Lactuca canadensisL.

Canada lettuce

WFO wfo-0000046828 Accepted WFO 2026-06 8 photographs CC0 / CC BY

Plate 1 figs. a–h · 8 separate observations

Lactuca canadensis, photographed by Ryan Sorrells
fig. a Ryan Sorrells, CC BY 4.0 / 2022-06-04 / obs. 203405444
Lactuca canadensis, photographed by Eric Schmidt
fig. b Eric Schmidt, CC BY 4.0 / obs. 205052353
Lactuca canadensis, photographed by mefisher
fig. c mefisher, CC0 1.0 / obs. 151721840
Lactuca canadensis, photographed by mefisher
fig. d mefisher, CC0 1.0 / obs. 151724176
Lactuca canadensis, photographed by Eric Schmidt
fig. e Eric Schmidt, CC BY 4.0 / obs. 167960926
Lactuca canadensis, photographed by mefisher
fig. f mefisher, CC0 1.0 / obs. 150521987
Lactuca canadensis, photographed by Cole Shoemaker
fig. g Cole Shoemaker, CC BY 4.0 / obs. 149236874
Lactuca canadensis, photographed by InAweofGod'sCreation
fig. h InAweofGod'sCreation, CC BY 4.0 / obs. 149315914

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 59 botanical countries

Regions where Lactuca canadensis is native: Alabama, Arizona, Arkansas, British Columbia, California, Colorado, Connecticut, Delaware, District of Columbia, Florida, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Manitoba, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Brunswick, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Nova Scotia, Ohio, Oklahoma, Ontario, Oregon, Pennsylvania, Prince Edward I., Québec, Rhode I., South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin, Wyoming, Yukon, Dominican Republic, Haiti AlabamaArizonaArkansasBritish ColumbiaCaliforniaColoradoConnecticutFloridaGeorgiaIdahoIllinoisIndianaIowaKansasKentuckyLouisianaMaineManitobaMarylandMassachusettsMichiganMinnesotaMississippiMissouriMontanaNebraskaNevadaNew BrunswickNew HampshireNew JerseyNew MexicoNew YorkNorth CarolinaNorth DakotaNova ScotiaOhioOklahomaOntarioOregonPennsylvaniaPrince Edward I.QuébecSouth CarolinaSouth DakotaTennesseeTexasUtahVermontVirginiaWashingtonWest VirginiaWisconsinWyomingYukonDominican RepublicHaiti DelawareDistrict of ColumbiaRhode I.
Native distribution of Lactuca canadensis, 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
Alabama ALA NORTHERN AMERICA
Arizona ARI
Arkansas ARK
British Columbia BRC
California CAL
Colorado COL
Connecticut CNT
Delaware DEL
District of Columbia WDC
Florida FLA
Georgia GEO
Idaho IDA
Illinois ILL
Indiana INI
Iowa IOW
Kansas KAN
Kentucky KTY
Louisiana LOU
Maine MAI
Manitoba MAN
Maryland MRY
Massachusetts MAS
Michigan MIC
Minnesota MIN
Mississippi MSI
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
Nova Scotia NSC
Ohio OHI
Oklahoma OKL
Ontario ONT
Oregon ORE
Pennsylvania PEN
Prince Edward I. PEI
Québec QUE
Rhode I. RHO
South Carolina SCA
South Dakota SDA
Tennessee TEN
Texas TEX
Utah UTA
Vermont VER
Virginia VRG
Washington WAS
West Virginia WVA
Wisconsin WIS
Wyoming WYO
Yukon YUK
Dominican Republic DOM SOUTHERN AMERICA
Haiti HAI

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 218 in flower of 467 examined

Peak flowering in Jul. Each bar is the share of Lactuca canadensis 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. 218 of 467 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 6 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 2,033 observations

Condition 5th percentile Median 95th percentile
Coldest month, mean daily low -13.7 °C -4.7 °C 4.7 °C
Warmest month, mean daily high 23.6 °C 28.2 °C 33.6 °C
Annual rainfall 843 mm 1,166 mm 1,473 mm
Rainfall in the driest quarter 80 mm 243 mm 309 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 2,033 research-grade observations of Lactuca canadensis 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 26 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.

  • Cicerbita canadensis (L.) Wallr.
  • Cicerbita elongata (Muhl. ex Willd.) Wallr.
  • Galathenium elongatum (Muhl. ex Willd.) Nutt.
  • Galathenium integrifolium Nutt.
  • Galathenium salicifolium Nutt.
  • Lactuca canadensis f. canadensis
  • Lactuca canadensis var. canadensis
  • Lactuca canadensis var. integrifolia (Torr. & A.Gray) Farw.
  • Lactuca canadensis var. latifolia Kuntze
  • Lactuca canadensis var. longifolia (Michx.) Farw.
  • Lactuca canadensis var. obovata Wiegand
  • Lactuca canadensis var. typica Wiegand
  • Lactuca elongata Muhl. ex Willd.
  • Lactuca elongata var. integrifolia Torr. & A.Gray
  • Lactuca elongata var. longifolia (Michx.) Torr. & A.Gray
  • Lactuca integrifolia Bigelow
  • Lactuca longifolia Michx.
  • Lactuca polyphylla Rydb.
  • Lactuca sagittifolia Elliott
  • Lactuca steelei Britton
  • Mulgedium canadense (L.) Farw.
  • Mulgedium canadense var. canadense
  • Mulgedium integrifolium Cass.
  • Sonchus pallidus Willd.

and 2 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.