Thlaspi perfoliatum Linnaeus, Sp. Pl. 2: 646. 1753

Stems unbranched or branched basally or distally, (0.3-)0.5-2.8(-4) dm. Basal leaves (not rosulate or loosely so); petiole 0.5-1.3 cm; blade ovate or broadly elliptic, 0.3-2(-2.7) cm × 2-10 mm, base cuneate or attenuate, margins entire or, rarely, obtusely and sparsely dentate, apex rounded. Cauline leaves: blade ovate-cordate or suboblong, (1-)2-4(-5.5) cm × (2-)5-15 (-20) mm, base cordate-amplexicaul, margins entire or repand, apex obtuse. Fruiting pedicels (2.5-)4-6 (-8) mm. Flowers: sepals (0.8-)1-1.5(-2) × 0.5-1 mm, (margins white); petals 1.5-3.5(-4.7) × 0.5-1.3 mm; filaments 1-1.5(-2) mm; anthers 0.1-0.2 mm. Fruits 3-6.5(-8) × (2.5-)3-6(-7) mm, base obtuse, apical notch 1-1.5 mm deep; wings 1-2 mm wide apically, much narrower basally; style obsolete or 0.1-0.3 mm. Seeds yellow-brown, 0.9-1.3(-1.5) × 0.7-1 (-1.2) mm. 2n = 14, 28, 42.

Flowering Mar-May. Waste grounds, roadsides, fields, plains, thickets; 0-500 m; introduced; Ill., Ind., Kans., Ky., Md., Mo., N.J., N.Y., N.C., Ohio, Pa., Tenn., Va., Wash., W.Va.; Europe; Asia; n Africa.