Species
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Stachytarpheta cayennensis (Rich.) Vahl

Blue snakeweed, Cayenne snakeweed, Dark-blue snakeweed, Bluetop, Blue porterweed, Nettle-leaf porterweed, Cayenne porterweed, Rattail, Blue rat's tail, Rough-leaf false vervain, Cayenne vervain, Nettleleaf vervain, Nettleleaf Velvetberry, False verbena, Joee, Cayenne porterweed, Cayenne porterweed; Verbena, Cayenne snakeweed

Climate known 61 photographs
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Every figure on this page is derived from public data by a stated rule and says its source; nothing here is written by a person or a model, except the Wikipedia passage, which is quoted and marked as such. How it is made.

Summary

Stachytarpheta cayennensis is a species of flowering plant in the verbena family known by many English language common names, including blue snakeweed, Cayenne snakeweed, dark-blue snakeweed, bluetop, nettle-leaf porterweed, rattail, rough-leaf false vervain, blue rat's tail, Brazilian tea, Cayenne vervain, false verbena, joee, nettleleaf velvetberry, and Cayenne porterweed. Names in other languages include honagasō (Japanese), gervão-urticante, piche de gato, rabo de zorro (Spanish), herbe à chenille, herbe bleue, queue de rat (French), ōi or ōwī (Hawaiian), sakura or ouchung (Chuukese), and tiāki (Māori). It is native to the Americas, from Mexico south through Central and South America to Argentina, as well as many islands of the Caribbean. It is known in many other parts of the world as an introduced species, including regions in Africa, India, Indonesia, Australia, Florida in the United States, and many Pacific Islands. More on Wikipedia ›

The opening of Wikipedia, “Stachytarpheta cayennensis”, CC BY-SA 4.0, quoted as written. Kept separate from everything derived here.

About the genus · Stachytarpheta

Stachytarpheta is a plant genus in the verbena family (Verbenaceae). The flowers are rich in nectar and popular with many butterflies, such as the South Asian crimson rose, Malabar banded swallowtail, and grass yellow. Hummingbirds, especially small species like Lophornis coquettes, Chlorostilbon emeralds, and Discosura thorntails, are especially attracted for nectar. More on Wikipedia ›

The opening of Wikipedia, “Stachytarpheta”, CC BY-SA 4.0, quoted as written.

Family
Verbenaceae
Described by
(Rich.) Vahl
Native to
Mexico Gulf, Mexico Southwest, Mexico Southeast +33
Wild records
967 in range· 792 open

At a glance

Warmest month
28°C
Feb, mean day; nights 22 °C (CHELSA)
Rain
1665mm/yr
12 wet months · peak Jan 175 mm (CHELSA)
Light
25–36DLI
mol/m²/day, winter to summer, open sky (CHELSA shortwave)
In short condensed by rule from the cultivation cards · not written by a person
Rain rule: no season, 70% of the rain takes 8 months (October to May at the habitat (not shifted)). Habitat rain 1665 mm a year, wettest January at 175 mm, driest August at 88 mm (habitat calendar, southern hemisphere). Open sky over the habitat: 25 to 36 mol/m²/day. Cold floor 13.6 °C (1st-percentile habitat night, NASA POWER).
Each sentence is one card's own one-line form, written by the same rule as the card (Its year, Rain, Light, Temperature); the note cannot say what a card does not. Months are given for the northern hemisphere (set your site in Settings to change this), and the habitat's own alongside. The cards · the figures.

Also known as Abena cayennensis (Rich.) Hitchc.; Lippia cylindrica Scheele; Stachytarpha cayennensis (Rich.) Vahl; Stachytarpha dichotoma (Ruiz & Pav.) Vahl; Stachytarpha lactea Schauer and 37 more.

Cultivation

Its year Rain rule: no season, 70% of the rain takes 8 months (October to May at the habitat (not shifted)).

This species’ habitat figures, and what two fixed rules read from them.

The rain rule reads no season: 70% of the year's rain (1251 mm of 1665 mm) takes 8 months, October to May. Mean temperature moves 3.1 °C between the warmest and coldest month. Months are the habitat's, southern hemisphere; with a flat temperature curve there is no season to reverse, so they are not shifted for a collection elsewhere.

Read from the median year of CHELSA monthly rainfall and mean temperature across the envelope cells: 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 gives a season to reverse. A reading of the curves, not an observation of the plant.

Rain Habitat rain 1665 mm a year, wettest January at 175 mm, driest August at 88 mm (habitat calendar, southern hemisphere).

This species’ habitat figures, with their source.

1665 mm a year at the habitat, 1251 mm of it October to May. Wettest month January at 175 mm, driest August at 88 mm. Across the envelope cells the year's total runs 1192 mm to 2839 mm (10th to 90th percentile of each cell's own year) (median year across the envelope cells, CHELSA; habitat calendar, southern hemisphere).

CHELSA monthly precipitation, median year across the envelope cells. The rain that falls where the species is recorded; nothing about how the plant takes water.

Light Open sky over the habitat: 25 to 36 mol/m²/day.

This species’ habitat figures, with their source.

Open sky over the habitat: 25 to 36 mol/m²/day across the year (daily light integral, median year across the envelope cells, CHELSA; the lowest 10th-percentile month across the cells is 17, the highest 90th-percentile month 42).

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.

Warmth and air Cold floor 13.6 °C (1st-percentile habitat night, NASA POWER).

This species’ habitat figures, with their source.

Temperature

Coldest: the 1st-percentile night over 44 years at the typical cell is 13.6 °C, the absolute minimum 10.9 °C, no frost in 44 years (NASA POWER daily minima). Warmest: the 99th-percentile day is 38.8 °C. Monthly means: coldest night 17.9 °C in July (across the envelope cells 11.2 °C to 23.3 °C), warmest day 28.3 °C in February (median year across the envelope cells, CHELSA). Cold floor: 13.6 °C, which is the 1st-percentile night over 44 years at the typical cell (NASA POWER).

NASA POWER daily minima and maxima 1981–2024 at the typical cell, lapse-corrected to its elevation; CHELSA monthly means, median year across the envelope cells, CHELSA. The cold floor is the figure named in its sentence. Not a measured survival limit for any plant in a pot.

Humidity

Relative humidity at the habitat: 63 to 65% across the year (monthly means, median year across the envelope cells, CHELSA). A figure about the air, saying nothing about how the plant takes water.

CHELSA relative humidity, median year across the envelope cells.

The figures the cards read from are in Climate below, and where they came from in Natural habitat.

Climate across the habitat

Habitat climate through the yearMean day from 25 °C in Jul to 28 °C in Feb; mean night from 18 °C in Jul to 22 °C in Jan. The cold quarter, Jun to Aug, is the three months around the coldest night. 1665 mm of rain a year, most in Jan. The bands show the 10th to 90th percentile across 836 habitat cells. Over 44 years at the typical cell the absolute minimum was 10.9 °C and the 99th-percentile day 38.8 °C; neither is dated to a month. Beneath: daily light integral and relative humidity through the year, each on its own scale.10°15°20°25°30°35°40°38.8° 99th-percentile day (undated)10.9° lowest night in 44 yrs (undated)°C · day and nightcold quarter0100200300400mm rainDLI 25–36RH 63–65 %JanFebMarAprMayJunJulAugSepOctNovDec
day night rain 10th–90th percentile across 836 habitat cells cold quarter: the three months around the coldest night extremes over 44 years at the typical cell, marked at the edge: undated DLI, mol/m²/dayRH %each on its own scale
Figures by month
JanFebMarAprMayJunJulAugSepOctNovDec
Day °C28 / 24–3128 / 25–3128 / 25–3127 / 24–3026 / 22–3025 / 20–3025 / 20–3026 / 21–3127 / 22–3128 / 23–3128 / 24–3028 / 24–31
Night °C22 / 17–2422 / 17–2421 / 17–2420 / 16–2419 / 14–2419 / 12–2418 / 11–2318 / 12–2419 / 14–2420 / 15–2421 / 16–2421 / 17–24
Rain mm175 / 53–325157 / 49–296156 / 49–305145 / 61–306132 / 43–321115 / 17–345105 / 11–29488 / 17–291106 / 41–297146 / 55–283167 / 52–261173 / 56–301
DLI35 / 27–4236 / 29–3934 / 29–3930 / 25–4127 / 20–3825 / 17–3527 / 19–3731 / 24–3833 / 27–3935 / 28–3935 / 26–4034 / 26–42
RH %64 / 59–7064 / 60–7064 / 60–7064 / 60–7065 / 58–7165 / 57–7164 / 54–7163 / 52–7063 / 54–7164 / 57–7164 / 59–7165 / 59–70

Each figure is the median across the 836 grid cells holding the 942 in-range records, with the 10th–90th percentile span across those cells after the slash where it differs. Extremes and elevation were read at the typical cell 2065:2706 (-13.275, -44.675). Over 44 years there: absolute minimum 10.9 °C, 1st-percentile night 13.6 °C, 99th-percentile day 38.8 °C. Normals: CHELSA V2.1 1981–2010 climatology, 0.05° cells (each the mean of ~36 1 km pixels). Envelope: median and 10th–90th percentile of each month across the 836 distinct grid cells holding the 942 in-range records; extremes and elevation at the typical cell 2065:2706 (its coldest month's mean night nearest the median across cells); its position is the cell centre. Extremes: NASA POWER (MERRA-2) daily 1981–2024, cell -13.50_-44.375, lapse-corrected +45 m at 6.5 °C/km. Elevation: ETOPO 2022, 665 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 every in-range record's cell, not at the marker.
Openly licensed records inside the range, framed on where they fall.
NativeMexico Gulf, Mexico Southwest, Mexico Southeast, Belize, Costa Rica, Guatemala, Honduras, Nicaragua, Panama, Cuba, Dominican Republic, Haiti, Jamaica, Leeward Is. AB Ant, Puerto Rico, Southwest Caribbean, Trinidad-Tobago, Venezuelan Antilles, Windward Is., French Guiana, Guyana, Surinam, Venezuela, Bolivia, Colombia, Ecuador, Galápagos, Peru, Brazil West-Central, Brazil Northeast, Brazil Southeast, Brazil North, Brazil South, Argentina Northeast, Argentina Northwest, Paraguay· introduced: Benin, Ivory Coast, Liberia, Togo, Central African Republic, Cameroon, Congo, Gabon, Gulf of Guinea Is., Zaïre, Kenya, Mozambique, Zimbabwe, China Southeast, Kazan-retto, Assam, East Himalaya, India, Myanmar, Malaya, Bismarck Archipelago, New Caledonia, Samoa, Marquesas, Tuamotu, Hawaii
Kew's description“subshrub or shrub” · “seasonally dry tropical”· quoted from WCVP, RBG Kew (CC BY 4.0); not derived here
Map marker-25.618, -57.131 · in the densest population, 229 records (24% of those in range)
Evidence usedThe map marker and the climate envelope rest on all 967 georeferenced records inside the native range; the map shows only the 792 openly licensed ones, which alone would put the marker 19 km away. 755 records outside the range (gardens, roadsides, misidentifications) ignored. 25 in-range records are placed to worse than 10 km and stay on the map but off the climate.
The map markerthe map marker: the openly licensed record nearest the middle of the densest 1° population inside the densest 4° block of the 967 in-range records; it decides nothing.

Photographs

Stachytarpheta cayennensisStachytarpheta cayennensisStachytarpheta cayennensisStachytarpheta cayennensisStachytarpheta cayennensisStachytarpheta cayennensisStachytarpheta cayennensisStachytarpheta cayennensis

Photographs: (c) Victor Farjalla Pontes, some rights reserved (CC BY) (3); (c) Tobias Thrien, some rights reserved (CC BY); no rights reserved · CC0 (3); (c) Ben Machado, some rights reserved (CC BY).

Photographs: iNaturalist did not answer when this page was built; what is shown came from the sources that did.

Papers naming this species

Works whose title or abstract names Stachytarpheta cayennensis, most cited first, from OpenAlex (CC0). A mention, not a cultivation source: nothing on this page is drawn from them.

Phytochemical constituents of some Nigerian medicinal plants
H. O. Edeoga, D. E. Okwu, B. O. Mbaebie (2005) · AFRICAN JOURNAL OF BIOTECHNOLOGY
Antiinflammatory and antinociceptive activities of extracts and isolated compounds from Stachytarpheta cayennensis
Elfrides Eva Scherman Schapoval, Mara Rubia Winter de Vargas, Célia G. Chaves, Raquel Bridi (1998) · Journal of Ethnopharmacology
Biochemical, hematological and histopathological evaluation of the toxicity potential of the leaf extract of Stachytarpheta cayennensis in rats
Oladotun A. Olayode, Michael Oluwatoyin Daniyan, Gbola Olayiwola (2019) · Journal of Traditional and Complementary Medicine
Anti-inflammatory and anti-ulcerogenic properties of Stachytarpheta cayennensis (L.C. Rich) Vahl
Carmen Penido, Karina A. Costa, Debor Futuro, Selma Ribeiro de Paiva (2005) · Journal of Ethnopharmacology
Plant species used in giardiasis treatment: ethnopharmacology and in vitro evaluation of anti-Giardia activity
Vanessa do Amaral Neiva, Maria Nilce de Sousa Ribeiro, Flávia Raquel Fernandes do Nascimento, Maria do Socorro Sousa Cartágenes (2014) · Revista Brasileira de Farmacognosia
Pharmacological study of Stachytarpheta cayennensis Vahl in rodents
Sonia Mesía-Vela, Caden Souccar, Maria Teresa R. Lima‐Landman, A.J. Lapa (2004) · Phytomedicine
Inhibition of Gastric Acid Secretion by the Aqueous Extract and Purified Extracts ofStachytarpheta cayennensis
Sonia Vela, Caden Souccar, Maria Teresa R. Lima‐Landman, Antônio José Lapa (1997) · Planta Medica
Screening of Natural Products Inhibitors of SARS-CoV-2 Entry
Pamela González-Maldonado, Nelson Alvarenga, Alberto Burgos-Edwards, Ma. Eugenia Flores-Giubi (2022) · Molecules
Stachytarpheta cayennensis Aqueous Extract, a New Bioreactor towards Silver Nanoparticles for Biomedical Applications
François Eya’ane Meva, Joel Olivier Avom Mbeng, Cécile Okalla Ebongue, Carsten Schlüsener (2019) · Journal of Biomaterials and Nanobiotechnology
Phenylethanoid glycosides from Stachytarpheta cayennensis (Rich.) Vahl, Verbenaceae, a traditional antimalarial medicinal plant
Sonja Froelich, Mahabir P. Gupta, Karsten Siems, Kristina Jenett‐Siems (2008) · Revista Brasileira de Farmacognosia
Antimicrobial and antispasmodic activity of leaf extract and fractions of Stachytarpheta cayennensis
TC Okoye, P. A. Akah, CO Okoli, AC Ezike (2010) · Asian Pacific Journal of Tropical Medicine

Similar habitat climate the 6 species whose habitat climate is nearest this one's: mean day and night, month by month, and rain on a log scale, in calendar order, so a habitat with the same seasons six months out is far, not near. Nothing else counts: not range, not family.

Other Stachytarpheta 2 in the reference

History & registers

Where this page came from built 2026-09-20 · dossier v2 · node
gbif.species answeredcarried from build of 2026-09-19 (offline re-derivation; the backbone was not asked)
gbif.synonyms answeredcarried from build of 2026-09-19 (offline re-derivation; the backbone was not asked)
gbif.vernacular answeredcarried from build of 2026-09-19 (offline re-derivation; the backbone was not asked)
wcvp.distribution answered
gbif.occurrences answeredGBIF occurrence download https://doi.org/10.15468/dl.3h4zam
climate answered
wikidata answeredcarried from build of 2026-09-19 (rederive); that build: carried from build of 2026-09-19 (rederive)
wikipedia answeredcarried from build of 2026-09-19; this build: skipped
inat.taxon not asked
inat.photos.wild answeredcarried from build of 2026-09-19; this build: skipped
inat.photos.cultivated nothing to reportcarried from build of 2026-09-19 (rederive); that build: carried from build of 2026-09-19 (rederive)
commons nothing to reportcarried from build of 2026-09-19 (rederive); that build: carried from build of 2026-09-19 (rederive)
gbif.media answered
openalex answeredcarried from build of 2026-09-19; this build: skipped

Every upstream is recorded as having answered, reported nothing, or refused. Only “nothing to report” is ever shown as an absence. Records came from 216 datasets via GBIF.org; each carries its own licence.