Cup plant flower (Silphium perfoliatum).
A native of the tallgrass prairie in the Midwest, USA, this perennial giant sports wonderfully yellow daisy-like flowers on long, stout stalks reaching up to 8' in height! Cup Plant, is named because its large broad leaves form a "cup" where they attach to the square stem. These cups catch and retain water for plants.
If you want more information about this flower, just search the plant's Latin (botanical) name on Google: