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Ambrosia hispida; photograph (c) Alexis López Hernández, some rights reserved (CC BY) CC BY(c) Alexis López Hernández, some rights reserved (CC BY) · observed growing wild · 2026-08-17

Ambrosia hispida Pursh

Coastal ragweed; Bay Tansy; Sweet Bay; Western Ragweed

Asteraceae · Florida, Mexico Gulf +13

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Ambrosia hispida, photograph (c) Alexis López Hernández, some rights reserved (CC BY)Ambrosia hispida, photograph (c) Alexis López Hernández, some rights reserved (CC BY)Ambrosia hispida, photograph (c) Alexis López Hernández, some rights reserved (CC BY)Ambrosia hispida, photograph (c) Alexis López Hernández, some rights reserved (CC BY)Ambrosia hispida, photograph (c) Alexis López Hernández, some rights reserved (CC BY)Ambrosia hispida, photograph (c) Peter Burka, some rights reserved (CC BY-SA) 61 photographs ›
Habitat figures
Cold floor (1 night in 100)
16.9°C
Record low 13.5 °C in 44 years, at a typical spot in the range NASA POWER
Warmest month, mean daily high
29°C
Jun, Jul, Aug and Sep at the habitat CHELSA
Rain a year (median across the range)
1,275mm
12 months of 25 mm or more in the median year CHELSA
Open-sky light
24–42DLI
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 October, 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

Ambrosia hispida, the coastal ragweed, is a species of perennial plant native to the Neotropics. It belongs to the family Asteraceae.

Quoted from Wikipedia, "Ambrosia hispida", CC BY-SA 4.0.

About the genus · Ambrosia

In the ancient Greek myths, ambrosia is the food or drink of the Greek gods, and is often depicted as conferring longevity or immortality upon whoever consumed it. It was brought to the gods in Olympus by doves and served either by Hebe or by Ganymede at the heavenly feast.

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

Cultivation

Seasons

The rain rule reads a summer growing season: 70% of the median year's rain (870 mm of 1,204 mm) falls in May to October, warmer than the year (wet-season mean 27.2 °C against a yearly mean of 25.8 °C). Months are the habitat's, northern hemisphere; shifted six months for a southern-hemisphere collection: November to April.

Rain

1,204 mm in the median year at the habitat, 870 mm of it May to October. Wettest month September at 195 mm, driest month April at 43 mm. Across the grid cells of the range the year's total runs 785 mm to 1,485 mm, the 10th to 90th percentile of each cell's own year. The median of the cells' own yearly totals, 1,275 mm, is the year's rain at the top of the page; the 1,204 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: 24 to 42 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 21, the highest 90th-percentile month 45).

Warmth and air
Temperature

Coldest: the 1st-percentile night over 44 years at a typical spot in the range is 16.9 °C, the absolute minimum 13.5 °C, no frost in 44 years (NASA POWER daily minima). Warmest: the 99th-percentile day is 38.0 °C. Monthly means: the coldest month's mean nightly low 21.4 °C in January (across the grid cells of the range 16.9 °C to 23.6 °C), the warmest month's mean daily high 29.4 °C in August (median year across the grid cells of the range, CHELSA). Cold floor: 16.9 °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: 59 to 64% 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 -22 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 Ambrosia hispida through the yearWarmest months June, July, August and September, mean daily high 29 °C; coldest month January, mean nightly low 21.4 °C; 1,204 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.10°15°20°25°30°35°40°38.0° 99th-percentile day, NASA POWER13.5° lowest night in 44 years, NASA POWER°C · day and nightcold quarter050100150200250mm rainDLI 24–42RH 59–64%JanFebMarAprMayJunJulAugSepOctNovDec
day night rain medians and 10th–90th percentile across 204 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 °C25 / 23–2726 / 23–2826 / 23–3027 / 24–3228 / 26–3229 / 27–3229 / 28–3229 / 28–3229 / 28–3128 / 27–2927 / 25–2826 / 23–27
Night °C21 / 17–2422 / 18–2422 / 19–2424 / 21–2525 / 23–2626 / 25–2726 / 25–2726 / 25–2726 / 25–2725 / 23–2624 / 21–2522 / 18–24
Rain mm54 / 27–8648 / 21–6747 / 17–7243 / 17–76100 / 46–123161 / 109–212118 / 84–184142 / 95–212195 / 127–227154 / 88–21586 / 38–13656 / 32–86
DLI25 / 23–2930 / 28–3436 / 34–4042 / 40–4442 / 40–4540 / 38–4341 / 40–4440 / 38–4235 / 33–3730 / 29–3326 / 24–3024 / 21–27
RH %59 / 58–6159 / 58–6159 / 57–6160 / 57–6262 / 58–6364 / 62–6563 / 62–6564 / 62–6564 / 63–6663 / 61–6561 / 59–6360 / 58–62
How this section is made
Each figure is the median across the 204 grid cells on land that hold in-range records (422 records in those cells; 44 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 1414:1784 (19.275, -90.775). Over 44 years there: absolute minimum 13.5 °C, 1st-percentile night 16.9 °C, 99th-percentile day 38.0 °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 204 distinct grid cells holding 422 of the 508 in-range records (44 further cells with records at sea, by the elevation layer, left out); extremes and elevation at the typical cell 1414:1784 (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 19.50_-90.625, lapse-corrected -22 m at 6.5 °C/km. Elevation: ETOPO 2022, 4 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.
NativeFlorida, Mexico Gulf, Mexico Southeast, Belize, Honduras, Bahamas, Cayman Is., Cuba, Dominican Republic, Haiti, Jamaica, Leeward Is. AB Ant, Puerto Rico, Windward Is., Guyana · introduced: Trinidad-Tobago · 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 marker20.847, -86.875 · in the densest population, 397 records (63% of those in range)
Kew's description“perennial” · “seasonally dry tropical” · quoted from WCVP, RBG Kew (CC BY 4.0); not derived here
Evidence usedThe map marker rests on all 629 georeferenced records inside the native range; the climate across the range on the 422 of them in the land cells it reads, of 508 placed to within 10 km; the map shows only the 317 openly licensed ones, which alone would put the marker 14 km away. 45 records outside the WCVP native range not used. 121 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 2° block of the 629 in-range records; it decides nothing. Records outside the native range, living specimens and records marked introduced are not used; which records count.

Photographs

Ambrosia hispida, photograph 1did not loadAmbrosia hispida, photograph 2did not loadAmbrosia hispida, photograph 3did not loadAmbrosia hispida, photograph 4did not loadAmbrosia hispida, photograph 5did not loadAmbrosia hispida, photograph 6did not load

Photographs: (c) Alexis López Hernández, some rights reserved (CC BY) (5); (c) Peter Burka, some rights reserved (CC BY-SA).

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

Thrinax radiata Thrinax radiata Florida thatch palm Photo: CC BY, José Javier Barrios FloresConocarpus erectus Conocarpus erectus Button mangrove Photo: CC BY, Alison NorthupBaccharis dioica Baccharis dioica Broombush false willow Photo: CC BY-SA, Stan ShebsTerminalia molinetii Terminalia molinetii Combretaceae Photo: CC BY, Josiah LonderéeErnodea littoralis Ernodea littoralis Coughbush Photo: CC BY, Tom FieldPithecellobium keyense Pithecellobium keyense Florida Keys blackbead Photo: CC BY, Josiah Londerée

Other Ambrosia 19 in the reference

Ambrosia acanthicarpa Ambrosia acanthicarpa Annual bursage Photo: CC BY, Anders HastingsAmbrosia ambrosioides Ambrosia ambrosioides Big bursage Photo: CC BY, Bruce HartmanAmbrosia arborescens Ambrosia arborescens Asteraceae Photo: CC BY, Efrain FreireAmbrosia artemisiifolia Ambrosia artemisiifolia Ragweed Photo: CC BY, Bobo-XAmbrosia bryantii Ambrosia bryantii Asteraceae Photo: CC BY, Juan Cruzado CortésAmbrosia chamissonis Ambrosia chamissonis Beachbur Photo: CC0, author not statedAmbrosia cheiranthifolia Ambrosia cheiranthifolia South Texas ambrosia Photo: CC BY, Eric KnightAmbrosia chenopodiifolia Ambrosia chenopodiifolia San Diego bursage Photo: CC BY, Sula VanderplankAmbrosia confertiflora Ambrosia confertiflora Weakleaf burr ragweed Photo: CC BY, CK2AZAmbrosia cordifolia Ambrosia cordifolia Tucson burr ragweed Photo: CC0, author not statedAmbrosia deltoidea Ambrosia deltoidea Triangle bursage Photo: CC BY, Matt BergerAmbrosia dumosa Ambrosia dumosa White bur-sage Photo: CC BY, CK2AZ all 20 ›

Names & registers

Also known as Ambrosia crithmifolia; Ambrosia maritima. (GBIF Backbone)

GBIFPOWOIPNIWFOWikidataWikipediaiNaturalist

The record

Family
Asteraceae
Described by
Pursh
Native to
Florida, Mexico Gulf, Mexico Southeast +12
Wild records
629 in range · 317 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; 6 records within 1 km of a botanic garden, herbarium or zoo left out (4 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 19.50_-90.625, lapse-corrected -22 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 2026-10-21
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 45 datasets via GBIF.org; each carries its own licence.

Cultifolio

Opening your plants…