"star thistle." YourDictionary, n.d. Web. 19 September 2018. <http://www.yourdictionary.com/star-thistle>.
star thistle. (n.d.). Retrieved September 19th, 2018, from http://www.yourdictionary.com/star-thistle
Any of several plants of the genus Centaurea of the composite family that have spiny yellow or purplish flower heads, especially C. solstitialis, native to Eurasia and widely naturalized in North America.