Family: Brassicaceae, Mustard view all from this family
Description This white-flowered mustard differs from other members of the mustard family by its triangular-shaped fruits and its deeply lobed leaves clustered at the base of the plant.
Habit: introduced annual herb; upright stems, somewhat hairy, possibly branched, rise from a basal rosette; taproot.
Height: 4-28 in (10-70 cm)
Leaf: in basal rosette, deeply pinnately lobed, stalked, to 6 in (15 cm) long by 1 in (25 mm) wide; on stem, alternate, linear, fewer, smaller, clasping.
Flower: small, white, 4-parted, about 0.125 in (3 mm) wide, with petals longer than sepals; in small flat terminal cluster, and on thin stalk held out from the stem.
Fruit: triangular or heart-shaped pod, notched at the tip, tapering to the base, smooth, to 0.4 in (10 mm) long and wide, containing numerous orange-yellow seeds.
Flower January to October.
Habitat Roadsides, gardens, fields, barren gravel, pastures, plantations, lawns, orchards, cultivated ground, waste areas, vineyards, mountain slopes, wet meadows, stream banks, disturbed sites; to 9200 ft (2800 m).
Range Native to Europe, now naturalized throughout North America and Hawaii, and in temperate climates around the globe.
Discussion Considered weedy or invasive in most areas. One authority (Coquillat, 1951), called sheperd's purse the second most common weed on earth, after Polygonum aviculare (knotweed).