Publication: Sp. Pl. 2: 973.
selected vouchers: WTU
Notes: SPNW: "This ruderal species has been considered native to Europe and probably introduced to North America, but recent phylogenetic research suggests that C. leporina evolved in western North America and was introduced to Europe. Flip-flopping between names C. leporina and C. ovalis is due to confusion about which plant specimen should be considered the type for the name C. leporina.