Français
Donate
Donner

Fact Sheets

FICHES DE
RENSEIGNEMENTS

Back To Index
print

Centaurea cyanus L.

Overview
General Information
ID Info
Similar Species
Need ID Help?
Aperçu
Renseignements Généraux
Informations D'identification
Espèces Semblables
Besoin d'aide pour l'identification?

Family :

Famille :

Asteraceae

Synonym(s) :

Synonyme(s) :

Cyanus segetum Hill. (USDA-ARS 2024)

Common Name(s) :

Nom(s) commun(s) :

Bachelor’s-button

(English) (USDA-ARS 2024)
Cornflower (English) (USDA-ARS 2024)
Barbeau (French) (USDA-ARS 2024)
Centaurée bleuet (French) (USDA-ARS 2024)
Kornblume (German) (USDA-ARS 2024)
Blåklint (Swedish) (USDA-ARS 2024)
Shi che ju (Chinese) (USDA-ARS 2024)
Vasiljok posevnoj (Russian) (USDA-ARS 2024)

Centaurea cyanus (cornflower) achenes

  • Centaurea cyanus (cornflower) achenes

  • Centaurea cyanus  (cornflower) achenes

  • Centaurea cyanus (cornflower) achenes, three views

  • Centaurea cyanus  (cornflower) achene

  • Centaurea cyanus  (cornflower) achene

  • Centaurea cyanus (cornflower) achenes, outer layer partially removed

Explore More :

Explore plus :

Overview

Aperçu

Regulation :

Remarques Réglementation:

    Regulation Notes:

    Distribution :

    Répartition :

    Centaurea cyanus is native to the Mediterranean and Northeast region of Europe, including Greece, Italy, Turkey, Romania, Bulgaria, Yugoslavia, Lebanon and Syria (Youssef et al. 2020; POWO 2024). The species has been introduced through agriculture to many countries in the Northern hemisphere including Europe, Russia, Central Asia, the Indian subcontinent, northern Africa, North and Central America (POWO 2024). It is not common south of the Equator, occurring in scattered countries of southern Africa, South America, and eastern Asia (POWO 2024).

    In North America, C. cyanus occurs across the United States and Canada, with the exception of Saskatchewan, Nunavut, Northwest Territories, Labrador and Prince Edward Island (FNA 1993+; Brouillet et al. 2010+).

    Habitat and Crop Association :

    Habitat et Cultures Associées :

    Centaurea cyanus is well-adapted to arable fields and cereal crops outside of the native range (Bellanger et al. 2012). The species occupies habitats with stony soils in the native Mediterranean region, and appears to prefer lighter soils in cultivated fields (Youssef et al. 2020; Stankiewicz-Kosyl et al. 2020; Wacławowicz et al. 2022).

    C. cyanus is primarily associated with winter cereal fields, including Triticum aestivum L. subsp. aestivum (wheat) and Secale cereale L. (rye), along with Brassica napus L. crops (oilseed rape) (Bellanger et al. 2012; Stankiewicz-Kosyl et al. 2020; Wacławowicz et al. 2022). The species has also been found in spring cereals, root crops and legume crops (Stankiewicz-Kosyl et al. 2020). C. cyanus can also occur in wastelands, disturbed sites, along railroads and field margins, and has been listed as invasive in the United States (Swearingen and Bargeron 2016; Wacławowicz et al. 2022).

    Economic Use, cultivation area, and Weed Association :

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

    Centaurea cyanus is a popular ornamental in wildflower mixes and gardens, cultivated since the 16th century (Warzecha et al. 2018; Pinke et al. 2023). The species can be an important food source for pollinators, including the domesticated Apis mellifera (honeybees) and for wild Bombus species (bumblebees) (Warzecha et al. 2018; Pinke et al. 2023).

    In Poland, young stems of C. cyanus were added to soups, and the flowers added to wine and beer (Pinke et al. 2023). Extracts have shown anti-hemolytic and anti-hypertensive properties with low toxicity (Escher et al. 2018).

    Duration of Life Cycle :

    Durée du cycle vital:

    Annual

    Dispersal Unit Type :

    Type d’unité de dispersion :

    Achene

    General Information

    RENSEIGNEMENTS GÉNÉRAUX

    Centaurea cyanus is closely associated with cultivation and is believed to have traveled from the northeastern Mediterranean region to western Europe as a crop companion species about 2000 years ago, and has spread worldwide with agriculture (Bellanger et al. 2012; Youssef et al. 2020).

    The species is now dependant on arable land and ruderal habitats and has dramatically declined in Western Europe over the last century with modern agricultural practices (e.g. larger fields, deep tillage and herbicide use) (Bellanger et al. 2012; Guillemin et al. 2017). A decline in pollinators and population isolation have also likely reduced the primarily out-crossing, insect pollinated C. cyanus in western European agroecosystems (Bellanger et al. 2015; Warzecha et al. 2018; Stankiewicz-Kosyl et al. 2020).

    It has been estimated that a plant of C. cyanus can produce more than a thousand achenes (Wacławowicz et al. 2022). Guillemin et al. (2017) found that achenes germinated readily when conditions were met, but only 50% were viable after 2 years in the soil, and 1-2% were viable after 4 years. This large decease in viability could also be contributing to the decline of this species in fields.

    Centaurea cyanus has been increasing in Poland and is considered one of the main weeds of winter cereals there (Marczewska-Kolasa et al. 2017; Stankiewicz-Kosyl et al. 2021). The presence of C. cyanus or Papaver rhoeas L. (corn poppy) reduced Triticum aestivum subsp. aestivum (wheat) yield by 12-37% (Stankiewicz-Kosyl et al. 2020). Extracts of C. cyanus leaves had a negative effect on the germination of T. aestivum subsp. aestivum and Secale cereale L. (rye) (Marczewska-Kolasa et al. 2017). Resistance to acetolactate synthase (ALS) herbicides was reported in Poland in 2006, and a recent investigation found additional populations resistant to Tribenuron, Florasulam, 2,4-D and Dicamba (Stankiewicz-Kosyl et al. 2021).

    .

    Identification

    Identification

    <
    >

    • Achene

      Size

      • Achene length: 5.4-6 mm; width: 1.5-1.8 mm (Bojňanský and Fargašová 2007)
      • Achene length: 4-5 mm (Lionakis-Meyer 2017)
      • Achene length: 4.6 mm; width: 2.4 mm (Rakizadeh et al. 2019)
      • Pappus length: 2-3 mm (Bojňanský and Fargašová 2007)
      • Pappus length: 2-4 mm (Lionakis-Meyer 2017)
      • Pappus length: 6.4 mm (Rakizadeh et al. 2019)
      • Point of attachment (scar) length: 2.3 mm (Rakizadeh et al. 2019)
      • The scar is generally 1/3 the length of the achene (Lionakis Meyer 2017)

      Shape

      • Achene is oblong shaped with a truncate pappus end, compressed in 3 dimensions
      • The narrow end is diagonally (obliquely) angled, with an oval-shaped depression (scar) containing a ridge of tissue (elaiosome)
      • The pappus bristles are flattened

      Surface Texture

      • Achene surface texture is smooth, with scattered long, soft hairs
      • Pappus edges with short teeth (barbed)

      Colour

      • Achene is commonly yellowish gray with longitudinal yellow lines, a yellow band at the pappus end and around the scar
      • The achene outer layer is translucent yellow, and the inner layer (fruit coat) is dark brown or blackish coloured
      • The pappus is generally light brown, can also be whitish, yellowish or reddish-brown coloured

      Other Features

      • The pappus is persistent, brush-like, and has an inner ring of bristles that are angled towards the center
      • The achene has a thin outer layer that can be removed; beneath is a hard fruit coat

      Centaurea cyanus (cornflower) achenes

    <
    >

    • Seed

      Size

      • Seed slightly smaller than achene

      Shape

      • Seed is oblong shaped with a pointed hilum end

      Surface Texture

      • Seed surface is smooth

      Colour

      • Seed is translucent orangish-coloured

      Other Features

      • Seed easily splits between the cotyledons
    <
    >

    • Embryo

      Size

      • Embryo fills the seed

      Shape

      • Embryo is spatulate shaped

      Endosperm

      • Nutritive tissue stored in the cotyledons
      • Cotyledons express oil when pressed with forceps

      Other Features

      • Embryo in an axial position

    Identification Tips

    CONSEILS POUR L’IDENTIFICATION

    The achenes of Centaurea cyanus have the features common to Centaurea species:

    • Persistent, brush-like pappus of numerous, flattened bristles
    • Oblong shape, compressed in 3 dimensions, with a truncate pappus end
    • End opposite pappus narrower, with a C-shaped or oblique angled notch on the side
    • Notch generally with tissue (elaiosome) present

    Centaurea cyanus achenes can be distinguished from other Centaurea species by:

    • The pappus is upright rather than angled away from the center
    • Pappus is brownish coloured
    • Achene is yellowish-grey, with a thin, translucent outer layer
    • Achene surface with long, soft hairs
    • Obliquely angled at the end opposite the pappus
    • Oblique end with an oval-shaped depression containing a ridge of tissue

    Centaurea cyanus  (cornflower) achene

    Additional Botany Information

    AUTRES RENSEIGNEMENTS BOTANIQUES

    Flowers/Inflorescence

    • Bracts surrounding the flower head (involucre) 12-16 mm long (FNA 1993+)
    • Individual bracts (phyllaries) ovate to oblong-shaped, with curled hairs or glabrous, edges jagged or tooth-like (FNA 1993+)
    • Bracts green with blackish coloured edges
    • Florets 25-35 per flower head, petals blue, white or purple (FNA 1993+), stamens blackish coloured
    • Outer sterile florets, 20-25 mm long, funnel-shaped with toothed edges (FNA 1993+)
    • Inner fertile florets 10-15 mm long, tubular (FNA 1993+)
    • Horticultural varieties can have ‘double flowers’, i.e. have more large funnel-shaped flowers than typical

    Vegetative Features

    • Plants 20-100 cm tall, generally with one stem that is branched at the top (FNA 1993+)
    • Basal leaves are narrow egg-shaped (linear-lanceolate), stem leaves are linear, generally with smooth edges (FNA 1993+)
    • Stem and leaves are covered in long greyish hairs

    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.

    Centaurea cineraria L.

    This ornamental species grown for silvery-grey foliage has achenes that are generally shorter (length: ± 3.5 mm, Lionakis Meyer 2017) compared to C. cyanus. Achenes of C. cineraria may be a similar or a whitish colour compared to C. cyanus. The attachment point scar is a C-shaped notch near the end of the achene compared to the oblique-angled, larger scar of C. cyanus. The pappus of C. cineraria is white-coloured, and made up of narrow bristles that angle away from the achene compared to the wider, brown, upright pappus bristles of C. cyanus.

    Click to select species

    Cliquez pour sélectionner les espèces

    Comparison Window

    Fenêtre de comparaison

    Need ID Help?

    Besoin d’aide pour l’identification?

    ID Forum
    Forum d'identification
    ID Tool
    Outil d'identification

    Reference(s)

    Référence(s)

    Bellanger, S., Guillemin, J.-P., Bretagnolle, V. and Darmency, H. 2012. Centaurea cyanus as a biological indicator of segetal species richness in arable fields. Weed Research 52: 551–563.

    Bellanger, S., Guillemin, J.-P., Touzeau, S. and Darmency, H. 2015. Variation of inbreeding depression in Centaurea cyanus L., a self-incompatible species. Flora 212: 24–29.

    Bojňanský, V. and Fargašová, A. 2007. Atlas of Seeds and Fruits of Central and East-European Flora: The Carpathian Mountains Region. Springer, The Netherlands. 1046 pp.

    Brouillet, L., Desmet, P., Coursol, F., Meades, S.J., Favreau, M., Anions, M., Bélisle, P., Gendreau, C. and Shorthouse, D. 2010+. Database of Vascular Plants of Canada (VASCAN), http://data.canadensys.net/vascan Accessed November 25, 2024.

    Escher, G.B., Santos, J.S., Rosso, N.D., Marques. M.B., Azevedo, L., do Carmo, M. A.V. , Daguer, H., Molognoni, L., do Prado-Silva, L., Sant’Ana, A.S., da Silva, M.C. and Granato, D. 2018. Chemical study, antioxidant, anti-hypertensive, and cytotoxic/cytoprotective activities of Centaurea cyanus L. petals aqueous extract. Food and Chemical Toxicology 118: 439-453.

    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 December 04, 2024.

    Guillemin, J.-P., Bellanger, S., Reibeil, C. and Darmency, H. 2017. Longevity, dormancy and germination of Cyanus segetum. Weed Research 57: 361–371

    Lionakis Meyer, D.J. 2017. Identification Guide for Some Common and Noxious Thistle and Knapweed Fruits (Asteraceae, tribe Cardueae). California Department of Food and Agriculture, Plant Pest Diagnostics Center. Sacramento, California USA. 13 pp.

    Marczewska-Kolasa, K., Bortniak, M., Sekutowski, T.R. and Domardzki, K. 2017. Influence of water extracts from cornflower on germination and growth of cereals seedlings. Journal of Research and Applications in Agricultural Engineering 62(3): 208-211.

    Pinke, G., Kapcsándi, V. and Czúcz, B. 2023. Iconic arable weeds: The significance of corn poppy (Papaver rhoeas), cornflower (Centaurea cyanus), and field larkspur (Delphinium consolida) in Hungarian ethnobotanical and cultural heritage. Plants 12, 84. https://doi.org/10.3390/plants12010084

    Plants of The World Online (POWO). 2024. Centaurea cyanus. Facilitated by the Royal Botanic Gardens, Kew. Published on the Internet; https://powo.science.kew.org/ Accessed December 04, 2024.

    Rakizadeh, S., Attar, F. and Sotoodeh, A. 2019. Taxonomic significance of achene morphology in the genus Centaurea L. (Asteraceae). Nova Biologica Reperta 6(3): 352-366.

    Stankiewicz-Kosyl, M., Haliniarz, M., Wrochna, M., Synowiec, A., Wenda-Piesik, A., Tendziagolska, E., Sobolewska, M., Domaradzki, K., Skrzypczak, G., Łykowski, W., Krysiak, M., Bednarczyk, M. and Marcinkowska, K. 2021. Herbicide resistance of Centaurea cyanus L. in Poland in the context of its management. Agronomy 11, 1954. https://doi.org/10.3390/agronomy11101954

    Stankiewicz-Kosyl, M., Synowiec, A., Haliniarz, M., Wenda-Piesik, A., Domaradzki, K., Parylak, D., Wrochna, M., Pytlarz, E. , Gala-Czekaj, D., Marczewska-Kolasa, K. , Marcinkowska, K. and Praczyk, T. 2020. Herbicide Resistance and Management Options of Papaver rhoeas L. and Centaurea cyanus L. in Europe: A Review. Agronomy 10, 874; https://doi.org/10.3390/agronomy10060874

    Swearingen, J. and Bargeron, C. 2016. Invasive Plant Atlas of the United States. University of Georgia Center for Invasive Species and Ecosystem Health. http://www.invasiveplantatlas.org/ Accessed December 3, 2024.

    United States Department of Agriculture-Agricultural Research Services (USDA-ARS). 2024. Germplasm Resources Information Network (GRIN), https://npgsweb.ars-grin.gov/gringlobal/taxon/taxonomysearch Accessed December 3, 2024.

    Wacławowicz, R. Tendziagolska, E., Synowiec, A., Bocianowski, J., Podsiadło, C., Domaradzki, K., Marcinkowska, K., Kwiecinska-Poppe, E. and Piekarczyk, M. 2022. Competition between winter wheat and cornflower (Centaurea cyanus L.) resistant or susceptible to herbicides under varying environmental conditions in Poland. Agronomy 12, 2751. https://doi.org/10.3390/agronomy12112751

    Warzecha, D., Diekötter, T., Wolters, V. and Jauker, F. 2018. Attractiveness of wildflower mixtures for wild bees and hoverflies depends on some key plant species. Insect Conservation and Diversity 11: 32–41.

    Youssef, S., Cambecèdes, J. and Vela, E. 2020. Is the Mesopotamian region a main source of western European segetal plants? Botany Letters 167(2): 290-299.

    Author(s)

    AUTEUR(S)

    Jennifer Neudorf

    Canadian Food Inspection Agency, Canada  ssts@inspection.gc.ca

     

    contactus@idseed.org

    Last updated
    on 2023-03-27

    © 2025 ISMA - International Seed Morphology Association