Prenanthes muralis Linnaeus, Sp. Pl. 2: 797. 1753; Lactuca muralis (Linnaeus) Gaertner

Leaf blades 35–120(–180+) × 10–50(–80+) mm. Peduncles filiform, 5–25+ mm. Involucres 7–11+ mm. Phyllaries: abaxial faces glabrous. Cypselae: bodies 2.5–3 mm, beaks 0.5–1 mm; pappi: outer 0.1–0.2 mm, inner 5–6 mm. 2n = 18.

Flowering Jun–Oct. Disturbed sites, openings in mixed forests, calcareous or sandy soils; 10–400 m; introduced; B.C., Ont., Que.; Maine, Mass., Mich., Minn., N.H., N.Y., Oreg., Vt., Wash.; Europe.