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. In the western United States, yellow starthistles are an invasive species. Around the year 1850, seeds from the plant had arrived to the state of California. It is believed that those seeds came from South America.