34.
Helianthus mollis
Buc'hoz, Herb. Color. Amérique. plate 61. 1783.
Ashy sunflower
Helianthus mollis
var.
cordatus
S. Watson
Perennials
, 50—150+ cm (rhizoma-tous).
Stems
erect, hirsute to villous.
Leaves
mostly cauline; mostly opposite (sometimes alternate among heads); sessile; blades (ashy or gray-green, 3-nerved distal to bases) lance-olate to broadly ovate, 5.5—14.5 × 1.8—6.5 cm, bases rounded to cordate, margins entire or serrulate, abaxial faces hispid to tomentose, gland-dotted.
Heads
1—15.
Peduncles
0.1—15 cm.
Involucres
broadly hemispheric, 12—25 mm diam.
Phyllaries
30—40, lanceolate, (5—)10—16 × 2—3.5 mm, apices usually acute, sometimes acuminate, abaxial faces densely hispid to villous or tomentose, densely gland-dotted.
Paleae
(oblanceolate) 9—11 mm, entire (1-toothed, densely hairy, densely gland-dotted).
Ray florets
17—22; laminae 25—30 mm (abaxial faces densely gland-dotted).
Disc florets
75+; corollas 6—7.5 mm, lobes yellow; anthers dark, appendages dark.
Cypselae
3.5—4 mm, distally villous;
pappi
of 2 aristate scales 2.8—3.2 mm.
2
n
= 34.
Flowering summer—early fall. Prairies, roadsides; 10—600+ m; Ont.; Ala., Ark., Conn., Del., D.C., Ga., Ill., Ind., Iowa, Kans., Ky., La., Maine, Md., Mass., Mich., Miss., Mo., Nebr., N.J., N.Y., N.C., Ohio, Okla., Pa., R.I., S.C., Tenn., Tex., Va., W.Va., Wis.
Helianthus mollis
is introduced in Ontario and adventive in the eastern United States (e.g., Maine), where it is continuing to spread, particularly along roads. Natural hybrids between
H. mollis
and
H. occidentalis
have been named
H.
cinereus
Torrey & A. Gray (R. C. Jackson and A. T. Guard 1957); they differ from
H. mollis
by having smaller heads with fewer ray florets and narrower leaves with cuneate bases. Hybrids of
H. mollis
with
H. giganteus
have been called
H.
doronicoides
Lamarck (Jackson 1956).
