Thlaspi bursa-pastoris Linnaeus, Sp. Pl. 2: 647. 1753; for more than 250 synonyms, see Index Kewensis.
Herbs (2-)10-50(-70) cm tall, sparsely to densely pubescent with sessile, 3-5-rayed stellate trichomes often mixed near base of plant with much longer simple trichomes. Stems erect, simple or branched. Basal leaves rosulate; petiole 0.5-4(-6) cm; leaf blade oblong or oblanceolate, (0.5-)1.5-10(-15) × 0.2-2.5(-5) cm, base cuneate or attenuate, margin pinnatisect, pinnatifid, runcinate, lyrate, dentate, repand, or entire, apex acute or acuminate. Cauline leaves sessile, sagittate, amplexicaul, or rarely auriculate, narrowly oblong, lanceolate, or linear, 1-5.5 (-8) cm × 1-15(-20) mm, margin entire or dentate. Fruiting pedicels (0.3-)0.5-1.5(-2) cm, divaricate, usually straight, slender, glabrous. Sepals green or reddish, oblong, 1.5-2 × 0.7-1 mm, margin membranous. Petals white, rarely pinkish or yellowish, obovate, (1.5-)2-4(-5) × 1-1.5 mm. Filaments white, 1-2 mm; anthers ovate, to 0.5 mm. Fruit (3-)4-9(-10) × (2-)3-7(-9) mm, flat, base cuneate, apex emarginate or truncate; valves with subparallel lateral veins, glabrous; style 0.2-0.7 mm. Seeds brown, oblong, 0.9-1.1 × 0.4-0.6 mm. Fl. and fr. Apr-Jul. 2n = 16, 32*.
Roadsides, gardens, fields, waste areas, mountain slopes. Throughout China [native to SW Asia and Europe; naturalized elsewhere as a cosmopolitan weed].
This species is used as a vegetable and in the treatment of eye diseases and dysentery. It is the second most common weed on Earth.