Hydrolea zeylanica(L.) Vahl

WFO wfo-0000726697 Accepted WFO 2026-06 8 photographs CC0 / CC BY / CC BY-SA

Plate 1 figs. a–h · 8 separate observations

Hydrolea zeylanica, photographed by Haneesh K M
fig. a Haneesh K M, CC0 1.0 / 2020-12-26 / obs. 108876670
Hydrolea zeylanica, photographed by 葉子
fig. b 葉子, CC0 1.0 / obs. 107814386
Hydrolea zeylanica, photographed by 葉子
fig. c 葉子, CC0 1.0 / obs. 103586088
Hydrolea zeylanica, photographed by Ramesh Shenai Jr.
fig. d Ramesh Shenai Jr., CC BY 4.0 / obs. 88002624
Hydrolea zeylanica, photographed by Sandipan Das
fig. e Sandipan Das, CC BY 4.0 / obs. 180337173
Hydrolea zeylanica, photographed by S.MORE
fig. f S.MORE, CC0 1.0 / obs. 111946648
Hydrolea zeylanica, photographed by Dinesh Valke
fig. g Dinesh Valke, CC BY-SA 4.0 / obs. 181296809
Hydrolea zeylanica, photographed by Dinesh Valke
fig. h Dinesh Valke, CC BY-SA 4.0 / obs. 132068085

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.

Native range 22 botanical countries

Regions where Hydrolea zeylanica is native: China South-Central, China Southeast, Hainan, Taiwan, Andaman Is., Assam, Bangladesh, Borneo, Cambodia, India, Jawa, Laos, Malaya, Myanmar, Nepal, Pakistan, Philippines, Sri Lanka, Sulawesi, Thailand, Vietnam, Queensland China South-CentralChina SoutheastHainanTaiwanAssamBangladeshBorneoCambodiaIndiaJawaLaosMalayaMyanmarNepalPakistanPhilippinesSri LankaSulawesiThailandVietnamQueensland Andaman Is.
Native distribution of Hydrolea zeylanica, 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
Andaman Is. AND ASIA-TROPICAL
Assam ASS
Bangladesh BAN
Borneo BOR
Cambodia CBD
India IND
Jawa JAW
Laos LAO
Malaya MLY
Myanmar MYA
Nepal NEP
Pakistan PAK
Philippines PHI
Sri Lanka SRL
Sulawesi SUL
Thailand THA
Vietnam VIE
China South-Central CHC ASIA-TEMPERATE
China Southeast CHS
Hainan CHH
Taiwan TAI
Queensland QLD AUSTRALASIA

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.

Where it actually grows measured, from 98 observations

Condition 5th percentile Median 95th percentile
Coldest month, mean daily low 10.9 °C 16.5 °C 22.2 °C
Warmest month, mean daily high 28.8 °C 31.4 °C 37.0 °C
Annual rainfall 1,018 mm 2,092 mm 3,767 mm
Rainfall in the driest quarter 2 mm 46 mm 138 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 98 research-grade observations of Hydrolea zeylanica 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.

Also published as 12 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.

  • Beloanthera oppositifolia Hassk.
  • Hydrolea arayatensis Blanco
  • Hydrolea ceilonica F.Muell.
  • Hydrolea inermis Lour.
  • Hydrolea javanica Blume
  • Hydrolea zeylanica var. ciliata Choisy
  • Hydrolea zeylanica var. glabra Brand
  • Nama erecta Roxb.
  • Nama zeylanica L.
  • Steris aquatica Burm.f.
  • Steris javana L.
  • Steris javanica L.

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. 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.