Diplotaxis muralis

Diplotaxis muralis, the annual wall-rocket, is a species of flowering plant in the family Brassicaceae. This plant is native to Europe, Asia, and Africa, but it is found throughout the temperate world, where it has naturalized. This is an erect mustard-like plant rarely reaching half a meter in height. It has lobed leaves and its stems are topped with dense inflorescences of yellow, or occasionally light purple, flowers with small oval petals and large anthers. The fruit is a podlike silique two to four centimeters long....read more on Wikipedia.