Arctium lappa

Plants to 100-300 cm. Basal leaves: petioles solid, 15-36 cm, glabrous or thinly cobwebby; blades 25-80 × 20-70 cm, coarsely dentate to subentire, abaxially thinly gray-tomentose, adaxially green, sparsely short-hairy to nearly glabrous. Heads usually in corymbiform clusters, long-pedunculate. Peduncles 2.5-6 cm. Involucres 25-45 mm diam. Phyllaries linear to linear-lanceolate, glabrous to loosely cobwebby, inner usually stramineous (sometimes purplish), margins with minute spreading or reflexed hairs. Florets 40+; corollas purple (occasionally white), 9-14 mm, glabrous. Cypselae light brown, often with darker spots, 6-7.5 mm; pappus bristles 2-5 mm. 2n = 32 (Japan), 34 (China), 36 (Japan); (Sweden).

Flowering summer-early fall (Jul-Oct). Waste places, roadsides, fields, forest clearings; 0-2200 m; introduced; Alta., B.C., Man., N.B., Ont., Que., Sask.; Ala., Ariz., Calif., Colo., Conn., Ill., Maine, Mass., Mich., Minn., Nev., N.H., N.Y., N.Dak., Pa., R.I., Utah, Vt., Wash., Wis.; Eurasia.

BONAP lists Georgia, Idaho, Indiana, Iowa, Maryland, Montana, New Jersey, North Carolina, Ohio, Oregon, and Wyoming; I have not seen specimens.

Roots and young leaves of Arctium lappa are edible and can be used in a variety of food preparations. Extracts of Arctium species purportedly have health benefits and are sold as food supplements. This species is sometimes cultivated as a minor crop.

To 1.5 or even 3 m; lvs petiolate, the petioles mostly solid, progressively shorter upwards, the blade ovate or broader, cordate, to 5 נ3 dm, thinly tomentose beneath, subglabrous above; infl corymbiform, with long, glandular or glandular-hairy peduncles commonly 3-10 cm; heads large, the invol (2.5-)3-4 cm wide, generally equaling or surpassing the fls, glabrous or slightly glandular, and often with a few long cobwebby hairs; achenes 6-7 mm; 2n=32, 36. Native of Eurasia, sparingly established as a weed along roadsides and in waste places over most of the n. U.S. and adj. Can. Aug.-Oct.

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

©The New York Botanical Garden. All rights reserved. Used by permission.

From Flora of Indiana (1940) by Charles C. Deam

 Indiana Coefficient of Conservatism: C = null, non-native

Wetland Indicator Status: n/a

Diagnostic Traits: Similar to common A. minus but with solid rather than hollow petioles, larger heads (2.5-4.5 cm wide) on elongated pedicels forming a corymbiform inflorescence, and their phyllaries smooth edged, distally green to brown.