This species, Petalostemum candidum WHITE PRAIRIE CLOVER, is rare at the James Woodworth Prairie. I've only seen three specimens in bloom over four summers of image capture. This is a wildflower species you will only find in original prairie, or, if deliberately planted, in restorations. The PURPLE PAIRIE CLOVER is much more abundant where I photograph. I hope to feature this Petalostemum candidum WHITE PRAIRIE CLOVER in my next book, Elusive Splendor.
I've just finished processing about a hundred images of this species to create the individual species identification sheet used in the species directory list at the James Woodworth Prairie. This image clearly shows the multiple flowers that make up the flower head.