Monographs Details: Onopordum
Authority: Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Scientific Name:Onopordum
Description:Genus Description - Coarse, branching biennial to 2 m, very strongly spiny, with broadly winged stem; herbage ± tomentose; lvs toothed or slightly lobed, sessile and decurrent, or the lower petiolate, the blade to 6 × 3 dm; heads 2.5–5 cm wide, the invol bracts all spine-tipped; achenes 4–5 mm, slightly compressed, transversely rugulose; pappus merely barbellate; 2n=34. A Eurasian weed, sparingly naturalized over much of the U.S. and s. Can. July–Oct.

Common Names:Scotch thistle