Lepidium didymum is an annual or biennial herb[4] with decumbent or ascending and glabrous green stems, up to 40 centimetres (16 in) long, radiating from a central position. The leaves are pinnate and alternate and can reach a length of 5 cm (2 in). It blooms between July and September. The flowers are inconspicuous, the four white petals very short or absent, with 2 (rarely 4),[5]: 54 stamens and the fruits consist of two rounded valves, notched at the apex, with a very short style between.[6]: 405 [7] They are also wrinkled and contain orange or reddish brown seeds, that are 1–5 mm long.[7]
Taxonomy
It was first described and published by the Swedish botanist Carl Linnaeus in 'Mant. Pl.' (Mantissa Plantarum) on page 92 in 1767.[8][1]
The specific epithetdidymum, refers to the Greek word δίδυμα for 'twin' or 'in pairs',[9] referring to the seed capsule.
Distribution
Lepidium didymum is of uncertain origin,[4] but is often cited as native to South America,[6][5] mainly Argentina, Bolivia, Brazil, Chile, Paraguay, Peru, Uruguay and Venezuela.[10] It has been introduced elsewhere as a weed of cultivation. It has naturalised across the globe, from Africa, Europe, Asia, Australasia, North America and South America.[10] In Britain, it had been recorded from the wild by 1778,[4] chiefly in England and the south of Ireland,[11] growing on cultivated and waste ground, in gardens and lawns, by paths and roadsides.
Uses
The leaves of this plant are edible, and have a salty, cress or mustard flavour.[12][13]
