Common Sunflower

The plant has an erect rough-hairy stem, reaching typical heights of 3 metres (10 feet). Sunflower leaves are broad, coarsely toothed, rough and mostly alternate; those near the bottom are largest and commonly heart-shaped. The plant flowers in summer. What is often called the “flower” of the sunflower is actually a “flower head” (pseudanthium), 3-5” (7.5–12.5 cm) wide, of numerous small individual five-petaled flowers (“florets”). The outer flowers, which resemble petals, are called ray flowers. The spirally arranged flowers in the center of the head are called disk flowers. These mature into fruit (sunflower “seeds”). In today’s market, most of the sunflower seeds provided or grown by farmers are hybrids, of which there are many.