Verbascum thapsus subsp. thapsus
Annuals or biennials. Stems 30–200 cm, densely and persistently tomentose, eglandular. Leaves: surfaces densely and persistently tomentose, eglandular; basal and proximal cauline with petiole 5–25 mm; blade broadly elliptic to elliptic-ovate, elliptic-obovate, or oblong, 7–30(–45) × 3.5–10(–14) cm, base gradually attenuate; cauline not clasping, gradually smaller distally, base decurrent, margins subentire or crenulate, apex of distal cauline and floral bracts acute to obtuse. Inflorescences unbranched, sometimes branched from proximal nodes, narrowly cylindric, flowers densely overlapping, in clusters of 2–7; rachis densely and persistently tomentose, eglandular; bracts ovate to lanceolate, 12–18 mm, base decurrent, apex acuminate, densely and persistently tomentose, eglandular. Pedicels mostly or completely adnate to rachis, 1–5 mm; bracteoles 2. Flowers: calyx (5–)8–12 mm, densely and persistently tomentose, eglandular, lobes lanceolate to triangular; corolla yellow, 14–20(–30) mm diam., pellucid glands relatively numerous; proximal filaments glabrous, distal pair villous, hairs white or yellow, anthers yellow; stigma capitate. Capsules elliptic-ovoid to ovoid, 7–10 mm, tomentose. 2n = 32, 36.
Phenology: Flowering May–Sep.
Habitat: Lake edges, stream banks, bottomlands, prairies, pastures, fields, woods edges, rocky slopes, railroad embankments, roadsides.
Elevation: 0–2300(–2700) m.
Introduced; Greenland, Alta., B.C., Man., N.B., Nfld. and Labr. (Nfld.), 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, introduced also in South America (Argentina, Chile), Asia, Pacific Islands (Hawaii, New Zealand), Australia.
Verbascum thapsus is known to have formed four hybrids in North America: V. ×kerneri Fritsch [V. thapsus × V. phlomoides]; V. ×pterocaulon Franchet [V. thapsus × V. blattaria]; V. ×spurium W. D. J. Koch [V. thapsus × V. lychnitis]; and V. ×humnickii Franchet [V. thapsus × V. densiflorum].
Subspecies crassifolium (Lamarck) Murbeck and subsp. giganteum (Willkomm) Nyman have densely villous abaxial stamens and occupy restricted ranges in Europe.