Descurainia sophia (L.) Webb

Descurainia sophia plant

Family - Brassicaceae

Stems - To 1m tall, herbaceous, stellate and simple pubescent, from thick taproot, branching above at inflorescence.

Leaves - Alternate, to 14cm long, 6-7cm broad, pinnate, dense stellate pubescent, reduced upward, sessile. Leaflets divided, those divisions again divided or lobed. Ultimate leaf divisions entire.

Inflorescence - Terminal racemes, compact in flower, much elongating in fruit to +30cm long.

Descurainia sophia inflorescenceInflorescence.

Flowers - Petals 4, yellow, 3-4mm long, 1mm broad, spatulate, recurving slightly at apex. Stamens 6, exserted. Filaments to 4mm long. Ovary terete, 2-3mm long. Sepals 4, yellow-green, glabrous, 3mm long, -1mm broad, linear.

Descurainia sophia flowers

Fruit - Silique to 2.5cm long, 1mm in diameter, many seeded. Pedicel to 1.5cm long, filiform.

Flowering - May - July.

Habitat - Waste ground, disturbed sites, roadsides, railroads.

Origin - Native to Europe.

Other info. - D. sophia is becoming common in this state and others. I first found it in Florida. The plant is easy to ID in the field because of the much divided leaves, densely pubescent stems, and ascending long fruits. D. pinnata, a native species, looks similar but has shorter fruits, glandular pubescent stems, and leaves which are slightly less divided.

Photographs taken off Highway 9, Platte County, MO., 5-2-00.