Sisymbrium sophia Linnaeus, Sp. Pl. 2: 659. 1753.

Herbs annual, (10-)20-70(-100) cm tall, eglandular, sparsely to densely pubescent with dendritic trichomes, sometimes glabrous distally. Stems erect, simple basally, often branched above. Basal and lowermost cauline leaves 2- or 3-pinnatisect, ovate or oblong in outline, to 15 × 8 cm; petiole 0.1-2(-3) cm; leaf blade ultimate division linear or oblong, entire, acute to 10 × 2 mm. Upper cauline leaves sessile or shortly petiolate, smaller and often with narrower ultimate lobes, often glabrous. Fruiting pedicels (0.5-)0.8-1.5(-2) cm, slender, much narrower than fruit, straight, divaricate or ascending. Sepals yellowish, oblong-linear, 2-2.5 × ca. 0.5 mm. Petals yellow, narrowly oblanceolate, 2-2.5 × ca. 0.5 mm; claw 1.5-2 mm. Filaments 2-3 mm; anthers ca. 0.5 mm. Ovules 20-40 per ovary. Fruit narrowly linear, (1.2-)1.5-2.7(-3) cm × 0.5-0.8(-1) mm; valves glabrous, torulose, with a prominent midvein; septum with a broad central longitudinal band appearing as 2 or 3 veins; style obsolete or to 0.2 mm. Seeds reddish brown, oblong, 0.7-1 × 0.3-0.6 mm. Fl. and Fr. Apr-Jun. 2n = 28*.

The seeds are sometimes used as a substitute for mustard. Preparations from the plant are taken internally to eradicate worms, and externally to treat indolent ulcers.

Roadsides, waste places, disturbed sites, fields, pastures, deserts; near sea level to 4200 m. Throughout China except Guangdong, Guangxi, Hainan, Taiwan [Afghanistan, Bhutan, Japan, Kashmir, Kazakhstan, Korea, Kyrgyzstan, Mongolia, Nepal, Pakistan, Russia, Sikkim, Tajikistan, Turkmenistan, Uzbekistan; N Africa, SW Asia, Europe; introduced elsewhere].