Centaurea is a genus of between 350 and 600 species of herbaceous thistle-likeflowering plants in the family Asteraceae. Members of the genus are found only north of the equator, mostly in the Eastern Hemisphere; the Middle East and surrounding regions are particularly species-rich.
Common names for this genus are centaury, centory, starthistles, knapweeds, centaureas and the more ambiguous “bluets”; a vernacular name used for these plants in parts of England is “loggerheads”.
The Plectocephalus group – possibly a distinct genus – is known as basketflowers. “Cornflowers” is used for a few species, but that term more often specifically means C. cyanus. The common name “centaury” is sometimes used, although this also refers to the unrelated plant genus Centaurium. (Wikipedia)