charlock

noun

1. a wild mustard, Brassica kaber, having lobed, ovate leaves and clusters of small, yellow flowers, often troublesome as a weed in grainfields.

noun

1. Also called: wild mustard a weedy Eurasian plant, Sinapis arvensis (or Brassica kaber), with hairy stems and foliage and yellow flowers: family: Brassicaceae (crucifers)
2. white charlock Also called: wild radish, runch (rʌntʃ) a related plant, Raphanus raphanistrum, with yellow, mauve, or white flowers and podlike fruits