1.
Inula helenium
Linnaeus, Sp. Pl. 2: 881. 1753.
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.
2
n
= 20.
Flowering mid—late summer. Roadsides, waste places, streamsides; 0—300(—600+) m; introduced; 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.
Inula helenium
is widespread in the Old World.
