Ottelia alismoides(L.) Pers.

Duck-LettuceWaterplantain Otteliaducklettuce

WFO wfo-0000769606 Accepted WFO 2026-06 8 photographs CC0 / CC BY / CC BY-SA

Plate 1 figs. a–h · 7 observations

This species has been photographed under an open licence only 7 times, so some figures below are different views of the same plant, taken on the same day, rather than different individuals. They are usually different parts of it: the leaf, the flower, the bark.

Ottelia alismoides, photographed by Rejoice Gassah
fig. a Rejoice Gassah, CC BY 4.0 / 2021-09-17 / obs. 169063826

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
327563
Filed as
Ottelia alismoides var. lanceolata Kuntze
Det. by
Unspecified Determiner
Collected
C. E. O. Kuntze 1875-12-06
Origin
IN
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 32 botanical countries

Regions where Ottelia alismoides is native: China North-Central, China South-Central, China Southeast, Hainan, Japan, Khabarovsk, Korea, Manchuria, Nansei-shoto, Primorye, Taiwan, Assam, Bangladesh, Borneo, Cambodia, India, Jawa, Lesser Sunda Is., Malaya, Maluku, Myanmar, Nepal, New Guinea, Philippines, Solomon Is., Sri Lanka, Sulawesi, Sumatera, Thailand, Vietnam, Northern Territory, Queensland China North-CentralChina South-CentralChina SoutheastHainanJapanKhabarovskManchuriaPrimoryeTaiwanAssamBangladeshBorneoCambodiaIndiaJawaLesser Sunda Is.MalayaMalukuMyanmarNepalNew GuineaPhilippinesSolomon Is.Sri LankaSulawesiSumateraThailandVietnamNorthern TerritoryQueensland KoreaNansei-shoto
Native distribution of Ottelia alismoides, 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
Borneo BOR
Cambodia CBD
India IND
Jawa JAW
Lesser Sunda Is. LSI
Malaya MLY
Maluku MOL
Myanmar MYA
Nepal NEP
New Guinea NWG
Philippines PHI
Solomon Is. SOL
Sri Lanka SRL
Sulawesi SUL
Sumatera SUM
Thailand THA
Vietnam VIE
China North-Central CHN ASIA-TEMPERATE
China South-Central CHC
China Southeast CHS
Hainan CHH
Japan JAP
Khabarovsk KHA
Korea KOR
Manchuria CHM
Nansei-shoto NNS
Primorye PRM
Taiwan TAI
Northern Territory NTA AUSTRALASIA
Queensland QLD

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 41 in flower of 48 examined

Proportion of examined Ottelia alismoides in flower, by month
Month In flower Examined Share 95% interval
Jan 1 1 too few examined
Feb 2 2 too few examined
Mar 1 1 too few examined
Apr 1 2 too few examined
May 1 1 too few examined
Jun 0 0 too few examined
Jul 6 7 86% 49% to 97%
Aug 9 10 90% 60% to 98%
Sep 7 9 78% 45% to 94%
Oct 7 7 100% 65% to 100%
Nov 4 5 80% 38% to 96%
Dec 2 3 too few examined

Peak flowering in Oct. Each bar is the share of Ottelia alismoides 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. 41 of 48 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 7 months have fewer than 5 examined observations, so no proportion is drawn for them. 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 272 observations

Condition 5th percentile Median 95th percentile
Coldest month, mean daily low -1.9 °C 13.7 °C 23.3 °C
Warmest month, mean daily high 27.9 °C 31.0 °C 38.6 °C
Annual rainfall 798 mm 1,372 mm 3,673 mm
Rainfall in the driest quarter 8 mm 105 mm 577 mm

It is found where winters bring light frost. This is not care advice and it is not a forecast. It is a measurement: we sampled the climate at every one of the 272 research-grade observations of Ottelia alismoides 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 35 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.

  • Boottia alata Gagnep.
  • Boottia bodinieri (H.Lév. & Vaniot) H.Lév. & Vaniot
  • Boottia lanceolata Gagnep.
  • Boottia thorelii Gagnep.
  • Damasonium alismoides (L.) R.Br.
  • Damasonium indicum Willd.
  • Damasonium javanicum Blume
  • Damasonium lactucifolium Planch.
  • Damasonium lancifolium C.Presl
  • Damasonium timorense Zipp. ex Span.
  • Damasonium tranquebariense Schult.f.
  • Hydrocharis bodinieri H.Lév. & Vaniot
  • Hymenotheca latifolia Salisb.
  • Ottelia alata (Gagnep.) H.Li
  • Ottelia alismoides f. lacustris Kom.
  • Ottelia alismoides f. oryzetorum Kom.
  • Ottelia alismoides var. cordifolia Kuntze
  • Ottelia alismoides var. javanica (Blume) Kuntze
  • Ottelia alismoides var. lacustris (Kom.) Kitag.
  • Ottelia alismoides var. lanceolata Kuntze
  • Ottelia alismoides var. oryzetorum (Kom.) Kitag.
  • Ottelia bodinieri (H.Lév. & Vaniot) Dandy
  • Ottelia condorensis Gagnep.
  • Ottelia dioecia S.Z.Yan

and 11 more.

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.