Sp. Pl. 2: 807. 1753.
Annual, biennials, or perennials, 10–50 cm (roots fibrous, shallow). Stems 1(–3+), erect to decumbent or prostrate, branched proximally or distally, hispid and/or setose. Leaves basal and cauline; petiolate; blades oblanceolate, runcinate, 3–13 × 1–3 cm, margins denticulate to pinnately lobed (lobes deltate to lanceolate, often sharply serrate, terminal relatively large), apices acute, faces hispid to villous (cauline sessile, blades ovate to lanceolate or linear, runcinate, bases auriculate, margins deeply pinnately lobed, lobes linear). Heads 3–10+, in cymiform arrays. Calyculi of 8–10, linear to lanceolate, densely hispid bractlets 2–5 mm (becoming lax). Involucres cylindric to turbinate, 7–16 × 4–13 mm. Phyllaries 8–12, lanceolate (bases strongly keeled, enclosing marginal cypselae, margins green), apices acute to attenuate, abaxial faces hispid or setose, adaxial with fine hairs. Florets 80–100+; corollas yellow (usually reddish purple adaxially), 9–16 mm. Cypselae (dimorphic) subcylindric, outer stout, 7–9 mm, nearly beakless, inner 12–17 mm, beaks 2–5 mm; pappi dull white, 3–7 mm. 2n = 10.
Phenology: Flowering Apr–Sep.
Habitat: Seashores, plains, hills, and mountains
Elevation: 80–1200 m
Introduced; Fla., Ga., Mass., N.C., Wis., Eurasia.
Crepis foetida is polymorphic; it is recognized by its annual or biennial habit, usually erect and hispid or setose stems, sharply runcinate leaves, hispid or setose involucres, and dimorphic cypselae.