Picris echioides

Medium to tall bristly plant, each bristle arising from a pimple.  Stems well branched.  Leaves elliptical to oblong, wavy edged, pimply and bristly with winged stalks, upper leaves unstalked and clasping the stem.  Flowers yellow 20 to 25 mm numerous, florets all rayed, flower bracts with bristly margins, the outer heart shaped.  Papus white. 

Courtesy of Naturespot - www.naturespot.org.uk