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.
Perennial herb 30 cm - 0.8 m tall Stem: upright, hairless or nearly so. Leaves: below the middle of the stem, pinnately divided to toothed, reverse lance-shaped to narrowly oblong, somewhat fleshy with a waxy coating (glaucous). The leaves have an unpleasant smell when crushed. Flowers: yellow. Sepals 5 - 8 mm long. Petals four, over 1 cm long. Stamens six. Fruit: a long, narrow pod, on a stipe (a type of supporting stalk), ascending, 2 - 5 cm long, each of the two sides with a prominent midvein. Seeds in two rows in each chamber.
Similar species: Diplotaxis muralis is similar but has leaves mainly at or near the base, longer sepals (2.5 - 5 mm), and fruit which is not on a stipe.
Flowering: late May to late September
Habitat and ecology: Introduced from Europe. Rare in the Chicago Region. Has been found along railroad tracks in ballast and on the weedy embankment of a highway. Look for it in waste ground.
Occurence in the Chicago region: non-native
Etymology: Diplotaxis comes from the Greek word diploos, meaning double, and taxis, meaning row, which refers to the double row of seeds in the pod. Tenuifolia means "of walls."
Glabrous or subglabrous, taprooted perennial (but sometimes blooming the first year), erect, 3-8 dm; lvs mostly cauline but below the middle of the stem, somewhat fleshy and glaucous, foetid when crushed, oblanceolate to narrowly oblong, toothed to more often deeply pinnatifid; lower pedicels becoming remote and 2-3 cm; pet yellow; frs ascending, 2-5 cm, the base of the valves elevated 1-2 mm above the scars of the perianth; 2n=22. Native of Europe, established as a weed in waste places here and there in our range, especially northward, and in w. 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.