Perennial or slimleaf wall-rocket, flixweed

Sisymbrium tenuifolium Linnaeus, Cent. Pl. I, 18. 1755

Perennials, (usually suffrutes-cent, roots with shoots from adventitious buds), strongly scented (with glucosinolates), (glaucescent). Stems erect, 2-7(-10) dm, glabrescent or sparsely pubescent basally. Basal leaves: blade elliptic to obovate, 2-15 cm × 10-60(-80) mm, margins sinuate to deeply pinnatifid, (2-5 lobes each side). Cauline leaves petiolate; similar to basal, (distal cauline shortly petiolate, blade similar, with narrower segments), surfaces usually glabrescent. Fruiting pedicels 8-35 mm. Flowers: sepals 4-6 mm, glabrous or pubescent, trichomes straight; petals yellow, 7-11(-13) × 5-8 mm, (apex rounded); filaments 4-8 mm; anthers 2.5-3 mm; gynophore 0.5-3 mm. Fruits usually erect, rarely ascending, (somewhat torulose, slightly compressed), 2-5 cm × 1.5-2.5 mm; terminal segment (stout), beaklike, 1.5-3 mm, seedless; (ovules 20-32(-46) per ovary). Seeds 1-1.3 × 0.6-0.9 mm. 2n = 22.

Flowering spring-fall. Waste places, disturbed areas, wharf and railroad ballast, sandy beaches, muddy shores, wet woods, mountain slopes; 0-2100 m; introduced; N.S., Ont., Que.; Ariz., Calif., Conn., Fla., Ga., Ind., Maine, Mass., Mich., Mo., N.J., N.Mex., N.Y., Ohio, Oreg., Pa., Tex.; Eurasia; Africa; introduced also in South America (Argentina), Australia.

Diplotaxis tenuifolia was introduced from Europe as a ballast plant in the last century. It may have failed to persist in some of the recorded provinces and states.