1. Raphanus raphanistrum L. (wild radish, jointed charlock)

Pl. 324 f; Map 1378

Roots not noticeably thickened. Stems (20–)30–80 cm long. Basal leaves (4–)6–30 cm long, the stem leaves 2–8 cm long. Sepals 8–11 mm long. Petals 16–25 mm long, pale yellow (sometimes fading to white), with dark purple veins. Fruits (2–)4–11(–14) cm long, 3–6(–11) mm wide, narrowly oblong to narrowly lanceolate in outline, somewhat corky, the beak 1–2(–5) cm long, strongly narrowed or constricted between the seeds, the surface strongly ribbed, especially when dry, at maturity breaking transversely into 1-seeded segments, the stalk 0.7–2.5 cm long. Seeds 4–12 per fruit, 2.5–3.5 mm long, oblong-ellipsoid to ovoid. 2n=18, 32. May–November.

Introduced, known thus far only from Christian and Jackson Counties and the city of St. Louis (native of Europe, Asia, Africa, introduced widely but sporadically in North America and Central America). Railroads.

A number of infraspecific taxa, most of questionable validity, have been named for this species in the Old World. The Missouri specimens all appear to represent typical R. raphanistrum.