Charlock

Appearance

"Sinapis arvensis" reaches on average 20–80 centimetres of height, but under optimal conditions can exceed one metre. The stems are erect, branched and striated, with coarse spreading hairs especially near the base.

The leaves are petiolate with a length of 1–4 centimetres. The basal leaves are oblong, oval, lanceolate, lyrate, pinnatifid to dentate, 4–18 centimetres long, 2–5 centimetres wide. The cauline leaves are much reduced and are short petiolate to sessile but not auriculate-clasping.

The inflorescence is a raceme made up of yellow flowers having four petals. The fruit is a silique 3-5 cm long with a beak 1-2 cm long that is flattened-quadrangular. The valves of the silique are glabrous or rarely bristly, three to five nerved. The seeds are smooth 1-1.5 mm in diameter.

Flowering occurs from May to September. The flowers are pollinated by various bees and flies. "Sinapis arvensis" is the host plant of the caterpillars of some Lepidoptera, such as the small white, "Pieris rapae". It contains chemicals of the class glucosinolates, including sinalbin.

Naming

The genus name "Sinapis" derives from the Greek word "sinapi" meaning 'mustard'. The species name "arvensis" is a Latin adjective meaning 'from/of the field'.

Distribution

A native of the Mediterranean basin, it is widespread in all temperate regions of the planet. It has also become naturalized throughout much of North America. It is a highly invasive species, a weed, such as in California.

Habitat

It grows in the plains and mountains, in pastures, fields, roadsides, waste places and ruins, but mainly in cultivated places. It prefers calcareous soils in sunny places, at an altitude of 0–1,400 metres above sea level.

Uses

The leaves of Wild Mustard are edible at the juvenile stage of the plant. In animals, except birds, the seeds are toxic and cause gastrointestinal problems, especially if consumed in large quantities. Once the seeds are ground, they produce a kind of mustard.