Louisiana Lettuce

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.

Sonchus ludovicianus Nuttall, Gen. N. Amer. Pl. 2: 125. 1818; Lactuca campestris Greene