Sisymbrium murale Linnaeus, Sp. Pl. 2: 658. 1753; Brassica muralis (Linnaeus) Boissier; Sinapis muralis (Linnaeus) R. Brown.

Herbs annual, sometimes perennial, (5-)20-50(-60) cm tall, scapose or subscapose, glabrous throughout or hirsute basally with simple, retrorse trichomes. Basal leaves rosulate, petiolate; leaf blade elliptic, spatulate, or narrowly ovate, 2-9 × 1-3 cm, dentate, sinuate, lyrate, or pinnatipartite with 2-6 oblong or ovate lateral lobes smaller than terminal lobe. Cauline leaves absent or few, sessile, not auriculate, much smaller than basal ones, dentate or entire. Fruiting pedicels slender, divaricate or ascending, straight, glabrous, (0.3-)0.8-1.4(-3) cm. Sepals oblong, 3.5-5.5 mm, glabrous or apically hairy. Petals yellow, obovate, (4.5-)6-8(-10) × 4-5 mm, cuneate to a short clawlike base. Filament 3.5-6 mm; anthers 1.5-2 mm. Ovules 20-36 per ovary. Fruit (1.5-)2.5-4(-4.5) cm × 1.5-(-2.5) mm, erect-patent, compressed, slightly torulose; gynophore 0.2-0.5 mm; style stout, beaklike, (1-)1.5-3(-3.5) mm; stigma entire. Seeds ovoid or ellipsoid, 0.9-1.3 × 0.6-0.9 mm. Fl. and fr. late Apr-Aug. 2n = 42.

Coastal weedy areas. Liaoning [native to Europe; naturalized elsewhere].