6. Lactuca ludoviciana (Nuttall) Riddell, W. J. Med. Phys. Sci. 8: 491. 1835.
Sonchus ludovicianus Nuttall, Gen. N. Amer. Pl. 2: 125. 1818; Lactuca campestris Greene
Biennials, 15–150 cm. Leaves on proximal 1/2–3/4 of each stem; blades of undivided cauline leaves obovate or oblanceolate to spatulate, margins denticulate (piloso-ciliate), midribs usually piloso-setose. Heads in paniculiform arrays. Involucres 12–15+ mm. Phyllaries usually reflexed in fruit. Florets 20–50+; corollas usually yellow, sometimes bluish, usually deliquescent. Cypselae: bodies brown to blackish (usually mottled), ± flattened, elliptic, 4.5–5+ mm, beaks ± filiform, 2.5–4.5 mm, faces 1(–3)-nerved; pappi white, 5–7(–11) mm. 2n = 34.
Flowering Jun–Sep. Openings in woods, stream banks, prairies; 100–1400 m; B.C., Man., Sask.; Ariz., Ark., Calif., Colo., Idaho, Ill., Ind., Iowa, Kans., Ky., La., Minn., Mont., Nebr., N.Mex., N.Dak., Okla., Oreg., S.Dak., Tex., Utah, Wash., Wis., Wyo.
