Cirsium

Jäger, E.J. 2011: Rothmaler, Exkursionsflora von Deutschland, Gefäßpflanzen: Grundband, ed. 20Meikle, R.D. 1985: Flora of Cyprus 2Stace, C. 2010: New flora of the British Isles, ed. 3
1Biennial without rhizomes; stem with basal rosette; leaves with rigid bristles on upperside; involucre 2.4-4(-5) cm wide
1'Perennial with long rhizomes; stem without basal rosette; leaves glabrous or with soft hairs on upperside; involucre 0.7-2.2 cm wide