originates in Europe and Asia but has long been introduced in the US, where it can be very abundant, carpeting whole fields; the species is classed as a noxious weed in many areas. Leaves and stems have a sparse covering of sticky, glandular hairs; white stalks, often topped by a light brown gland. Plants produce small numbers of flowers towards the stop of the stem, blooming over a period of several months.
Flowers are formed of four greenish-purple sepals, partly fused into a tube a quarter of an inch long, and four spreading magenta-pink petals, narrow (clawed) at the base and similar in length to the sepals. The fruit is a gently upwards-curved green pod, up to 2 inches long. The plant exudes a strong, musky aroma.