charlock

[chahr-luh k] /ˈtʃɑr lək/
noun
1.
a wild mustard, Brassica kaber, having lobed, ovate leaves and clusters of small, yellow flowers, often troublesome as a weed in grainfields.
Origin
before 1000; Middle English cherlok, Old English cerlic < ?
British Dictionary definitions for charlock

charlock

/ˈtʃɑːlɒk/
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
Word Origin
Old English cerlic, of obscure origin
Encyclopedia Article for charlock

(Brassica kaber, or Sinapis arvensis), early-flowering weed of the mustard family (Brassicaceae), once widespread in grainfields in Europe and North America. Charlock reaches 1 metre (3 feet) and has stiff bristles on the stems and leaves. The long pod fruits, which form after the yellow flowers bloom, each enclose 10 to 12 black seeds that may remain viable for more than a decade. The closely related white mustard (B. hirta or Sinapis alba) has vanilla-fragrant, yellow flowers from which develop three to six large, yellow-seeded, bristly pods, swollen around the seeds. The seeds of both species contain a clear oil that is poisonous to livestock. White mustard seeds are a source of the condiment known as mustard, and the seedlings at the cotyledon stage yield cress.

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