Sonchus

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  S. arvensis

  1a. Plants perennial, with deep-seated, creeping rhizomes; capitula 3–5 cm wide in flower; involucre 14–22 mm tall in fruit
• See list of 2 species in 1b
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  1b. Plants annual, with taproots; capitula 1.5–2.5 cm wide in flower; involucre 9–13 mm tall 
in fruit
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    S. asper

    2a. Cypsela body with 3 (–5) ribs on each face, otherwise smooth; leaf blades relatively firm, with stiff prickles and rounded basal auricles [Fig. 460]; peduncles glandular-pubescent
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    S. oleraceus

    2b. Cypsela body with 5–7 ribs on each face and transversely rugulose; leaf blades relatively soft, with softer prickles and triangular to narrow-triangular basal auricles; peduncles glabrous or infrequently with a few glandular hairs

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 Show photos of:   Each photo represents one species in this genus.