Stems 2-8 dm, tending to be appressed- hairy, mostly freely-branched above; lvs linear to linear-oblong or linear-oblanceolate, 2-5 cm, usually ascending, sessile, rough-hairy; racemes numerous, eventually 5-10 cm; mature pedicels erect or ascending, 1-2 mm; bracts linear or lanceolate, 3-10 mm; cor blue, 2-3(-4) mm wide; nutlets 3-4 mm, the outer face lanceolate, roughened, surrounded by 2(3) rows of prickles, those of the inner row usually the longer; 2n=48. Native of Eurasia, established as a weed in waste places in much of the U.S. and s. Can., in our range more common northward. May-Sept. (L. echinata; L. lappula)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.