Fact Sheets


Anthoxanthum odoratum L.

Family :

Famille :


Synonym(s) :

Synonyme(s) :

Common Name(s) :

Nom(s) commun(s) :

Sweet vernal grass

  • Anthoxanthum odoratum each a fertile floret enclosed in two sterile florets (dispersal units)

  • Anthoxanthum odoratum each a fertile floret enclosed in two sterile florets (dispersal units)

  • Anthoxanthum odoratum fertile florets

  • Anthoxanthum odoratum fertile floret enclosed in two sterile florets (dispersal unit)

  • Anthoxanthum odoratum fertile floret enclosed in two sterile florets (dispersal unit)

  • Anthoxanthum odoratum fertile floret and caryopsis

  • Anthoxanthum odoratum fertile floret enclosed in two sterile florets (dispersal unit), spikelet, fertile floret, and caryopsis

  • Anthoxanthum odoratum spikelet

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Regulation :

Remarques Réglementation:

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

Regulation Notes:

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

*Quarantine lists of countries may be updated without notice.

Distribution :

Répartition :

This species is native to northern Africa and Eurasia. Introduced in South Africa, Australia, New Zealand, and North and South America (USDA-ARS 2017). In the United States, it occurs in the western, eastern and southern states (USDA-NRCS 2017).

Habitat and Crop Association :

Habitat et Cultures Associées :

Sweet vernal grass grows in pastures, hay fields, lawns, meadows, grassy beaches, coastal bluffs, open woodlands, roadsides and waste places (Barkworth et al. 2007; CABI 2017).

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:


Dispersal Unit Type :

Type d’unité de dispersion :

Fertile floret enclosed in two sterile florets (dispersal unit)

General Information


This species was previously grown as a pasture plant. It produces large quantities of seeds and is able to tolerate a wide range of environmental conditions. In southern BC, it is invading coastal bluffs where it impacts native species (CABI 2017).


Field of Anthoxanthum odoratum (Forest and Kim Starr, Starr Environmental, Bugwood.org)



  • Size

    • Dispersal unit length: 2.7 – 3.4 mm (average: 3.1 mm); width: 0.7 – 1.0 mm (average: 0.9 mm)
    • Fertile floret length: 1.8 – 2.3 mm (average: 2.0 mm); width: 0.7 – 0.9 mm (average: 0.8 mm)
    • Major awn length: 4.5 – 7.8 mm (average: 6.0 mm) ; minor awn length: 4.2 – 5.5 mm (average: 4.7 mm)


    • Dispersal units are oblong-shaped, flattened
    • Fertile florets are spindle-shaped

    Surface Texture

    • The surface of the dispersal unit is roughened like sandpaper, covered with stiff hairs and awned from the back of the lemma
    • Enclosed fertile floret surface is smooth


    • The dispersal units are reddish brown and pale at their tips
    • Fertile florets are glossy reddish-brown

    Other Features

    • Tips of the dispersal unit have a short, dark-coloured fringe of hairs; a few florets have a pale fringe
    • Caryopsis is yellowish, minutely pitted and translucent

Identification Tips


Additional Botany Information


Similar Species


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.

Anthoxanthum aristatum (annual vernal grass)

Anthoxanthum aristatum  dispersal units are a similar size, flattened oblong shape, reddish-brown colour, awned, with a hairy surface.

Anthoxanthum aristatum  floret awns are generally larger (average length of major awn: 6.5 mm; minor awn: 5.1 mm) than sweet vernal grass. The dispersal units have stiff hairs in vertical lines and their tips are smooth or have a pale fringe of hairs. The caryopsis has a smaller embryo than sweet vernal grass.

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Barkworth, M. E., Capels, K. M., Long, S., Anderton, L. K. and Piep, M. B., (eds.) 2007. Volume 24. Magnoliophyta: Commelinidae (in part): Poaceae, part 1. Oxford University Press, New York, New York.

Centre for Agriculture and Bioscience International (CABI). 2017. Invasive Species Compendium, CAB International, Wallingford, UK. https://www.cabidigitallibrary.org/journal/cabicompendium  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/2705975 Accessed December 29, 2022.

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-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.



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

Canadian Food Inspection Agency