Publication: Enum. Pl. suppl.: 54. 1814.
Origin: Introduced from Europe
selected vouchers: WTU
Notes: FNA19: "The type of Hieracium flagellare may have resulted from a cross between plants of H. caespitosum and H. pilosella (A. Cronquist 1980)."
Although generally treated as a hybrid, this plant is often found in the absence of both of its parents, and is a widespread weed in eastern North America (Lepage 1967). Recently collected in San Juan County.