Thlaspi campestre Linnaeus, Sp. Pl. 2: 646. 1753; Neolepia campestris (Linnaeus) W. A. Weber

Annuals; densely hirsute. Stems simple from base, erect, unbranched or branched distally, (0.8-)1.2-5(-6.3) dm. Basal leaves rosulate; petiole (0.5-) 1.5-6 cm; blade oblanceolate or oblong, (1-)2-6(-8) cm × 5-15 mm, margins entire, lyrate, or pinnatifid. Cauline leaves sessile; oblong, lanceolate, or narrowly deltate-lanceolate, (0.7-)1-4(-6.5) cm × (2-)5-10(-15) mm, base sagittate or auriculate, margins dentate or subentire. Racemes much-elongated in fruit; rachis hirsute, trichomes spreading, straight. Fruiting pedicels horizontal, straight or slightly recurved, (terete), (3-)4-8(-10) × 0.3-0.4 mm, hirsute. Flowers: sepals oblong, (1-)1.3-1.8 × 0.6-0.8 mm; petals white, spatulate, (1.5-)1.8-2.5(-3) × (0.2-)0.5-0.7 mm, claw 0.6-1 mm; stamens 6; filaments (1.2-)1.5-1.8(-2) mm, (glabrous); anthers 0.3-0.5 mm. Fruits broadly oblong to ovate, (4-)5-6(-6.5) × (3-)4-5 mm, (curved adaxially), apically broadly winged, apical notch (0.2-)0.4-0.6 mm deep; valves thin, papillate except for wing, not veined; style 0.2-0.5(-0.7) mm, slightly exserted beyond, or included in, apical notch. Seeds (dark brown), ovoid, 2-2.3(-2.8) × 1-1.4 mm. 2n = 16.

Flowering May-Jun. Roadside, pastures, gardens, open flats, pine woodlands, rocky slopes, forests, waste grounds, disturbed areas, meadows, fields; 0-2600 m; introduced; B.C., Nfld. and Labr. (Nfld.), N.S., Ont., P.E.I., Que., Sask.; Ala., Ark., Calif., Colo., Conn., Del., D.C., Fla., Ga., Idaho, Ill., Ind., Iowa, Kans., Ky., La., Maine, Md., Mass., Mich., Miss., Mo., Mont., Nebr., Nev., N.H., N.J., N.Mex., N.Y., N.C., Ohio, Oreg., Pa., R.I., S.C., Tenn., Utah, Vt., Va., Wash., W.Va., Wis., Wyo.; Europe; Asia; introduced also in South America, South Africa.