserved (CC BY-SA) (2); (c) Stefan Wolmarans, some rights reserved (CC BY) (2).

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

Adromischus umbraticola Adromischus umbraticola Crassulaceae Photo: CC BY, Justin PonderCrinum graminicola Crinum graminicola Grass Crinum Photo: CC0, author not statedLedebouria luteola Ledebouria luteola Highveld African hyacinth Photo: CC BY, Henry de LangeDelosperma herbeum Delosperma herbeum Highveld White Vygie Photo: CC BY-SA, Antoinette Eyssell KnoxKhadia acutipetala Khadia acutipetala Khadi Rootfig Photo: CC BY-SA, TamTrachyandra erythrorrhiza Trachyandra erythrorrhiza Asphodelaceae Photo: CC BY-SA, Andrew Hankey

Other Berkheya 8 in the reference

Berkheya armata Berkheya armata Giant African Thistle Photo: CC BY-SA, Tony RebeloBerkheya bipinnatifida Berkheya bipinnatifida Asteraceae Photo: CC BY-SA, Tony RebeloBerkheya cirsiifolia Berkheya cirsiifolia Lesotho African Thistle Photo: CC BY, Morten Ross Berkheya macrocephala Asteraceae Berkheya multijuga Berkheya multijuga Thorny African Thistle Photo: CC BY-SA, Tony RebeloBerkheya purpurea Berkheya purpurea Purple African Thistle Photo: CC BY, Morten RossBerkheya speciosa Berkheya speciosa Pretty African Thistle Photo: CC BY-SA, Tony RebeloBerkheya umbellata Berkheya umbellata Umbel African Thistle Photo: CC BY, Sunčana Bradley

Names & registers

Also known as Berkheya adlami; Crocodilodes radula; Stobaea radula. (GBIF Backbone)

GBIFPOWOIPNIWFOWikidataiNaturalist

The record

Family
Asteraceae
Described by
(Harv.) De Wild.
Native to
Zimbabwe, Botswana, Cape Provinces +3
Wild records
439 in range · 139 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 2026-10-21
GBIF species record gbif.species answeredasked 2026-10-21GBIF's key 3115316 is Berkheya radula (Harv.) Burtt Davy; the page links Kew's Berkheya radula (Harv.) De Wild., and the name is cited as Kew cites it
GBIF synonyms gbif.synonyms answeredasked 2026-10-21
GBIF common names gbif.vernacular answeredasked 2026-10-21names fetched 2026-10-21
WCVP native range wcvp.distribution answeredas of 2026-06-04
GBIF occurrence records gbif.occurrences answeredas of 2026-10-21GBIF occurrence download https://doi.org/10.15468/dl.hbdw64, of 2026-10-21; 3 records within 1 km of a botanic garden, herbarium or zoo left out (1 at a botanic garden or arboretum, 2 at a zoo; Wikidata's list)
Habitat climate climate answeredasked 2026-10-21
Daily extremes (NASA POWER) climate.extremes answeredasked 2026-10-21NASA POWER (MERRA-2) daily 1981–2024, cell -26.00_28.125, lapse-corrected -7 m at 6.5 °C/km
Wikidata wikidata answeredasked 2026-10-21IPNI and POWO linked by Kew's number for Berkheya radula (Harv.) De Wild. (the item's: IPNI 60477547-2, POWO 184616-1)
Wikipedia wikipedia nothing to reportasked 2026-10-21
iNaturalist photographs, wild inat.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 2026-10-22
iNaturalist photographs, cultivated inat.photos.cultivated not asked
GBIF media gbif.media answeredasked 2026-10-21
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 8 datasets via GBIF.org; each carries its own licence.

Cultifolio

Opening your plants…