I am not sure which sunflower this was in the evening prairie, but I do know it is one of the last ones I’ll see this season. There are many, many distinctive sunflowers to be found in the native prairie of Illinois. All seem to mimic the yellow ball of light in the wide open sky above. Many sunflowers are named for the leaf shape, many named for the bloom; this was one of the tall species. My novice knowledge and respect for “stay on the path” signs in this preserve did not allow me to confirm it as Cup Plant or Ox Eye or Compass Plant…. but I’m leaning toward it being a Compass Plant (Rosin Weed) bloom.
The Compass Plant is named by pioneers who noticed that the broad leaves point north and south, as if to show the way. Truth be told, the broad flat leaves are actually facing east and west to catch as much solar energy as possible for photosynthesis needed for the plant to grow to over six feet tall.
I’m glad to see you’re interested in prairies.
Here’s the most common Silphium we have in Austin: