The pattern created by the leaves of this wildflower caught my eye. 

These tall sunflowers are blooming now with many small yellow blossoms, but the thing that’s striking about this plant is the leaves; they are very narrow and they whorl around the stem. 

At the PGT there are only a few of these plants and they are widely scattered in the prairies, so I can’t tell you exactly where to find them. Just look for the unusual leaves on very tall plants.