Helianthus
From Freepedia
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| Image:A sunflower.jpg Sunflower (Helianthus annuus) | ||||||||||||||||
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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.
However, at least the two species Helianthus annuus (sunflower) and Helianthus tuberosus (Jerusalem artichoke) are cultivated in Europe and other parts of the world today.
These are usually tall, annual or perennial plants, growing to a height of 60-390 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.
Species
- Helianthis agrestis : Southeastern Sunflower
- Helianthus angustifolius : Swamp Sunflower
- Helianthus annuus : Sunflower, Mirasol
- 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 cusickii : Cusick's Sunflower
- Helianthus debilis : Cucumberleaf Sunflower
- Helianthus debilis ssp. cucumerifolius : Cucumberleaf Sunflower
- Helianthus debelis ssp. debilis : Cucumberleaf Sunflower
- Helianthus debilis ssp. silvestris : Cucumberleaf Sunflower
- Helianthus debilis ssp. tardiflorus : Cucumberleaf Sunflower
- Helianthus debilis ssp. vestitus : Cucumberleaf Sunflower
- Helianthus decapetalus : Thinleaf Sunflower
- Helianthus divaricatus
- Helianthus eggertii : Eggert's Sunflower
- Helianthus floridanus : Florida Sunflower
- Helianthus giganteus
- Helianthus glaucophyllus : Whiteleaf Sunflower
- Helianthus gracilentus : Slender Sunflower
- Helianthus grosseserratus
- 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 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. nuttallii : Nuttall'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 ss. 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)
