Annuals, roots not fleshy; sparsely to densely pubescent. Stems usually simple from base, (2-)3-8 dm, (retrorsely hispid). Basal leaves: petiole 1-6 cm; blade oblong, obovate, or oblanceolate in outline, lyrate or pinnatifid, sometimes undivided, 3-15(-22) cm × 10-50 mm, margins dentate, apex obtuse or acute; lobes 1-4 each side, oblong or ovate, to 4 cm × 20 mm (smaller than terminal). Cauline leaves (distal) subsessile; blade often undivided. Fruiting pedicels divaricate or ascending, 7-25 mm, (straight). Flowers: sepals 7-11 × 1-2 mm, sparsely pubescent; petals yellow or creamy white (veins dark brown or purple), 15-25 × 4-7 mm, claw to 15 mm; filaments (slender), 7-12 mm; anthers 2-2.5 mm. Fruits cylindrical or narrowly lanceolate; valvular segment 1-1.5 mm; terminal segment (1.5-) 2-11(-14) cm × (2.5-)3-8(-11) mm, (base rounded), strongly constricted between seeds (usually breaking), strongly ribbed, beak narrowly conical; style 10-50 mm. Seeds (reddish brown or dark brown to black), oblong or ovoid, 2.5-3.5 × 1.8-2.5 mm. 2n = 18. Flowering May-Jul. Disturbed waste places, cultivated fields, roadsides, orchards, hill slopes; 0-800 m; introduced; Greenland; St. Pierre and Miquelon; Alta., B.C., Man., N.B., Nfld. and Labr., N.S., Ont., P.E.I., Que., Sask.; Ala., Alaska, Ariz., Ark., Calif., Colo., Conn., Del., D.C., Fla., Ga., Idaho, Ill., Ind., Iowa, Kans., Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., Mont., Nebr., Nev., N.H., N.J., N.Mex., N.Y., N.C., N.Dak., Ohio, Okla., Oreg., Pa., R.I., S.C., S.Dak., Tenn., Tex., Utah, Vt., Va., Wash., W.Va., Wis., Wyo.; Europe; Asia; introduced also in Mexico, Central America, South America, Africa, Atlantic Islands, Australia. North American representatives of Raphanus raphanistrum are referable to subsp. raphanistrum. Four other subspecies are restricted to Europe.

Coarse annual from a stout taproot, 3-8 dm, usually sparsely hispid; lower lvs obovate-oblong, 1-2 dm, pinnatifid into 5-15 oblong segments, the lower segments very small, the upper progressively larger; upper lvs reduced and often entire; pet yellow, turning white, 10-15 mm; mature pedicels ascending, 8-15 mm; fr nearly cylindric when fresh, when dry becoming prominently several-ribbed and constricted between the 4-10 seeds, the body 2-4 cm, the beak 1-3 cm, the lower member 1-2 mm, its upper margin indicated by a line or projecting rim extending half way to all around the fr; 2n=18. Native of Eurasia, established as a weed in fields and waste places and along roadsides throughout most of the U.S. and s. Can. June-Aug.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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