Thlaspi arvense L.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Glabrous annual or winter-annual 1–5 dm; cauline lvs sessile, oblong to lanceolate, entire or few-toothed, bearing at base 2 narrow, divergent, acute auricles 1–5 mm; fls 3 mm wide, the pet twice as long as the sep; mature pedicels ascending; frs orbicular to broadly elliptic, 10–17 mm, winged all around, deeply (2–3 mm) notched; seeds concentrically ridged-striate, numerous in each locule; 2n=14. Native of Europe, commonly established in waste places throughout much of N. Amer. Apr.–June.