Ill. Observ. Bot., 44, plate 20A. 1773.
Annuals; densely hirsute proximally, glabrescent distally. Stems usually branched basally, (widely) branched distally, (1–)3–7(–10) dm. Basal leaves: (rosettes persistent); petiole (broad) 2–10 cm; blade lyrate to pinnatisect, 2–30 cm × 10–50(–100) mm, (margins serrate-dentate), 4–10 lobes each side. Cauline leaves sessile; blade (reduced in size distally, distalmost bractlike), base tapered, not auriculate or amplexicaul. Racemes not paniculately branched. Fruiting pedicels widely spreading, 8–15 mm. Flowers: sepals 5–4.5 × 1–1.5 mm; petals pale yellow, fading or, sometimes, white, oblanceolate, 4–7 × 1.5–2(–2.5) mm, claw 1–3 mm, apex rounded; filaments 2.5–4 mm; anthers 1–1.3 mm; gynophore to 1 mm. Fruits (shortly stipitate); widely spreading to ascending (not appressed to rachis), torulose, cylindric, 3–7 cm × 2–4(–5) mm; valvular segment with 6–12(–15) seeds per locule, 2.2–5 cm, terminal segment 1(–3)-seeded, (cylindric, stout), 10–20 mm. Seeds light reddish brown or black, 1–1.2 mm diam.; seed coat prominently reticulate, mucilaginous when wetted. 2n = 20.
Phenology: Flowering Feb–Apr.
Habitat: Roadsides, waste places, old fields, washes, open desert areas intermixed with desert shrubs
Elevation: 0-800 m
Introduced; Ariz., Calif., Nev., Tex., Utah, Europe, Asia, Africa, introduced also in nw Mexico, Australia.
Brassica tournefortii was first reported from California (Imperial, Riverside, and western San Bernardino counties) by W. L. Jepson ([1923–1925]), with the first collections appearing from southern California in 1941 (R. C. Rollins and I. A. Al-Shehbaz 1986), Arizona in 1959 (T. H. Kearney and R. H. Peebles 1960), Nevada in 1977, and Texas in 1978 (D. E. Lemke and R. D. Worthington 1991).