Conyza canadensis (L.) Cronquist
  • Bull. Torrey Bot. Club 70
  • Vergerette du Canada


Cite taxon page as 'WFO (2021): Conyza canadensis (L.) Cronquist. Published on the Internet;http://www.worldfloraonline.org/taxon/wfo-0000129910. Accessed on: 18 Oct 2021'

General Information

Plants erect, (3–)50–200(–350+) cm, branched mostly distally. Leaves: faces usually glabrate (proximal margins ± ciliolate, hairs usually stiff, spreading and hispid on nerves, hairs erect); proximal blades oblanceolate to linear, 20–50(–100+) × 4–10(–15+) mm, toothed to entire; distal similar, smaller, entire. Heads usually in paniculiform, sometimes corymbiform arrays. Involucres 3–4 mm. Phyllaries usually glabrous, sometimes sparsely strigose (margins chartaceous to scarious); outer greenish to stramineous, lanceolate to linear, shorter; inner stramineous to reddish, lance-attenuate to linear. Receptacles 1–1.5(–3) mm diam. in fruit. Pistillate florets 20–30(–45+); corollas ± equaling or surpassing styles, laminae 0.3–1 mm. Disc florets 8–30+. Cypselae uniformly pale tan to light gray-brown, 1–1.5 mm, faces sparsely strigillose; pappi of 15–25, white bristles 2–3 mm. 2n = 18.

  • Provided by: [G].Flora of North America @ efloras.org
    • Source: [
    • 2
    • ]. 

    Conyza canadensis (L.) Cronquist, Bull. Torrey Bot. Club 70: 632. 1943; Erigeron canadensis L.

    Anuales, 0.2–2 m de alto; tallos teretes, rígidos, erectos, mayormente simples, estriados, híspidos, hirsutos a glabros. Hojas oblanceoladas a linear-oblanceoladas, 2–6 cm de largo y 0.1–0.6 cm de ancho, escasamente híspidas a glabras; hojas inferiores pecioladas, las superiores no marcadamente pecioladas. Capitulescencias de panículas racemosas o corimbosas, los últimos pedúnculos 2–10 mm de largo; capítulos numerosos, 3–5 mm de largo; involucros turbinado-campanulados; filarias en 2–3 series, lineares, 2–4 mm de largo, desiguales, márgenes fuertemente escariosos, glabras o casi glabras; flósculos del radio 40–80, en 1–2 series, las lígulas 0.6–1 mm de largo; flósculos del disco 20–60, las corolas ca 2.6 mm de largo, 4–5-lobadas, amarillas. Aquenios oblongo-elípticos, ca 1.2 mm de largo, escasamente pubescentes; vilano de (10) 20–30 cerdas estrigulosas, 2–2.7 mm de largo.

    Esta especie se parece superficialmente a C. bonariensis pero se diferencia rápidamente por sus capítulos más numerosos, más pequeños y con menos flores.

  • Provided by: [F].Flora de Nicaragua
    • Source: [
    • 3
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    Coarse erect, sparingly branched ephemeral herb to 1.5 m tall; stems striate, glabrous to puberulent. Leaves to 10 cm long, linear or linear-lanceolate, sessile, entire or sparingly toothed, apically acute or acuminate, membranaceous, glabrous or sparingly pubescent on both sides, the midvein prominent and the minor venation obscure. Inflorescence a many-flowered open terminal panicle, much branched; bracts scattered, rarely to 15 mm long; pedicels slender, to 10 mm long. Heads small, disciform with many florets; involucral bracts imbricate in 2-3 unequal series, 3-4.5 mm long, mostly thin and glabrous; receptacle flat or slightly convex, 1-1.5 mm across, muricate; outer florets numerous, white, capillary, 2.5-3 mm long with a definite, short ( 0.7 mm) ligule; inner florets few, corolla, yellowish; slender, clearly differentiated about halfway up into a slender, cylin- drical limb, sparingly pubescent or glabrous, the lobes deltoid-acuminate, the anthers ca. 0.5 mm long, basally obtuse and with obtuse appendages, the style branches flattened with short-deltoid appendages, thickened at the margins, glandular-verrucose dorsally and glandular pilose at the junction of branch and appendage. Achene compressed, the margins slightly thickened by two prominent veins, glabrous or pubescent, especially near base and apex; pappus of fine strigulose bristles in 1 series reaching or somewhat exceeding the inner florets.

  • Provided by: [C].Flora de Panama
    • Source: [
    • 4
    • ]. 

    "Annual or winter-annual, 1–15 dm, simple or nearly so to the infl; lvs numerous, ± pubescent, or at least coarsely ciliate at the base, oblanceolate to linear, acute, toothed (especially the lower) or entire, gradually reduced upwards, the cauline ones to 8 cm × 8 mm, the basal ones larger and broader but generally deciduous; heads, except in depauperate plants, numerous m a long and open infl; invol 3–4 mm, glabrous or with a few small scattered hairs, the bracts strongly imbricate, brown or with a brown or pale midvein and greener sides; rays mostly 25–40, commonly ca 34, white or sometimes pinkish, 0.5–1.0 mm, equaling or shortly surpassing the style and pappus; 2n=18. A weed in waste places and old fields, throughout the U.S. and s. Can. and to trop. Amer. Late summer and autumn. (Leptilon c.; Erigeron c.) Var. canadensis, our common phase, has the stem coarsely spreading-hirsute, and lacks purple tips on the bracts. Var. pusilla (Nutt.) Cronquist, chiefly along the coast or on the coastal plain, from Conn. to trop. Amer., has the stem glabrous or nearly so, and some of or all the invol bracts are minutely purple-tipped. (Leptilon p.)"

  • Provided by: [H].New York Botanical Garden
    • Source: [
    • 5
    • ]. 

    Morphology

    20–80(–120) cm hoch, ± rauhaarig. Blätter lanzettlich, ganzrandig oder gezähnt. Gesamtblütenstand schmal zylindrisch. Hülle 3–4 mm lang und 2–3 mm breit (zur Fruchtreife bis 5 mm), kahl oder spärlich behaart. Blüten gelblich-weiss. Ra

  • Provided by: [E].Flora Helvetica – Illustrierte Flora der Schweiz
    • Source: [
    • 7
    • ]. 

    Habit

    herb

  • Provided by: [C].Flora de Panama
    • Source: [
    • 4
    • ]. 

    Ecology

    7–9. Wegränder, Schuttplätze, Waldschläge, kollin-montan(-subalpin). CH.

  • Provided by: [E].Flora Helvetica – Illustrierte Flora der Schweiz
    • Source: [
    • 7
    • ]. 

    Distribution

    nearly cosmopolitan in distribution but is perhaps more plentiful in temperate regions. In Panama it is found in weedy areas in upland Chiriqui. Plants from Europe tend to have more prominently ciliate leaves.

  • Provided by: [C].Flora de Panama
    • Source: [
    • 4
    • ]. 

    Distribution Map

     
    • Native distribution
    Found in
    • Southern America Brazil Bahia
    • Paraní
    • Rio Grande do Sul
    • Santa Catarina
    • Minas Gerais
    • Rio de Janeiro
    • São Paulo
    • Brazilia Distrito Federal
    • Goiás

    Other Local Names

    NameLanguageCountry
    Vergerette du CanadaFrenchCH
    Kanadisches BerufkrautGermanCH
    Saeppola canadeseItalianCH
    Rigera canadaisaRaeto-RomanceCH
    Horseweed
    Pascueta Orozuz

      Bibliography

     Information From

    Compositae
    CC0 1.0 Universal (CC0 1.0). https://creativecommons.org/publicdomain/zero/1.0
    • A CC0 1.0 Universal (CC0 1.0).
    MBG Floras Images
    http://www.tropicos.org/ImageSearch.aspx
    Flora images. Missouri Botanical Garden. Accessed on Jun. 2018.
    • B Missouri Botanical Garden
    Flora de Panama
    http://www.tropicos.org/Project/PAC
    Robert E. Woodson, Jr. and Robert W. Schery Annals of the Missouri Botanical Garden Vol. 67, No. 4 (1980), pp. ii-xxxiii
    • C Missouri Botanical Garden
    Brazilian Flora 2020 project - Projeto Flora do Brasil 2020
    http://floradobrasil.jbrj.gov.br
    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
    • D Group Brazil Flora, REFLORA Program
    Flora Helvetica – Illustrierte Flora der Schweiz
    http://www.flora-helvetica.ch
    Flora Helvetica – Illustrierte Flora der Schweiz, Konrad Lauber, Gerhart Wagner, Andreas Gygax. Haupt Verlag 2018.
    • E All Rights Reserved
    Flora de Nicaragua
    http://www.tropicos.org/projectwebportal.aspx?projectid=7&pagename=Home&langid=66
    WD Stevens, CU Ulloa, A Pool and OM Montiel. Missouri Botanical Garden Press, 2001
    • F Missouri Botanical Garden
    Flora of North America @ efloras.org
    http://www.efloras.org/flora_page.aspx?flora_id=1
    'Flora of North America @ eFloras (2008). Published on the Internet http://www.efloras.org/flora_page.aspx?flora_id=1 [accessed August 2016]' Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.
    • G 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.
    • H Content licensed under Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License