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Lactuca oblongifolia Nutt.

Overview
General Information
ID Info
Similar Species
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Aperçu
Renseignements Généraux
Informations D'identification
Espèces Semblables
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Family :

Famille :

Asteraceae

Synonym(s) :

Synonyme(s) :

Lactuca tatarica (L.) C. A. Mey. subsp. pulchella (Pursh) Stebbins (Jones et. al 2018; USDA-ARS 2023)

Lactuca pulchella (Pursh) DC. (Jones et. al 2018; USDA-ARS 2023)

Mulgedium pulchellum (Pursh) G. Don  (Jones et. al 2018; USDA-ARS 2023)

Lactuca tatarica (L.) C. A. Mey. var. pulchella (Pursh) Breitung (USDA-ARS 2023)

Mulgedium oblongifolium (Nutt.) Reveal (USDA-ARS 2023)

Sonchus pulchellus Pursh (USDA-ARS 2023)

 

 

Common Name(s) :

Nom(s) commun(s) :

Blue lettuce

Lactuca oblongifolia (blue lettuce) achenes

  • Lactuca oblongifolia (blue lettuce) achenes

  • Lactuca oblongifolia (blue lettuce) achene

  • Lactuca oblongifolia (blue lettuce) achene

  • Lactuca oblongifolia (blue lettuce) achene

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Overview

Aperçu

Regulation :

Remarques Réglementation:

  • ​Quarantine lists of countries e.g. China *may be updated without notice

Regulation Notes:

On quarantine lists of countries e.g. China*.

*Quarantine lists of countries may be updated without notice.

Distribution :

Répartition :

This species is native to North America, where it is common in the western and central United States and Canada and less so in the east (USDA-ARS 2017; USDA-NRCS 2017).

Habitat and Crop Association :

Habitat et Cultures Associées :

Blue lettuce grows in cultivated fields, prairies, meadows, clearings in forests or shrublands, shores, railway lines, roadsides and disturbed areas (Gleason and Cronquist 1991; Darbyshire 2003; FNA 2017). Prefers moist areas (Gleason and Cronquist 1991).

Economic Use, cultivation area, and Weed Association :

Utilisation économique, zone de culture et association de mauvaises herbes :

Duration of Life Cycle :

Durée du cycle vital:

Perennial

Dispersal Unit Type :

Type d’unité de dispersion :

Achene

General Information

RENSEIGNEMENTS GÉNÉRAUX

This species has showy blue flowers and deep creeping roots. It has increased in abundance with agricultural expansion (Gleason and Cronquist 1991).

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Identification

Identification

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  • Achene

    Size

    • Achene length: 5.6 – 7.1 mm (average: 6.4 mm); width: 0.9 – 1.3 mm (average: 1.2 mm)

    Shape

    • Long oval-shaped achene with a long, tapered ‘beak’ at one end (style appendage); achene is flattened

    Surface Texture

    Achene surface has longitudinal ridges covered with small transverse wrinkles

    Colour

    • Achene is dull, dark-brown to reddish-brown; the ‘beak’ is light coloured

    Other Features

    • The pappus is made of long, thin, white strands; may not be present on mature achenes

    Lactuca oblongifolia (blue lettuce) achenes

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Identification Tips

CONSEILS POUR L’IDENTIFICATION

Additional Botany Information

AUTRES RENSEIGNEMENTS BOTANIQUES

Similar Species

ESPÈCES SEMBLABLES

Similar species are based on a study of seed morphology of various species, and those with similar dispersal units are identified. The study is limited by physical specimen and literature availability at the time of examination, and possibly impacted by the subjectivity of the authors based on their knowledge and experience. Providing similar species information for seed identification is to make users aware of similarities that could possibly result in misidentification.

Sonchus arvensis (perennial sow thistle)

Sonchus arvensis is a similar long oval shape, reddish brown colour, longitudinally- ridged surface and pappus strands as blue lettuce.

Sonchus arvensis achenes are generally smaller (average length: 3.1 mm; average width: 1.1 mm) and lack the long ‘beak’ of blue lettuce achenes.

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Reference(s)

Référence(s)

Darbyshire, S. J. 2003. Inventory of Canadian Agricultural Weeds. Agriculture and Agri-Food Canada, Research Branch. Ottawa, ON.

Flora of North America (FNA) Editorial Committee, eds. 1993+. Flora of North America North of Mexico [Online]. 22+ vols. New York and Oxford. http://beta.floranorthamerica.org. Accessed April 25, 2017.

Flora of North America (FNA) Editorial Committee, eds. 1993+. Flora of North America North of Mexico [Online]. 22+ vols. New York and Oxford.  Accessed December 29, 2022.

Global Biodiversity Information Facility (GBIF) Secretariat. 2022. https://doi.org/10.15468/39omei Accessed via https://www.gbif.org/species/3140419 Accessed December 29, 2022.

Gleason, H. A. and Cronquist, A. 1991. Manual of Vascular Plants of Northeastern United States and Adjacent Canada. Second Edition. The New York Botanical Garden, Bronx, New York. 993 pp.

Jones K. E., Schilling E. E., Dias E. F. & Kilian N. 2018. Northern Hemisphere disjunctions in Lactuca
(Cichorieae, Asteraceae): independent Eurasia to North America migrations and allopolyploidization. – Willdenowia
48: 259 – 284. doi: https://doi.org/10.3372/wi.48.48206.full

U.S. Department of Agriculture-Agricultural Research Services (USDA-ARS). 2017. Germplasm Resources Information Network (GRIN), https://npgsweb.ars-grin.gov/gringlobal/taxon/taxonomysearch Accessed April 25, 2017.

U.S. Department of Agriculture-Agricultural Research Services (USDA-ARS). 2023. Germplasm Resources Information Network (GRIN), https://npgsweb.ars-grin.gov/gringlobal/taxon/taxonomysearch Accessed August 14, 2023.

U.S. Department of Agriculture-Natural Resources Conservation Service (USDA-NRCS). 2017. The PLANTS Database. National Plant Data Team, Greensboro, NC USA. https://plants.usda.gov/home Accessed April 25, 2017.

Author(s)

AUTEUR(S)

Jennifer Neudorf, Angela Salzl, Ruojing Wang, Karen Castro, Katrina Entwistle

Canadian Food Inspection Agency