The genus Centaurea Linnaeus

Remark The words or terms in red (actually dark orange) in the text are defined in a glossary.

oct_05_02c.gthmb can't be loaded. Centaurea is a genus of about 350 to 500 species of herbaceous thistles and thistle-like flowering plants in the family Asteraceae. The genus is mostly native to Mediterranean Europe and North Africa, i.e. chiefly centered in the Mediterranean region. 72 species can be found in the USA, several of them introduced. The genus includes a wide variety of annuals, biennials and perennial, some used as garden plants, such as Centaurea cyanus and Centaurea americana.

The genus Centaurea, long recognized as a polyphyletic assemblage, has traditionally been considered to be a complicated taxon. On the basis of morphology, pollen, karyology and DNA sequence analysis, some botanists have defines informal groups in the genus but without precise delimitation and relationships.


In Greek κενταυριν (kentaurin) means Knapweed the standard common name of many Centaurea species. As for the name κενταυριν it is likely coming from κενταυροσ (kentauros) that means centaur. One of the famous centaur was Chiron, known for his exceptional goodness and wisdom and for his knowledge of medicinal plants. He raised Asclepius, a god of healing and taught him medicine which Asclepius went on to perfect. Since some species of the Centaurea genus have been used as medicinal herbs, the genus name might come from the association of Chiron, centaur, to Centaurea. For an other origin of the name, some sources say that Chiron used the flower of some Centaurea species to heal wounds, including his own, after battle.

Some of the vernacular names of name for many species of the genus are: Knapweed, Thistle, Thornless Thistle, Star Thistle, Cornflower and Bluet, while the common vernacular French name is Centaurée.


The genus Centaurea or species of this genus have been known under other names, i.e. under the genera names Acosta, Grossheimia, Jacea or Leucacantha.


Centaurea are copious nectar producers, especially on high-lime soils, and are major honey plants for beekeepers. This varietal honey is light and slightly tangy. It is one of the finest honeys produced in the US. The high nectar yield of the genus makes it very attractive to insects such as butterflies and day-flying moths. The larvae of some other Lepidoptera species use Centaurea species as food plants.

The introduced species are among the most invasive of non-indigenous plants that have colonized western North America over the last century. Several species have invaded millions of hectares of western United States and Canadian grasslands.

The Centaurea of Québec

In Québec one can find the following nine species: and the two following hybrids: