Helianthus

Helianthus: see sunflower.

Any of 60 species of annual herbaceous plants in the genus Helianthus (composite family), native mostly to North and South America. The common sunflower (H. annuus) has a rough, hairy stem 3–15 ft (1–4.5 m) high; broad, coarsely toothed, rough leaves 3–12 in. (7.5–30 cm) long; and large (3–6 in., or 7.5–15 cm, in diameter), flat, platelike compound flowers. Disk flowers swirl in a tight brown, yellow, or purple spiral; ray flowers are yellow. The leaves are used as fodder, the flowers yield a yellow dye, and the seeds contain oil and are used for food. The oil is used for cooking, as an ingredient of soaps and paints, and as a lubricant. Only a few species are cultivated, some for their spectacular size.

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The Helianthus L. genus 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).

Species

• Helianthis agrestis : Southeastern Sunflower
• Helianthus angustifolius : Swamp Sunflower
• Helianthus annuus : Common Sunflower, Mirasol (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
• 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
• 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

• Helianthus praetermissus : New Mexico Sunflower
• Helianthus pumilus : Little Sunflower
• Helianthus radula : Rayless Sunflower
• Helianthus resinosus : Resindot Sunflower
• Helianthus salicifolius : Willowleaf Sunflower
• Helianthus schweinitzii : Schweinitz's Sunflower
• Helianthus silphioides : Rosinweed Sunflower
• Helianthus simulans : Muck Sunflower
• Helianthus smithii : Smith's Sunflower
• Helianthus strumosus : Paleleaf Woodland Sunflower
• Helianthus tuberosus : Jerusalem Artichoke, Sunchoke

External links

• See here for a more complete list of species