Fact Sheets


Anthoxanthum aristatum Boiss.

Family :

Famille :


Synonym(s) :

Synonyme(s) :

Common Name(s) :

Nom(s) commun(s) :

Annual vernal grass

  • Anthoxanthum aristatum each is a fertile floret enclosed in two sterile florets (dispersal unit)

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

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

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

  • Anthoxanthum aristatum fertile florets

  • Anthoxanthum aristatum fertile floret and caryopsis

  • Anthoxanthum aristatum fertile floret enclosed in two sterile florets (dispersal units), fertile floret, and caryopsis

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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 southern Europe. It has been introduced in northern Europe and in North 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 :

This species grows in mesic to dry fields and open, disturbed habitats (Barkworth et al. 2007, Klinkenberg 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


Annual vernal grass was a weed of cereal crops in Europe but has declined due to improved seed cleaning techniques (BRC 2017). It is not common in North America (Barkworth et al. 2007).




  • Size

    • Dispersal unit length: 2.1 – 3.5 mm (average: 2.9 mm); width: 0.7 – 1.0 mm (average: 0.8 mm)
    • Fertile floret length: 1.6 – 2.0 mm (average 1.8 mm); width: 0.7 – 0.9 mm (average: 0.8 mm)
    • Major awn length: 5.3 – 8.5 mm (average: 6.5 mm) ; minor awn length: 3.9 – 6.6 mm (average 5.1 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 in vertical lines 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 are smooth or with a fringe of short, pale hairs
    • 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 odoratum (sweet vernal grass)

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

Anthoxanthum odoratum floret awns are generally smaller (average length of major awn: 6.0 mm; minor awn 4.7 mm) than annual vernal grass. The dispersal units are covered by stiff hairs and have a fringe of short, dark hairs at their tips. The caryopsis has a larger embryo than annual 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.

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/2705972 Accessed December 29, 2022.

Klinkenberg, B. (ed.) 2017. E-Flora BC: Electronic Atlas of the Plants of British Columbia. Lab for Advanced Spatial Analysis, Department of Geography, University of British Columbia, Vancouver, BC., http://www.geog.ubc.ca/biodiversity/eflora/index.shtml Accessed March 28, 2017.

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