Crotalaria retusaL.

Rattlepodrattleweed

WFO wfo-0000210930 Accepted WFO 2026-06 8 photographs CC0 / CC BY

Plate 1 figs. a–h · 8 separate observations

Crotalaria retusa, photographed by Sunday Berlioz KAKPO
fig. a Sunday Berlioz KAKPO, CC BY 4.0 / 2022-04-27 / obs. 196278601

Every figure is a research-grade observation under CC0, CC BY or CC BY-SA, rehosted with the photographer’s name, the licence and the observation it came from. Photographs under a NonCommercial licence are excluded from this site and are never stored, which costs us a great many pictures and is not negotiable.

The specimen a real sheet, in a real collection

Herbarium
The New York Botanical Garden
Accession
590836
Filed as
Crotalaria retusa L.
Det. by
M. T. K. Arroyo 1972-01-01
Collected
N. T. da Silva 1964-07-10
Origin
BR
The sheet
View the digitised specimen (CC BY 4.0)

A real pressed plant, in a real collection, under the accession number above. Not an illustration of one. The holding institution does not serve this sheet’s image to third parties, so there is no photograph here. The record is real and the link goes to it. Where we hold no openly licensed sheet for a species this section is simply absent, and where a sheet never recorded who determined it, that field stays empty rather than being filled in. Roughly half of all herbarium sheets never recorded a determiner, which is ordinary.

Native range 41 botanical countries

Regions where Crotalaria retusa is native: Comoros, Kenya, Madagascar, Mauritius, Mozambique, Réunion, Rodrigues, Somalia, Tanzania, China Southeast, Hainan, Iran, Oman, Saudi Arabia, Taiwan, Yemen, Assam, Bangladesh, Bismarck Archipelago, Borneo, Cambodia, East Himalaya, India, Jawa, Laccadive Is., Laos, Lesser Sunda Is., Malaya, Maldives, Maluku, Myanmar, Nepal, New Guinea, Philippines, Sri Lanka, Sumatera, Thailand, Vietnam, West Himalaya, Northern Territory, Western Australia KenyaMadagascarMozambiqueSomaliaTanzaniaChina SoutheastHainanIranOmanSaudi ArabiaTaiwanYemenAssamBangladeshBismarck ArchipelagoBorneoCambodiaEast HimalayaIndiaJawaLaosLesser Sunda Is.MalayaMalukuMyanmarNepalNew GuineaPhilippinesSri LankaSumateraThailandVietnamWest HimalayaNorthern TerritoryWestern Australia ComorosMauritiusRéunionRodriguesLaccadive Is.Maldives
Native distribution of Crotalaria retusa, after Kew’s World Checklist of Vascular Plants. Introduced, extinct and doubtful records are excluded, so this is where the plant is from, not everywhere it now grows. Regions too small to draw at this scale are marked with a dot.
RegionTDWG codeContinent
Assam ASS ASIA-TROPICAL
Bangladesh BAN
Bismarck Archipelago BIS
Borneo BOR
Cambodia CBD
East Himalaya EHM
India IND
Jawa JAW
Laccadive Is. LDV
Laos LAO
Lesser Sunda Is. LSI
Malaya MLY
Maldives MDV
Maluku MOL
Myanmar MYA
Nepal NEP
New Guinea NWG
Philippines PHI
Sri Lanka SRL
Sumatera SUM
Thailand THA
Vietnam VIE
West Himalaya WHM
Comoros COM AFRICA
Kenya KEN
Madagascar MDG
Mauritius MAU
Mozambique MOZ
Réunion REU
Rodrigues ROD
Somalia SOM
Tanzania TAN
China Southeast CHS ASIA-TEMPERATE
Hainan CHH
Iran IRN
Oman OMA
Saudi Arabia SAU
Taiwan TAI
Yemen YEM
Northern Territory NTA AUSTRALASIA
Western Australia WAU

Region boundaries approximated from Natural Earth (public domain) and mapped to TDWG World Geographical Scheme for Recording Plant Distributions (WGSRPD) level-3 botanical countries (Brummitt 2001). Indicative, not the official WGSRPD geometry.

Flowering 239 in flower of 272 examined

Proportion of examined Crotalaria retusa in flower, by month
Month In flower Examined Share 95% interval
Jan 26 30 87% 70% to 95%
Feb 27 28 96% 82% to 99%
Mar 24 27 89% 72% to 96%
Apr 27 30 90% 74% to 97%
May 21 24 88% 69% to 96%
Jun 13 14 93% 69% to 99%
Jul 20 23 87% 68% to 95%
Aug 16 20 80% 58% to 92%
Sep 12 13 92% 67% to 99%
Oct 24 28 86% 69% to 94%
Nov 13 13 100% 77% to 100%
Dec 16 22 73% 52% to 87%

Peak flowering in Nov. Each bar is the share of Crotalaria retusa observations in which someone actually recorded the reproductive state and found the plant in flower, not the raw number of flowering records. That distinction matters: people observe plants far more in spring than in winter, so a bare count of flowering records partly measures when people go outside. Dividing by the number examined removes that. 239 of 272 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. This is still a global aggregate and not a forecast for your garden: the same species flowers on different dates in different hemispheres. Where a species has fewer than 30 flowering records we do not draw this chart at all. Computed from 10.15468/dl.cgje2x.

Where it actually grows measured, from 1,561 observations

Condition 5th percentile Median 95th percentile
Coldest month, mean daily low 12.9 °C 20.9 °C 24.7 °C
Warmest month, mean daily high 21.4 °C 28.9 °C 35.4 °C
Annual rainfall 709 mm 1,794 mm 3,488 mm
Rainfall in the driest quarter 3 mm 192 mm 592 mm

It is not found anywhere that gets close to freezing. This is not care advice and it is not a forecast. It is a measurement: we sampled the climate at every one of the 1,561 research-grade observations of Crotalaria retusa that carry a coordinate, and this is the range those places actually span. The 5th and 95th percentiles are used rather than the minimum and maximum, because a single cultivated specimen in a heated conservatory should not widen a tropical plant's range to the Arctic.

This is not a hardiness zone. A USDA zone is the average annual extreme minimum temperature. The figure above is the mean daily minimum of the coldest month, which is a different quantity and is typically far warmer. Reading one as the other would place a plant several zones too warm, so we do not publish a hardiness zone, because we do not have one. Climate from CHELSA V2.1 (Karger et al. 2017); occurrences from 10.15468/dl.cgje2x.

Also published as 10 synonyms

A synonym is not an error. It is a record of botanists disagreeing, in print, about where this plant belongs. Each of these was somebody’s considered answer.

  • Crotalaria atusia Buch.-Ham. ex Steud.
  • Crotalaria cuneifolia (Forssk.) Schrank
  • Crotalaria hostmannii Steud.
  • Crotalaria retusa var. maritima Trimen
  • Crotalaria retusifolia Stokes
  • Crotalaria tunguensis Pires de Lima
  • Crotalaria tunguensis Lima
  • Dolichos cuneifolius Forssk.
  • Hedysarum inaequale Noronha
  • Lupinus cochinchinensis Lour.

Sourcesevery claim on this page

  1. World Flora Online Plant List. accepted name, authority, classification. CC0. Retrieved 2026-07-12.
  2. iNaturalist. photographs and flowering annotations, CC0 / CC BY / CC BY-SA only. per photograph. Retrieved 2026-06-27.
  3. Wikidata. common name (P1843), joined on the World Flora Online identifier (P7715). CC0. Retrieved 2026-07-13.
  4. Kew, World Checklist of Vascular Plants (WCVP v16). native distribution by TDWG level-3 botanical country, and life form. CC BY 3.0. Retrieved 2026-06-04.

We publish what we can source and we say so when we cannot. This page has no care advice and no toxicity claim, because we do not yet have those from a source we can cite.