Helianthus annuus

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Helianthus annuus L.

alt=Description of SunflowerSunset.jpg picture.
Order Asterales
Family Compositae
Genus Helianthus

2n = 34

Origin : United States and Mexico

wild and cultivated

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French {{{french}}}



Popular names

  • English: sunflower
  • French: tournesol

see more European names

Biology

Classification

  • subsp. lenticularis (Dougl.) Cockerell (1914) is the wild form from western North America. It is many branches with small heads.
  • subsp. annuus var. annuus is a weedy form from eastern North America.
  • subsp. annuus var. macrocarpus (DC). Cockerell (1914) includes cultivated forms, which have only one stem and a terminal big head.

Cultivars

  • Cultivars used for their seeds eaten as snacks have usually big heads and big akenes striped with brown and white.
  • Cultivars grown for the extraction of oil have small heads and small black akenes.
    • Usual oil sunflower cultivars give an oil with 24% oleic acid and 65% linoleic acid.
    • High oleic cultivars give an oil with 50% to 90% oleic acid. They must be grown in isolation from

History

It comes from the same wood engraving. It represents a cultivated type with only one big head. Leaves are drawn as alternate, although they are in fact opposite decussate.

During centuries, sunflower was grown as an ornamental. Targioni-Tozzetti mentions it as an ornamental, and Candolle omits it because he did not deal with ornamentals.

Read Targioni-Tozzetti (1853), Gray & Trumbull (1883) and Sturtevant (1919) articles.

Uses

References

Links