Elodea nuttallii(Planch.) H.St.John

western waterweed

WFO wfo-0000770762 Accepted WFO 2026-06 8 photographs CC0 / CC BY / CC BY-SA

Plate 1 figs. a–h · 8 separate observations

Elodea nuttallii, photographed by Grzegorz Grzejszczak
fig. a Grzegorz Grzejszczak, CC BY-SA 4.0 / 2021-09-04 / obs. 186744475

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
Smithsonian, US National Herbarium
Accession
US 986759
Filed as
Elodea nuttallii (Planch.) H.St.John
Det. by
Haynes, R. R.
Collected
W. R. Maxon 1917-06-21
Origin
US
The sheet
View the digitised specimen (CC0 1.0)

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 44 botanical countries

Regions where Elodea nuttallii is native: Arkansas, British Columbia, California, Colorado, Connecticut, Delaware, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Maine, Manitoba, Maryland, Massachusetts, Michigan, Minnesota, Missouri, Montana, Nebraska, Nevada, New Brunswick, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Ontario, Oregon, Pennsylvania, Québec, Rhode I., South Dakota, Tennessee, Vermont, Virginia, Washington, West Virginia, Wisconsin, Wyoming ArkansasBritish ColumbiaCaliforniaColoradoConnecticutIdahoIllinoisIndianaIowaKansasKentuckyMaineManitobaMarylandMassachusettsMichiganMinnesotaMissouriMontanaNebraskaNevadaNew BrunswickNew HampshireNew JerseyNew MexicoNew YorkNorth CarolinaNorth DakotaOhioOklahomaOntarioOregonPennsylvaniaQuébecSouth DakotaTennesseeVermontVirginiaWashingtonWest VirginiaWisconsinWyoming DelawareRhode I.
Native distribution of Elodea nuttallii, 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
Arkansas ARK NORTHERN AMERICA
British Columbia BRC
California CAL
Colorado COL
Connecticut CNT
Delaware DEL
Idaho IDA
Illinois ILL
Indiana INI
Iowa IOW
Kansas KAN
Kentucky KTY
Maine MAI
Manitoba MAN
Maryland MRY
Massachusetts MAS
Michigan MIC
Minnesota MIN
Missouri MSO
Montana MNT
Nebraska NEB
Nevada NEV
New Brunswick NBR
New Hampshire NWH
New Jersey NWJ
New Mexico NWM
New York NWY
North Carolina NCA
North Dakota NDA
Ohio OHI
Oklahoma OKL
Ontario ONT
Oregon ORE
Pennsylvania PEN
Québec QUE
Rhode I. RHO
South Dakota SDA
Tennessee TEN
Vermont VER
Virginia VRG
Washington WAS
West Virginia WVA
Wisconsin WIS
Wyoming WYO

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 536 observations

Condition 5th percentile Median 95th percentile
Coldest month, mean daily low -13.8 °C -3.4 °C 2.5 °C
Warmest month, mean daily high 18.2 °C 24.0 °C 29.0 °C
Annual rainfall 509 mm 867 mm 1,409 mm
Rainfall in the driest quarter 72 mm 153 mm 278 mm

It is found where winters bring hard 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 536 research-grade observations of Elodea nuttallii 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 6 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.

  • Anacharis nuttallii Planch.
  • Elodea columbiana H.St.John
  • Elodea minor (Engelm. ex Casp.) Farw.
  • Philotria minor (Engelm. ex Casp.) Small
  • Philotria nuttallii (Planch.) Rydb.
  • Udora verticillata var. minor Engelm. ex Casp.

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.