Leafy-stemmed annual or usually biennial 3-25 dm, glabrous or occasionally coarsely hirsute, often ±glaucous; lvs highly variable, entire or toothed to pinnately lobed or cleft, sagittate or sometimes narrowed to the base, 10-35 נ1.5-12 cm; heads numerous, small, with 13-22 yellow fls; invol 10-15 mm in fr; achenes blackish, very flat, with a median nerve on each face, transversely rugulose, 4.5-6.5 mm overall, the slender beak from a little more than half to about as long as the body; mature pappus 5-7 mm; 2n=34. Fields, waste places, and woods; Que. and P.E.I. to Sask., s. to Fla. and Tex. July-Sept. (L. sagittifolia; L. steelei)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.