Centaurea (/ˌsɛntɔːˈriːə/) is a genus of between 350 and 600 species of herbaceous thistle-like flowering 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" (Common Knapweed). 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 (sometimes also called "Basket Flower"). The common name "centaury" is sometimes used, although this also refers to the unrelated plant genus Centaurium.