Lesser swine-cress

Lepidium didymum (often Coronopus didymus), the lesser swine-cress or wart-cress, is a small low-growing annual or biennial herb in the family Brassicaceae. The decumbent to ascending, hairless green stems radiate outwards from a central rosette and rise only to about 40 cm. The alternate, pinnately divided leaves are roughly 5 cm long with narrow, toothed or lobed segments. From July to September the plant produces inconspicuous flowers in short axillary racemes, each with four very small white petals (sometimes absent) and only two to four stamens. The fruit is a tiny, two-lobed silicle whose rounded valves are notched at the apex and conspicuously wrinkled, containing one orange to reddish-brown seed each. The species is native to temperate South America, including Argentina, Bolivia, Brazil, Chile, Paraguay, Peru, Uruguay and Venezuela, and is now naturalised worldwide as a weed of gardens, lawns, paths, roadsides and waste ground. The leaves have a strong, salty, mustard-like flavour and have been used as a wild salad green.