Plants 100-200 cm. Stems simple to much branched, ± glandular, ± tomentose. Leaves: basal and proximal cauline leaves shortly winged-petiolate, distal cauline sessile, clasping; blades oblong-elliptic to narrowly obovate, margins ± subentire or 1-2-pinnately lobed, lobes lanceolate to triangular, margins revolute, spiny-dentate, spine-tipped, spines slender, 2-4 mm; abaxial faces densely gray- or white-tomentose, adaxial faces green, glandular-scabrous. Secondary heads 3-6 cm diam. Involucres 15-25 mm. Outer phyllaries ± glandular, inner phyllary apices attenuate, expanded, fringed. Corollas white to pale blue, 12-14 mm, tube ca. 5.5 mm, lobes ca. 7 mm. Cypselae 7-10 mm; pappi of ± connate, ciliate scales 1-1.5 mm. 2n = 30, 32. Flowering summer (Jun-Aug). Disturbed sites; 0-1700 m; introduced; Man., Ont., Que., Sask.; Calif., Colo., Conn., Ill., Ind., Iowa, Ky., Maine, Md., Mass., Mich., N.H., N.Y., Pa., Vt., Va., Wash., W.Va., Wis.; Eurasia. Echinops sphaerocephalus is sometimes cultivated, and sometimes it escapes from cultivation. The species has been reported from Saskatchewan and may be introduced there; that appears questionable.
Coarse, branching, to 2.5 m; stem spreading-hairy (some of the hairs gland-tipped), also tomentose above; lvs white-tomentose beneath, green and merely scabrous or hirsute above (many of the hairs gland-tipped), sessile and clasping (at least the middle and upper), not decurrent, pinnatifid, to 3.5 נ2 dm; secondary heads naked-pedunculate, 3.5-6 cm thick, pale bluish; proper invol 1.5-2 cm, its bracts puberulent on the back; subtending bristles seldom half as long as the invol; 2n=30, 32. Waste places; native of Eurasia, sometimes cult., and casually established as a weed here and there in e. U.S. and adj. Can. July-Sept.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.