Sisymbrium officinale (L.) Scop.
Diagnostic description:
An erect annual or biennial. Stems erect, branched above, up to 90 cm tall, bristly hairy in the lower parts. Lower leaves pinnatisect with up to 4 pairs of side lobes, the terminal one being the largest. The upper leaves smaller, with hastate terminal lobe and 1 to 2 pairs of side lobes. Inflorescence a raceme of small yellow flowers with 4 petals; about 3 mm across. Siliqua 1 to 2 cm long, cylindrical, held stiffly against the flowering stem.
Distribution:
Local: Common in Gibraltar. Found widespread as a weed in urban areas, and along footpaths on the Upper Rock.
Global: Found throughout Europe.
Ecology:
Flowers from March, April, May to June.
Habitat:
Grows on cultivated ground, waste ground and waysides.