Helianthus

Helianthus
	; Sunflower (Helianthus annuus)
Scientific classification
Kingdom:	Plantae;
(unranked):	Angiosperms;
(unranked):	Eudicots;
(unranked):	Asterids;
Order:	Asterales;
Family:	Asteraceae;
Subfamily:	Helianthoideae;
Tribe:	Heliantheae;
Genus:	Helianthus; L.
Species
	See text.

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The genus Helianthus L. (pronounced /ˌhiːliˈænθəs/)^[1] comprises 67 species and several subspecies in the Asteraceae family, all of which are native to North America, with some species (particularly Helianthus annuus (sunflower) and Helianthus tuberosus (Jerusalem artichoke) cultivated in Europe and other parts of the world as food crops and ornamental plants.

These are usually tall, annual or perennial plants, growing to a height of 50-390 cm. The rough and hairy stem is branched in the upper part. The petiolate leaves are dentate and often sticky. The lower leaves are opposite, ovate or often heart-shaped. The upper leaves are alternate and narrower.

They bear several to many wide, terminal capitula (flower heads), with bright yellow ray florets at the outside and maroon disc florets inside. These flower heads follow the direction of the sun, going from east to west during the day.

Helianthus species are used as food plants by the larvae of some Lepidoptera species (see list of Lepidoptera that feed on Helianthus).

[edit] Species

Helianthis agrestis : Southeastern Sunflower
Helianthus angustifolius : Swamp Sunflower
Helianthus annuus : Common Sunflower, Girasol (Spanish)
Helianthus anomalus : Western Sunflower
Helianthus argophyllus : Silverleaf Sunflower
Helianthus arizonensis : Arizona Sunflower
Helianthus atrorubens
Helianthus bolanderi : Serpentine Sunflower
Helianthus californicus : California Sunflower
Helianthus carnosus : Lakeside Sunflower
Helianthus ciliaris : Texas Blueweed
Helianthus cinereus
Helianthus couplandii : Prairie Sunflower
Helianthus cusickii : Cusick's Sunflower

Prairie Sunflower (Helianthus petiolaris)

Helianthus debilis : Cucumberleaf Sunflower
- Helianthus debilis ssp. cucumerifolius : Cucumberleaf Sunflower
- Helianthus debelis ssp. debilis : Beach Sunflower, Dune Sunflower
- Helianthus debilis ssp. silvestris : Cucumberleaf Sunflower
- Helianthus debilis ssp. tardiflorus : Cucumberleaf Sunflower
- Helianthus debilis ssp. vestitus : Cucumberleaf Sunflower
Helianthus decapetalus : Thinleaf Sunflower
Helianthus deserticola
Helianthus divaricatus : Woodland Sunflower
Helianthus eggertii : Eggert's Sunflower
Helianthus floridanus : Florida Sunflower
Helianthus giganteus
Helianthus glaucophyllus : Whiteleaf Sunflower
Helianthus gracilentus : Slender Sunflower
Helianthus grosseserratus: Sawtooth Sunflower
Helianthus heterophyllus : Variableleaf Sunflower
Helianthus hirsutus
Helianthus laciniatus : Alkali Sunflower
Helianthus laetiflorus
Helianthus laevigatus : Smooth Sunflower
Helianthus longifolius : Longleaf Sunflower

Willowleaf Sunflower (Helianthus salicifolius)

Helianthus maximiliani : Maximillian Sunflower
Helianthus microcephalus : Small Woodland Sunflower
Helianthus mollis
Helianthus multiflorus
Helianthus neglectus : Neglected Sunflower
Helianthus niveus
- Helianthus niveus ssp. canescens : Showy Sunflower
- Helianthus niveus ssp. tephrodes : Algodones Sunflower
Helianthus nuttallii
- Helianthus nuttallii ssp. nuttallii : Nuttall's Sunflower
- Helianthus nuttallii ssp. parishii : Parish's Sunflower
- Helianthus nuttallii ssp. Rydbergii : Rydberg's Sunflower
Helianthus occidentalis : Fewleaf Sunflower
- Helianthus occidentalis ssp. occidentalis : Fewleaf Sunflower
- Helianthus occidentalis ssp. plantagineus : Fewleaf Sunflower
Helianthus paradoxus : Paradox Sunflower
Helianthus pauciflorus
- Helianthus pauciflorus ssp. pauciflorus : Stiff Sunflower
- Helianthus pauciflorus ssp. subrhomboideus : Stiff Sunflower
Helianthus petiolaris
- Helianthus petiolaris ssp. fallax : Prairie Sunflower
- Helianthus petiolaris ssp. petiolaris : Prairie Sunflower
Helianthus porteri : Porter's Sunflower
Helianthus praecox
- Helianthus praecox ssp. hirtus : Texas Sunflower
- Helianthus praecox ssp. praecox : Texas Sunflower
- Helianthus praecox ssp. runyonii : Runyon's Sunflower