A medium-large dandelion with erect leaves of a dark, often rather lustrous green but with dark smudges on the interlobes and mid-rib above. Petioles narrowly winged to almost unwinged below, red, often brightly so. Leaf side-lobes 2-4, often strongly sigmoid on distal margin, acuminate-dentate on proximal lobes. Leaf end-lobe very distinctive, long, helmet-shaped and often with an excurrent apex. Exterior bracts very narrow and rather insubstantial, reflexed. Capitulum large, to 65 mm diameter when expanded, ochre-yellow with brown-purple ligule stripes. Most likely to be confused with T. huelphersianum amongst British species. The latter has a different leaf end-lobe and more leaf side-lobes.