Biennials, 15-80(-120) cm. Leaves on proximal 1/3-2/3 of each stem; blades of undivided cauline leaves ± ovate, margins denticu-late (sometimes ± ciliate), midribs usually piloso-setose. Heads in corymbiform to paniculiform arrays. Involucres 12-18+ mm. Phyllaries usually reflexed in fruit. Florets 12-24+; corollas usually yellow, sometimes drying bluish, usually deliquescent. Cypselae: bodies brown, ± flattened, elliptic, 4.5-5+ mm, beaks ± filiform, 2.5-3.5 mm, faces 1(-3)-nerved; pappi white, 6.5-8(-10+) mm. 2n = 34.
Similar to no. 3 [Lactuca canadensis L.], often more hairy, and with some tendency for the lvs to be basally disposed; lvs pinnatisect, with broad, toothed lobes that are commonly more than 1 cm wide and often somewhat narrowed at the base; heads larger, the invol 15-22 mm in fr, the achenes 7-9 mm, the mature pappus 8-12 mm; 2n=34. Dry open woods and clearings; P.E.I. to n. Fla., w. to Mich., Mo., and Tex. June-Sept. (Var. sanguinea, the less hairy phase)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.