Plants 50–100(–200) cm. Leaves: basal blades ± elliptic, mostly 15–40 cm × 100–200+ mm (bases decurrent onto strongly ribbed petioles, margins callose-denticulate, otherwise entire, abaxial faces velvety-woolly, adaxial thinly hairy); cauline blades ovate or elliptic to lanceolate, 10–30 cm × 45–120 mm, bases cordate, clasping, margins serrate. Involucres (20–)30–40 mm diam. Outer phyllaries ovate, oblong, or ± deltate to lanceolate, 12–20(–25+) × 6–8(–20+) mm (abaxially velvety-hairy); inner phyllaries progressively narrower, less hairy, more scarious. Ray florets (15–)50–100+; corolla laminae (10–)20–30+ mm. Disc corollas 9–11 mm. Cypselae 3–4 mm, glabrous; pappi of (40–)50–60 basally connate, barbellate bristles or setiform scales 6–10 mm. 2n = 20.
Phenology: Flowering mid–late summer.
Habitat: Roadsides, waste places, streamsides
Elevation: 0–300(–600+) m
Distribution
B.C., Man., N.B., N.S., Ont., P.E.I., Que., Calif., Conn., Del., Ill., Ind., Iowa, Ky., Maine, Md., Mass., Mich., Minn., Mo., N.H., N.J., N.Y., N.C., Ohio, Oreg., Pa., R.I., Tenn., Utah, Vt., Va., Wash., Wis., Europe, introduced, Asia and beyond.
Discussion
Inula helenium is widespread in the Old World.
Selected References
None.