Image 43 (far left image, white flowers) was taken near downtown Knoxville TN, on either the Ross Marble Quarry or Mead's Quarry trail, on Oct. 5, 2012. There are, what appear to be, petals of 2, opposing, with lanceolate leaves.
Image 47 (far right image) was taken on a greenway, on the same day, very near to where the above image was taken. It is similar in appearance to the Yellow Crownbeard (image 50 - just for comparison - center image).
If I can get help with these, be on the lookout for others. Many thanks, fellow wildflower lovers.