Helianthus annuus
Helianthus ×laetiflorus
common sunflower, hairy leaf sunflower, sunflower
cheerful sunflower, hélianthe à belles fleurs, mountain sunflower
erect, usually hispid.
erect, slightly hairy.
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.
basal and cauline; mostly opposite;
petioles 1–5 cm;
blades lanceolate to lance-ovate, 10–25 × 2–8 cm, bases cuneate, margins serrulate to serrate, abaxial faces sparsely hispid, gland-dotted.
2–20 cm.
7–14 cm.
hemispheric or broader, 15–40(–200+) mm diam.
hemispheric, 14–18 mm diam.
(13–)17–30(–100+);
laminae 25–50 mm.
15–20;
laminae 25–37 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).
75+;
corollas 7–7.5 mm, lobes reddish (at least at tips);
anthers dark, appendages dark to yellowish (style branches yellow).
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.
25–35, oblong-lanceolate, 7–12 × 3–3.5 mm (strongly unequal), apices acuminate, abaxial faces usually puberulent, gland-dotted.
1–9.
3–6.
(3–)4–5(–15) mm, glabrate;
pappi of 2 lanceolate scales 2–3.5 mm plus 0–4 obtuse scales 0.5–1 mm.
(seldom formed) 4–5 mm, glabrate;
pappi of 2 aristate scales 2.5–3.5 mm.
9–11 mm, 3-toothed (middle teeth long-acuminate, glabrous or hispid).
9–10 mm, entire or 3-toothed (apices reddish).
= 34.
= 102.
Helianthus annuus
Helianthus ×laetiflorus
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.)
Helianthus ×laetiflorus is introduced in Ontario, Newfoundland, and probably in Quebec; it was excluded from British Columbia by G. W. Douglas et al. (1989–1994, vol. 1); and it was reported in New Brunswick by H. R. Hinds (2000).
Plants called Helianthus ×laetiflorus are usually interpreted to be hybrids and backcrosses of H. tuberosus and H. pauciflorus; they are widely cultivated and often escape. An alternative treatment has been to use the name H. laetiflorus for plants that are treated here as H. pauciflorus, sometimes with infraspecific taxa.
Helianthus atrorubens Lamarck 1789, not Linnaeus 1753, has been applied to plants here called H. ×laetiflorus.
(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
- Local floras: BC
- Local Web sites: Flora NW, IL Wildflowers, KS Wildflowers, MD Biodiversity, MI Flora, MN Wildflowers, MO Plants, PNW Herbaria
- WildflowerSearch
- iNaturalist (observations)
- USDA Plants Database
- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
