Lactuca virosa
Sp. Pl. 2: 795. 1753.
Introduced
Biennials, 20–120(–200+) cm. Leaves on proximal 1/2–2/3 of each stem; blades of undivided cauline leaves obovate to spatulate, margins denticulate, midribs usually prickly-setose. Heads in paniculiform arrays. Involucres 12–15 mm. Phyllaries usually reflexed in fruit. Florets 10–15; corollas yellow, usually deliquescent. Cypselae: bodies purplish to blackish, ± flattened, ± elliptic, 3.5–4 mm, beaks ± filiform, 2.5–3.5 mm, faces 5–7-nerved; pappi white, 5–6 mm. 2n = 18.
Phenology: Flowering May, Oct.
Habitat: Disturbed sites
Elevation: 10–400 m
Distribution
Introduced; Ala., Calif., D.C., Europe.
Discussion
Selected References
None.
Lower Taxa
None.