Charlock

n.
  1. A cruciferous plant (Brassica sinapistrum) with yellow flowers; wild mustard. It is troublesome in grain fields. Called also chardock, chardlock, chedlock, and kedlock.
  2. Jointed charlock, White charlock ,
    a troublesome weed (Raphanus Raphanistrum) with straw-colored, whitish, or purplish flowers, and jointed pods: wild radish.