Seasonal Wild Flowers

Latin name

Sinapis alba

Family

Brassicaceae

Flowering season

June to August

English distribution

It is found throughout the country but is less common in

parts of the North.

See the BSBI distribution map for White Mustard

Habitat

It is an archaeophyte, which used to be grown for mustard.

It is a common naturalised escape originating from bird-

seed and from fields, where it is occasionally grown for

mustard seed or as a green manure.

It is the mustard half of the salad ‘mustard and cress’.

It is naturalised on waste ground by roads and paths,

and is a weed of arable crops, especially on lime.

Description

White Mustard is an annual, robust herb, growing up

to 1m.

The flowers are in groups of up to 8, each approximately

50mm with well-spaced yellow petals.

Petals are up to 15mm long, bright yellow and clawed

at the base.

There are 6 stamens.

The stigma looks capitate but is made up of 2 indistinct

lobes.

The sepals are spreading.

Fruits are up to 4cm long and 4mm wide.

They have a distinct, often curved,

beak and 3 valves containing the seeds.

The seed-pods are stiffly hairy.

The leaves are up to 15cm, stalked and coarsely pinnately

lobed with a larger terminal lobe.

Stems are erect, usually branched, ridged and with stiff,

downwardly pointing hairs.