Silphium laciniatum, Compass Plant
When collecting seeds, the disk florets (interior blooms) are sterile and as such do not produce seeds. The ray florets (exterior) are where you will find the large, flat seeds.
S. laciniatum is a slow growing perennial. When grown from seed, it may take 2-3 years before individual flowers. There have been reports of this plant living up to 100 years.