Helianthus annuus
Helianthus smithii
common sunflower, hairy leaf sunflower, sunflower
Smith's sunflower
erect, usually hispid.
(usually purplish) erect, glabrous (glaucous).
mostly cauline; mostly alternate;
petioles 2–20 cm;
blades lance-ovate to ovate, 10–40 × 5–40 cm, bases cuneate to subcordate or cordate, margins serrate, abaxial faces usually ± hispid, sometimes gland-dotted.
cauline; opposite (proximal) or alternate;
petioles to 1.3 cm;
blades (light to dark green, 1-nerved) lance-linear to lanceolate, 7–18 × 1–1.8 cm, bases ± cuneate, margins serrulate, abaxial faces ± hispid, gland-dotted.
2–20 cm.
3–6 cm.
hemispheric or broader, 15–40(–200+) mm diam.
hemispheric, 5–15 mm diam.
(13–)17–30(–100+);
laminae 25–50 mm.
6–9;
laminae 10–15 mm.
150+(–1000+);
corollas 5–8 mm (throats ± bulbous at bases), lobes usually reddish, sometimes yellow;
anthers brownish to black, appendages yellow or dark (style branches yellow).
25+;
corollas 5.5–6 mm, lobes yellow;
anthers dark, appendages dark.
20–30(–100+), ovate to lance-ovate, 13–25 × (3–)5–8 mm, (margins usually ciliate) apices abruptly narrowed, long-acuminate, abaxial faces usually hirsute to hispid, rarely glabrate or glabrous, usually gland-dotted.
15–20, lanceolate, 6–9 × 2–2.7 mm, (margins ciliate) apices short-acuminate, abaxial faces glabrous or glabrate, not gland-dotted.
1–9.
1–5.
(3–)4–5(–15) mm, glabrate;
pappi of 2 lanceolate scales 2–3.5 mm plus 0–4 obtuse scales 0.5–1 mm.
2.8–3 mm, glabrate;
pappi of 2 aristate scales 1.5–2 mm.
9–11 mm, 3-toothed (middle teeth long-acuminate, glabrous or hispid).
5.5–6.5 mm, 3-toothed (gland-dotted).
= 34.
= 68.
Helianthus annuus
Helianthus smithii
Helianthus annuus is widely distributed, including weedy, cultivated, and escaped plants. It is the only native North American species to become a major agronomic crop. Despite its considerable variability, attempts have failed to produce a widely adopted infraspecific system of classification. Forms with red-colored ray laminae, known from cultivation and occasionally seen escaped, trace their ancestry to a single original mutant plant. It hybridizes with many of the other annual species.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Of conservation concern.
Helianthus smithii is known from relatively few sites. T. A. Storbeck (1984) concluded that it is a distinct species; he could not rule out the possibility that it might be a hybrid of H. microcephalus and H. strumosus. It may also be an extreme variant of H. strumosus that has relatively narrow leaves and small heads.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
- Local floras:
BC, 
CA, 
OR, 
WA - Local Web sites: CalFlora, CalPhotos,
Flora NW, 
Go Botany, 
IL Wildflowers, 
KS Wildflowers, 
LA Plants, 
MD Biodiversity, 
MI Flora, 
MN Wildflowers, 
MO Plants, 
PNW Herbaria, 
SW CO Wildflowers, Turner Photog. 
WildflowerSearch
iNaturalist (observations)
USDA Plants Database- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
