Helianthus annuus L.

Common Sunflower

Helianthus_annuus_plant.jpg
STATS

Native
CC = 0
CW = 3
MOC = 46

© DETenaglia

Family - Asteraceae/Heliantheae

Stems - No info. yet.

Helianthus_annuus_stem.jpg

© DETenaglia

Leaves - No info. yet.

Helianthus_annuus_lower_leaf.jpg Lower leaf.

© DETenaglia

Helianthus_annuus_upper_leaves.jpg Upper leaves.

© DETenaglia

Inflorescence - No info. yet.

Involucre. - No info. yet.

Helianthus_annuus_involucre.jpg Involucre.

© DETenaglia

Ray flowers - No info. yet.

Disk flowers - No info. yet.

Helianthus_annuus_flowers.jpg

© DETenaglia

Flowering - July - November.

Habitat - Cultivated.

Origin - Native to U.S.

Other info. - The plant pictured above is one of the many cultivated varieties of H. annuus. These varieties range in size from shorter than a meter to over 2.5 meters. Many of the cultivated plants do not grow true from seed and will eventually revert back to the wild type plants over a few generations.

The largest of these cultivated H. annuus get massive taproots that exceed 2.5m in length. The taller plants often need to be staked as the large flower heads weigh too much for the stem to support.
Cultivated sunflowers are the plants from which birdseed, sunflower oil, and our edible sunflower seeds arise. These cultivated plants do not readily escape in Missouri.
The lower-most leaves of the stem on this species are opposite but quickly become alternate for the rest of the stem length. Seedling plants have opposite leaves.

Photographs taken at the Peck Ranch Wildlife Refuge, Carter County, MO., 7-12-03.