Monographs Details: Carduus
Authority: Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Description:Genus Description - Much like Cirsium, differing chiefly in its pappus of merely capillary, not at all plumose bristles; stem commonly spiny-winged; achenes quadrangular or somewhat flattened, with 5–10 or more nerves, or nerveless. 100, Old World.