Saffron thistle

Erect annual thistle to 1 (rarely to 1.5) m high. Stems ribbed, branched above, hairless to downy. Leaves variable; basal leaves in a rosette, lanceolate, initially with few lobes but older leaves more dissected, to 20 cm long and to 5 cm wide; stem leaves to 11 cm long and to 5 cm wide, usually hairless but some plants with hairy leaves, base stem-clasping and not on a leaf stalk. Seeds ovoid, grey-brown.