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Sunflower (Helianthus annuus)
Sunflower field with focus on three tall sunflowers
Ewen Charlton / Getty Images
In the U.S., at least, sunflowers are one of the most well-known flower giants. While other botanical behemoths are confined to remote rainforests and the occasional botanical garden, the common sunflower displays its oversized inflorescence all over the states. These flowers are native to the Americas and were domesticated around 1,000 B.C. The oil that comes from their seeds continues to be a staple crop.
When given room, sun, and ample water, these sun-resembling blooms can grow up to 30 feet tall and be more than a foot in diameter. The heads usually contain 13 to 30 ray flowers and hundreds (sometimes thousands) of disc flowers.