P. Gaertner, B. Meyer & Scherbius, Oekon. Fl. Wetterau. 2: 426. 1800.
(Linnaeus) A. S. Hitchcock
fusiform or cylindrical, fleshy or woody.
5-12 (-20) dm.
petiole to 60 cm (broadly expanded basally); blade broadly oblong, oblong-lanceolate, or ovate, (10-)20-45(-60) cm × (30-)50-120(-170) mm, margins usually coarsely crenate, rarely pinnatifid.
proximal shortly petiolate, blade oblong to linear-oblong (lobed), smaller than basal, margins pinnatifid or pinnatisect; distal sessile or shortly petiolate, blade linear to linear-lanceolate, base cuneate or attenuate, margins usually serrate or crenate, rarely entire.
to 40 cm.
ascending, 8-20 mm.
sepals 2-4 mm; petals obovate or oblanceolate, 5-7 (-8) mm, claw to 1.5 mm; filaments 1-2.5 mm; anthers 0.5-0.8 mm.
(rarely produced), 4-6 mm; style obsolete or to 0.5 mm; stigma well-developed.
compressed (often not produced, rarely to 4 per locule).
Flowering Mar-Jul. Fields, moist stream banks, roadsides, ditches, disturbed sites, open woods, along railroads, shallow ponds, marshes, waste places; 0-1100 m; introduced; B.C., Man., N.B., N.S., Ont., P.E.I., Que., Sask.; Calif., Colo., Conn., Idaho, Ill., Ind., Iowa, Maine, Mass., Mich., Minn., Mo., Mont., Nebr., N.H., N.J., N.Mex., N.Y., N.C., N.Dak., Ohio, Oreg., Pa., R.I., S.Dak., Tenn., Utah, Vt., Va., Wash., W.Va., Wis., Wyo.; Europe; Asia; introduced also nearly worldwide.
has been widely cultivated for about 2000 years for its fleshy roots that are grated to produce the pungent horseradish sauce. The plant is also a noxious weed that is very difficult to eradicate, even tiny root fragments are capable of regenerating new plants.