At a glance
Essentials
- Size
- Height of 20 to 100 cm; heads 1.5 to 3 cm in diameter; achenes 5 mm. The range may vary with age, sex and population.
- Distribution
- Native to temperate Europe, it has naturalized in North America and parts of Australia, and is recorded as a weed in Central Asia and Siberia.
- Habitat
- Historically grew as a weed in cereal fields, although it is also found in grasslands, road edges and disturbed areas.
- Activity
- Blooms during spring and summer, with a flowering period spanning from May to September.
- Conservation
- In its native European habitat, agricultural intensification and the use of herbicides have reduced its population, although it is considered not threatened at the global level according to extinction risk predictions.
Observation guide
What to look for
- 01
Intense blue coloration of the peripheral florets, attributed to the anthocyanin pigment protocyanin.
- 02
Bell-shaped involucre with outer bracts that have white to black lateral appendages and a scarious apical fringe.
- 03
Angular stems and branched at the top, covered with woolly pubescence.
Lighting, age and viewing angle can hide features. If identification affects consumption, handling or conservation, consult specialist sources.
Ecology
Description and characteristics
Centaurea cyanus is an annual herbaceous plant, rarely biennial, reaching a height of between 20 and 100 centimeters. It has upright stems, branched at the top and covered with a woolly pubescence. The leaves are linear, with longitudinal venation and arranged alternately; the basal ones may be spatulate and the upper ones narrower. The species produces flower heads 1.5 to 3 cm in diameter, characterized by a ring of peripheral florets, generally of an intense blue color, surrounding a center of disc florets. The involucre is bell-shaped and its outer bracts have membranous lateral appendages. The fruit is an achene of approximately 5 mm, provided with a pappus of stiff bristles.