Wild mustard, charlock
Sinapis arvensis (Sysimbrium orientale)

Upright annual, seed-propagated weed with a short taproot, originates from Eurasia.

Characteristic yellow flowers.

Cotyledons: Vigorous, inverse-cordate, petiolate, strongly sinuate at the tip.

Stems: Erect, with ramified branches especially at the top, roughly haired below, up to 60 cm (23.62 inch) high.

Leaves: Lower leaves petiolate, lobed, or sinuate-dentate, nearly lyre-formed.
Upper leaves ovate-oblong, only short-petiolate to sessile, irregularly dentate, usually undivided.
The first true leaf has a broad, rounded tip and shallow indentations along its margins.