• Wind Cave National Park - Two Worlds

    Wind Cave

    National Park South Dakota

Seed Study - Helianthus annuus

Helianthus annuus - Annual Sunflower

Helianthus annuus - Annual Sunflower

NPS Photo

Species: Helianthus annuus
Common name: annual sunflower

Seedling Identification: Fairly large rounded cotyledons with large, pubescent true leaves.


Helianthus annuus – common sunflower
Average number of good seeds per gram bulk matter: 74
Average number of good seeds per gram cleaned: 1667
Commercial estimates of seeds per gram: n.a.
Percent seed: n.m.
Percent live: 62
Collection dates: September 9 and 15
Collection effort: 29 grams in 6 person hours.
Collection notes: Easy to collect if large amounts can be found. Seed tend to be damaged by insects so collect more than you think you will need.
Cleaning notes: Bulk seed measurement was off the receptacle (disk) but with lots of bracts. Cleaned seed was hard seeds only.

Did You Know?

American bison on the Wind Cave National Park prairie

The American bison is the largest terrestrial mammal in North America. Male bison can weigh a ton and can run 35 miles per hour. Do not approach bison. They weigh more and can outrun you. More...