Many, Many Thanks to Carl Hunter!
He has identified this as Slender Mountain Mist, which can be found on Page 190 of his widely book, "Wildflowers of Arkansas."

Grayish white blooms grow in fairly flat clusters on top.

Leaves are numerous thin little needle shapes.

The plants grow 18" to 24" tall, it seems.


Photos by Lauren Hawkins, 7/03
Plants on mounded, moist-soil prairie near Town Branch of the West Fork of the White River in Fayetteville, Arkansas. The wetland has been permitted for development by the U.S. Corps of Engineers.