C. Stace, New flora of the British Isles, ed. 3. 2010R. Jahn & P. Schönfelder, Exkursionsflora für Kreta. 1995
but modified and used names differing
1Phyllaries yellowish-green, glabrous or nearly so; capitula 3-5 mm wide at fruiting
1'Phyllaries greyish-green, more or less hairy; capitula 5-11 m wide at fruiting
2Inflorescence pyramidal; phyllaries not or minutely red-tipped; capitula 5-8 mm wide at fruiting; leaves dull green
2'Inflorescence with long lateral branches often overtopping terminal branches, subcorymbose; phyllaries often conspicuously red-tipped; capitula 7-11 mm wide ar fruiting; leaves greyish-green