Described are several new taxa of the genus Cirsium that occur in the state of Utah: C. eatonii (Gray) Robins, var. harrisonii Welsh; C. eatonii var. murdockii Welsh; C. ownbeyi Welsh; C. scariosum Nutt. var. thorneae; and C. virginensis Welsh.
Welsh, Stanley L.
"New taxa of thistles (Cirsium; Asteraceae) in Utah,"
Great Basin Naturalist: Vol. 42
, Article 3.
Available at: http://scholarsarchive.byu.edu/gbn/vol42/iss2/3