Lincoln's-weed

Diplotaxis tenuifolia, the perennial wall rocket, narrow-leaved bittercress or Lincoln’s-weed, is a glabrous, somewhat woody-based perennial herb in the family Brassicaceae growing up to about 1.3 m tall on solid stems with spreading branches. The deeply pinnate leaves are up to 12 cm long, often somewhat fleshy, with a distinctly peppery taste and a musty smell when crushed; they are divided more than halfway to the midrib into narrow lobes. From May to September the plant produces loose terminal racemes of up to about thirty showy flowers, each with four bright yellow petals up to 15 mm long and six stamens, followed by straight flat siliques up to 5 cm long that hold seeds in two distinct rows per valve, an identifying feature of the genus. Native to most of Europe and east to Turkey and Syria, it is a typical ruderal of sunny, alkaline, often saline waste ground, roadsides, railway ballast and coastal banks, and is now naturalised through much of the world’s temperate zone. It is widely cultivated commercially as ‘wild rocket’.