Annual herb 30 cm - 0.8 m tall Stem: upright. Flowers: in stiff, branched clusters (racemes). Sepals four, ascending. Petals four, light yellow, 3 - 4 mm long. Fruit: a long, narrow pod (silique), closely appressed, 8 mm - 1.5 cm long, 1 - 1.5 mm wide at base, awl-shaped, sometimes hairy. Seeds in one row. Lower leaves: alternate, deeply pinnately divided, stalked, bases often large-lobed, toothed. Lateral segments oblong to egg-shaped. The terminal segments are rounded. Upper leaves: alternate, stalkless or nearly so, often non-toothed.
Similar species: No information at this time.
Flowering: May to mid-November
Habitat and ecology: Introduced from Europe. A frequent weed of cultivated and waste ground, usually growing in high-nitrogen soils.
Occurence in the Chicago region: non-native
Etymology: Sisymbrium is the Ancient Greek name for various plants. Officinale means "sold in shops; official." This may apply to medicinal, edible, and otherwise useful plants.
Erect, 3-8 dm; lower lvs petioled, deeply pinnatifid, the segments oblong to ovate or the terminal one rotund, angularly toothed, upper lvs sessile or nearly so and often entire; pet light yellow, 3-4 mm; racemes stiffly erect, the mature pedicels closely appressed, 2-3 mm, thickened above; frs closely appressed, subulate, 8-15 mm, 1-1.5 mm wide at base; 2n=14. Native of Eurasia, commonly established as a weed throughout most of the U.S. May-Sept.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
A weed in pastures, waste places, and open woodland and along roads and railroads. My specimens, however, are all from the northern part of the state. [Plants with pubescent pods have been referred to var. leiocarpum.] This is a weed with habitats similar to those of [var. officinale] but it is much more common and is found throughout the state.