Rapistrum rugosum (L.) All.
An erect, rough-hairy annual, with stems up to 60 cm tall. Lower leaves 10 to 15 cm long, arranged in a rosette, rough-hairy, pinnately lobed, the end lobe larger than the lateral ones, rounded, toothed. The upper leaves almost hairless, stalkless, not lobed. Flowers with 4 petals, pale yellow, 8 to 10 mm across, in long, many-flowered racemes. Silicula up to 1 cm long, with two distinct sections; the upper section globular 2 to 4 mm across, with distinct wavy vertical ribs; the lower section narrower, cylindrical, up to 3 mm long.
Local: Rare in Gibraltar. Found mainly on Windmill Hill Flats and along Mediterranean Steps.
Global: Found throughout Southern Europe and the Mediterranean region.
Flowers from (March) April, May to June.
Grows on open ground and along waysides.