Lactuca canadensis L.
  • C. von Linnaeus, Sp. Pl.. 1753
  • Almeirão-serralha

Cite taxon page as 'WFO (2021): Lactuca canadensis L. Published on the Internet; Accessed on: 30 Nov 2021'

General Information

Biennials, (15–)40–200(–450+) cm. Leaves on proximal 1/2–3/4 of each stem; blades of undivided cauline leaves oblong, obovate, or lanceolate to spatulate or lance-linear, margins entire or denticulate, midribs sometimes sparsely pilose. Heads in ± corymbiform to paniculiform arrays. Involucres 10–12+ mm. Phyllaries usually reflexed in fruit. Florets 15–20+; corollas bluish or yellowish, usually deliquescent. Cypselae: bodies brown (often mottled), ± flattened, elliptic, 2.5–3.5 mm, beaks ± filiform, 1–3 mm, faces 1(–3)-nerved; pappi white, 5–6 mm. 2n = 34.

  • Provided by: [C].Flora of North America @
    • Source: [
    • 1
    • ]. 

    "Leafy-stemmed annual or usually biennial 3–25 dm, glabrous or occasionally coarsely hirsute, often ± glaucous; lvs highly variable, entire or toothed to pinnately lobed or cleft, sagittate or sometimes narrowed to the base, 10–35 × 1.5–12 cm; heads numerous, small, with 13–22 yellow fls; invol 10–15 mm in fr; achenes blackish, very flat, with a median nerve on each face, transversely rugulose, 4.5–6.5 mm overall, the slender beak from a little more than half to about as long as the body; mature pappus 5–7 mm; 2n=34. Fields, waste places, and woods; Que. and P.E.I. to Sask., s. to Fla. and Tex. July–Sept. (L. sagittifolia; L. steelei)"

  • Provided by: [D].New York Botanical Garden
    • Source: [
    • 2
    • ]. 

    Distribution Map

    • Introduced distribution
    Introduced into
    • Southern America Brazil Paraní
    • São Paulo

    Other Local Names



     Information From

    Brazilian Flora 2020 project - Projeto Flora do Brasil 2020
    Brazil Flora G (2014): Brazilian Flora 2020 project - Projeto Flora do Brasil 2020. v393.147. Instituto de Pesquisas Jardim Botanico do Rio de Janeiro. Dataset/Checklist. doi:10.15468/1mtkaw
    • A Group Brazil Flora, REFLORA Program
    CC0 1.0 Universal (CC0 1.0).
    • B CC0 1.0 Universal (CC0 1.0).
    Flora of North America @
    'Flora of North America @ eFloras (2008). Published on the Internet [accessed August 2016]' Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.
    • C Flora of North America Association
    New York Botanical Garden
    Descriptions of plants should be attributed to the full citation for each individual article, chapter or book that is the source for each record, which should include the authors of original publication.
    • D Content licensed under Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License
    World Flora Online consortium
    World Flora Online Data. 2018.
    • E CC0 1.0 Universal (CC0 1.0).