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Chamaecrista absus; photograph (c) Robert Taylor, some rights reserved (CC BY) CC BY(c) Robert Taylor, some rights reserved (CC BY) · observed growing wild · 2026-04-25

Chamaecrista absus (L.) H.S.Irwin & Barneby

Tropical sensitive pea; Hairy Cassia; Pig's Senna

Fabaceae · Cape Verde, Benin +76

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Chamaecrista absus, photograph (c) Robert Taylor, some rights reserved (CC BY)Chamaecrista absus, photograph (c) Robert Taylor, some rights reserved (CC BY)Chamaecrista absus, photograph (c) Robert Taylor, some rights reserved (CC BY)Chamaecrista absus, photograph (c) Shedron Mukhumo, some rights reserved (CC BY)Chamaecrista absus, photograph (c) Shedron Mukhumo, some rights reserved (CC BY)Chamaecrista absus, photograph (c) Shedron Mukhumo, some rights reserved (CC BY) 68 photographs ›
Habitat figures
Cold floor (1 night in 100)
9.5°C
Record low 5.1 °C in 44 years, at a typical spot in the range NASA POWER
Warmest month, mean daily high
34°C
Nov at the habitat CHELSA
Rain a year (median across the range)
942mm
7 months of 25 mm or more in the median year CHELSA
Open-sky light
30–45DLI
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 June to September (December 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.

Summary

Chamaecrista absus (syn. Cassia absus), the pig's senna or tropical sensitive pea, is a species of flowering plant in the family Fabaceae, with a worldwide distribution in the tropics and subtropics. An annual herb reaching 60 cm (24 in), it is a common weed of cultivated and waste places, and its seeds are regularly harvested and sold for use in traditional medicine in Africa and Asia.

Quoted from Wikipedia, "Chamaecrista absus", CC BY-SA 4.0.

About the genus · Chamaecrista

Chamaecrista is a genus of flowering plants in the pea family, Fabaceae, subfamily Caesalpinioideae. Members of the genus are commonly known as sensitive pea. Several species are capable of rapid plant movement. More on Wikipedia ›

Quoted from Wikipedia, "Chamaecrista", CC BY-SA 4.0.

Cultivation

Seasons

The rain rule reads a summer growing season: 70% of the median year's rain (689 mm of 857 mm) falls in December to March, warmer than the year (wet-season mean 27.7 °C against a yearly mean of 25.6 °C). Months are the habitat's, southern hemisphere; shifted six months for a northern-hemisphere collection: June to September.

Rain

857 mm in the median year at the habitat, 689 mm of it December to March. Wettest month January at 222 mm, driest month August at 2 mm; 2 months under 5 mm. Across the grid cells of the range the year's total runs 590 mm to 1,488 mm, the 10th to 90th percentile of each cell's own year. The median of the cells' own yearly totals, 942 mm, is the year's rain at the top of the page; the 857 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: 30 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 9.5 °C, the absolute minimum 5.1 °C, no frost in 44 years (NASA POWER daily minima). Warmest: the 99th-percentile day is 42.3 °C. Monthly means: the coldest month's mean nightly low 14.8 °C in July (across the grid cells of the range 10.6 °C to 21.5 °C), the warmest month's mean daily high 33.6 °C in November (median year across the grid cells of the range, CHELSA). Cold floor: 9.5 °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 61% 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 +5 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 Chamaecrista absus through the yearWarmest month November, mean daily high 34 °C; coldest month July, mean nightly low 14.8 °C; 857 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.0°10°20°30°40°50°42.3° 99th-percentile day, NASA POWER5.1° lowest night in 44 years, NASA POWER°C · day and nightcold quarter0100200300400mm rainDLI 30–45RH 50–61%JanFebMarAprMayJunJulAugSepOctNovDec
day night rain medians and 10th–90th percentile across 564 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 °C32 / 29–3432 / 28–3532 / 28–3432 / 26–3430 / 24–3227 / 22–3027 / 21–2928 / 23–3131 / 25–3533 / 27–3734 / 28–3733 / 29–36
Night °C24 / 20–2624 / 20–2623 / 20–2521 / 17–2419 / 15–2416 / 12–2215 / 11–2216 / 12–2219 / 15–2222 / 17–2524 / 19–2624 / 20–26
Rain mm222 / 79–343217 / 69–347116 / 48–25942 / 20–12713 / 4–1227 / 1–784 / 1–552 / 0–406 / 2–6326 / 16–7468 / 33–122134 / 54–251
DLI39 / 35–4237 / 34–4037 / 34–4036 / 30–3833 / 26–3530 / 24–3331 / 25–3537 / 28–3942 / 32–4345 / 35–4644 / 38–4742 / 37–44
RH %60 / 53–6561 / 54–6659 / 52–6456 / 49–6353 / 46–6352 / 45–6451 / 44–6550 / 42–6451 / 42–6552 / 44–6354 / 48–6257 / 51–63

Records on both sides of the equator: the 182 cells at least 10° north of it have seasons six months apart and are left out, not combined into a year no place has. These figures are across the 564 cells that remain: the 504 at least 10° south and the 60 within 10° of the equator, which stay in either way.

How this section is made
Each figure is the median across the 564 grid cells on land that hold in-range records (681 records in those cells; 2 more cells hold records but no land by the elevation layer, so those records sit at sea and the cells are 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 2103:6261 (-15.175, 133.075). Over 44 years there: absolute minimum 5.1 °C, 1st-percentile night 9.5 °C, 99th-percentile day 42.3 °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 564 distinct grid cells holding 681 of the 886 in-range records (2 further cells with records at sea, by the elevation layer, left out) on the southern side of the equator (182 cells poleward of 10° north, 504 poleward of 10° south: the two sides' seasons are not combined, and cells within 10° of the equator stay in); extremes and elevation at the typical cell 2103:6261 (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 -15.00_133.125, lapse-corrected +5 m at 6.5 °C/km. Elevation: ETOPO 2022, 165 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.
NativeCape Verde, Benin, Burkina, The Gambia, Ghana, Guinea-Bissau, Guinea, Ivory Coast, Mali, Mauritania, Nigeria, Niger, Senegal, Sierra Leone, Togo, Burundi, Central African Republic, Cameroon, Congo, Gabon, Rwanda, Zaïre, Chad, Eritrea, Ethiopia, Socotra, Somalia, Sudan, Kenya, Tanzania, Uganda, Angola, Malawi, Mozambique, Zambia, Zimbabwe, Botswana, Namibia, Swaziland, Northern Provinces, Iran, Yemen, Hainan, Assam, Bangladesh, East Himalaya, India, Nepal, Pakistan, Sri Lanka, West Himalaya, Myanmar, Thailand, Vietnam, Northern Territory, Queensland, Western Australia, Arizona, Mexico Northeast, Mexico Gulf, Mexico Northwest, Mexico Southwest, Mexico Southeast, Guatemala, Honduras, Aruba, Jamaica, Netherlands Antilles, Windward Is., Venezuela, Bolivia, Colombia, Ecuador, Peru, Brazil West-Central, Brazil Northeast, Brazil North, Paraguay · introduced: Comoros, Madagascar, Jawa, Lesser Sunda Is., Sulawesi, New Guinea, Costa Rica · 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-14.233, 132.621 · in the densest population, 313 records (21% of those in range)
Kew's description“annual, subshrub or shrub” · “seasonally dry tropical” · quoted from WCVP, RBG Kew (CC BY 4.0); not derived here
Evidence usedThe map marker rests on all 1490 georeferenced records inside the native range; the climate across the range on the 681 of them in the land cells it reads, of 886 placed to within 10 km; the map shows only the 1326 openly licensed ones, which alone would put the marker in the same place. 37 records outside the WCVP native range not used. 604 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 inside the densest 4° block of the 1490 in-range records; it decides nothing. Records outside the native range, living specimens and records marked introduced are not used; which records count.

Photographs

Chamaecrista absus, photograph 1did not loadChamaecrista absus, photograph 2did not loadChamaecrista absus, photograph 3did not loadChamaecrista absus, photograph 4did not loadChamaecrista absus, photograph 5did not loadChamaecrista absus, photograph 6did not load

Photographs: (c) Robert Taylor, some rights reserved (CC BY) (3); (c) Shedron Mukhumo, some rights reserved (CC BY) (3).

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

Crotalaria verrucosa Crotalaria verrucosa Blue rattlesnake Photo: CC BY, Lucas ChristofidesGalactia striata Galactia striata Florida hammock milkpea Photo: CC BY, Tom FieldCommelina ensifolia Commelina ensifolia Commelinaceae Photo: CC BY, Cody HinchliffTinospora smilacina Tinospora smilacina Snake Vine Photo: CC BY, murrayokePetalostigma pubescens Petalostigma pubescens Quinine bush Photo: CC BY-SA, Lachlan CopelandAphyllodium biarticulatum Aphyllodium biarticulatum Fabaceae Photo: CC BY, Russell Cumming

Other Chamaecrista 11 in the reference

Chamaecrista desvauxii Chamaecrista desvauxii Fabaceae Photo: CC BY, Connor Connolly-MoylsChamaecrista ensiformis Chamaecrista ensiformis Fabaceae Photo: CC BY, Diogo LuizChamaecrista fasciculata Chamaecrista fasciculata Showy partridge-pea Photo: CC BY, Paul RootsChamaecrista garambiensis Chamaecrista garambiensis Fabaceae Photo: CC BY, Min-Hsuan NIChamaecrista glandulosa Chamaecrista glandulosa Jamaican broom Photo: CC BY-SA, Oscar C. González MartínezChamaecrista greggii Chamaecrista greggii Gregg's sensitive pea Photo: CC BY, Cody HinchliffChamaecrista mimosoides Chamaecrista mimosoides Japanese-tea Photo: CC BY, Hildegard KleinChamaecrista nictitans Chamaecrista nictitans Sensitive partridge pea Photo: CC0, author not statedChamaecrista nomame Chamaecrista nomame Field sensitive pea Photo: CC BY, WATANABE Hitoshi 渡辺仁Chamaecrista rotundifolia Chamaecrista rotundifolia Roundleaf sensitive pea Photo: CC BY, geosesarmaChamaecrista serpens Chamaecrista serpens Slender sensitive pea Photo: CC BY, Daniel McNair

Names & registers

Also known as Cassia absus; Cassia exigua; Cassia foliolis; Grimaldia absus; Senna absus and 1 more. (GBIF Backbone)

GBIFPOWOIPNIWFOWikidataWikipediaiNaturalist

The record

Family
Fabaceae
Described by
(L.) H.S.Irwin & Barneby
Native to
Cape Verde, Benin, Burkina +75
Wild records
1490 in range · 1326 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 2026-10-21
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; 8 records within 1 km of a botanic garden, herbarium or zoo left out (8 at a botanic garden or arboretum; 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 -15.00_133.125, lapse-corrected +5 m at 6.5 °C/km
Wikidata wikidata answeredasked 2026-10-21
Wikipedia wikipedia answeredasked 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 2026-10-21none of the photographs on this page is credited to GBIF: those shown are other sources', and GBIF's were the same photographs or were set aside by the photograph rules
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 130 datasets via GBIF.org; each carries its own licence.

Cultifolio

Opening your plants…